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= Hamate ; : = Scaphoid : = Lunate : = Triquetrum : = Pisiform ; : 1 = Radius :2 = Ulna :3 = Metacarpus }} | MeshName = Carpal+Bones | MeshNumber = A02.835.232.087.144 | Dorlands = two/000017562 | DorlandsID = Carpus | FMA = 71335 }} Carpus is the anatomical assembly connecting the hand to forearm. This term derives its meaning from the Latin carpus and the Greek καρπός (karpós), both meaning "wrist." In human anatomy, the main role of the carpus is to facilitate effective positioning of the hand and powerful use of the extensors and flexors of the forearm, but the mobility of individual carpal bones increase the freedom of movements at the wrist.〔Kingston 2000, pp 126-127〕 In tetrapods, the carpus is the sole cluster of bones in the wrist between the radius and ulna and the metacarpus. The bones of the carpus do not belong to individual fingers (or toes in quadrupeds), whereas those of the metacarpus do. The corresponding part of the foot is the tarsus. The carpal bones allow the wrist to move and rotate vertically.〔 ==Structure== In human anatomy, the carpal bones can be classified as belonging to two transverse rows or three longitudinal columns. The pair of rows together form an arch which is convex proximally and concave distally. On the palmar side, the carpus is concave, forming the carpal tunnel which is covered by the flexor retinaculum. 〔Platzer 2004, p 124〕 Because the proximal row is simultaneously related to the articular surfaces of the radius and the distal row, it adapts constantly to these mobile surfaces. The bones of this row - scaphoid, lunate, and triquetrum - have their individual movements. The scaphoid contributes to the stability of the midcarpus as it articulates distally with the trapezium and the trapezoid. The distal row is more rigid as its transverse arch moves with the metacarpals. 〔Schmidt-Lanz 2003, p 29〕 Biomechanically and clinically, the carpal bones are better understood as arranged in three longitudinal columns:〔''Thieme Atlas of Anatomy'' 2006, p 224〕 # A radial scaphoid column consisting of the scaphoideum, trapezium, and trapezoideum # A lunate column consisting of the lunate and capitate # An ulnar triquetral column consisting of the triquetrum and hamatum. In this context the pisiform is regarded as a sesamoid bone embedded in the tendon of the flexor carpi ulnaris.〔 The ulnar column leaves a gap between the ulna and the triquetrum, and therefore, only the radial or scaphoid and central or capitate columns articulate with the radius. The wrist is more stable in flexion than in extension more because of the strength of various capsules and ligaments than the interlocking parts of the skeleton. 〔 Almost all carpals (except the pisiform) have six surfaces. Of these the ''palmar'' or ''anterior'' and the ''dorsal'' or ''posterior surfaces'' are rough, for ligamentous attachment; the dorsal surfaces being the broader, except in the lunate. The ''superior'' or ''proximal,'' and ''inferior'' or ''distal surfaces'' are articular, the superior generally convex, the inferior concave; the ''medial'' and ''lateral surfaces'' are also articular where they are in contact with contiguous bones, otherwise they are rough and tuberculated. The structure in all is similar: cancellous tissue enclosed in a layer of compact bone. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Carpal bones」の詳細全文を読む スポンサード リンク
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