Extending the arms beyond 90 degrees during a procedure may cause injury to which part?

Extending the arms beyond 90 degrees during a surgical procedure may cause injury to the brachial plexus. The brachial plexus is a network of nerves that originates from the lower cervical and upper thoracic spinal cord (C5-T1) and innervates the muscles and skin of the upper limb. When the arms are positioned excessively outward, beyond 90 degrees, there is an increased risk of strain or compression on this nerve network, which can lead to conditions such as neuropraxia or brachial plexus injury. Proper arm positioning is crucial during surgeries to prevent such complications, as stretching or compressive forces can directly affect the function of the nerves within the brachial plexus.

In contrast, the other answer choices refer to different anatomical structures. The humeral head relates to the shoulder joint and is less likely to be injured from arm extension beyond 90 degrees in a surgical context. The femoral nerve serves the lower extremity, and while improper positioning can cause various injuries, it is not directly relevant to arm positioning. The supraspinatus is a muscle of the rotator cuff that stabilizes the shoulder, but it typically does not suffer injury in the same manner as the brachial plexus