Skip to main content icon/video/no-internet
icon backReturn to Entries

Sesamoiditis

The sesamoid bones of the foot were named because of their resemblance to sesame seeds. Unlike most bones, which are connected to each other through muscles and tendons, the two small sesamoid bones are found embedded in the muscle/tendon of the flexor hallucis longus muscle. Injury to these bones often occurs when great stresses are placed on the foot, such as in running and ballet dancing.

Anatomy

The flexor hallucis longus muscle is found on the undersurface (plantar surface) of the foot. It is responsible for flexing the great toe and is important in weight bearing and in transmitting forces through the foot, especially during push-off. The sesamoid bones act as a pulley for the muscle and, as such, allow much greater forces to be transmitted; a similar functional phenomenon elsewhere in the body is the kneecap (patella), which is also a sesamoid bone. The sesamoids also cushion and protect the joint where the big toe meets the foot (first metatarsalphalangeal joint).

Causes

Injury to the sesamoid bone/hallucis complex can occur as the result of a direct, acute injury or in a more chronic fashion, as in overuse or repetitive injuries. Either of the two sesamoid bones can be injured, but the medial sesamoid (closer to the inside of the foot or tibial side) is more commonly involved.

Fracture

Fracture of a sesamoid bone can occur as the result of a direct blow or forced hyperdorsiflexion (bending of the toe upward); alternatively, it can result from cumulative repetitive injury. A fracture results in immediate pain over the ball of the foot in the area underneath the great toe. There may or may not be swelling and bruising, and it may be difficult to bend or straighten the toe. Attempts at maintaining a normal gait will cause pain in this area of injury.

Stress Fracture and Sesamoiditis

Not uncommonly, however, pain develops gradually in the same area and may be the result of a stress fracture or sesamoiditis. A stress fracture results from repetitive injury, often during a period of more intense or frequent training. In a stress fracture, the repetitive, frequent microtrauma to the bone overwhelms the bone's ability to heal itself. It occurs more frequently in ballet dancers and long-distance runners, for whom frequent, forceful toe-offs are necessary. Additionally, football players are at risk, especially when playing on artificial surfaces.

In a similar manner, irritation and inflammation of the bone and surrounding soft tissue structures—the muscle, tendon, and bursa, collectively called the sesamoid complex—can occur. This condition is called sesamoiditis (Figure 1).

Diagnosis

History and Exam

Evaluation of this type of injury can be performed by a health care provider comfortable with disorders in the foot and ankle. The patient's main complaint is pain under the first metatarsalphalangeal joint (the “ball of the foot”), which worsens with weight-bearing activity and is somewhat relieved with getting off the injured foot. A thorough history is often the key to diagnosis, especially in chronic injuries. In addition to the location and character of the pain, important clues on history include any changes in training (frequency, intensity, duration) and in the footwear and surface used by the athlete.

...

  • Loading...
locked icon

Sign in to access this content

Get a 30 day FREE TRIAL

  • Watch videos from a variety of sources bringing classroom topics to life
  • Read modern, diverse business cases
  • Explore hundreds of books and reference titles

Read next

More like this

Sage Recommends

We found other relevant content for you on other Sage platforms.

close

Have you created a personal profile? Login or create a profile so that you can save clips, playlists and searches

close
close
close Signed In to profile You are signed in as:
close
Logged in Institution Institution