It is approximately the size and shape of a cashew.
The scaphoid is the largest bone of the proximal row. It is situated at the radial side of the carpus, its long axis being from above downward, lateralward, and forward.
The etymology derives from the Greek skaphe which means "a boat," and the Greek eidos which means "form".
The inferior surface, directed downward, lateralward, and backward, is also smooth, convex, and triangular, and is divided by a slight ridge into two parts, the lateral articulating with the greater multangular, the medial with the lesser multangular.
On the dorsal surface is a narrow, rough groove, which runs the entire length of the bone, and serves for the attachment of ligaments.
The volar surface is concave above, and elevated at its lower and lateral part into a rounded projection, the tubercle, which is directed forward and gives attachment to the transverse carpal ligament and sometimes origin to a few fibers of the Abductor pollicis brevis.
The lateral surface is rough and narrow, and gives attachment to the radial collateral ligament of the wrist.
The medial surface presents two articular facets; of these, the superior or smaller is flattened of semilunar form, and articulates with the lunate bone; the inferior or larger is concave, forming with the lunate a concavity for the head of the capitate bone.
The distal convex surface articulates with trapezium and trapezoid.
Fractures of the scaphoid must be recognized and treated quickly, as prompt treatment is the key to proper healing. Delays may complicate healing. Even rapidly immobilized fractures may require surgical treatment, including use of the Herbert screw to bind the two halves together.
Clicking of the scaphoid, or no anterior translation can indicate scapholunate instability.