Final answer:
A fracture of the surgical neck of the humerus, with inability to raise the arm and sensory loss in the upper lateral arm, likely indicates damage to the axillary nerve. Considering the muscle options provided, the deltoid muscle is the one supplied by the axillary nerve, making it the correct answer.
Step-by-step explanation:
The 60-year-old female's presentation of a fall on her right elbow with inability to raise her right arm and loss of sensation over the upper lateral side of the right arm and shoulder, along with a fracture of the surgical neck of the humerus, suggests injury to the axillary nerve. This nerve typically provides sensory and motor innervation to the area described. Given the choices provided, the deltoid muscle is the most likely candidate as it is innervated by the axillary nerve and is responsible for abducting the arm, an action the patient is unable to perform. The deltoid also covers the shoulder providing the described sensory distribution.
On the other hand, the biceps brachii and brachialis are muscles that primarily flex the forearm and are supplied by other nerves. The supraspinatus, another rotator cuff muscle, is mainly involved in the first 15 degrees of arm abduction and is innervated by the suprascapular nerve. Therefore, the correct answer to the question, 'Which of the following muscles is supplied by the nerve that is most likely damaged?' is A) Deltoid.