The MCP joint, or metacarpophalangeal joint, is where your fingers meet your hand. These are the joints that allow you to make a fist or point your fingers. Specifically, they are the diarthrodial joints formed where the large, convex heads of the distal metacarpals (the long bones in your hand) articulate with the concave-shaped proximal aspect of each phalanx (the bones in your fingers).
Anatomy and Function
- Location: Found at the base of each finger where it connects to the hand.
- Structure: Each MCP joint consists of the head of a metacarpal bone and the base of a phalanx bone.
- Type: Diarthrodial, meaning they are freely movable.
- Movement: MCP joints allow for flexion (bending), extension (straightening), abduction (moving away from the midline of the hand), adduction (moving toward the midline of the hand), and circumduction (a circular motion).
Clinical Significance
MCP joints are susceptible to various conditions, including:
- Arthritis: Osteoarthritis and rheumatoid arthritis can affect the MCP joints, causing pain, stiffness, and swelling.
- Injuries: Sprains and dislocations can occur due to trauma.
- De Quervain's Tenosynovitis: Although typically associated with the wrist, pain can sometimes radiate to the MCP joints.
- Skier's Thumb (Gamekeeper's Thumb): Injury to the ulnar collateral ligament of the MCP joint of the thumb.
- Ulnar Collateral Ligament (UCL) Injury: An injury of the UCL makes it difficult to pinch or grip with your thumb.
Importance of MCP Joints
The MCP joints are essential for hand function, enabling a wide range of movements necessary for daily activities such as grasping, writing, and manipulating objects. Maintaining the health of these joints is crucial for preserving hand dexterity and overall quality of life.
