Capsules of the Metacarpophalangeal Joints, Anterior View

Description

Palmar anatomy of the adult male hand is presented with the metacarpals and proximal phalanges aligned in anatomical position, while the fibrous capsules of the metacarpophalangeal (MCP) joints form circumferential sleeves around the heads of the second through fifth metacarpals. Each capsule blends proximally with the periosteum of the metacarpal neck and distally with the base of the proximal phalanx, enclosing the joint space and sitting deep to the flexor tendon apparatus. Along the radial and ulnar margins of each MCP joint, the capsule is reinforced by collateral ligament complexes, while the palmar aspect thickens into the volar plate, which lies anterior to the metacarpal head and deep to the flexor tendons and their synovial sheaths. Orientation is clear. Clinically, the anterior (palmar) view is the one you want when teaching why MCP stability is not just collateral ligaments but also the volar plate and the capsule’s continuity with the deep transverse metacarpal ligament, a configuration that resists hyperextension and limits splaying of the digits. Palmar plate injuries and capsular disruption occur in MCP hyperextension sprains and dorsal MCP dislocations, where the volar plate can become interposed and block closed reduction. The same capsuloligamentous sleeve becomes a surgical boundary during A1 pulley release and during exposure for MCP arthrotomy, where preserving collateral ligament integrity matters for postoperative pinch and grip. Use this illustration for gross anatomy and hand surgery teaching modules, exam figures on MCP joint articulation, and clinical guides explaining knuckle sprains, volar plate injury, and dorsal MCP dislocation reduction mechanics. It also fits well in radiology correlation pages when pairing surface anatomy with MRI or ultrasound discussions of capsular thickening in inflammatory arthropathies. Anatomical accuracy verified by SciePro's Medical Advisory Board.