Presentation
Traumatic anterior dislocation of the right shoulder 3 years ago. Now with a pseudoparalysis of his shoulder. EMG showed axillary nerve palsy.
Patient Data









The MRI sequences demonstrate atrophy of the deltoid and teres minor muscles without fatty infiltration.
No cystic or solid focal lesion is seen in the quadrilateral space.
Marrow oedema of the greater tuberosity with no rotator cuff tear is seen.
Case Discussion
Quadrilateral space syndrome is a rare neurovascular compression syndrome characterised by posterior humeral circumflex artery (PHCA) and/or axillary nerve compression within the quadrilateral space. The compression may be due to fibrous bands, trauma, or hypertrophy of the muscular borders.
The axillary nerve leaves axilla through the quadrangular space to the upper arm and provides motor innervation to the deltoid and teres minor muscles.
Traumatic anterior shoulder dislocations are considered the most common aetiology of acute axillary nerve palsy with as a consequence atrophy +/- fatty infiltration of the deltoid and teres minor muscles supplied by the axillary nerve 1.