Sesamoid bones are small, rounded bones embedded in tendons where they pass over joints. They serve to reinforce tendons and protect them from stress and wear. Examples include the patella, which protects the quadriceps tendon at the knee, and sesamoids in the hands and feet. Sesamoid bones lack periosteum, do not form a Haversian system, and ossify after birth. Their functions are to resist pressure on tendons, alter the direction of muscle pull, reduce friction, and maintain local circulation. Conditions involving sesamoid bones can include sesamoiditis, fracture, and Fabella syndrome.

1. SESAMOID BONES
SUGANTHI.S
FIRST YEAR M.P.T
SBCP.

3. TYPE SHAPE FUNCTIONS EXAMPLE
FLAT BONE SHIELD PROTECTS
INTERNAL
ORGANS
SKULL
LONG BONE STICK FACILITATE
MOVEMENT
FEMUR
SHORT BONE CUBE STABILITY &
MOVEMENT
CARPALS
IRREGULAR COMPLEX PROTECT
INTERNAL
ORGANS
VERTEBRAE
SESAMOID ROUND REINFORCE
TENDONS
PROTECTS
FROM STRESS
& WEAR

5. SESAMOID BONES
• Latin word sesum (seed like)
• Sesame Seeds
• Small rounded masses of bones
• Tendons at point subjected to great
pressure.
• Bony nodules embedded in the
tendons or joint capsules.

7. Sesamoid Bones of Upper Limb
• Pisiform – lying within the tendon of
flexor carpi ulnaris
• 2 SB – palmar surface of the head of
First MC bone (FPL)
• 1 SB – capsule of IPJ of the thumb
• 1 SB – ulnar side of the capsule of MCPJ
Of little finger

9. Sesamoid Bones of Lower
Extremity
• Patella – quadriceps tendon
• Fabella – lateral head of
Gastrocnemius
• 2 SB - first metatarsal bone connects to
the big toe.
• Riders bone – Adductor Longus

11. PECULIARITY
• No Periosteum
• Haversion Canal System not
Present
• Ossifies after birth
• Absence delay puberty
• Serve to protect the tendon as it flexes,
and also help to keep the toe aligned.

12. FUNCTIONS
• They resist the pressure
• They alter the direction of the pull of the
muscle
• Reduce the friction
• Maintain local circulation

13. APPLIED ANATOMY
• Sesamoiditis
• Fracture
• Fabella Syndrome

15. KNEE CAP - PATELLA

16. FLAT BONES – SKULL, STERNUM, SCAPULA