Medial cuneiform

The medial cuneiform is one of the tarsal bones located between the navicular and base of first metatarsal, medial to the intermediate cuneiform bone.

Gross anatomy

Osteology

The medial cuneiform is one of the cuneiforms, it is the most medial in the distal row of tarsal bones.

It has a narrow dorsal surface and a flat plantar surface which receives a slip from the tibialis posterior tendon. The distal surface is reniform, congruent with the articulating base of first metatarsal and proximal surface has a pyriform facet for the navicular. The medial surface is subcutaneous, convex vertically and exhibits an impression for the tibialis anterior. The lateral surface shows dorsal facets for the articulations with intermediate cuneiforms and second metatarsal base. The distal plantar aspect of the lateral surface demonstrates a groove for the peroneus longus tendon.

Articulations

As described above, the medial cuneiform exhibits various facets separated by bony ridges, articulating with the first and second metatarsal bases, the intermediate cuneiform and navicular bones.

Attachments

Musculotendinous

These are mainly along the plantar aspect:

• tibialis posterior tendon insertion at proximal margin
• third plantar interosseus muscle origin along lateral margin
• peroneus longus tendon part insertion at plantar aspect of the lateral margin
• tibialis anterior tendon insertion at medial margin

Ligamentous

The plantar aspect of the lateral surface shows ligamentous attachments to the first, second and third metatarsal bases via plantar tarsometatarsal ligaments and recieves a slip from the plantar cuneonavicular ligament.

Proximally it is attached to the intermediate cuneiform through interosseous intercuneiform ligament.

Blood supply

This bone receives medial, lateral and dorsal surface arterial branches from the dorsal arterial network.

Innervation

It is supplied by the deep peroneal and medial plantar nerves.

Variant anatomy

• bipartite medial cuneiform
• sesamoid bones associated with medial cuneiform are os intercuneiforme and pars peronea metatarsalis.

Development

Ossification

This bone usually has one ossific centre but may have two centres in some cases. The ossific centre appears at two years of age.