Final answer:
The radial nerve is at risk with AP interlock in a humeral nail due to its close proximity to the surgical site. Injury to this nerve can lead to wrist drop and loss of hand function, thus highlighting the need for careful surgical technique and knowledge of anatomy.
Step-by-step explanation:
The nerve at risk with AP interlock in a humeral nail is the radial nerve. This nerve runs in close proximity to the humerus and is particularly vulnerable during orthopedic procedures such as nailing for humeral fractures.
When a humeral nail is inserted anteroposteriorly (AP), the radial nerve, which spirals around the midshaft of the humerus, may be at risk of injury. It is imperative that surgeons take care during the procedure to avoid damaging this nerve, as it is responsible for the innervation of the extensor muscles of the forearm and hand, as well as providing sensation to part of the hand. A radial nerve injury can result in a condition known as wrist drop, where the patient is unable to extend the wrist and fingers properly.
Precise knowledge of the anatomy and careful surgical technique are crucial to prevent radial nerve palsy. The use of intraoperative nerve monitoring and considering alternative surgical approaches when anatomy is deemed at high risk may mitigate the chances of nerve injury.