6 - 10 Anatomy SBAs for the Primary FRCA
Question 6
Following a painfully long laparoscopic gynae procedure in steep Trendelenburg with shoulder braces, your patient wakes unable to abduct the shoulder or flex her elbow.
Which part of the brachial plexus is most likely affected?
- Posterior cord
- Inferior trunk
- Superior and middle trunks
- Medial cord
- Ulnar nerve at elbow
Answer
- Superior and middle trunks
Stretching of the upper plexus (C5-C6) will lead to an Erb's palsy style of injury.
- The posterior cord would affect extensors
- Inferior trunk would cause ulnar symptoms (claw hand)
- Medial cord would produce sensory deficits in the hand
- Ulnar injury is more distal lesion
A quick reminder of the brachial plexus structure:
- Roots: C5–T1
- Trunks - superior, middle, inferior
- Divisions - anterior, posterior
- Cords - lateral, posterior, medial
- Branches