Nutrient artery of ulna

The nutrient artery of the ulna is the principal intraosseous blood vessel that supplies the diaphysis (shaft) of the ulna. It is a direct branch of the ulnar artery or the anterior interosseous artery, which itself arises from the common interosseous artery (a branch of the ulnar artery). The nutrient artery enters the ulna through the nutrient foramen, which is typically located on the anterior surface of the proximal third of the ulnar shaft. The foramen is directed proximally (toward the elbow), following the general rule that nutrient arteries of long bones in the upper limb are directed "toward the elbow" (i.e., away from the growing end).

Key anatomical features:

• Origin: Anterior interosseous artery

• Entry point: Nutrient foramen on the anterior (volar) surface of the ulna, usually in the proximal one-third of the shaft

• Function: Provides the primary blood supply to the medullary cavity, endosteum, and inner two-thirds of the cortical bone of the ulnar diaphysis