The Cuboid Bone (os cuboideum) is placed on the lateral side of the foot, in front of the calcaneus, and behind the fourth and fifth metatarsal bones. It is of a pyramidal shape, its base being directed medialward.
Surfaces
The dorsal surface, directed upward and lateralward, is rough, for the attachment of ligaments.
The plantar surface presents in front a deep groove, the peroneal sulcus, which runs obliquely forward and medialward; it lodges the tendon of the Peronæus longus, and is bounded behind by a prominent ridge, to which the long plantar ligament is attached. The ridge ends laterally in an eminence, the tuberosity, the surface of which presents an oval facet; on this facet glides the sesamoid bone or cartilage frequently found in the tendon of the Peronæus longus. The surface of bone behind the groove is rough, for the attachment of the plantar calcaneocuboid ligament, a few fibers of the Flexor hallucis brevis, and a fasciculus from the tendon of the Tibialis posterior.
The lateral surface presents a deep notch formed by the commencement of the peroneal sulcus.
The posterior surface is smooth, triangular, and concavo-convex, for articulation with the anterior surface of the calcaneus; its infero-medial angle projects backward as a process which underlies and supports the anterior end of the calcaneus.
The anterior surface, of smaller size, but also irregularly triangular, is divided by a vertical ridge into two facets: the medial, quadrilateral in form, articulates with the fourth metatarsal; the lateral, larger and more triangular, articulates with the fifth.
The medial surface is broad, irregularly quadrilateral, and presents at its middle and upper part a smooth oval facet, for articulation with the third cuneiform; and behind this (occasionally) a smaller facet, for articulation with the navicular; it is rough in the rest of its extent, for the attachment of strong interosseous ligaments.
Articulations
The cuboid articulates with four bones: the calcaneus, third cuneiform, and fourth and fifth metatarsals; occasionally with a fifth, the navicular.
