The pisiform is a small, pea-shaped bone located in your wrist. It's one of eight carpal bones forming the wrist joint, and its name comes from the Latin word pisum, meaning "pea". You can feel it on the inner (ulnar) side of your wrist.
Key Characteristics of the Pisiform Bone
- Sesamoid Bone: The pisiform is classified as a sesamoid bone, meaning it develops within a tendon (the flexor carpi ulnaris tendon). This distinguishes it from the other carpal bones which are directly connected to other bones.
- Location and Articulation: Situated on the anterior (palmar) side of the wrist, it articulates (forms a joint) only with the triquetrum bone. This means it directly connects with only one other carpal bone in the wrist.
- Function: While small, the pisiform plays a crucial role in wrist stability and acts as an attachment point for several tendons and ligaments. Its location on the ulnar side of the wrist, bordering the carpal tunnel, further contributes to hand and wrist function. It helps prevent triquetral subluxation (partial dislocation).
- Clinical Significance: Although rarely fractured, pisiform fractures and dislocations can occur, particularly from direct trauma. In cases of severe pain or instability, surgical intervention like pisiformectomy (removal of the pisiform) or pisotriquetral fusion might be considered.
Additional Information from Sources:
- Physiopedia: Highlights the pisiform's role as an attachment point for tendons and ligaments, noting the flexor carpi ulnaris tendon's coverage of its volar (palm-facing) surface. https://www.physio-pedia.com/Pisiform
- Wikipedia: Emphasizes the pisiform's location as forming the ulnar border of the carpal tunnel. https://en.wikipedia.org/wiki/Pisiform_bone
- Radiopaedia: Describes the pisiform as a sesamoid bone located on the medial (inner) side of the proximal row of carpal bones. https://radiopaedia.org/articles/pisiform
- UpToDate: Notes that pisiform fractures are relatively uncommon compared to other carpal bone fractures. https://www.uptodate.com/contents/pisiform-fractures/print
