Anatomy of the Feet and Toes

Nearly one-fourth of all bones in the human body are in the feet. These complex, flexible structures contain bones, joints, and more than 100 muscles, tendons and ligaments, all working together to enable movement and balance.

The foot is divided into three sections, the forefoot, the midfoot and the hindfoot:

  • The hindfoot includes the heel (calcaneus), which is the largest bone in the foot, and the ankle.
  • The midfoot contains a pyramid-like group of bones, strengthened by tendons, muscles and ligaments to form three curves, or arches (medial, lateral and fundamental longitudinal), at the bottom of the foot.
  • The forefoot has five toes (14 phalanges) and five longer bones (metatarsals). One phalanx of each of the five toes connects to one of the five metatarsals.
  • The big toe, or great toe (hallux), contains two joints, the MTP and DIP.
  • Each of the four lesser digits, or smaller toes, contains three joints: the metatarsophalangeal joint (MTP) connects the toe to the foot; the middle joint is the proximal interphalangeal joint (PIP); and the distal interphalangeal joint (DIP) is the small joint at the end of the toe.

Difficulties with the feet and toes can lead to more serious problems, not only for the feet, but also for other areas of the body, including the hips and spine.

What Are Foot and Toe Ulcers?

An ulcer is an open sore or wound that doesn’t heal or keeps recurring. While anyone can develop a foot ulcer, they are most common in those with diabetes. This is because a complication of diabetes, known as neuropathy or diabetic foot, results in a loss of feeling in the feet. For someone suffering from this complication, even a small cut, puncture or scrape can go unnoticed, eventually develop into an ulcer, and without treatment become infected. In some cases, the infection resists treatment and cannot be cleared, leading to surgical amputation. Approximately 15% of those with diabetes will get a foot ulcer, often on the bottom of the foot. Of these, some require hospitalization to control the infection, and as many as 14% to 24% require amputation.

Symptoms of a Foot or Toe Ulcer

As an ulcer begins to develop on the foot or toe, you may notice irritation, swelling, pain, or a burning sensation. Surrounding skin may be dry, cracked or scaly, and there may also be a rash.

Additional symptoms include:

Callus—A callus can be a precursor to a developing sore and without treatment, may lead to an ulcer.

Size and depth—Untreated, an ulcer typically worsens and may grow wider, longer, and deeper, in some cases reaching down to the bone.

Halo—A halo, or ring, around the center of the wound that is harder than surrounding skin can be a sign of an ulcer in an advanced stage.

Strong odor and drainage—An unpleasant smell or a damp or wet area on the bottom of a sock or shoe insole are signs of infection and draining.

Color—Foot ulcers can vary in color, and may be red, yellow, pink or grey. Brown discoloration is typically a sign that the area has poor circulation. Black indicates that cell tissues have died, which is known as necrosis or gangrene.

Causes and Risk Factors

Diabetics are most likely to develop a foot ulcer, as are older men, and those of Native American, African American and Hispanic descent, primarily because these ethnic groups have a higher incidence of diabetes. If you are at risk, it’s important to discuss prevention strategies with your podiatric physician.

Common causes and risk factors include:

  • Diabetes, uncontrolled blood sugar, or insulin use
  • Diabetes-related kidney, eye, and cardiovascular (heart) disease
  • Foot conditions or deformities, such as bunions or hammer toe
  • Neuropathy
  • Obesity or overweight
  • Peripheral vascular disease (poor circulation)
  • Certain lifestyle behaviors, such as tobacco or alcohol use
  • Wearing ill-fitting or improper shoes or other footwear

Diagnosing Foot and Toe Ulcers

During your physical examination, your podiatric specialist will check your foot for location and appearance of the wound, its borders, and the skin surrounding the ulcer. Your doctor may also require diagnostic imaging studies such as X-rays, computed tomography (CT scan), or magnetic resonance imaging (MRI) to determine the depth of the ulcer and whether any infection has spread to nearby bone.

Nonsurgical Treatment

Seeking immediate treatment for a foot wound or ulcer is important to prevent infection. If your podiatric physician detects infection, antibiotics will likely be prescribed. In some cases, hospitalization may be needed. Healing time varies and may range from weeks to months.

Treatment to promote healing and prevent infection may include:

Debridement—Damaged, infected or necrotic (dead or dying) tissue, or any foreign debris, is removed from the wound.

Bandages, dressings—Keeping the wound covered, moist and protected lowers the risk of infection.

Off-loading—Your specialist may recommend a brace, special footgear, casting, or use of a wheelchair or crutches to reduce weight and pressure on the wound.

Elevation—In addition to reducing swelling and pressure, elevating the foot above the level of the heart helps improve blood flow to the wound, which promotes healing.

Topical medication—These range from saline solution to cleanse the wound to growth factors that promote cell migration and proliferation. Your physician may also use skin substitutes, which imitate the natural structure of the skin and stimulate regeneration of tissue.

Management of blood glucose and other health issues—Controlling blood glucose levels is an essential component in treating a diabetic foot ulcer.

To be avoided—Whirlpools and soaking are not recommended, and you should not use peroxide or betadine on your wound, especially at full strength, because these can cause additional complications.

Surgery

When nonsurgical options to treat a foot wound or ulcer are not successful, surgery may be necessary to relieve pressure on the affected area of the foot.

Examples of surgical treatments include:

  • Correcting foot deformities or conditions, such as a hammer toe, bunion, or bony projection, bump or spur
  • Excising or shaving bone
  • Achilles tendon lengthening
  • Removal of scar tissue (tenotomy)
  • Realignment of the big toe (metatarsal osteotomy)
  • Reconstructive surgery

Prevention

If you are at risk and discover a wound or sore, even if it seems small, or you suspect you are developing a foot ulcer, be sure to contact your doctor immediately.

  • See your podiatrist regularly
  • Wear appropriate shoes and socks
  • Inspect legs and feet daily, including tops, bottoms and between toes; report blisters, cuts, cracks, sores, or signs of a developing ulcer to your podiatrist
  • Care for toenails properly; cut straight across to avoid ingrown toenails
  • Manage diabetes and other health issues
  • Maintain a healthy weight and diet
  • Exercise
  • Stop smoking