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The carpometacarpal (CMC) joints are five joints in the wrist that articulate the distal row of carpal bones and the proximal bases of the five metacarpal bones.. The CMC joint of the thumb or the first CMC joint, also known as the trapeziometacarpal (TMC) joint, differs significantly from the other four CMC joints and is therefore described separately.
The intermetacarpal joints are in the hand formed between the metacarpal bones. The bases of the second, third, fourth and fifth metacarpal bones articulate with one another by small surfaces covered with cartilage. The metacarpal bones are connected together by dorsal, palmar, and interosseous ligaments.
In human anatomy, the metacarpal bones or metacarpus, also known as the "palm bones", are the appendicular bones that form the intermediate part of the hand between the phalanges and the carpal bones (wrist bones), which articulate with the forearm. The metacarpal bones are homologous to the metatarsal bones in the foot.
A real differentiation appeared an estimated 70 mya in early primates, while the shape of the human thumb CMC finally appears about 5 mya. The result of this evolutionary process is a human CMC joint positioned at 80° of pronation, 40 of abduction, and 50° of flexion in relation to an axis passing through the second and third CMC joints. [40]
The muscle is inserted onto the radial sesamoid bone of the metacarpophalangeal joint. It acts to flex, adduct, and abduct the thumb, and is therefore also able to oppose the thumb. The superficial head is innervated by the median nerve , while the deep head is innervated by the ulnar nerve (C8-T1). [ 6 ]
In human anatomy, the radial (RCL) and ulnar (UCL) collateral ligaments of the metacarpophalangeal joints (MCP) of the hand are the primary stabilisers of the MCP joints. [1] A collateral ligament flanks each MCP joint - one on either side. Each attaches proximally at the head of the metacarpal bone, and distally at the base of the phalynx.
These joints are of the condyloid kind, formed by the reception of the rounded heads of the metacarpal bones into shallow cavities on the proximal ends of the proximal phalanges. [1] Being condyloid, they allow the movements of flexion, extension, abduction, adduction and circumduction (see anatomical terms of motion) at the joint. [1]
The hamate bone (from Latin hamatus, "hooked"), or unciform bone (from Latin uncus, "hook"), Latin os hamatum and occasionally abbreviated as just hamatum, [1] [2] [3] is a bone in the human wrist readily distinguishable by its wedge shape and a hook-like process ("hamulus") projecting from its palmar surface.