Saturday, October 10, 2009

Anatomy MCQ Thorax #1

An 18-year-old man, in shock and bleeding profusely is brought to the emergency department after being stabbed in the chest. An examination shows a knife wound to the right first intercostal space,immediately lateral to the manubrium. The knife entered parallel to the ground and penetrated to a depth of 6.5 cm. which of the following structures is most likely injured?

A) Left common carotid artery

B) Ascending aorta

C) Superior vena cava

D) Right ventricle

E) Right subclavian artery

Answer: C) Superior venacava

Explanation: Just lateral to the sternum on the right side, from superior to inferior, would be the superior vena cava and the right atrium of the heart. Because the knife entered lateral to the manubrium in the first intercostal space, above the sternal angle, the structure entered must be the superior vena cava. The right atrium is located inferior to the sternal angle.