After surgical incision of an abscess situated in the mid-right posterior triangle of the neck, the patient complained of shoulder pain and could no longer raise her right hand above her head to brush her hair.
Which one of the following nerves is most likely injured in this patient?
Correct Answer B: The accessory nerve (CN XI) runs through the posterior triangle, so it is likely to be injured in posterior neck triangle operations. If the accessory nerve is damaged there, the trapezius will be denervated, the tip of the shoulder will be drooping and the patient will have inability to raise her hand above her head.
Symptoms and signs of accessory nerve injury:
A young woman who was involved in a cliff diving accident is brought into the emergency department by her boyfriend. She is not breathing and is unresponsive to deep pain with a right pupil that is dilated and nonreactive.
The left pupil is normal. The most appropriate initial management is:
Correct Answer A: After establishing unresponsiveness (tap, shake, or shout) and absence of breathing, begin basic life support following the mnemonic CAB (Compression, Airway, Breathing) - note that the 2010 CPR Guidelines rearranged the order of CPR steps (CAB instead of ABC).
Direct inguinal hernias pass:
Correct Answer A: Inguinal Hernias The anatomic considerations of inguinal hernias are notoriously difficult to appreciate and warrant spending time with.
Direct inguinal hernias are the result of the passage of intestine through a weakness of the transversalis fascia between “Hesselbach’s triangle” and medial to the inferior epigastric artery.
Indirect inguinal hernias are the most common hernias among men and women originating in the deep inguinal ring and passing lateral to the inferior epigastric artery (See Fig B.) below. The often descend into the scrotal sac or labia majora.
PEARL: Direct inguinal hernias pass medially to the inferior epigastric artery.
A 12-year-old white male is brought to your office after accidentally cutting his left hand with a pocketknife. On examination you find a deep 2-cm laceration at the base of the thenar eminence. To test for motor injury to the median nerve you would have the patient:
Correct Answer B: The ability to touch the tip of the thumb to the tip of the little finger indicates normal motor function of the median nerve (choice B).
→ The radial nerve controls extension of the thumb and fingers (choice A).
→ The median nerve partially controls flexion of the wrist (choice C), but the site of innervation is proximal to the wound site at the base of the thumb.
→ Damage of the radial nerve causes wrist drop and inability to extend hand at wrist (choice D).
→ Finger adduction (choice E) is a function of the ulnar nerve.
Note: The flexor pollicis brevis has two heads. It acts to flex, adduct, and abduct the thumb, and is therefore also able to oppose the thumb. The superficial head is innervated by the median nerve, while the deep head is innervated by the ulnar nerve.
A 32 year old male presents with history of trauma to the right shoulder. On examination the outer aspect of the right shoulder is flattened and the shoulder cannot be moved. Skin sensation is absent over the lower part of the right deltoid muscle. X-ray shows anterior dislocation of the right shoulder.
Which one of the following nerves is most likely injured?
Correct Answer E: The axillary nerve innervates the teres minor and then divides into anterior and posterior branches to innervate the posterior, middle, and anterior deltoid muscle. In addition, it provides sensation to the glenohumeral joint and the skin overlying the deltoid muscle.
Injury to the axillary nerve can occur close to the inferior capsule of the glenohumeral joint, where it is susceptible to direct trauma secondary to glenohumeral dislocation, laceration during surgery, as well as to direct compression such as during the misuse of crutches. Entrapment of this nerve can also occur at the quadrilateral space. Injuries to the axillary nerve at the quadrilateral space can occur as a result of stretching or crushing.
The axillary nerve palsy causing dysfunction of the deltoid muscle is a catastrophic event to the shoulder girdle. Forward elevation can be limited to 33 degrees (range of 0 to 75 degrees). With this degree of loss of motion, attempts at elevation and abduction will result in superior subluxation of the humeral head. The patient, however, may use "trick movements" to achieve full elevation of the arm by rotating the scapula, contracting the rotator cuff, long head of the biceps, and clavicular portion of the pectoralis major muscle.
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