Case

A 35yo with delivers a large baby vaginally. The delivery duration is elongated during the process the infants head emerged, but the shoulders stuck against the pubic symphysis. The obstetrician had to hold the head to execute tilting motions to free the shoulder and complete delivery. The infant was noted by the nurse to have a good cry, pink color, but was not moving their right arm. The infant has a limp wrist but did respond with finger movements to stroking the palm.

Question 2/2 - The most likely etiology is an Erb's palsy. Which nerve root(s) have been affected?

Click on your selected option(s) below  (correct = 1, over-thinking = 2+)

Case Complete

Incorrect. The involvement of C4 would only occur in the anomalies where the individual has a C4 contribution to the plexus (called a 'prefixed cord').

Correct!  Erb's palsy is an injury to the C5,6 nerve roots.

Incorrect.  This type of injury is called an Extended Erb's palsy, where there is involvement of C7 in addition to the normal Erb's palsy injured roots.   

Incorrect. Outside of a vanishingly rare penetrating trauma to just C7, none of the common brachial plexus palsy's affect a singular root in the middle of the plexus.

Incorrect. A palsy of C8,T1 is Klumpke's palsy, most commonly from a forcible arm stretch over the head mechanism of injury. The 'stuck shoulder' mechanism that occurred in our patient is not consistent with a Klumpke's palsy.

Incorrect. This is a total brachial plexus palsy which would result in flail arm. In flail arm there is no movement or sensation from the affected limb as all roots of the brachial plexus are injured.  However, in our patient's history, there is motor response to a sensory touch of the palm ruling out a total plexus palsy.