Anatomy, Sesamoid Bones

Excerpt

A sesamoid bone is a small bone commonly found embedded within a muscle or tendon near joint surfaces, existing as focal areas of ossification and functioning as a pulley to alleviate stress on that particular muscle or tendon. Unlike standard bones, which connect via joints, sesamoid bones connect to muscles via tendons. The word "sesamoid" derives from the Arabic word 'sesamum' translating to sesame, given that many sesamoid bones are small. Sesamoid bones are most commonly located in the foot, hand, and wrist; the largest and most well-known is the patella. There are many sesamoid bones in a person, with up to 42 reportedly found in an individual.

These bones are often formed in response to added strain to muscles and tendons but can also be normal variants, most commonly present in the hand. Sesamoid bones relieve tension within muscles and tendons, allowing for increased weight-bearing and tolerance by redistributing forces throughout a muscle or tendon, thereby protecting them from significant strain and injury. While most sesamoid bones are small, these bones play a critical role in our body in leverage, decreasing overall friction and allowing for our body's unique biomechanics and distinct range of motion.