Sesamoid bones

Sesamoid bones

1. Sesamoid bones Sesame=seed

2. Sesamoid bones Sesamoid bones are seed like bony nodules. They develop in certain muscle tendons where they rub against convex bony surface during the movement of the joint. The rubbing surface of the sesamoid bone is covered with an articular cartilage.

3. Sites of sesamoid bones Patella-in tendon of quadriceps femoris in front of knee joint. Fabella-in lateral head of gastrocnemius behind the knee joint. Pisiform-in the tendon of the flexor carpi ulnaris. One sesamoid bone on the ulnar side of head of 1 st metacarpal bone in the tendon of abductor pollicis One sesamoid bone in the tendon of peroneus longus where it binds around the cuboid bone Two sesamoid bones below the head of 1 st metatarsal bone in the tendon of flexor hallicis brevis.

4. Functions of sesamoid bones Acts as pulleys for muscle contraction Alter the direction of the pull of the muscle. Minimize the friction of tendon against the bone to prevent it’s attrition.

5. Characteristics of sesamoid bones Develop in the tendon of the muscles. Devoid of periosteum. Ossify after birth by multiple centers. They lack haversian system.

6. 🔹 patella is the largest sesamoid bone in the body and the cartilage covering,its articular surface is the thickest articular cartilage. 🔹 sesamoid bones are not true bones.(Not covered by periosteum)

7. . Failure is the Opportunity to begin again more intelligetry. Source:Vishram Singh General Anatomy 3 rd edition

8. Thank you