Pisiform bone

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Pisiform bone
Pisiform bone (left hand) 01 palmar view.png
Left hand anterior view (palmar view). Pisiform bone shown in red.
Gray224.png
The left pisiform bone
Details
Originsulnar collateral ligament
Articulationstriangular
Identifiers
LatinOs pisiforme
MeSHD051220
TAA02.4.08.007
FMA23718
Anatomical terms of bone

The pisiform bone (/ˈpsɪfɔːrm/ or /ˈpɪzɪfɔːrm/), also spelled pisiforme (from the Latin pisifomis, pea-shaped), is a small knobbly, sesamoid bone that is found in the wrist. It forms the ulnar border of the carpal tunnel.

Structure[edit]

The pisiform is a sesamoid bone, with no covering membrane of periosteum. It is the last carpal bone to ossify. The pisiform bone is a small bone found in the proximal row of the wrist (carpus). It is situated where the ulna joins the wrist, within the tendon of the flexor carpi ulnaris muscle.[1]:199,205

It only has one side that acts as a joint, articulating with the triquetral bone. It is on a plane anterior to the other carpal bones and is spheroidal in form.

The pisiform bone has four surfaces:

  1. The dorsal surface is smooth and oval, and articulates with the triquetral: this facet approaches the superior, but not the inferior border of the bone.
  2. The palmar surface is rounded and rough, and gives attachment to the transverse carpal ligament, the flexor carpi ulnaris and the abductor digiti quinti.
  3. The lateral surface is rough, and concave.
  4. The medial surface' is rough and usually convex.

Function[edit]

Unlike the other carpal bones, the pisiform is not involved in movement of the wrist.[2] :5

Etymology[edit]

The etymology derives from the Latin pīsum which means "pea".

Other animals[edit]

All other tetrapods have pisiform, being the most common sesamoid.[3] As compared with apes, which have an elongated Pisiform, humans have a shorter pisiform bone. This is due to the loss of the single growth plate typically found in other mammalian pisiforms.[4] This may be because of evolutionary benefits from having a shorter pisiform bone, including facilitating ulnar deviation of the hand and preventing hyperextension of the wrist, motions that improve the action of clubbing.[5]

See also[edit]

Additional images[edit]

References[edit]

  1. ^ Tim D. White, Human Osteology, 2nd edition (San Diego: Academic Press, 2000)
  2. ^ Beasley's Surgery of the Hand. Thieme New York. 2003. ISBN 9781282950023.
  3. ^ Liem (2005) functional anatomy of the vertebrates
  4. ^ Kjosness, Kelsey M.; Hines, Jasmine E.; Lovejoy, C. Owen; Reno, Philip L. (November 2014). "The pisiform growth plate is lost in humans and supports a role for in growth plate formation". Journal of Anatomy. 225 (5): 527–538. doi:10.1111/joa.12235. PMC 4292754. PMID 25279687.
  5. ^ Young, Richard W. (January 2003). "Evolution of the human hand: the role of throwing and clubbing". Journal of Anatomy. 202 (1): 165–174. doi:10.1046/j.1469-7580.2003.00144.x. PMC 1571064. PMID 12587931.

External links[edit]