Collateral Ligaments of the Proximal Interphalangeal Joints, Posterior View

Description

Running along the dorsolateral margins of each proximal interphalangeal (PIP) joint, the collateral ligaments span from the distal aspect of the proximal phalanx to the base of the middle phalanx, flanking the hinge axis of the articulation. From a posterior (dorsal) perspective, the proximal, middle, and distal phalanges align in series distal to the metacarpals, with the PIP joint capsules forming a fibrous cuff around the articular margins. The extensor side of the joints sits superficially, while the collateral complexes remain positioned slightly lateral and medial to the joint line to resist varus and valgus deviation. Dorsal visualization of the PIP collateral ligaments matters because these bands define lateral stability during flexion, the position where the proper collateral ligament is most taut, and where many sports-related injuries declare themselves clinically. Forced ulnar or radial deviation can produce collateral ligament sprain or avulsion at the proximal phalanx condyle, and a careful understanding of their insertions helps interpret focal tenderness, stress testing, and radiographic “fleck” signs at the PIP level. Small structures, big consequences. Use this artwork in gross anatomy and hand surgery teaching to contrast the PIP collateral ligament complex with the nearby joint capsule and to orient learners to phalangeal landmarks used in exam, splinting, and operative planning. It also fits cleanly into orthopedic and emergency medicine content addressing PIP dislocations, collateral ligament injuries, and post-reduction stability assessment in adult male anatomy. Anatomical accuracy verified by SciePro's Medical Advisory Board.