What is the average anatomic neck-shaft angle of the humerus?

What is the average anatomic neck-shaft angle of the humerus?

• A. 130
• B. 135
• C. 132.5
• D. 140

Answer: (C)

The neck-shaft angle of the humerus is the angle formed between the axis of the humeral head/neck and the axis of the humeral shaft. In adults, this angle varies but typically falls within about 125–140 degrees. Across many anatomical studies, the mean value is reported near 132.5 degrees, which sits between 130 and 135 and often serves as a central reference for the average adult humerus. Among the given options, 132.5 best represents this average, reflecting the common central tendency rather than a specific boundary value. Remember that individual variation exists due to measurement method, population differences, and normal anatomical variation.

The neck-shaft angle of the humerus is the angle formed between the axis of the humeral head/neck and the axis of the humeral shaft. In adults, this angle varies but typically falls within about 125–140 degrees. Across many anatomical studies, the mean value is reported near 132.5 degrees, which sits between 130 and 135 and often serves as a central reference for the average adult humerus. Among the given options, 132.5 best represents this average, reflecting the common central tendency rather than a specific boundary value. Remember that individual variation exists due to measurement method, population differences, and normal anatomical variation.