The trapezium bone (greater multangular bone) is a carpal bone in the hand. It forms the radial border of the carpal tunnel.
Step-by-step explanation:
The trapezium is distinguished by a deep groove on its anterior surface. It is situated at the radial side of the carpus, between the scaphoid and the first metacarpal bone (the metacarpal bone of the thumb). It is homologous with the first distal carpal of reptiles and amphibians.
Surfaces
The trapezium is an irregular-shaped carpal bone found within the hand. The trapezium is found within the distal row of carpal bones, and is directly adjacent to the metacarpal bone of the thumb. On its ulnar surface are found the trapezoid and scaphoid bones.[1]: 708
The superior surface is directed upward and medialward; medially it is smooth, and articulates with the scaphoid; laterally it is rough and continuous with the lateral surface.
The inferior surface is oval, concave from side to side, convex from before backward, so as to form a saddle-shaped surface for articulation with the base of the first metacarpal bone. This saddle-shaped articulation is partially responsible for the thumb's opposable motion.
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The trapezium is a quadrilateral with one pair of parallel opposite sides. The parallel sides of a trapezium are called bases and the non-parallel sides of a trapezium are called legs. It is also called a trapezoid. Sometimes the parallelogram is also called a trapezoid with two parallel sides.
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Answer:
The trapezium bone (greater multangular bone) is a carpal bone in the hand. It forms the radial border of the carpal tunnel.
Step-by-step explanation:
The trapezium is distinguished by a deep groove on its anterior surface. It is situated at the radial side of the carpus, between the scaphoid and the first metacarpal bone (the metacarpal bone of the thumb). It is homologous with the first distal carpal of reptiles and amphibians.
Surfaces
The trapezium is an irregular-shaped carpal bone found within the hand. The trapezium is found within the distal row of carpal bones, and is directly adjacent to the metacarpal bone of the thumb. On its ulnar surface are found the trapezoid and scaphoid bones.[1]: 708
The superior surface is directed upward and medialward; medially it is smooth, and articulates with the scaphoid; laterally it is rough and continuous with the lateral surface.
The inferior surface is oval, concave from side to side, convex from before backward, so as to form a saddle-shaped surface for articulation with the base of the first metacarpal bone. This saddle-shaped articulation is partially responsible for the thumb's opposable motion.
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