sesamoid bone

anatomy

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Last updated

July 13, 2026

Quick Summary

A sesamoid bone is a nodular mass of bone or cartilage found within a tendon, typically near a joint or bony prominence. The patella, or kneecap, is a well-known example of a sesamoid bone. These bones are not present in all individuals and can vary in size and location.12

In the context of foot anatomy, sesamoid bones are located beneath the first metatarsophalangeal (MTP) joint of the big toe. These small bones play a crucial role in the biomechanics of the foot, helping to absorb stress during activities like walking, running, and jumping, and they also assist in the function of the flexor hallucis brevis muscle. Injuries to these sesamoid bones, often associated with conditions like turf toe, can cause significant pain and functional disability.3

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joint
Structure and elements of synovial joints
…cartilages or partly ossified as sesamoid bones (small, flat bones developed in tendons that move over bony surfaces). Parts of the synovial layer project into the cavity to form fatty pads. In a few diarthroses the fibrous layer also projects inward to become intra-articular disks, or menisci. These various structures…
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…cartilages or partly ossified as sesamoid bones (small, flat bones developed in tendons that move over bony surfaces). Parts of the synovial layer project into the cavity to form fatty pads. In a few diarthroses the fibrous layer also projects inward to become intra-articular disks, or menisci. These various structures…
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adaptation
…so-called panda’s thumb, or radial sesamoid bone, is a wrist bone that now functions as an opposable thumb, allowing giant pandas to grasp and manipulate bamboo stems with dexterity. The ancestors of giant pandas and all closely related species, such as black bears, raccoons, and red pandas, also have sesamoid…
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…so-called panda’s thumb, or radial sesamoid bone, is a wrist bone that now functions as an opposable thumb, allowing giant pandas to grasp and manipulate bamboo stems with dexterity. The ancestors of giant pandas and all closely related species, such as black bears, raccoons, and red pandas, also have sesamoid…
Read More