Review Question - QID 1401

The anterolateral branch of the anterior circumflex artery, called the arcuate artery terminally, provides blood supply to the entire humeral head, lesser tuberosity and greater tuberosity except for a small posterior area. The posterior portion of the greater tuberosity and a small posteroinferior portion of the humeral head are supplied by the posterior circumflex artery.

Gerber et al performed an anatomical study of the arteries of the humeral head to determine their intraosseous distributions. They injected a radiopaque suspension into the anterior circumflex, posterior circumflex, suprascapular, thoracoacromial, or subscapular artery and then analyzed the specimens macroscopically and radiographically. The humeral head was shown to have been perfused by the anterolateral ascending branch of the anterior circumflex artery in all specimens. The posterior circumflex artery vascularized only the posterior portion of the greater tuberosity and a small posteroinferior part of the head.

While previous literature suggested that the anterior humeral circumflex artery provided the main blood supply to the humeral head, more current literature supports the posterior circumflex humeral artery as the predominant blood supply. Despite the anterior humeral circumflex artery being disrupted in approximately 80% of proximal humeral fractures, the occurrence of resultant osteonecrosis is still infrequent. This inconsistency also suggests a greater role for the posterior humeral circumflex artery.

Hettrich et al. performed a cadaveric study assessing the vascularity of the proximal part of the humerus. They injected gadolinium into the axillary artery proximally, and then either the anterior humeral circumflex artery or the posterior humeral circumflex artery was ligated. MRI was then performed and the specimens were dissected to determine the dominant blood supply. They found that the posterior humeral circumflex artery provided 64% of the blood supply to the humeral head, whereas the anterior humeral circumflex artery supplied 36%. The posterior humeral circumflex artery also provided significantly more of the blood supply in three of the four quadrants of the humeral head.

Illustration A depicts the humeral head vascular supply with #2 being the posterior circumflex, #3 being the anterior circumflex arteries, and #4 being the anterolateral humeral circumflex artery.