Following a difficult shoulder dystocia, a term newborn holds the affected right arm adducted and internally rotated with the elbow extended, forearm pronated, and wrist flexed. Finger and wrist movements are preserved. Which roots are injured?
- A C8 and T1
- B C5 and C6 ✓
- C C7 and C8
- D T1 and T2
Correct answer: B. C5 and C6
Explanation
The waiter's tip posture describes Erb-Duchenne palsy, an upper trunk brachial plexus injury of C5 and C6 caused by lateral traction on the head during shoulder dystocia. Klumpke paralysis involves C8 and T1, affects the hand, and is rare in obstetric practice. Preservation of finger and wrist function excludes a lower trunk lesion and localizes the injury to the upper trunk.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.