Left hand anterior view (palmar view). Trapezium shown in red.
The left trapezium bone
1st metacarpal distally |
2nd metacarpal medially
|Latin||Os trapezium, os multangulum majus|
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.
The trapezium is an irregularly-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.:708
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.
The dorsal surface is smooth.
The palmar surface is narrow and rough. At its upper part is a deep groove, running from above obliquely downward and medialward; it transmits the tendon of the Flexor carpi radialis, and is bounded laterally by an oblique ridge. This surface gives origin to the Opponens pollicis and to the Abductor and Flexor pollicis brevis; it also affords attachment to the transverse carpal ligament.
The lateral surface is broad and rough, for the attachment of ligaments.
Tubercle of trapezium
The trapezium is susceptible to arthritis at the joint with the metacarpal bone of the thumb, due to overuse.
- Position of trapezium (shown in red). Left hand. Animation.
- Trapezium of the left hand. The hook-like process is called hamulus.
- Trapezium bone.
- Right hand posterior view (dorsal view). Thumb on bottom.
- Right hand anterior view (palmar view). Thumb on top.
- Bones of the left hand. Palmar surface. Trapezium shown in yellow.
- Bones of the left hand. Dorsal surface. Trapezium shown in yellow.
- Cross section of wrist (thumb on left). Trapezium shown in red (labelled as "Greater Multang").
- Transverse section across the wrist and digits. Trapezium is shown in yellow (labelled as "Greater Multang").
- Ligaments of wrist. Anterior view
- Tendons of forefinger and vincula tendina.
|Wikimedia Commons has media related to Trapezium (bone).|
- Drake, Richard L.; Vogl, Wayne; Tibbitts, Adam W.M. Mitchell; illustrations by Richard; Richardson, Paul (2005). Gray's anatomy for students. Philadelphia: Elsevier/Churchill Livingstone. ISBN 978-0-8089-2306-0.
- Eathorne, SW (Mar 2005). "The wrist: clinical anatomy and physical examination--an update.". Primary care. 32 (1): 17–33. doi:10.1016/j.pop.2004.11.009. PMID 15831311.
- Harper, Douglas. "Trapezium". Online Etymology Dictionary. Retrieved 5 January 2014.