First metatarsal bone
|First metatarsal bone|
|The first metatarsal. (Left.)|
|Bones of the right foot. Dorsal surface. The first metatarsal bone is shown in yellow farthest to the left|
|Latin||Os metatarsale I|
|Gray's||subject #64 272|
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 flatten giving it to sides; the plantar (towards the sole of the foot) and the dorsal side (the area facing upwards while standing).
The base presents, as a rule, no articular facets (joint surfaces) on its sides, but occasionally on the lateral side there is an oval facet, by which it articulates with the second metatarsal. On the lateral part of the planter surface there is a rough oval prominence, or tuberosity, for the insertion of the tendon of the fibularis longus.
The first metatarsal articulates (forms joints) with the medial cuneiform, and to a small extent to the intermediate cuneiform bone. Its proximal articular surface is large and kidney-shaped; its circumference is grooved, for the tarsometatarsal ligaments, and medially gives insertion to part of the tendon of the tibialis anterior;
The body of the bone is strong, and of well-marked prismoid form.
The head is large; on its plantar surface are two grooved facets, on which glide sesamoid bones; the facets are separated by a smooth elevation.
The tibialis anterior inserts a the basis of the bone, while the fibularis longus inserts at the tuberosity. The lateral part of the first dorsal interossei muscle originates from the medial side of the bone. The function of the muscle is to spread the toes.
|Tibialis anterior||Insertion||Basis of first metatarsal|
|Fibularis longus||Insertion||Tuberosity of first metatarsal|
|Dorsal interossei I||Origin||Lateral part of first metatarsal|
Sesamoid bones at the distal end of the first metatarsal.
- Bojsen-Møller, Finn; Simonsen, Erik B.; Tranum-Jensen, Jørgen (2001). Bevægeapparatets anatomi [Anatomy of the Locomotive Apparatus] (in Danish) (12th ed.). p. 246. ISBN 978-87-628-0307-7.
- Platzer 2004, p 218
- Bojsen-Møller, Finn; Simonsen, Erik B.; Tranum-Jensen, Jørgen (2001). Bevægeapparatets anatomi [Anatomy of the Locomotive Apparatus] (in Danish) (12th ed.). pp. 364–367. ISBN 978-87-628-0307-7.
- Bojsen-Møller, Finn; Simonsen, Erik B.; Tranum-Jensen, Jørgen (2001). Bevægeapparatets anatomi [Anatomy of the Locomotive Apparatus] (in Danish) (12th ed.). pp. 300–301. ISBN 978-87-628-0307-7.
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