MCQ – 88856

Correct Answer � C Explanation

Answer C) Pneumothorax due to pleural injury

Pneumothorax due to pleural injury

• The pleural membrane covering the apex of the superior lobe of the lung extends approx. 2.5 cm above the medial end of the clavicle. 

• A penetrating injury to the supraclavicular parasternal region, like the one sustained by this patient, can pierce the parietal pleural membrane, permitting air to enter the pleural space and causing an ipsilateral pneumothorax.

 Rotator cuff tear due to supraspinatus muscle injury

• The supraspinatus muscle is part of the rotator cuff, which stabilizes the shoulder joint. It runs from the superior portion of the scapula to the greater tubercle of the humerus.

• Because this patient’s wound is on the upper margin of the right clavicle, injury of the supraspinatus muscle is unlikely.

Trapezius muscle paresis due to spinal accessory nerve injury

• The spinal accessory nerve exits the skull through the jugular foramen and sends a branch to the sternocleidomastoid muscle 3 cm below the mastoid process before entering the posterior triangle of the neck to innervate the trapezius muscle. 

• Spinal accessory nerve injury resulting in trapezius (and sternocleidomastoid) paralysis would be expected if there were an injury to the upper aspect of the posterior triangle of the neck.

Hemothorax due to azygos vein injury

• Azygos vein injury would cause hemothorax. However, the azygos vein drains into the superior vena cava at the level of the 4th thoracic vertebra (T4).

•  It does not extend into the supraclavicular space and would therefore not be susceptible to injury in a penetrating trauma to the right supraclavicular space.