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Surgical Neck of the Humerus

collum chirurgicum humeri

The surgical neck of the humerus is the narrow junction between the proximal humeral metaphysis and the humeral shaft, just below the greater and lesser tubercles. It is the most common fracture site in the proximal humerus (approximately 60% of proximal humeral fractures), particularly in elderly patients with osteoporosis after low-energy falls. The axillary nerve and the anterior circumflex humeral artery encircle the surgical neck.

Region: Shoulder

Clinical Relevance

Clinical Notes

Surgical neck fractures are classified by the Neer system: 2-part (displaced shaft), 3-part (tubercle + shaft), and 4-part (both tubercles + shaft, highest AVN risk). Axillary nerve injury occurs in 5-30% of surgical neck fractures from stretch or direct injury, producing deltoid weakness and a sensory patch over the lateral deltoid (regimental badge area). Management ranges from sling and rehabilitation for minimally displaced fractures to ORIF or arthroplasty for complex 3- and 4-part injuries.

Pathology

Common Injuries & Conditions

Axillary Nerve Injury in Surgical Neck Fracture

The axillary nerve encircling the surgical neck of the humerus is stretched or contused in displaced surgical neck fractures, producing deltoid paralysis and loss of the lateral arm sensory patch; most neuropraxias recover within 3-6 months with EMG monitoring, while persistent deficit beyond 6 months warrants nerve exploration.