Neuropathologic observations in congenital phrenic nerve palsy.

A right phrenic nerve palsy with severe respiratory and feeding difficulties throughout the patient's 2 1/2 years of survival was found at autopsy to relate to grossly complete atrophy of the muscle of the right diaphragm. An oblique fibrotic scar transected the right phrenic nerve at the level of the brachial plexus. There was marked reduction of the number of anterior motor neurons in the right central portion of cervical segments 2, 3, and 4. The lesion in the phrenic nerve is what would be expected following stretching during delivery.