OBJECTIVE: To investigate the compression feature, clinical manifestation and the results of treatment of quadrilateral space syndrome. METHODS: Four patients with axillary nerve entrapment at quadrilateral space had been treated and followed up for 5 to 12 months from May 1999 to June 2000. The causes, symptoms, signs and the treatment management of those cases were analyzed. RESULTS: Among the 3 cases which received operation, sensation and motor function completely recovered in 2 cases and partially recovered in 1 case. No obvious recovery of sensation and motor function in the case which received local nerve blocking treatment. CONCLUSION: The main diagnostic evidence for axillary nerve entrapment is the deltoid muscle paralysis and paresthesia in the lateral side of shoulder, and early neurolysis is recommended as soon as the diagnosis is clarified.