Combined Quadrilateral Space Syndrome and Brachial Plexus Injury: A Case Report.

Case Diagnosis: Combined brachial plexus injury with quadrilateral space syndrome

Case Description or Program Description: This patient presented after sustaining a fall on an outstretched hand off 1 step while vacationing in Mexico. He reported frank numbness in the right upper arm, which continued down the medial arm to his small finger as well as his right deltoid. He was evaluated at a hospital and was found to have a dislocated right shoulder and toren labrum subsequent shoulder reduction but with a 5 day period before he could return home to US. He had significant right shoulder abduction and flexion weakness with no pain at rest but sharp pain shooting down arm with active shoulder abduction. At that time he was engaged in PT and had no functional improvement and was out of work as he was required to lift 50lbs to work. He noted he did have diffuse swelling and bruising of his right arm and right rib cage after the fall without overt supraclavicular bruising or swelling. He had numbness down his lateral arm with radiation to small finger. His orthopedist ordered a shoulder MRI which notably revealed extensive inferior glenohumeral capsular and labral tear with fluid dissecting into the quadrilateral space.

Setting: Outpatient rehabilitation clinic

Assessment/Results: EMG/NCS and 3T brachial plexus MRI results suggestive of right traumatic brachial plexopathy (right axillary nerve region predominant and lateral trunk), while right shoulder MRI noted edema in the quadrilateral space (axillary nerve region) and lateral trunk injury and serratus anterior injury of long thoracic nerve.

Discussion (relevance): This case represents a rare presentation of combined brachial plexus injury with quadrilateral space syndrome.

Conclusions: Patients with traumatic shoulder injuries should be evaluated for quadrilateral space syndrome as well as brachial plexus injuries.