Which nerve is at risk with malpositioned humeral head reduction resulting in pinched nerve?

• A. Axillary nerve
• B. Radial nerve
• C. Median nerve
• D. Musculocutaneous nerve

Answer: (A)

Proximity of the axillary nerve to the proximal humerus makes it most vulnerable when the humeral head is malpositioned during reduction. The axillary nerve runs just below the shoulder joint, crossing near the surgical neck in the quadrangular space, where it can be compressed or stretched if the humeral head isn’t reduced correctly. When this nerve is affected, weakness of the deltoid and teres minor can occur, leading to impaired shoulder abduction beyond about 15 degrees, and there may be numbness over the lateral shoulder area.

The other nerves are less likely to be involved in this scenario. The radial nerve travels with the deep brachial artery along the radial groove, so it’s more at risk with midshaft injuries. The median and musculocutaneous nerves lie more medially and anteriorly, so they’re not typically pinched by malpositioned reduction of the humeral head.