The sesamoid bones in the foot act as a pulley for which muscle?

The sesamoid bones in the foot act as a pulley for which muscle?

• A. Flexor Hallucis Brevis.
• B. Flexor Digitorum Longus.
• C. Extensor Hallucis Longus.
• D. Abductor Hallucis.

Answer: (A)

Sesamoid bones at the first metatarsophalangeal joint act as pulleys to redirect the pull of tendons passing over the joint, boosting their mechanical advantage during toe flexion. Specifically, the tendon of the flexor hallucis brevis runs over these two plantar sesamoids and splits around them, using the bones as a pulley to redirect force and increase the flexion moment of the big toe at the MTP joint during push-off. This setup also protects the tendon from compression and reduces friction as the toe bends. The other muscles listed anatomy-wise do not rely on the sesamoid pulleys in the same way: the long flexor tends to the other toes, the extensor extends the toe dorsally, and the abductor primarily abducts the big toe without using the sesamoids as a pulley.

Sesamoid bones at the first metatarsophalangeal joint act as pulleys to redirect the pull of tendons passing over the joint, boosting their mechanical advantage during toe flexion. Specifically, the tendon of the flexor hallucis brevis runs over these two plantar sesamoids and splits around them, using the bones as a pulley to redirect force and increase the flexion moment of the big toe at the MTP joint during push-off. This setup also protects the tendon from compression and reduces friction as the toe bends. The other muscles listed anatomy-wise do not rely on the sesamoid pulleys in the same way: the long flexor tends to the other toes, the extensor extends the toe dorsally, and the abductor primarily abducts the big toe without using the sesamoids as a pulley.