Medical Abbreviation for the Knuckle Joint
The medical abbreviation for the metacarpophalangeal joint (the knuckle joint connecting the hand to the fingers) is MCP. 1, 2
Joint Nomenclature in Hand Anatomy
The hand contains three primary joint types in the fingers, each with standardized abbreviations used universally in medical documentation:
- MCP (Metacarpophalangeal): The knuckle joint where the metacarpal bones of the hand meet the proximal phalanges of the fingers 1, 2
- PIP (Proximal Interphalangeal): The middle joint of the finger 1, 2
- DIP (Distal Interphalangeal): The joint closest to the fingertip 1, 2
Clinical Significance of MCP Joint Terminology
Understanding MCP joint terminology is essential because different rheumatologic and orthopedic conditions target specific joint patterns:
- Rheumatoid arthritis predominantly affects MCP and PIP joints while characteristically sparing DIP joints 2
- Osteoarthritis primarily targets DIP joints (Heberden's nodes) and PIP joints (Bouchard's nodes), with less frequent MCP involvement 1, 2
- Psoriatic arthritis can affect DIP joints as a distinguishing feature, which helps differentiate it from rheumatoid arthritis 2
The MCP joint is specifically included in the American College of Rheumatology and European League Against Rheumatism 2010 classification criteria for rheumatoid arthritis as part of the "small joint" category 2. In hand osteoarthritis guidelines, the index and middle finger MCP joints are recognized as characteristic target sites, though less commonly affected than interphalangeal joints 1.