What exactly is the Pisiform Bone
The pisiform (Latin: os pisiforme) is a small pea-shaped bone in the human wrist and the tiniest of the eight carpal bones [1]. The name actually comes from ‘pisum’, the Latin term for ‘pea’, in reference to the characteristic shape of the bone [2].
Where can it be Found
It is one of the bones in the proximal carpal row [3], situated on the palmar side of the triquetral bone [4], above the ulna (lower arm bone) [5]. Positioned on the outer side of the proximal row, it is bounded by the hamate bone on its inner side. The pisiform can be palpated on the palmar side of the wrist, underneath the little finger.
Pisiform Bone
Growth and Ossification
The pisiform bone develops within the flexor carpi ulnaris (FCU) tendon, making it a sesamoid bone [1]. It is the final wrist bone to ossify, becoming visible on an x-ray only when a child is around 8 to 12 years old [6], frequently later in boys than in girls [3].
Pisiform Bone X-Ray
Pisiform Anatomy and Structure
Surfaces and Connections
The flat dorsal surface of pisiform articulates with the palmar side of the triquetral bone [7].
The rounded and rough palmar surface of pisiform attaches to the robust spindle-shaped hand muscle abductor digiti minimi [3, 5].
The pea-shaped bone also forms an attachment with the carpal ligament on its lateral, medial, and palmar surfaces [5].
Pisiform Articular Surface Anatomy
Blood Supply
The ulnar artery supplies its arterial blood [8].
Functions: What is the Function of the Pisiform Bone
Together with the other seven carpal bones, the pisiform helps sustain the structure, mobility, and functioning of the human wrist.
This small bone also safeguards the FCU tendon by enabling it to connect with the triquetral bone, supporting the tendon’s movements during wrist flexion [5].
Related Conditions and Common Injuries
Tendinopathy of the flexor carpi ulnaris can lead to acute or chronic pain in and around the pisiform due to its close attachment to the tendon. Other common issues and injuries include osteoarthritis, bony fractures, and pain/inflammation from overuse of the wrist. Soft tissue thickening and fluid collection around the bone may also occur [5].
References
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- https://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/pisiform-bone
- https://www.dartmouth.edu/~humananatomy/resources/etymology/Forearm_hand.htm
- https://radiopaedia.org/articles/pisiform
- http://aclandanatomy.com/multimediaplayer.aspx?multimediaid=10528069
- https://www.healthline.com/human-body-maps/pisiform-bone
- http://sketchymedicine.com/2016/01/carpal-bone-ossification/
- http://anatomyzone.com/anatomy-feed/pisiform-bone/
- https://www.karger.com/Article/Pdf/147877
