Description[edit | edit source]
Sesamoid bones are a type of bone that develops in some tendons where they cross the ends of long bones. Sesamoids ossify during puberty and delayed ossification can indicate delayed onset of puberty.
Sesamoid bones in the human body include:
- Patella - in the quadriceps tendon at the knee
- Hallux sesamoids - medial/tibia and lateral/fibular in the flexor hallucis brevis tendon at the 1st metatarsophalangeal joint
- In the hand at the head of the 1st metacarpal - 1 in the combined tendon of the flexor pollicis brevis and abductor pollicis brevis, 1 in the tendon of the adductor pollicis
- Pisiform - in the flexor carpi ulnaris tendon
Function[edit | edit source]
Sesamoids protect tendons from excessive wear and act as a spacer to change the angle of tendons before the reach their attachment point. The change in angle improves muscle force generation.
Clinical relevance[edit | edit source]
Pathology in sesamoids can be congenital or a result of trauma. Common pathology seen in sesamoid bones include:
- Bipartite or multipartite patella
- Fracture - such as patella fracture
- Avascular necrosis
Management of the different pathologies varies depending on the diagnosis. Physiotherapy or conservative management is typically the first line of treatment for atraumatic pathology of sesamoids.
Resources[edit | edit source]
Sesamoid bones are discussed starting at 1:32.
References[edit | edit source]
- Moore KL, Dalley AF, R. AAM. Clinically oriented anatomy. Philadelphia, PA: Lippincott Williams and Wilkins; 2018.
- Oohashi Y, Koshino T, Oohashi Y. Clinical features and classification of bipartite or tripartite patella. Knee Surg Sports Traumatol Arthrosc. 2010 Nov;18(11):1465-9.
- Bartosiak K, McCormick JJ. Avascular Necrosis of the Sesamoids. Foot Ankle Clin. 2019 Mar;24(1):57-67.
- RegisteredNurseRN. Types of Bones Anatomy: Long, Short, Flat, Irregular, Sesamoid, Sutural. Available from: https://www.youtube.com/watch?v=YPiEc8OZAKU [last accessed 21/2/2022]