著者

那須 哲夫 黒木 昭浩 浜名 克己 村上 隆之 斎藤 勇夫

出版者

宮崎大学農学部

雑誌

宮崎大学農学部研究報告 (ISSN:05446066)

巻号頁・発行日

vol.29, no.2, pp.p259-267, 1982-12

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牛(ホルスタイン種,雌, 8カ月齢)の単蹄肢(左右前肢)について解剖学的観察を行った.得られた結果は次のとおりである.### 1. 中手骨の遠位中手管は右肢で完全に閉鎖していた.第四中手骨の外側遠位部に第五中手骨が遺残し,またそれに関節する指骨(基節骨)の遺残を認めた.中手骨の滑車は右肢に1個,左肢に2個存在し,左肢の滑車間切痕は浅くなっていた.### 基節骨,中節骨および末節骨は左右両肢とも第三,四指のものがそれぞれ完全に癒合していた.### 近位種子骨は右肢に2個,左肢に3個存在し,遠位種子骨は左右肢とも各1個が存在した.### 2. 右肢において第三指伸筋,第四指伸筋および総指伸筋の腱は中手・指節関節部で合一し,幅広い腱を形成して中節骨および末節骨の前面に停止していた.左肢では総指伸筋のみは独自の腱を形成して,基節骨の近位端に停止していた.### 浅指屈筋と深指屈筋の腱は中手・指節関節部で分岐することなく,単一のまま走行し,浅指屈筋腱は中節骨後面に,深指屈筋腱は末節骨後面に停止していた.### 3. 正中動脈と橈骨動脈は中手骨の掌側面を下行し,中手骨中間部において深掌動脈弓を形成する.この動脈弓から指骨の外側および内側へ分布する2本の枝が出ており,これらの枝は指骨背側面で互に吻合していた.### 前骨間動脈は細い枝となり中手骨の背面に分布していたが,指骨にまで達していなかった.### 4. 正中神経は中手骨の掌側面を下行し,中手骨近位端1/3のところで分岐し指骨の外側および内側へ分布していた.### 尺骨神経掌側枝は骨間筋の外側を下行し指骨の外側へ分布していた.### 中手骨背側面を下行する外側前腕皮神経は途中で消失しており,それより遠位部では確認できなかった.A pair of forelimbs of 8-month-old Holstein-Freisean cow which had solid hoof was dessected to be description. The details were reported as follows.### 1. The distal perforating canal was absent from the right metacarpus. On the lateral-distal part of the metacarpal bone there were vestiges of the fifth metacarpus and the first phalanx which were jointed earch other. The right metacarpus had one distal trochlea and the left had two trochleas. The intertrochlear notch of the left metacarpus was relatively shallow. All the phalanges of front feet were completely fused. The left foot had three proximal sesamoid bones and a distal sesamoid bone, but the right had only two proximal sesamoid bones and a distal sesamoid bone.### 2. The lateral, medial and common digital extensor tendons of right forelimb fused into a wide aponeurotic plate at the fetlock joint and inserted on the extensor surfaces of the second and the third phalanx. The tendon of the left "common digital extensor did not fuse but inserted into the proximal end of the first phalanx. The superficial and deep digital flexor tendons coursed normally but did not divide into two branches at the level of the fetlock joint, the former inserted on the palmar surface of the second phalanx and the latter inserted on that of third phalax.### 3. The median and the radial arteries descended on the volar side of the metacarpus and anastomosed each other to form the deep palmar arch.### Arising from the deep palmar arch, two branches terminated by entering the lateral and the medial volar surfaces of the digit, where they formed an anastomosing arches.### The small cranial interosseus artery which descended the dorsal surface of the metacarpus did not reach the digital bone.### 4. The median nerve descended on the mediovolar side of the metacarpus. At the proximal third of the metacarpus, this nerve divided into two branches which innervated the medial and the lateral volar sides of the digit.### The palmar branch of the ulnar nerve descended along the lateral side of the interosseus muscle to the laterovolar side of the digit. The lateral cutaneous antebrachial nerve which was a slender branch of the radial nerve disappeared during its course on the volar surface of the metacarpus.