Sesamoid bone

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Sesamoid bone
Gray350.png
Sagittal section of right knee-joint.
Sesamoidbone.png
Sesamoid bones at the distal end of the first metatarsal bone of the foot.
Latinossa sesamoidea
TAA02.0.00.016
FMAFMA:32672
 
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Sesamoid bone
Gray350.png
Sagittal section of right knee-joint.
Sesamoidbone.png
Sesamoid bones at the distal end of the first metatarsal bone of the foot.
Latinossa sesamoidea
TAA02.0.00.016
FMAFMA:32672

In anatomy, a sesamoid bone (/ˈsɛsəmɔɪd/[1][2]) is a bone embedded within a tendon.


Human anatomy[edit]

Sesamoid bones can be found on joints throughout the body, including:

Injuries and variation[edit]

In other animals[edit]

In equine anatomy, the term sesamoid bone usually refers to the two sesamoid bones found at the back of the fetlock or metacarpophalangeal/metatarsophalangeal joints in both hindlimbs and forelimbs. Strictly these should be termed the proximal sesamoid bones whereas the navicular bone should be referred to as the distal sesamoid bone. The patella is also a form of sesamoid bone in the horse.

In both the giant panda[6] and the red panda,[7] the radial sesamoid is larger than the same bone in counterparts such as bears. It is primarily a bony support for the pad above it, allowing the panda's other digits to grasp bamboo while eating it. The panda's thumb is often cited as a classical example of exaptation, where a trait evolved for one purpose is commandeered for another.[8]

See also[edit]

Footnotes[edit]

  1. ^ OED 2nd edition, 1989 as /sεsəmɔɪd/.
  2. ^ Entry "sesamoid" in Merriam-Webster Online Dictionary.
  3. ^ Tim D. White, Human Osteology, 2nd edition (San Diego: Academic Press, 2000), 199, 205.
  4. ^ White, Human Osteology, 2nd edition, 257-261.
  5. ^ http://www.footankleinstitute.com/sesamoid-fracture/
  6. ^ Arthro.com: The Panda's Thumb
  7. ^ Evidence of a false thumb in a fossil carnivore clarifies the evolution of pandas PNAS December 30, 2005
  8. ^ The Panda's Peculiar Thumb, Nature Magazine Vol. LXXXVII No. 9, Nov. 1978, by Stephen J. Gould

References[edit]