Proximal Phalanx's Base, Posterior View

Description

Proximal phalanx base anatomy is presented from a posterior (dorsal) perspective, centering the broad, concave articular surface that meets the metacarpal head at the metacarpophalangeal (MCP) joint. The dorsal rim of the base reads as a slightly raised lip superiorly, while the shaft narrows distally into the diaphysis, giving a clear proximal-to-distal orientation. Along the medial and lateral margins, subtle roughened areas and shallow fossae indicate capsular attachment and the origins of the proper collateral ligaments adjacent to the articular cartilage. Dorsal cortex dominates the frame. Dorsal appreciation of the proximal phalangeal base matters because this is the bony side of common MCP trauma and operative exposure, where surgeons judge joint congruity, dorsal rim integrity, and the relationship of the collateral ligament footprints to the articular margin. Collateral ligament injuries (for example, index finger radial collateral tears in ball sports) and intra-articular base fractures are discussed using these margins as landmarks, and the posterior view supports that conversation without the distraction of palmar structures such as the volar plate. Edges and curvature are easy to read. The single fixed perspective also helps when correlating with oblique hand radiographs, where dorsal rim fragments and subtle step-offs may be appreciated only by understanding the normal contour of the base. Hand anatomy courses and osteology labs can use this illustration to teach phalangeal orientation, joint surface morphology, and the distinction between articular cartilage boundaries and nonarticular cortical bone. It also suits orthopedic and hand surgery publications describing dorsal MCP approaches, collateral ligament repair, and classification of proximal phalanx base fractures in adults. Anatomical accuracy verified by SciePro's Medical Advisory Board.