A 22-year-old man is admitted to the emergency department after he was beaten up in a street fight. Radiographic examination reveals that he has suffered a forehead fracture from a blow with a club, resulting in black and swollen eyes. Because the patient is suffering from severe pain, an anesthetic solution is ordered to be injected into his orbit. Which of the following nerves is most likely to be anesthetized?
High-Yield Explanation
(a) Source: GAS 879-883; GA 461-462 Anesthetics are injected into the submuscular layer of delicate (areolar) connective tissue, the layer that contains nerves of the eyelid. This space is continuous with the "danger zone" of the scalp. A blow to the forehead can result in a "black eye," with the passage of blood into the submuscular space. Infections can, likewise, pass within this space. One can insert a needle through the upper eyelid, near the orbital margin, and then direct it deeply toward the orbital apex. The anesthetic can there infiltrate the branches of the ophthalmic nerve, including its nasociliary branch, resulting in anesthesia of the area.