Intercostal muscle OR Intercostal Membrane?

Q: Need inserted at 5th intercostal space on left of sternum pierces, which structure will be damage FIRST?

A. Internal intercostal muscle

B. External intercostal membrane
C. Left atrium
D. Left lung
E. Left Ventricle

Answer: If they give you such questions (Needle pierces JUST Left or Right of the sternum) then ALWAYS select "External intercostal membrane"

REMEMBER: JUST LEFT or RIGHT

If they give you some specific distance from Sternum (lets suppose Left to the sternum in mid-clavicular line) then DON'T select External intercostal membrane.

Q 2: Need inserted at 5th intercostal space on left of sternum pierces, which structure will be damage FIRST?

A. Internal intercostal muscle

B. Internal intercostal membrane

C. Left atrium
D. Left lung
E. Left Ventricle

Answer: See here option B is INTERNAL (NOT External) intercostal membrane so selecting option B is wrong. Here correct answer would be Internal intercostal muscle (Option A). Internal intercostal membrane is on POSTERIOR side (External is on ANTERIOR)

To understand this whole concept check this picture (taken from Gray's Anatomy Student Ed)