It begins at the vertical (vertebral or medial) border by a smooth, triangular area over which the tendon of insertion of the lower part of the Trapezius glides.

Of the three borders, the anterior is attached to the dorsal surface of the bone; the posterior, or crest of the spine, is broad, and presents two lips and an intervening rough interval.

The lateral border, or base, the shortest of the three, is slightly concave; its edge, thick and round, is continuous above with the under surface of the acromion, below with the neck of the scapula.

It forms the medial boundary of the great scapular notch, which serves to connect the supra- and infraspinatous fossae.

This article incorporates text in the public domain from page 203 of the 20th edition of Gray's Anatomy (1918)