To give you a better understanding of orthopaedic conditions and treatments, Shoreline Orthopaedics offers clear definitions of commonly used medical and orthopaedic terms.

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Movement of an extremity away from the body.

A pus-filled area that affects skin or organs.

The receptacle for the head of the femur; formed by the ilium, ischium, and pubis.

Achilles tendinitis
Inflammation of the Achilles tendon often caused by increased activity, improper footwear, or tight hamstrings.

Acquired immune deficiency syndrome (AIDS)
A disease that is characterized by profound immune system suppression and associated with opportunistic infections, secondary neoplasms, and neurologic manifestations. Caused by the human immunodeficiency virus (HIV).

Overgrowth of the bones of the hands, feet, and face.

Acromion process
A lateral condensation of bone that is the attachment site for the lateral and posterior two thirds of the deltoid muscle.

The insertion of needles into precisely defined points on the body; thought to realign imbalances of yin-yang and qi and thereby bring harmony to the “climate” of an individual.

Movement of an extremity toward the body.

Enlargement of the glands.

Adhesive capsulitis
Self-limiting condition resulting from any inflammatory process about the shoulder in which capsular scar tissue is produced, resulting in pain and limited range of motion; also called frozen shoulder.

Aerobic exercise
Exercise that uses oxidative metabolic pathways to provide energy.

Muscles that produce body movement in the same direction.

A substance that produces an allergic reaction.

Biologic tissue from a cadaver that is used to surgically replace damaged tissue.

Alternative medicine
A wide spectrum of treatments-many finding support from collective anecdotal evidence-that is not considered standard therapy because of the lack of a scientific rationale, clinical evidence, or a favorable historic tradition.

Ambulatory condition
Assessment of the injured athlete where the athlete is seen by the athletic trainer at some point following the injury.

Loss of the menstrual cycle. Considered part of the female athlete triad.

Anabolic steroids
Synthetic derivatives of testosterone originally developed to treat hypogonadism in men, lost muscle mass in patients debilitated by illness, and severe anemia. Sometimes used to enhance muscle-building effects in athletes.

Anaerobic exercise
Exercise of short duration, not requiring the body’s utilization of oxygen to make fuel available.

Anaerobic metabolism
Oxygen debt; when the cardiovascular system is unable to meet the needs of the working muscles, the anaerobic metabolism is activated.

The relief of pain.

A pain-relieving effect with no loss of consciousness.

A violent hypersensitivity reaction, resulting in shock.

Chest pain.

Ankylosing spondylitis
An inflammatory disorder that affects the low back and pelvis and produces stiffness and pain.

Marked stiffness of a joint typically observed with end-stage arthritis, following a complex intra-articular fracture, delayed treatment of septic arthritis, or severe rheumatoid arthritis.

Annulus fibrosus
A region of the intervertebral disk that provides support for the nucleus.

Anorexia nervosa
A nutritional disorder that occurs in as many as 1% of individuals in a vulnerable population in which an individual refuses to maintain body weight over a minimal normal weight for age and height.

Muscles that produce body movement in opposing directions.

Anterior compartment syndrome
Increased soft-tissue pressure in the anterior compartment of the lower leg, resulting in pain, decreased sensation, and muscle paralysis.

Anterior cruciate ligament tears
An acute knee injury that occurs when the foot is planted, the knee is flexed, and a valgus force is applied to the knee with the lower leg in external rotation; commonly occurs in sports that require twisting, jumping, and pivoting.

Anterior superior iliac spine
Blunt bony projection on the anterior border of the ilium, forming the anterior end of the iliac crest. Serves as the origin of the sartorius muscle.

Anterior surface
Surface at the front of the body, facing the examiner.

Anteromedial rotatory instability
When the medial plateau of the tibia rotates anteriorly and medial joint opening occurs, indicating disruption of the superficial tibia collateral ligament, medial and posteromedial capsular structures, and anterior cruciate ligament.

Anteroposterior (AP) view
Anterior-posterior view in which the x-ray tube is in front and the film cassette is in back. The x-ray beam passes from front to back.

A substance that can counteract a poison.

Foreign substances that can infiltrate the body, including bacteria, fungi, parasites, toxic chemicals, and abnormal body cells, prompting the production of antibodies that attempt to destroy the substances.

A drug that counteracts the effects of histamine; one use is to relieve the symptoms of an allergic reaction.

A fever-relieving or -reducing property.

Anulus fibrosus
The outer ring of fibrous material surrounding the nucleus of the intervertebral disks

A broad, fibrous sheet that attaches one muscle to another.

A cartilaginous structure at the insertion of major muscle groups into bone that may be susceptible to overuse syndromes and acute fractures in pediatric athletes.

Inflammation of the appendix, the small intestinal pouch that extends from the cecum.

Irregular heartbeat.

Small tubular branches of the arteries.

Aspiration of a joint.

The surgical fusion of a joint. The procedure removes any remaining articular cartilage and positions the adjacent bones to promote bone growth across a joint. A successful fusion eliminates the joint and stops motion. The usual purpose is pain relief or stabilization of an undependable joint.

A procedure in which a contrast medium is injected into a joint to outline soft tissues such as the meniscus in the knee or a torn structure such as the rotator cuff in the shoulder. MR arthrography is a technique in which a diluted contrast medium such as gadolinium is injected into a joint to improve the delineation of soft tissues. Standard MRI is obtained following the injection.

Arthrokinematic motion
Vertebral motion that occurs within the joint capsule at the articulations.

procedure to replace or mobilize a joint, typically performed by removing the arthritic surfaces and replacing them with an implant. Total joint arthroplasty is replacement of both sides of the joint. Hemiarthroplasty replaces only one side of a joint.

A form of minimally invasive surgery in which a fiberoptic camera, the arthroscope, is introduced into an area of the body through a small incision.

Articular cartilage
A smooth, glistening surface that covers the ends of bones that articulate with each other to form a joint.

Removal of fluids from a body cavity; often done to obtain specimens for analysis.

A chronic inflammatory disorder of the airways associated with changes in airway hyperresponsiveness.

Athlete’s foot
An infection of the toe web space.

Athletic trainer
A qualified allied healthcare provider who is educated in the management of healthcare problems of athletes.

Atlantoaxial subluxation (AAS)
An orthopaedic problem seen frequently in athletes with Down syndrome that poses a significant risk to athletes participating in sports that involve bodily contact. Joint looseness, ligamentous laxity, or malformation of the vertebrae or surrounding structures causes the C1 vertebra to slip forward and compress the spinal cord, particularly when the neck is in flexion or extension.

Atlanto-occipital fusion
A rare condition consisting of congenital fusion of the ring of the atlas to the occiput; considered an absolute contraindication for contact sports.

The first cervical vertebra (C1).

The upper chambers of the heart, composed of the left and right atria.

Biologic tissue from the patient’s own body that is used to surgically replace damaged tissue.

Autonomic dysreflexia
A health concern for athletes with a spinal cord injury above level T8 in which the athlete experiences dizziness, sweating, headaches, and potentially severe hypertension. A plugged urethral catheter is the most common trigger; however, fecal impaction, renal calculi or infections, and pressure sores can also cause the condition.

Avascular necrosis
A condition in which cells die as a result of inadequate blood supply; see also osteonecrosis.

Avulsion fracture
A fracture that occurs when a ligament or tendon pulls off a sliver of the bone.

Avulsion fractures
A fracture caused by a violent muscle contraction or sudden passive stretch. Also, pulling off of the osseous insertion or origin in a child.

Axial compression
A force directed along the vertical axis of the cervical spine that is part of almost every serious injury.

Axial loading
A load directed vertically along the axis of the cervical spine during a compression force such as spearing or a head-on collision.

The second cervical vertebra (C2).

A grade II nerve injury resulting from nerve stretching in which the endoneurium remains intact.


One of five types of microorganisms that commonly causes disease, characterized by absence of a nucleus and endoplasmic reticulum. Bacteria are classified according to their shape and are designated as gram positive or gram negative.

Classification of antibiotic in which bacteria are destroyed.

Classification of antibiotic in which bacteria are not killed, but are prevented from reproducing.

Bankart fracture
A small chip fracture off of the anterior and inferior rims of the glenoid that is seen after an anterior dislocation of the shoulder.

Bankart lesion
An anterior capsulolabral injury associated with a tear of the anteroinferior glenoid labrum.

Sedative-hypnotic drugs.

Basal ganglia
Demarcated masses of gray matter in the interior of the cerebral hemispheres.

Basal metabolic rate (BMR)
The rate at which an individual burns calories while performing an activity.

Baseball finger
Rupture of the extensor tendon at or near its insertion on the terminal phalanx caused by a sudden flexion force on the distal interphalangeal joint while the finger is actively extended; also known as mallet finger.

Biceps tendinitis
Inflammation of the biceps tendon in its subacromial location.

The study of external and internal forces applied to the body and their relationship to stability and motion.

Bipartite patella
An accessory bony fragment connected to the body of the patella by a line of cartilage.

Potent inhibitors of osteoclasts and bone resorption. May be used to treat osteoporosis and Paget disease.

Body fat percentage (%BF)
The percentage of an individual’s weight that is made up of fat.

Bone densitometry
A procedure used to detect osteopenia in which a special density gradient plate is used to evaluate the comparative density of the spine, femur, or distal radius. Photons from a single- or dual-emitting source are used to measure the density of the bone. These are then compared with normal values for a large patient population based on sex and age.

Bone remodeling
A process that couples bone resorption by osteoclasts with deposition of osteoblasts (new bone cells).

Bone scan
A study used to identify lesions in bone such as fracture, infections, or tumor. A radioisotope is injected into a vein and allowed to circulate through the body. The distribution of radioactivity in the skeleton is measured by a special camera that can detect the emission of gamma rays. Lesions in bone with increased metabolic activity (eg, fracture, tumor, or infection) will show increased uptake of the radioisotope and appear as a dark area in the bone. Also called bone scintigraphy.

Boutonnière deformity
Rupture of the central slip of the extensor tendon of the middle phalanx caused by rapid, forceful flexion at the proximal interphalangeal joint; characterized by flexion of the proximal interphalangeal joint and hyperextension of the distal interphalangeal joint.

Unusually slow, but regular heartbeat.

A classification of material that deforms little before failure, such as glass.

Bucket-handle tear
Complete longitudinal tear of the central segment of the meniscus with the torn fragment “flipped” into the joint like the handle of a bucket.

A blister that is larger than 1 cm.

Prominence of the first metatarsal head often associated with lateral shift of the great toe (hallux valgus deformity).

A neurapraxia from a stretch injury to the brachial plexus; most commonly seen in football players. Also known as a stinger.

Burner (stinger) syndrome
An acute upper trunk brachial plexus injury resulting from head, neck, or shoulder contact in football.

A sac formed by two layers of synovial tissue that is located where there is friction between tendon and bone or skin and bone.

Inflammation of a bursa.

Burst fracture
A compression-type fracture of a vertebra that involves posterior displacement of the fragments, often into the spinal canal.

Burst laceration
A facial injury where the skin is compressed against underlying bony prominences at impact and a jagged opening occurs with a variable amount of ischemia and necrosis.


Café au lait spots
Congenital pigmented skin marks; the color of coffee with milk.

A substance found in some food and drinks that stimulates the central nervous system; excess caffeine can cause nervousness, muscular tremors, and heart palpitations.

Heel bone.

A buildup of the keratin layer from repetitive friction or injury; frequently occurs on the plantar surface of the foot around the great toe.

Calorie (energy) requirement
The calorie intake required to offset calorie expenditure, resulting in a constant body weight.

Abnormally growing cells that can invade local tissue, often metastasizing (spreading) to distant areas of the body through the lymphatic system or bloodstream.

Small, thin-walled blood vessels that have close contact with individual cells of the body.

A collagenous structure that surrounds a joint like a sleeve. The capsule allows motion of joints and protects the articular cartilage. The capsule, along with ligaments, tendons, and bony structure, provides stability of the joint.

One of the six classifications of nutrients and one of the three types of energy-yielding nutrients. Carbohydrates are classified by the number of sugar molecules they contain.

Carbohydrate loading
The practice of maximizing glycogen stores by decreasing training and increasing carbohydrate intake during the week before an endurance event.

Cardiovascular (circulatory) system
A complex arrangement of connected tubes comprising the heart, arteries, arterioles, capillaries, venules, and veins.

Carpal tunnel syndrome
Median nerve compression at the wrist that is characterized by pain, numbness, and weakness in the median nerve distribution of the hand.

Carrying angle of the elbow
The angle formed by the long axis of the humerus and ulna, resulting in an abducted position of the forearm relative to the humerus.

A cellular tissue that, in the adult, is specific to joints, but in children forms a template for bone formation and growth. Hyaline cartilage is a low-friction cellular tissue that coats joint surfaces. Fibrocartilage is tough with high collagen content, such as found in the meniscus of the knee, or the anulus fibrosus portion of the intervertebral disk.

Excessive height of the longitudinal arch of the foot.

Inflammation of subcutaneous tissue. Can be caused by trauma or infection.Cellulitis is a bacterial infection of the soft tissues that most often occurs after trauma to the skin or prior surgery. Also, a spreading redness and swelling of the skin in response to an insect bite.

Cerebral concussion
The least severe sport-related brain injury that is characterized by immediate and transient impairment of neural functions.

Cerebral contusion
A bruise of the brain substance that may result from an impact of the skull and an object.

Cerebrospinal fluid (CSF)
An almost protein-free fluid that acts as a shock absorber to cushion and protect the brain.

Cervical intervertebral disk herniation
An injury where disk material pushes against or ruptures the annulus fibrosus to impinge against the spinal cord or nerve root.

Cervical lordosis
Forward curvature of the cervical spine.

Charley horse
Muscle soreness and stiffness caused by overstrain or a contusion; also known as a quadriceps contusion.

A local cold injury from repeated, prolonged exposure of bare skin to low temperatures and high humidity, resulting in swollen, tender areas on the fingers and toes.

Infection or inflammation of the gallbladder.

The cells that form cartilage.

The cells in cartilage that produce proteoglycans.

Chondroitin sulfate
An important class of glucosaminoglycans in articular proteoglycans; the oral form is thought to prevent degradation of joint cartilage and relieve symptoms.

Softening of the articular surface that results from exposure of normal cartilage to excessive pressure or shear.

A primary sarcoma formed from cartilage cells or their precursors but without direct osteoid formation.

Chronic rotator cuff tear
Tear of the rotator cuff of the shoulder resulting from degeneration within the rotator cuff tendon.

Chronic subacromial impingement syndrome
Shoulder pain with active flexion, abduction, and/or internal rotation, but near normal passive range of motion; most commonly found in the senior athlete.

Chronic subluxating patella
A stage in the continuum of patellofemoral dysplasias; the patella partially dislocates out of the intercondylar groove and snaps back into place rather than completely dislocating.

A sensation of coolness with pain.

The collarbone.

Clavicular epiphyseal fracture
Fracture of the growth plate of the clavicle; may appear clinically as a dislocation, especially if some displacement is present.

Claw toe
Deformity involving hyperextension of the MTP joint and a hyperflexion of the interphalangeal joint.

Closed chest injuries
An injury to the chest in which the skin has not been broken.

Closed fracture
A fracture that does not disrupt the integrity of the surrounding skin.

Closed reduction
A procedure to restore normal alignment of a fractured bone or dislocated joint in which the fractured bones are simply manipulated and no incision is needed.

A complex foot disorder that includes three separate deformities: metatarsus adductus, ankle equinus, and heel varus.

Coach’s finger
A painful, stiff finger with a fixed-flexion deformity of the joint resulting from a hyperextension injury.

A triple helix protein that is the major structural macromolecule of the extracellular matrix of articular cartilage; found also in bone, tendon, and ligament. Collagen is a family of stiff, helical, insoluble protein macromolecules that function as scaffolding and provide tensile strength in fibrous tissues and rigidity in bone.

Colles fracture
Fracture of the distal radius, with dorsal displacement of the fragments; often caused by a fall on an outstretched arm with the hand extended.

Comminuted fracture
A fracture with more than two fragments.

Common peroneal nerve
Nerve lying below the head of the fibula that controls movement at the ankle and supplies sensation to the top of the foot.

Compartment syndrome
Ischemia of the nerves and muscles within a fascial compartment caused by elevated pressure within the compartment; frequently seen in association with tibial fractures.

Compartment syndrome
A condition that occurs when the amount of swelling and/or bleeding in a muscle compartment causes pressure that is greater than the capillary pressure and results in tissue ischemia and potential tissue necrosis.

Compound fracture
Any fracture in which the overlying skin has been penetrated.

Computed tomography (CT, CAT scan)
A radiographic modality that allows cross-sectional imaging from a series of x-ray beams. The x-ray tube is rotated 360° around the patient, and the computer converts these images into a two-dimensional axial image. CT is capable of imaging bone in three planes: coronal, sagittal, and oblique. This modality is particularly useful in evaluating fractures and bone tumors.

Transfer of heat from the body, which is warmer, to a cooler object such as a cold, wet shirt or an ice pack.

A rounded process at the end of a long bone.

Congenital spinal stenosis
A syndrome often seen in athletes of short stature or dwarf in which individual vertebrae of the spine may contain short pedicles that decrease the diameter of the spinal canal.

Connective tissue
Tissue that connects and supports the structures of the body

Contact dermatitis
Inflammation of the skin caused by materials or substances coming in contact with it; may involve either allergic or nonallergic mechanisms.

Contagious disease
A disease that can be transmitted from one person to another.

Bruise; injury to soft tissue without a break in the skin

Transfer of heat to the cooler air as air moves across the body surface. The air is warmed and the body is cooled.

Coracoacromial arch
A structure formed by the acromion process and the coracoacromial ligament; comprises the roof over the lateral shoulder.

A muscle that assists in flexion and adduction of the glenohumeral joint.

A buildup of compacted keratin that exerts pressure on the skin when shoes are worn; usually occurs on the soles of the feet.

Coronal plane
A coronal plane is any plane of section in the anatomical position that passes vertically through the body and is perpendicular to the median plane. It divides the body into anterior and posterior sections.

Cortical bone
Dense bone that is responsible for skeletal homeostasis.

Cortisone-like medicines that are used to provide relief for inflamed areas of the body. They lessen swelling, redness, itching, and allergic reactions. Often used for a number of other diseases such as asthma or other auto immune diseases.

Costal arch
Fused costal cartilages of the sixth to tenth ribs forming the upper border of the abdomen.

Costovertebral angle
Angle that is formed by the spine and the tenth rib; the kidneys lie beneath the back muscles in the costovertebral angle.

Cyclooxygenase-1 enzyme; an enzyme that is present in most bodily tissues (including platelets and gastrointestinal mucosal tissues) and serves as a “housekeeping” enzyme to form prostaglandins.

Cyclooxygenase-2 enzyme; an enzyme that is thought to be present in the body only when induced in response to injury and is responsible for the formation of prostaglandins that mediate pain and inflammation.

Coxa magna
A deformity of the hip in which the ball of the hip joint is enlarged. May be secondary to Legg-Perthes disease or arthritis.

Coxa valgus
A valgus or abduction deformity of the hip. The neck/shaft angle in increased.

Cranial bones
Eight bones of the skull that protect the brain; include the frontal bone, two parietal bones, two temporal bones, occipital bone, sphenoid bone, and ethmoid bone.

Cranial nerves
Twelve pairs of special nerves that are associated with various sensory and motor functions.

A nutritional supplement used to increase anaerobic power and strength.

Continued deformation of soft tissue in response to a maintained load.

A grating or grinding sound.

Crush injury
An injury produced as a result of continuous pressure applied to a part of the body, usually an extremity.

The therapeutic use of cold.

Cubital tunnel syndrome
Compression of the ulnar nerve at the elbow.

Cubitus (Elbow)
Cubitus varus is a bowing (or adduction) deformity of the elbow. Cubitus valgus is an elbow aligned in the opposite direction..

The removal of growths from within cavity walls; in the treatment of musculoskeletal tumors, the scraping of tumor out of bone.

A procedure in which the bladder is filled with a radiographic contrast agent and a radiograph is obtained, followed by a second radiograph after the contrast agent has been drained; used to determine bladder injuries.


Deep venous thrombosis (DVT)
Venous clot formation caused by immobilization, hypercoagulation, obstructed venous flow, or endothelial injury, among others.

The amount of lengthening or shortening in a structure divided by the structure’s original length.

Degenerative joint disease (DJD)
Deterioration of the articular cartilage that lines a joint, which results in narrowing of the joint space and pain; osteoarthritis.

Dehydroepiandrosterone (DHEA)
An adrenal hormone that is a metabolic precursor for the production of testosterone, estrogen, and other hormones. Sold as an over-the-counter nutritional agent that is sometimes used as a substitute for anabolic steroids or testosterone to decrease fat mass and increase muscle mass.

Delayed-onset muscle soreness (DOMS)
Muscle pain or discomfort that follows unaccustomed vigorous exercise and persists for several days despite the cessation of activity.

Delayed union
A delay in normal fracture healing; not necessarily a pathologic process.

A change in electricity in the heart caused by an electrical impulse and resulting in contraction of individual myocardial cells.

Inflammation of the skin that encompasses a broad range of disorders; usually appears as an itchy area of redness or scaling.

The layer of skin that contains connective tissue and gives skin elasticity and strength.

A metabolic disorder characterized by hyperglycemia caused by defects in insulin secretion, insulin action, or both.

The shaft of a long bone.

Diarthrodial joint
A specialized articulation in the acromioclavicular capsule that permits free movement.

Separation of the distal tibia and fibula.

Relaxation of the heart muscle.

Dietary fat
The most concentrated source of energy in the diet, made up of saturated, monounsaturated, and polyunsaturated fats, which each provide 9 calories per gram of fat.

Discography (diskography)
A procedure in which a radiopaque material is injected into a lumbar or cervical intervertebral disk to outline the disk. This procedure used in conjunction with CT to help identify the source of back pain. The pain produced by the injection is correlated with the patient’s symptoms.

Discoid meniscus
A congenital deformity in young athletes in which the meniscus is discoid in shape rather than semilunar.

A surgical decompression procedure in which an intervertebral disk is removed.

Complete disruption in the normal relationship of two bones forming a joint (ie, no contact of the articular surfaces). The direction of the dislocation is described by the position of the distal bone (eg, with an anterior dislocation of the shoulder, the humerus is displaced anterior to the scapula).

Displaced fracture
A fracture that produces deformity of the limb.

Location in an extremity nearer the free end; location on the trunk farther from the midline or from the point of reference.

A separation of joint surfaces with no dislocation or ligament rupture.

Toward the posterior surface of the body.

Down syndrome
A congenital condition that is characterized by mental retardation and various physical characteristics. Approximately 50% of individuals with Down syndrome have a congenital heart defect.

Dual-energy x-ray absorptiometry (DEXA or DXA)
A diagnostic imaging technology that uses two different x-ray voltages to assess bone density.

A classification of material that deforms extensively before failure, such as soft metal.

Dura mater
The outermost tough fibrous membrane that lies immediately inside the bone as part of the meninges.

In strength training, the time necessary to complete a desired exercise.

Short stature characterized by an adult height of less than 58″ in males or a standing height below the third percentile for age.

Dynamic stabilization
The use of muscle strength and muscle coordination during performance of activities; used in rehabilitation.

Dynamic strength
The magnitude of isotonic or isokinetic contraction.

Discomfort following meals as a result of impairment of digestive function.

A broad term that describes a condition affecting growth or development in which the primary defect is intrinsic to bone or cartilage.

A state of difficult or labored breathing that results from either trauma or disease.

A condition resulting from defective or faulty nutrition, broadly construed to include nourishment of tissue by all essential substances, including those normally manufactured by the body itself.


Eccentric exercises
Exercises in which the muscle lengthens despite resisting a force, as in slowly lowering a weight.

Bruising or bluish discoloration associated with bleeding within or under the skin.

Condition in which fluid escapes into the tissues from vascular or lymphatic spaces and causes local or generalized swelling.

The presence of fluid within a joint; intra-articular swelling.

Electrical muscle stimulation (EMS)
Treatment in which the biphasic current delivers stimulation to muscles in a variety of ways, including pulse, surged, or tetanizing contractions.

Electrocardiogram (EKG)
A recording of electrical currents that flow through the heart in the form of a series of waves and complexes that are separated by regular intervals.

Electromyography (EMG)
A test that measures the electrical response of muscle contraction.

Enchondral bone healing
Process in which capillaries grow among mesenchymal cells, forming a fibrovascular tissue known as callus that bridges the gap between bone ends.

Enchondral ossification
The process of long bone formation where the cartilage model is replaced by bone.

A fibrous tissue that coats axons.

The layer of skin that protects against ultraviolet damage and provides cutaneous immunity.

Epidural hematoma
A blood clot located outside the dura mater.

A disorder caused by abnormal electrical activity in the brain that results in recurring seizures.

An agent that rapidly produces bronchodilation to reverse the effects of an allergen on a patient’s airway.

Epiphyseal line
The part of a long bone that produces growth.

A part of a long bone developed from a center of ossification distinct from that of the shaft and separated at first from the latter by a layer of cartilage; the rounded end of a long bone at the joint.

A glistening, synovial-like membrane that envelops the tendon surface.

An imaginary line that divides a surface into two approximately equal areas.

Plantar flexed position of the ankle.

Redness of the skin.

Ewing sarcoma
A primary sarcoma of the bone that usually arises in the diaphyses of long bones, ribs, and flat bones of children and adolescents.

A spur or bony overgrowth.

Movement of an extremity posterior to or behind the body.

A muscle, the contraction of which causes movement at a joint with the consequence that the limb or body assumes a more straight line, or so that the distance between the parts proximal and distal to the joint is increased or extended; the antagonist of a flexor.

Extensor mechanism
Complex interaction of muscles, ligaments, and tendons that stabilizes the patellofemoral joint and acts to extend the knee.

External fixation
Stabilization of a fracture or unstable joint by inserting pins into bone proximal and distal to the injury that are then attached to an external frame.

External rotation
Lateral rotation of an extremity relative to the body.

A liquid product that has escaped from blood vessels and been deposited in tissue as a result of inflammation.


Sheet or band of tough fibrous connective tissue; lies deep under the skin and forms an outer layer for the muscles.

Bundles of fibers within muscle fibers.

Surgical incision of the fascia.

Fast twitch fibers
The speed of contraction of type II muscle fibers.

Fast twitch muscle fibers
Type II muscle fibers.

Fat embolism syndrome
Respiratory distress and cerebral dysfunction caused by droplets of marrow fat released at a fracture site and deposited in the lungs or brain.

Fat-free mass (FFM)
All tissue in the body that is not fat, including bone, muscle, organ, and connective tissue.

Fatigue fracture
Microfracture that occurs when the bone is subjected to frequent, repeated stresses, such as in running or marching long distances, and the rate of bone breakdown exceeds the rate of bone repair.

Fat pad
Specialized soft tissue structure for weight bearing and absorbing impact.

Infection of the pulp of the distal phalanx of the finger.

Female athlete triad
The constellation of abnormal or absent menses, eating disorders, and osteoporosis/stress fractures seen in female athletes.

Femoral anteversion

Femoral condyles
Two surfaces at the distal end of the femur that articulate with the superior surfaces of the tibia.

Femoral head
Proximal end of the femur, articulating with the acetabulum,

Femoral neck
The bone connecting the head and the shaft of the femur; fractures frequently occur in this area.

Femoral nerve palsy
Pain and weakness in the femoral nerve distribution as the result of a stretch or trauma to the nerve.

A mesh of collagen fibers, proteoglycans, and glycoproteins, interspersed with fibrochondrocytes.

Cells that are able to synthesize fibrous extracellular proteins and have the rounded appearance of chondrocytes.

Diffuse pain in multiple sites that does not result from trauma and is associated with emotional disturbances.

Fibrous scar
The typical patching material for wound repair.

Fibular collateral ligament
Ligament that inserts from the femoral condyle to the fibular head.

Fibular stress fracture
A fracture usually located a few centimeters above the ankle joint as the result of repetitive loads on the bone that cause an imbalance of bone resorption over formation.

Flail chest
A fracture of at least four consecutive ribs in two or more places; the most serious of chest wall injuries.

The capacity of a muscle to lengthen or stretch.

Movement of an extremity anterior to or in front of the body.

A muscle the action of which is to flex or bend a joint.

Floating ribs
The eleventh and twelfth ribs, which do not connect to the sternum.

A special type of radiograph that shows continuous motion of the structure, such as wrist motion.

Inflammation of a follicle or follicles, most often hair follicles.

Food Guide Pyramid
A guide to daily food choices presented by the US government that includes food from five groups that provide essential nutrients.

The space between the pedicles of two adjacent vertebrae through which the nerve root exits at eachlevel in the cervical spine.

An action that changes the state or motion of a body to which it is applied. Can be external, such as gravity, or internal, such as forces generated by muscles, bone, and soft-tissue deformation.

A disruption in the integrity of a bone.

Fracture callus
Bone developed after a fracture; initially formed from a hematoma at the bleeding edges of bone, it eventually forms a cartilage mass that is remodeled into mature bone.

A fracture of bone associated with a dislocation of its adjacent joint.

Fracture reduction
The realignment of fracture fragments to restore normal anatomy of the bone.

Freiberg’s disease
An osteochondrosis or osteonecrosis of the metatarsal head.

In strength training, the number of workouts completed per unit of time; also refers to how many workouts occur during 1 week.

Frozen shoulder
A condition characterized by restricted shoulder movement resulting from acute trauma or a periarticular biceps or rotator cuff tendon injury.

Functional knee pain
Pain that cannot be linked with any anatomic pathology.

Fusion (arthrodesis)
The joining of two bones into a single unit, thereby obliterating motion between the two. May be congenital, traumatic, or surgical.


Galeazzi fracture
Dislocated ulna with a fractured radius.

Gamekeeper’s thumb
Rupture of the ulnar collateral ligament.

A mass of nerve cell bodies usually found lying outside the central nervous system.

Gastrocnemius-soleus strain
An injury that involves the medial side of the complex; symptoms include sudden pain with a popping sensation in the calf, followed by swelling and ecchymosis; also known as tennis leg.

An irritation or inflammation of the gastrointestinal tract that is indicated by vomiting or diarrhea.

Genu (knee)
Genu valgum is knock-knee deformity; genu varum is bowleg deformity.

Genu valgum

Genu varum

Gerdy’s tubercle
The attachment site for the iliotibial band.

Gestational diabetes (GDM)
Form of diabetes that is first detected in pregnancy and usually resolves when the pregnancy is completed.

Glenohumeral dislocation
Injury in which the humeral head may displace from the joint; most of these dislocations are anterior and inferior to the glenoid rim.

Glenohumeral instability
Excessive shoulder laxity accompanied by pain or feelings of instability.

Glenohumeral joint
True shoulder joint.

Glenoid labrum
A soft fibrous rim surrounding the glenoid fossa that deepens the socket and provides stability for the humeral head.

Glenoid labrum tear
Tear of the glenoid labrum; can result from acute trauma or overuse.

Glucosamine sulfate
A fundamental component in the synthesis of both hyaluronic acid and chondroitin that is thought to promote cartilage repair and synthesis; the oral form is taken as a dietary supplement to treat arthritis.

An inflammatory arthritis associated with deposition of urate in the joint.

Gracilis muscle
One of the three hamstring muscles of the knee that make up the pes anserine and help protect the knee against rotatory and valgus stress (the other ones are the sartorius and semitendinosus).

Greater trochanter
Broad, flat process at the upper end of the lateral surface of the femur to which several muscles are attached

Greenstick fracture
A fracture that disrupts only one side of the bone. This fracture pattern is seen in children because of the greater plasticity of their bones.

Ground strike
A type of lightning strike in which the lightning hits the ground first and travels along the ground to the individual.

Growth factors
Proteins that are produced and released by one cell, and then act on the same cell, adjacent cells, or remote cells to influence growth and division.


The body’s posture or physique.

The great toe.

Hallux rigidus
A painful loss of motion of the great toe metatarsophalangeal joint caused primarily by arthrosis.

Hallux valgus
Deformity at the first metatarsophalangeal joint where the proximal phalanx deviates laterally; also known as a bunion.

Hammer toe
Flexion deformity of the distal interphalangeal joint of the foot.

Three muscles in the posterior region of the buttock and thigh that provide an extension force at the hip and a flexion force at the knee.

The upper or proximal portion of a structure; the head of a bone is the rounded end that allows joint rotation.

A collection of blood within a joint.

A collection of blood resulting from injury.

The presence of blood in the urine.

Bones located on each side of the sacrum; composed of the fused ilium, ischium, and pubis.

Paralysis of one side of the body.

Herniated disk
Rupture of the nucleus pulposus or anulus fibrosus of the intervertebral disk.

Heterotopic ossification
The formation of bone in any nonosseous tissue; often occurs following trauma.

Hill-Sachs lesion
An indentation or compression fracture of the posterior superolateral articular surface of the humeral head that is created by the sharp edge of the anterior glenoid as the humeral head dislocates over it.

The mineral component of bone matrix that is deposited into the organic framework to make the bone hard and strong.

A condition in which blood sugar rises above normal levels, leading to excretion of glucose in the urine and excessive thirst and urination.

An increase in normal motion.

Hypomobile facet
A painful dysfunction where a facet of the vertebral body becomes “locked.”

The amount of relaxation, or variation in the load-deformation relationship, that takes place within a single cycle of loading and unloading in soft tissue.


Ice, compression, elevation, and splinting.

Iliotibial band (ITB) syndrome
An overuse injury where repetitive flexion and extension causes inflammation of the iliotibial band when it rubs over the lateral femoral condyle.

Immune hyperplasia
An increase in activity of the spleen.

Impacted fracture
A fracture pattern in which the fragments are pushed together, thus imparting some stability.

A contagious skin condition in which flaccid crusts and blisters cluster in involved areas, most commonly around the mouth.

Impingement syndrome
Shoulder pain caused by tendinosis of the rotator cuff tendon or irritation of the subacromial bursa. See also Rotator cuff impingement, external, and Rotator cuff impingement, internal.

Infectious disease
A disease caused by an abnormal invasion of a host by a bacteria, virus, or parasite.

A localized tissue response initiated by the injury or destruction of vascularized tissues. Inflammation Heat, redness, swelling, and pain that accompany musculoskeletal injuries; occurs when tissue is crushed, stretched, or torn.

Looseness, unsteadiness, or an inability to withstand normal physiologic loading without mechanical deformation.

The degree of work or effort exerted by the athlete during strength training.

Internal fixation
Surgical insertion of a device that stops motion across a fracture or joint to encourage bony healing or fusion.

Internal rotation
Medial rotation of an extremity relative to the body.

Intervertebral disk
A fibrocartilaginous disk located between the bodies of each of the vertebrae.

Intramedullary nailing or rodding
A procedure for the fixation of fractures in which a nail or rod is inserted into the intramedullary canal of the bone from one of its two ends.

Intramembranous ossification
Bone formation characterized by the aggregation of undifferentiated mesenchymal cells, which differentiate into osteoblasts; the growth of bone without a cartilage model.

Inversion injury
Ankle injury resulting from landing on the lateral aspect of the foot.

The administration of medication through the skin by direct electrical current.

Tissue deprived of a blood supply.

Literally, “same speed”; when applied to muscle action, it implies constant velocity of shortening.

Isokinetic exercise
In isokinetic contractions, the muscle contracts and shortens at constant speed.

Literally, “same length”; when applied to muscle action, it implies that the muscle length is held constant even with varying loads. Accomplished by contracting the flexors and extensors of a joint at equal loads so that the joint does not move.

When applied to muscle action, the condition when a muscle shortens against a constant load, as in lifting a weight.

Isotonic exercise
Contraction of muscles concentrically or eccentrically against resistance with movement of the part so that the load remains constant


The junction between the ends of two adjacent bones.

Joint capsule
A thin, but strong structure in the elbow that plays a role in ligamentous restraint.

Joint manipulation
Skilled, passive movement of a joint (or spinal segment) either within or beyond its active range of motion; also known as joint mobilization.

Joint mobilization
Passive movement techniques used to treat joint dysfunctions such as stiffness, reversible joint hypomobility, and pain.

Joint play
Capsular laxity that allows movement at the joint that may be demonstrated passively, but cannot be actively performed by the patient; used in joint mobilization.

Jones fracture
Stress fracture of the proximal shaft of the fifth metatarsal; a fracture that frequently heals with difficulty.

Jumper’s knee
Chronic tendinosis of the patellar tendon; frequently limited to the distal pole of the patella rather than being diffused throughout the tendon.

Juvenile rheumatoid arthritis
A chronic inflammatory disease in children that is characterized by pain, swelling, and tenderness in one or more joints and may result in impaired growth and development.


Kaposi’s sarcoma
A neoplasm seen in AIDS patients in the form of a malignancy of the skin.

Kenny Howard splint
A type of splint used to reduce any significant displacement in the treatment of an epiphyseal fracture of the clavicle.

A form of acidosis (accumulation of acids in the body) in uncontrolled diabetes in which accumulation of certain acids occurs as the result of unavailable insulin.

Organic substances in the urine that are derived from fat metabolism. Presence in the urine indicates that exercise should be cancelled for the day.

The study of the movement of rigid structures without reference to the cause of motion, ie, independent of the forces that produce it.

The study of motion of the human body.

A term used to define the body’s ability to detect positional changes.

Kinetic energy (KE)
The energy of a moving body; equals one half the mass times the square of the velocity.

The study of the forces that produce movements.

Klippel-Feil anomaly
A condition where there is congenital fusion of two or more vertebrae; participation in contact sports depends on numerous factors and requires extensive evaluation.

Kohler disease
Osteochondrosis of the tarsal navicular.

Curvature of the spine that is convex posteriorly.


Lachman test
A test to confirm integrity of the anterior cruciate ligament of the knee.

Mature layered bone.

Lamellar bone
Mature, well-organized form of cortical bone.

A surgical decompression procedure in which part of the posterior arch of a vertebra is removed; allows access to the disk.

Lying away from the midline.

Lateral articular surface
A bony process on each end of the clavicle.

Lateral condyle
Forms the lateral border of the upper surface of a joint.

Lateral epicondylitis
Inflammation of the lateral epicondyle; also known as tennis elbow.

Lateral malleolus
Bony prominence at the end of the fibula that is part of the ankle joint.

Lateral meniscus
The lateral C-shaped fibrocartilaginous structure of the knee.

Lateral patellar compression syndrome (LPCS)
The mildest form of patellofemoral dysplasia with some degree of malalignment.

Lateral view
A view that passes from side to side at 90° to an AP or PA view.

The irrigation or thorough washing of an infected joint with high-volume saline solution.

Legg-Calvé-Perthes disease
Osteonecrosis of the proximal femoral epiphysis that most commonly affects boys aged 3 to 8 years.

White blood cells that migrate toward increasing concentrations of mediators at the site of injury.

A collagenous tissue that connects two bones to stabilize a joint.

Limb salvage
Surgical removal of a tumor without amputation of the affected extremity.

Lisfranc fracture
A fracture-dislocation of the tarsometatarsal joint.

Any force or combination of forces applied to the outside of a structure.

Load-deformation curve
The mathematical relationship of the load applied to a structure; used to determine the strength and stiffness of a structure.

Longitudinal arch
Arch along the long axis of the foot formed by the bones of the foot starting at the weight-bearing surface of the calcaneus and ending at the metatarsal heads.

Loose-packed position
The position in which a joint capsule is most relaxed and the greatest amount of joint play is possible.

Curvature of the spine that is convex anteriorly.

Low-density lipoprotein (LDL) cholesterol
One of the two types of cholesterol; the so-called “bad” cholesterol.

Low-molecular-weight heparins (LMWHs)
Anticoagulants that work by binding to antithrombin-III and catalyze its inactivation of factor Xa.

Lyme disease
An infectious disease that is commonly spread by the bite of an infected tick.

Cancer of the lymphatic tissue first arising in the lymph nodes.


Magnetic resonance imaging (MRI)
An imaging modality that depends on the movement of protons in water molecules. When subjected to a magnetic field, protons that are normally randomly aligned become aligned. Radiowaves directed at the tissue to be studied are used to change the alignment of these photons. When the radiowaves are turned off, the protons emit a signal that is detected and processed by a computer into an image. In the musculoskeletal system, MRI is useful in diagnosing soft-tissue injuries, tumors, stress fracture, and infection.

Mallet finger
Rupture of the extensor tendon at or near its insertion on the terminal phalanx caused by a sudden flexion force on the distal interphalangeal joint while the finger is actively extended; also known as baseball finger.

Healing of a fracture in an unacceptable position.

Marfan’s syndrome
A rare genetic disorder that is inherited as an autosomal dominant condition in which connective tissue is affected, weakening the aorta and causing an aneurysm or rupture of the aorta.

Maximal heart rate (MHR)
A method of determining the maximal heart rate that estimates a rate of 220 beats per minute minus the individual’s age in years.

Maximal oxygen consumption (VO2max)
The criterion measure of cardiovascular fitness representing the maximal ability of the cardiopulmonary system to deliver oxygen to the working muscles and the muscle’s ability to use that oxygen to produce adenosine triphosphate (ATP) aerobically.

Mechanism of injury
A representation of the patterns of energy that cause traumatic injuries

Lying toward the midline.

Medial articular surface
A bony process on each end of the clavicle.

Medial collateral ligament injuries
An acute knee injury that is the result of a blow to the lateral side of the knee when the foot is planted; commonly seen in football players and snow skiers.

Medial condyle
Forms the medial border of the upper surface of a joint.

Medial epicondyle
A bony prominence located proximal and medial to the trochlea; serves as the attachment site for the flexor-pronator muscle group and the ulnar collateral ligament.

A type of skin cancer characterized by an asymmetric pigmented lesion with an irregular border that usually arises from a previously normal mole. Risk factors include fair skin, family history, more than 50 moles on the body, or a history of sunburn as a child.

A soft-tissue structure that lines some joints and provides load distribution, shock absorption, and lubrication.

Mesenchymal syndrome
A subset of sports trauma patients who are at risk for connective tissue breakdown following relatively benign load or use.

The five bones of the hand that extend from the wrist to the fingers.

The broad portion of a long bone adjacent to a joint. In children, the broad portion of a long bone includes the epiphysis, the physis, and the metaphysis; the flare at either end of a long bone.

The transfer of disease from one part of the body to another; tumor metastasis usually occurs via the bloodstream or the lymphatic system.

Generalized pain in the forefoot.

Metatarsus valgus
Congenital deformity of the forefoot in which the forefoot is rotated laterally in relation to the hindfoot; also called metatarsus abductus.

Metatarsus varus
Congenital deformity of the forefoot in which the forefoot is rotated medially in relation to the hindfoot; also called metatarsus adductus.

Destruction of a small number of cells caused by additive effects of repetitive forces.

Imaginary straight vertical line drawn from midforehead through the nose and the umbilicus to the floor.

Physical agents that can create an optimum environment for injury healing, while reducing pain and discomfort.

Monteggia fracture
Dislocation of the radial head in association with an ulnar fracture.

Morton’s neuroma
An interdigital neuroma of the foot causing pain, numbness, and tingling.

Morton foot
Congenital abnormality characterized by a short first metatarsal, which throws weight-bearing stresses to the second metatarsal head, often resulting in pain.

Multidirectional instability (MDI)
Symptomatic glenohumeral instability in more than two directions.

Contractile connective tissues that affect movement; a component of nearly all organs and body systems.

One of five types of microorganisms that commonly causes disease, characterized by a single cell and with no rigid cell wall. Mycoplasma are similar to bacteria.

A radiographic study in which a water-soluble contrast agent is injected into the subarachnoid space to form a column of opacified fluid that outlines the thecal sac of the spinal cord. Used to assess herniated disks and spinal stenosis. This study has been largely replaced by MRI and CT.

An abnormal condition of the spinal cord, whether through disease or compression. The usual consequences are spasticity, impairment of sensation, and impairment of bowel and bladder function.

The embryonic cells that develop into skeletal muscle cells.

Myocardial contusion
Bruising of the heart muscle.

Myocardial infarction
Heart attack resulting from blockage of the major coronary vessels and lack of oxygen to the myocardium, causing permanent damage to or death of the heart muscle.

Myofascial pain syndrome
A painful musculoskeletal response following muscle trauma.

The fibers that constitute a muscle.

A slender thread within a muscle fiber that functions in muscle contraction.

A protein that serves as a storage site for oxygen and speeds the diffusion of oxygen into muscle fibers.

A wide and varied group of primary muscle disorders characterized by weakness.

Myositis ossificans
The formation of lamellar bone within muscle, often as a result of blunt trauma.

The areas of muscle that are supplied by a particular nerve root.


Navicular bone
Bone with which the head of the talus articulates on the medial side of the foot; also a bone in the wrist that articulates with the trapezium, trapezoid, and other carpal bones.

Navicular stress fracture
A fracture that occurs with repetitive stress activities and results in medial foot pain and tenderness over the dorsal navicular.

The constricted portion of a structure (eg, femoral neck).

Nerve conduction studies
Studies that test the speed by which motor, sensory, or mixed (combined motor and sensory) nerves transmit impulses.

Pain along the course of a nerve.

A temporary loss of neural function.

Inflammation or irritation of a nerve.

A tumor composed of nerve cells.

Neuropathic arthritis
The chronic, progressive destruction of a joint that is caused by the loss of sensation from an underlying neurologic dysfunction; also known as Charcot arthropathy.

An abnormal condition involving a peripheral nerve.

A grade V injury in which there is complete nerve disruption leading to the death of the distal axons and wallerian degeneration of myelin.

A substance poisonous to nerve tissue.

A type of granular leukocyte.


Nondisplaced fracture
Fracture in which there is no deformity of the limb.

Nonossifying fibromas
Osteolytic and sometimes painful proliferative lesions composed of spindle (fibrous) cells.

Nonsteroidal anti-inflammatory drugs (NSAIDs)
A broad group of chemically heterogeneous drugs that share important clinical and tissue effects: all have some analgesic, antipyretic, and anti-inflammatory activity. Includes aspirin, ibuprofen, indomethacin, naproxen, and others.

Failure of healing of a fracture or osteotomy. With continued motion through a nonunion, a pseudarthrosis will form.

Nucleus pulposus
A region of the intervertebral disk that functions as a shock absorber against axial loads.


Oblique fracture
A fracture in which the fracture line crosses the bone diagonally.

Odontoid anomalies
A developmental malformation that can lead to instability between C1 and C2; considered an absolute contraindication for contact sports.

Olecranon bursa
Bursa in the elbow that separates the skin from the underlying ulna; allows the soft tissue to glide smoothly over the olecranon process.

Open reduction
An open surgical procedure in which normal or near-normal relationships are restored to a fractured bone or dislocated joint.

Open reduction and internal fixation (ORIF)
A procedure that involves incising the skin and soft tissue to repair a fracture under direct visualization.

A class of drugs that includes heroin, morphine, and codeine.

The more fixed end or attachment of a muscle.

Osgood-Schlatter disease
Partial avulsion of the tibial tubercle because the tubercle is subjected to traction forces by the patellar tendon insertion; also known as tibial osteochondrosis.

Osteitis pubis
Inflammation of the pubis symphysis; an inflammatory condition of the pubic bones caused by repetitive stress on the symphysis pubis.

Osteoarthritis (OA)
A deterioration of the weightbearing surface; distinguished by destruction of the hyaline cartilage and narrowing at the joint space.

Cells that form new bone.

Osteochondral fractures
Injuries that disrupt articular cartilage and the underlying subchondral bone.

Osteochondritis dissecans (OCD)
A localized abnormality of a focal portion of the subchondral bone, which can result in loss of support for the overlying articular cartilage.

Bone-resorbing cells.

The cells of established bone.

Osteogenesis imperfecta
A hereditary disorder of connective tissue caused by mutations in the gene for type I collagen.

The organic matrix of bone; a protein framework composed of collagen that allows growth and remodeling.

Osteoid osteoma
A small, benign, but painful tumor usually found in the long bones or the posterior elements of the spine.

Osteokinematic motions
Vertebral motion associated with range of motion; includes flexion, extension, rotation, and lateral flexion in the lumbar spine.

Dissolution of bone, particularly as resulting from excessive resorption.

Infection of bone, either bacterial or mycotic.

In lamellar bone, a concentric series of layers of mineralized matrix surrounding the central canal.

The death of bone, often as a result of obstruction of its blood supply.

Bone fragility as the result of a low-calcium diet.

A painful inflammation of the periosteum or lining of bone.

Overgrowth of bone, common in osteoarthritis and spinal stenosis.

Deterioration of bone tissue resulting in an increased risk of fracture as the result of a low-calcium diet.

A primary sarcoma of the bone that is characterized by the direct formation of bone or osteoid tissue by the tumor cells.

The process of bony union, as in fracture healing. It is a biologic welding process that is sometimes facilitated with grafts of bone from the iliac crest and insertion of fixation devices.

Literally, cutting a bone. Used to describe surgical procedures in which bone is cut and realigned.

Overload principle
A principle that states that strength, power, endurance, and hypertrophy of muscles increase only if muscles perform workloads that are greater than those previously encountered.

Overuse injury
Any injury caused by repetitive submaximal stress that surpasses the tissue’s natural repair processes.


Paget disease
A condition of abnormally increased and disorganized bone remodeling.

A sensory and emotional reaction precipitated by actual or anticipated injury; results from damage to tissue or nerves and is made worse by pressure or inflammation.

The anterior surface of the forearm, wrist, and hand.

Panner disease
Osteonecrosis of the capitellum seen in teenagers.

A proliferation of synovium beginning at the periphery of the joint surface as seen in rheumatoid arthritis.

A raised lesion in the skin that is less than 1 cm in diameter.

Parasympathetic (craniosacral) nervous system
A part of the autonomic nervous system that causes blood vessels to dilate, slows the heart rate, and relaxes muscle sphincters.

A loose areolar tissue that surrounds the epitenon in tendons that move in a straight line and are capable of great elongation.

Abnormal sensations such as tingling, burning, or prickling.

Infection of the folds of tissue along the edge of the nail.


Patella alta
An abnormally high patella.

Patella baja
A condition where the patella is 1 cm more inferior than that of the contralateral knee following a rupture of the quadriceps.

Patellar sleeve fracture
An avulsion of the unossified distal patella from a sudden forceful quadriceps contraction with the knee flexed.

Patellar tendinitis
A condition that results in pain and inflammation of the patella tendon; a common problem in jumping sports.

Surgical excision of the patella.

Patellofemoral groove
Groove that runs anteriorly between the condyles of the femur; the patella lies in the trochlear groove.

Patellofemoral joint
The joint between the patella and the femur.

Patellofemoral pain syndrome (PFPS)
Muscle tightness or imbalance resulting in lateral pulling of the patella and dull, aching knee pain and crepitus with range of motion.

Pathologic fracture
A fracture caused by a normal load on abnormal bone, which is often weakened by tumor, infection, or metabolic bone disease.

A bony ring, consisting of the sacrum, coccyx, and innominate bones, that connects the trunk to the lower extremities, supports the abdominal contents, and allows passage of the excretory canals.

Percutaneous pinning
Insertion of pins into bone through small puncture wounds in the skin for stabilization of a fracture or a dislocated joint that was realigned by closed reduction.

A connective tissue that covers individual fascicles.

A sleeve of connective tissue that surrounds the shaft of the bone and contributes to fracture healing.

Inflammation of the periosteum.

Peripheral obesity
The location of excessive body fat resulting in a pear shape; not associated with serious cardiovascular complications.

Inflammation of the tendon sheath, marked by pain, swelling, and, occasionally, local crepitus.

A structure composed of the epitenon and the paratenon.

Contamination of the peritoneum or peritoneal cavity by the bacteria-laden contents of a ruptured bowel.

Peroneal tendon injuries
A classification of injuries that includes tendinitis, acute and chronic dislocations, longitudinal tears, and tendon ruptures.

The process by which white blood cells ingest debris or microorganisms.

Bones making up the finger bones (three in each finger and two in the thumb).

The transdermal introduction of a topically applied medication (usually either an anti-inflammatory or analgesic) into soft tissue using ultrasound.

The administration of medication through the skin by ultrasound.

The growth plate. Specialized cartilaginous tissue interposed between the metaphysis and epiphysis in long bones in children. Provides growth in length of the bone.

Pigmented villonodular synovitis
A proliferative process of the synovial membrane of unknown etiology.

The sole, or flexor surface, of the foot.

Plantar fasciitis
Irritation of the plantar fascia at its insertion on the plantar aspect of the heel; a common cause of inferior heel pain.

Flattening of the arch of the foot.

Portable transcutaneous electrical nerve stimulation (TENS) unit
A portable therapeutic modality that uses electrical stimulation to attempt to modulate pain, strengthen muscles, and enhance soft-tissue healing.

Posterior arch
The posterior division of the vertebral column that includes the facet joints on either side of the arch and the posterior spinous process.

Posterior glenohumeral dislocation
Disruption of the glenohumeral joint in a posterior direction.

Posterior process
That part of each vertebra that can be palpated, as it lies just under the skin in the midline of the back.

Posterior sternoclavicular dislocation
Disruption of the sternoclavicular joint posteriorly,

Posterior tibial syndrome
Pain along the posterior medial border of the tibia; thought to be secondary to a tight posterior tibial muscle “pulling” on the periosteum in this area; associated with running.

Posterolateral rotatory instability
The lateral tibial plateau rotates posteriorly in relationship to the femur.

Posttraumatic arthritis
A form of secondary osteoarthritis caused by a loss of joint congruence and normal joint biomechanics.

Preparticipation physical examination
A physical examination held prior to participation in an organized sport that can lay a foundation for the team physician and athletic trainer in an athlete’s future care.

Progressive resistance exercise (PRE)
A type of strengthening exercise based on a 10-repetition maximum that overloads muscle in a progressive, gradual manner that avoids overtraining and fatigue.

Flattening of the foot that occurs during walking and running.

A sense or perception, usually at a subconscious level, of the movements and position of the body and especially its limbs, independent of vision; this sense is gained primarily from input from sensory nerve terminals in muscles and tendons (muscle spindles) and the fibrous capsule of joints combined with input from the vestibular apparatus.

Complex macromolecules that consist of a protein core with covalently bound polysaccharide (glycosaminoglycan) chains.

Describing structures that are closer to the trunk.


A false joint produced when a fracture or arthrodesis fails to heal.

Lines of radiolucency that represent stress fractures with unmineralized osteoid.


Quadriceps angle (Q angle)
An angle formed by the intersection of two lines: one line is drawn from the anterosuperior iliac spine to the midpatella; the second is drawn from the midpatella to the anterior tibial tuberosity. These lines parallel the quadriceps and patellar tendons.

Quadriceps tendinitis
A condition that results in tendon insertion pain just proximal to the patella; commonly occurs in running and jumping sports that involve changing directions.


Radial fossa
A depression that lies immediately above the capitellum on the anterior aspect of the humerus.

Radial styloid
Bony prominence felt on the lateral (thumb) side of the wrist.

Disease of the nerve roots.

Range of motion (ROM)
The amount of movement available at a joint.

Referred pain
Pain that is perceived in a different location from the location of pathology.

Fairly fixed pattern of response or behavior similar for any given stimulus; does not involve a conscious action.

The production of tissue that is structurally and functionally identical to tissue damaged by injury.

Restoration, following disease, illness, or injury, of the ability to function in a normal or near-normal manner.

The replacement of damaged or lost cells and matrix with new cells and matrix that are not necessarily identical in structure and function to normal tissue.

Resection arthroplasty
A procedure in which the surfaces of diseased bone are excised, allowing fibrocartilage to grow in its place.

Resting metabolic rate
A measure of the calories required for maintaining normal body functions such as respiration, cardiac function, and thermoregulation.

A procedure to provide an additional blood supply to fractured bone.

The concept that a muscle will atrophy from disuse and detrain if not consistently trained toward a set goal.

Excessive muscle breakdown.

Rheumatoid arthritis
A chronic inflammatory disease that is probably triggered by an antigen-mediated inflammatory reaction against the synovium in the joint.

A method of treatment of acute injury that is used to counteract the body’s initial response to injury; RICE is an acronym for rest, ice, compression, and elevation.

The childhood form of osteomalacia.

Rigid splint
Splint made from firm material and applied to sides, front, and/or back of an injured extremity to prevent motion at the injury site.

Rotator cuff
The rotator cuff is made up of four muscles and their tendons. These combine to form a “cuff” over the head of the humerus. The four muscles-the supraspinatus, infraspinatus, subscapularis, and teres minor-originate from the scapula and together form a single tendon unit that inserts on the greater tuberosity of the humerus. The rotator cuff helps to lift and rotate the arm and to stabilize the ball of the shoulder within the joint.

Rotator cuff impingement, external
Impingement of the rotator cuff on the acromion and the coracoacromial ligament; causes microtrauma to the cuff, resulting in local inflammation, edema, cuff softening, pain, and poor function of the cuff.

Rotator cuff impingement, internal
A condition in the shoulder of throwing athletes that results in tears of the underside of the rotator cuff and the posterior labrum.

Rotator cuff muscles
Muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) that act in concert to steer or rotate the proximal humerus.

Rotator cuff tear
An injury of the rotator cuff that is described as acute or chronic and partial or full thickness; also classified by estimated size.


Sacroiliac joint
The joint formed by the articulation of the sacrum and ilium.

One of the three bones (sacrum and two pelvic bones) that make up the pelvic ring,

Muscle-cell membrane and its associated basement membrane.

The fundamental components of the contracting unit of the myofibril.

The loss of muscle mass and strength as a result of aging.

Scaphoid nonunion advanced collapse (SNAC) wrist
A nonunion of the scaphoid seen on a PA view of the wrist, along with a radioscaphoid arthritis and later a capitolunate arthritis.

Scapholunate advanced collapse (SLAC) wrist
A pattern of carpal injury and secondary osteoarthritis seen on a PA view of the wrist. Following a scapholunate dissociation, osteoarthritis develops between the radius and the scaphoid and later between the capitate and lunate.

Scapulothoracic joint
Articulation in which the scapula is suspended from the posterior thoracic wall through muscular attachments to the ribs and spine.

Scheuermann disease
Osteochondrosis of the vertebral epiphysis resulting in increased thoracic kyphosis in the preteen and early adolescent years.

Schwann cell
A specialized support cell that encases nerve fibers.

Another name for nuclear scan such as a bone scan.

Hardening, as in margins along a fracture line in bone.

Lateral curvature of the spine.

Secondary bone healing
The repair process that is characterized by the formation of fracture callus, which then remodels to form new bone.

Secondary osteoarthritis
Osteoarthritis resulting from known precipitants such as bone ischemia, trauma, and neuropathy.

Secondary osteoporosis
Osteoporosis characterized by conditions in which bone is lost because of the presence of another disease, such as hormonal imbalances, malignancies, or gastrointestinal disorders, or because of corticosteroid use.

Second-degree burns
Partial-thickness burns that extend down to the dermis; characterized by painful blistering of the skin.

Results of abnormal and excessive discharge from a set of neurons in the brain ranging from blanking out to generalized uncoordinated muscle activity.

Septic arthritis
Infection of a joint, either bacterial or mycotic.

Acute or chronic inflammation of the sesamoid.

Sever’s disease
Heel pain in the area of the calcaneal apophysis; also called calcaneal apophysitis.

The long, straight, cylindrical midportion of a bone.

Shearing stress
One of three stresses generated in a brain injury; involves a force that moves across the parallel organization of tissue.

Shear strain
The amount of angular deformation in a structure or change in the original angle of the structure in response to torque loading.

Shin splints
An overuse syndrome that results from cyclical loading at the posterior tibial and soleus muscle attachments onto the tibia; also known as posterior tibial stress syndrome.

Sinding-Larsen-Johanssen syndrome
Overuse traction apophysitis caused by repetitive microtrauma at the insertion point of the proximal patellar tendon onto the lower patellar pole; also known as patellar osteochondrosis.

Skeletal (voluntary) muscle
Striated muscles that are attached to bones and usually cross at least one joint.

The skeletal system; the supporting framework of the human body, composed of 206 bones.

Skier’s hip
Intertrochanteric and subtrochanteric fractures of the hip joint that frequently occur in skiers.

SLAP (Superior Labral, Anterior to Posterior) lesion
An injury to the biceps tendon anchor and/or superior labrum.

Slipped capital femoral epiphysis
A unique fracture of the femoral epiphysis that fractures through the epiphysis and shifts; commonly occurs in adolescents.

Smooth muscle
Nonstriated, involuntary muscle that constitutes the bulk of the gastrointestinal tract and is present in nearly every organ to regulate automatic activity.

Snapping scapula
A sensation of snapping as the scapula glides against the chest wall.

Spinal column
Central supporting bony structure of the body; vertebral column.

Spinal cord
Extension of the brain, composed of virtually all the nerves carrying messages between the brain and the rest of the body. It lies inside of and is protected by the vertebrae and the spinal column.

Spinal stenosis
Developmental narrowing of the cervical spine; arrowing of the canal housing the spinal cord; commonly caused by encroachment of bone.

Column of 33 vertebrae extending from the base of the skull to the tip of the coccyx.

A structure located at the base of the scapular spine and formed by the convergence of the scapular spine with the glenoid and the coracoid processes; also known as the greater scapular notch.

Spinous processes
Palpable prominences in the vertebrae.

Spiral fracture
A fracture caused by a twisting force that results in a helical fracture line.

Device used to immobilize part of the body.

Displacement of one vertebra on another through the spondylitic defect of the pars interarticularis.

A defect (possibly a type of stress fracture) in the pars interarticularis of the vertebrae. Also, an overuse injury to the pediatric athlete’s spine, most frequently the lumbosacral spine, in which the athlete reports an insidious, nontraumatic onset that lasts longer than 3 weeks.

Sports medicine
The practice of medicine that physicians, athletic trainers, paramedics, and other allied health professionals provide to athletes.

Partial or complete tear of a ligament.

Spur formation
Degenerative and age-related changes in the neck where spurs form along the vertebral end plates in an attempt to autostabilize vertebral motion.

Staphylococcus aureus
A type of bacteria that is commonly found on the skin of healthy individuals and causes infection when it enters deeper tissues, commonly through open skin wounds.

Stem cells
Cells with the unlimited ability of self-renewal and regeneration; serve to regenerate tissue.

A stricture of any canal or orifice. In the spine, a narrowing of the spinal canal secondary to a combination of disk narrowing, thickening of the ligamentum flavum, and osteophytes from arthritis of the facet joints.


A neurapraxia from a stretch injury to the brachial plexus; most commonly seen in football players. Also known as a burner.

Deformation in a structure under loading; partial tear of a muscle.

The force or tension a muscle or muscle group can exert against a resistance in one maximal effort. Also, a mechanical property of material in terms of elastic storage; represented by the area under the entire stress-strain curve.

The load per unit area that develops on a plane surface within a structure in response to externally applied loads.

Stress fracture
An overuse injury in which the body cannot repair microscopic damage to the bone as quickly as it is induced, leading to painful, weakened bone.

Subcutaneous fat
The layer of skin that insulates and protects the body.

Subdural hematoma
A blood clot located beneath the dura mater.

An incomplete disruption in the relationship of two bones forming a joint, ie, a partial dislocation. The joint surfaces retain partial contact.

Subungual hematoma
A collection of blood under the nail.

Superior radioulnar joint
A uniaxial, diarthrodial joint that functions with the inferior radioulnar joint to produce rotation of the forearm or supination and pronation.

Evidence of change in body functions apparent to the patient and expressed to the examiner on questioning.

A fainting spell or a transient loss of consciousness.

Syndesmosis sprain
A more disabling sprain compared with a lateral ankle sprain; examination will most likely reveal a positive squeeze test, a positive external rotation stress test, and point tenderness.

Synovial fluid
A fluid that has a very low coefficient of friction and provides lubrication and nutrients for joint chondrocytes; the straw-colored fluid in the joint that is formed by filtration of capillary plasma.

Synovial joints
A joint formed by the articulation of two bones, the ends of which are lined with hyaline cartilage and is surrounded by a capsule which is lined with synovium.

Cells that form the synovial membrane, remove debris, and secrete hyaluronic acid.

A condition characterized by inflammation of the synovial lining.

A complex, highly permeable, and vascular tissue that lines the inner surface of joint capsules, bursae, tendons, and ligaments; the thin membrane that lines a joint capsule. There are two types of synovial cells. Type A act as macrophages and type B produce synovial fluid for joint lubrication. Marked hypertrophy of the synovium occurs with an inflammatory arthritis.


Tarsal coalition
A congenital failure of segmentation between two or more tarsal bones; fusion of two or more of the major tarsal bones (talus, navicular, calcaneus, and cuboid).

Tarsal tunnel syndrome
A neuritis of the posterior tibial nerve resulting in pain and/or numbness along the course of the nerve.

Team physician
The physician who is the leader of the sports medicine team and oversees all aspects of the sports medicine program.

Any injury that produces an inflammatory response within the tendon substance; injury to the tendon or musculotendinous unit caused by the application of mechanical loads of high intensity or high frequency.

An avascular degenerative process that represents the result of failed tendon healing seen with aging or following repetitive microtrauma.

Tendinosis lesion
Asymptomatic tendon degeneration caused either by aging or by cumulative microtrauma without inflammation.

A tough, rope-like cord of fibrous tissue at both the origin and insertion of muscle; a specialized type of collagenous tissue that attaches muscle to bone. Tendons transmit forces of muscular contraction to cause motion across a joint.

Tennis elbow
Inflammation of muscle origins at the lateral epicondyle; also called lateral epicondylitis.

The cells in tendons.

Inflammation of the thin inner lining of a tendon sheath.

The sheath surrounding a tendon that enhances movement or gliding of the tendon as it transmits muscle forces across joints.

Tensile stress
One of three stresses generated in a brain injury; involves pulling or stretching of tissue.

Tension-side fractures
A stress fracture that occurs on the superior portion of the femoral neck.

The increase in energy expenditure greater than the resting metabolic rate that can be measured for several hours after a meal; also known as the thermic effect of food.

Thoracic kyphosis
Backward curvature of the cervical spine.

Thoracic outlet syndrome
Secondary compression of the brachial plexus or subclavian vessels in the thoracic outlet as the result of trauma and anatomic changes because of throwing mechanics.

Tibial stress fracture
A fracture of the lower extremity caused by repetitive loads on the bone that cause an imbalance of bone resorption over formation; often occurs after a recent increase or change in the training regimen.

A radiographic modality that allows visualization of lesions or tissues that are obscured by overlying structures. Structures in front of and behind the level of tissue to be studied are blurred, which allows the object to be studied to be brought into sharp focus. Tomography has been used to evaluate the degree of fracture healing and to evaluate tumors such as osteoid osteoma. Increasingly, CT has replaced tomography as the imaging modality of choice in these circumstances.

Torus (buckle) fracture
A pediatric fracture that occurs at the diaphyseal-metaphyseal junction when the diaphyseal cortex is driven into the metaphysis.

Action of drawing or pullng on an object.

Transcutaneous electric nerve stimulation (TENS)
A therapeutic modality that uses electrical stimulation to modulate pain, strengthen muscles, and enhance soft-tissue healing.

Transverse fracture
A fracture in which the fracture line is perpendicular to the shaft of the bone.

Transverse plane
Horizontal section of the body.

Traumatic brain injury (TBI)
An injury to the brain that is classified as focal or diffuse depending on the nature and severity of the injury.

Traumatic spondylolysis
The condition in which one vertebra slips anterior to the one below it secondary to a trauma-induced defect in the right and left pars interarticularis.

Triangular fibrocartilaginous complex (TFCC)
A small, fibrocartilaginous structure in the wrist located between the distal end of the ulna and the carpals.

A groove in a bone that articulates with another bone, or serves as a channel for a tendon to track in.

Trochlear groove
A central depression in the trochlea, a convex-shaped distal segment of the humerus.

Trochlear notch
The concave-shaped proximal segment of the ulna.

Prominence on a bone where tendons insert.

Turf toe
A hyperextension injury of the first metatarsophalangeal joint associated with athletic activity on hard surfaces.


Ultrasound (Ultrasonography)
An imaging modality in which images are created from high-frequency sound waves (7.5 to 10 MHz [1 MHz = one million cycles per second]) that reflect off of different tissues. The reflected sound waves are recorded and processed by a computer and then converted into an image. Ultrasound is used to evaluate infant hip disorders and tears of the rotator cuff.


Angulation of a distal bone away from the midline in relation to its proximal partner. Genu valgum is a knock-knee deformity, with abduction of the tibia in relation to the femur. Can also be used to describe angulation of fractures or bony deformities.

Angulation of a distal bone toward the midline in relation to its proximal partner. Genu varum is a bowleg deformity, with adduction of the tibia in relation to the femur. Can also be used to describe angulation of fractures or bony deformities.

Vertebral arch
Part of the vertebra composed of the right and left pedicles and the right and left laminae; also called neural arch.

Vertebral column
Segmented spinal column composed of 24 movable vertebrae, 5 fixed sacral vertebrae, and 4 fixed coccygeal vertebrae.

Vertical dystopia
A change in the vertical position of the pupil in relation to the uninjured eye.

A clear fluid-filled blister that is less than 1 cm.

Vicarious liability (also called respondent superior)
A doctrine in which an employer may be held accountable for wrongful acts of an employee committed within the course and scope of employment.

Having mechanical properties that depend on the loading rate of an applied force.

Intra-articular hyaluronic acid preparations commonly used to treat osteoarthritis; thought to increase joint lubrication.

Toward the anterior surface of the body.

Voluntary (skeletal) muscle
Muscle, under direct voluntary control of the brain, which can be contracted or relaxed at will.