The =intermediate carpal= bone (Os carpi intermedium, semilunar, lunar)
is somewhat wedge-shaped, wider in front than behind. The =superior= or
=proximal surface= is saddle-shaped, and articulates with the middle
facet on the distal end of the radius. The =inferior= or =distal
surface= is smaller, convex in front, concave behind, and articulates
with the third and fourth carpal bones. The =internal surface= has upper
and lower facets for articulation with the radial carpal, and between
these it is excavated and rough. The =external surface= is similar to
the preceding and articulates with the ulnar carpal. The =anterior= or
=dorsal surface= is rough and slightly convex. The =posterior= or =volar
surface= bears a tuberosity on its lower part.