Final answer:
When giving an influenza vaccination in the deltoid muscle, proper technique involves avoiding the axillary nerve and the humerus to prevent complications.
Step-by-step explanation:
When administering an influenza shot into the deltoid muscle, it is important to avoid hitting any nerves to prevent complications such as pain or nerve damage. The area of concern when injecting into the deltoid muscle is not the sciatic nerve, which is found in the lower limb, but rather the axillary nerve, which runs close to the deltoid muscle. This nerve supplies the deltoid and teres minor muscles as well as the skin over part of the deltoid region, and it runs through the quadrilateral space near the humerus. Sarah should also take care to avoid hitting the bone in this area, which is the humerus, not the clavicle, greater trochanter, or the forearm muscles as mentioned in the distractors of the original question.