BCSE Anatomy 3 — Questions and Answers
Question 1: A patient cannot dorsiflex or evert the foot after a fibular neck fracture. Which nerve is injured?
- Tibial nerve
- Common fibular (peroneal) nerve (Correct answer)
- Sural nerve
- Saphenous nerve
Correct answer: Common fibular (peroneal) nerve
The common fibular nerve winds around the fibular neck and innervates muscles responsible for dorsiflexion and eversion; its injury causes foot drop.
Question 2: Which coronary artery most commonly supplies the sinoatrial (SA) node?
- Left anterior descending
- Left circumflex
- Right coronary artery (Correct answer)
- Posterior descending artery
Correct answer: Right coronary artery
In approximately 60% of individuals the SA nodal artery is a branch of the right coronary artery.
Question 3: The femoral triangle contains all of the following EXCEPT:
- Femoral nerve
- Femoral artery
- Femoral vein
- Obturator nerve (Correct answer)
Correct answer: Obturator nerve
The femoral triangle contains the femoral nerve, artery, and vein (lateral to medial: nerve, artery, vein); the obturator nerve exits through the obturator foramen medially.
Question 4: Which muscle forms the floor of the anatomical snuffbox?
- Abductor pollicis longus
- Extensor pollicis brevis
- Extensor pollicis longus
- Scaphoid bone (Correct answer)
Correct answer: Scaphoid bone
The scaphoid bone (and trapezium) forms the floor of the anatomical snuffbox, and tenderness there after a fall suggests a scaphoid fracture.
Question 5: Which structure is at greatest risk when the long thoracic nerve is damaged?
- Pectoralis major
- Serratus anterior (Correct answer)
- Subscapularis
- Rhomboids
Correct answer: Serratus anterior
The long thoracic nerve innervates the serratus anterior; its damage causes winging of the scapula because the muscle can no longer hold the scapula against the thoracic wall.
Question 6: The calot triangle (cystohepatic triangle) contains the:
- Cystic artery (Correct answer)
- Right hepatic artery
- Common hepatic duct
- Portal vein
Correct answer: Cystic artery
The cystic artery is the key structure found within the triangle of Calot, formed by the cystic duct, common hepatic duct, and liver edge.
Question 7: A lesion of the medial longitudinal fasciculus (MLF) produces which classic finding?
- Ipsilateral gaze palsy
- Internuclear ophthalmoplegia (Correct answer)
- Homonymous hemianopia
- Contralateral ptosis
Correct answer: Internuclear ophthalmoplegia
An MLF lesion disrupts communication between CN VI and contralateral CN III nuclei, causing internuclear ophthalmoplegia with impaired adduction ipsilaterally and nystagmus contralaterally.
BCSE Anatomy 3
A patient cannot dorsiflex or evert the foot after a fibular neck fracture.
Which nerve is injured?