Sesamoid Bone, Anterior View

Description

Palmar anatomy is presented with the hand and wrist in anterior view, aligning the phalanges distal to the metacarpals and the carpal bones proximally at the radiocarpal joint. A sesamoid bone is highlighted on the volar aspect of the digit, embedded within a tendon as it crosses the metacarpophalangeal region, where sesamoids typically sit anterior to the joint surface and act as a gliding fulcrum. Carpal landmarks remain visible proximally, while the metacarpal heads and proximal phalanges frame the sesamoid’s relationship to the joint line. Small bone, big landmark. Clinically, palmar sesamoids matter most at the thumb metacarpophalangeal joint, where the radial and ulnar sesamoids lie within the flexor pollicis brevis and adductor pollicis complex and help define the course of the flexor pollicis longus tendon. This view supports teaching and documentation of sesamoid fractures and sesamoiditis after hyperextension injuries, and it also helps orient the reader to adjacent soft-tissue stabilizers implicated in ulnar collateral ligament injury (skier’s thumb) and volar plate trauma. Surgeons often reference the sesamoids when planning approaches to the thumb MCP joint and when interpreting palmar radiographs where a bipartite sesamoid can mimic a fracture. Hand anatomy faculty can drop this plate directly into musculoskeletal blocks, gross anatomy labs, or orthopaedic and radiology teaching files that cover MCP joint mechanics, tendon-sesamoid relationships, and common thumb injuries. It also fits cleanly into patient-facing materials that explain why a small “extra” bone can generate focal volar pain at the thumb base or finger MCP region. Anatomical accuracy verified by SciePro's Medical Advisory Board.