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Other Terms: Navicular of foot, Navicular, Os naviculare, Os naviculaire
This short, disc-like bone is positioned between the distal end of the talar head and the proximal end of the three cuneiform bones. Its proximal and distal surfaces present as flattened oval faces. The proximal surface forms a shallow oval concavity. The distal surface, being transversely convex, divides into three aspects that form articular surfaces with the three cuneiform bones. Dorsal, lateral, plantar, and medial surfaces form a rough circumference to the disk. The medial surface projects as a rounded tubercle while the lateral surface presents as a small, smooth articular surface. The dorsal surface is convex and the plantar surface concave.
The word navicular is from the Latin root navis meaning a ship. When navis combines the diminutive suffix -icula the word translates as a little ship. With a little imagination one can see the convex keel and the concave hull of a little ship.
The navicular bone articulates with four bones and occasionally five: the talus, lateral cuneiform, intermediate cuneiform, and medial cuneiform bones. Sometimes, the bone also forms a small articulation with the cuboid bone. Its proximal end forms a shallow concavity for articulation with the talus. The distal surface divides into three articular faces that articulate with the cuneiform bones, the medial surface being the largest. Sometimes the lateral surface of the bone forms a small articular facet with the cuboid bone.
The navicular bone ossifies from a single center. It is the last tarsal bone to ossify beginning at the end of the third year. Like the other tarsal bones it completes its ossification around puberty.