Q- A 35-year-old man fractures the midshaft of his humerus. He cannot extend his wrist or fingers. Which nerve is injured?
A- Axillary nerve
B- Radial nerve
C- Median nerve
D- Ulnar nerve
B- Radial nerve. The radial nerve runs in the radial (spiral) groove of the humerus and is injured in midshaft fractures, causing wrist drop and sensory loss over the dorsal hand. Surgical neck fractures injure the axillary nerve, supracondylar fractures the median nerve, and medial epicondyle fractures the ulnar nerve.
Q- After a delivery complicated by shoulder dystocia, a newborn’s right arm hangs adducted and internally rotated, with the elbow extended and the forearm pronated. Which nerve roots are injured?
A- C5 and C6
B- C8 and T1
C- C7 only
D- The posterior cord
A- C5 and C6. This is Erb palsy (upper trunk injury), giving the “waiter’s tip” posture from loss of the deltoid, supraspinatus, infraspinatus, and biceps. Klumpke palsy (C8 and T1) affects the hand muscles and causes a claw hand, sometimes with Horner syndrome.
Q- During inguinal hernia repair, the hernia sac is found medial to the inferior epigastric vessels, pushing through the posterior wall of the inguinal canal. What type of hernia is this?
A- Indirect inguinal hernia
B- Direct inguinal hernia
C- Femoral hernia
D- Umbilical hernia
B- Direct inguinal hernia. Direct hernias pass through the Hesselbach triangle, medial to the inferior epigastric vessels, and are common in older men. Indirect hernias pass through the deep inguinal ring, lateral to these vessels, through a patent processus vaginalis. Femoral hernias pass below the inguinal ligament, are more common in women, and have the highest risk of strangulation.
Q- After a total thyroidectomy, a patient has a hoarse voice. Which nerve was most likely injured?
A- External branch of the superior laryngeal nerve
B- Recurrent laryngeal nerve
C- Hypoglossal nerve
D- Glossopharyngeal nerve
B- Recurrent laryngeal nerve. It supplies all intrinsic muscles of the larynx except the cricothyroid and runs close to the inferior thyroid artery. Unilateral injury causes hoarseness, and bilateral injury can cause airway obstruction. The external branch of the superior laryngeal nerve runs with the superior thyroid artery and supplies the cricothyroid, so its injury causes voice fatigue and loss of high pitch.
Q- A patient has a fracture of the neck of the fibula. He cannot dorsiflex or evert his foot and has numbness over the dorsum of the foot. Which nerve is injured?
A- Tibial nerve
B- Common fibular (peroneal) nerve
C- Femoral nerve
D- Obturator nerve
B- Common fibular (peroneal) nerve. It wraps around the fibular neck and is easily injured there, causing foot drop and a high-stepping gait. Tibial nerve injury causes loss of plantarflexion and inversion with numbness of the sole, femoral nerve injury causes loss of knee extension, and obturator nerve injury causes loss of thigh adduction.
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