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The second metatarsal bone is a long bone in the foot. The second metatarsal bone is the longest of the metatarsal bones, being prolonged backward and held firmly into the recess formed by the three cuneiform bones. The second metatarsal forms joints with the second proximal phalanx (a bone in the second toe) through the metatarsophalangeal joint, the cuneiform bones, third metatarsal and occasionally the first metatarsal bone. As the four other metatarsals bone it can be divided into three parts; base, body and head. The base is the part closest to the ankle and the head is closest to the big toe. The narrowed part in the middle is referred to as the body of the bone. The bone is somewhat flattened giving it two sides; the plantar (towards the sole of the foot) and the dorsal side (the area facing upwards while standing).〔 Its base is broad above, narrow and rough below. It presents four articular surfaces: one behind, of a triangular form, for articulation with the intermediate cuneiform bone; one at the upper part of its medial surface, for articulation with the medial cuneiform; and two on its lateral surface, an upper and lower, separated by a rough non-articular interval. Each of these lateral articular surfaces is divided into two by a vertical ridge; the two anterior facets articulate with the third metatarsal; the two posterior (sometimes continuous) with the lateral cuneiform. A fifth facet is occasionally present for articulation with the first metatarsal; it is oval in shape, and is situated on the medial side of the body near the base. The second metatarsal base acts as a "keystone" (like in an arch) for the lisfranc joint. == Muscle attachments == The first and second dorsal interossei muscles attaches to the second metatarsal bone. The first dorsal interossei from the medial side of the bone and the second dorsal interossei from the lateral side. The function of the muscle is to spread the toes. The horizontal head of the adductor hallucis also originates from the lateral side of the metatarsophalangeal joint and from the deep transverse metatarsal ligament,〔 a narrow band which runs across and connects together the heads of all the metatarsal bones. 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「second metatarsal bone」の詳細全文を読む スポンサード リンク
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