Quadrilateral Space Syndrome: Diagnosis and Clinical Management

Abstract

Quadrilateral space syndrome (QSS) is a rare disorder characterized by axillary nerve and posterior humeral circumflex artery (PHCA) compression within the quadrilateral space. Impingement is most frequently due to trauma, fibrous bands, or hypertrophy of one of the muscular borders. Diagnosis can be complicated by the presence of concurrent traumatic injuries, particularly in athletes. Since many other conditions can mimic QSS, it is often a diagnosis of exclusion. Conservative treatment is often first trialed, including physical exercise modification, physical therapy, and therapeutic massage. In patients unrelieved by conservative measures, surgical decompression of the quadrilateral space may be indicated.

A very rare case of an accessory subscapularis muscle and its potential clinical significance

“…For example, the accessory muscle can cause compression of the axillary nerve, and quadrilateral space syndrome (QSS) can result [ 12 ]. The axillary nerve innervates the teres minor and deltoid muscles, which function in abduction and external rotation [ 6 ], so the main symptom of QSS is weakness and atrophy of these muscles [ 12 ]. Diffuse pain around the shoulder and paresthesia in the lateral region of the shoulder also can be caused by compression of the axillary nerve [ 6 , 12 ].…”

“…The structure of this anomalous muscle can block flow from the axillary artery, with negative consequences. Embolization of the axillary artery or its branches is associated with subsequent cyanosis, digital ischemia, and cold intolerance [ 6 ]. Other problems associated with compression of this structure are aneurysm formation, segmental dissection, focal intimal hyperplasia, and branch vessel aneurysms [ 4 ].…”

Fluoroscopic-guided quadrilateral space block for the treatment of quadrilateral space syndrome - A case report

“…Furthermore, fibrous bands, trauma, osteochondroma, and muscular hypertrophy have all been described as causes of neural entrapment or vascular compression leading to QSS. 4,5 Under those circumstances, cases of QSS in the literature commonly involve younger patients, less than forty years of age. Unlike Cahill's original description of presenting symptoms, patients often present with vague complaints of pain without specifically localizing to the posterior shoulder, let alone directly overtop the quadrilateral space.…”

“…In fact, Hang et al recently discussed a patient in their practice who underwent a labral repair, subacromial decompression, exploratory surgery, first rib resection, anterior/middle scalenectomy, neurolysis, and pectoralis minor release before the appropriate diagnosis of QSS was taken. 4 Owing to the fact that most literature on QSS is limited to case series and case reports, there continues to be much variability in the treatment of QSS. Conservative management should be trialed before surgical options are entertained; this include the use of nonsteroidal anti-inflammatories, activity modification focused at avoiding abduction and external rotation, and physical therapy.…”

Diagnosis of hypothenar hammer syndrome in a patient with acute ulnar artery occlusion

“…vQSS is caused by compression or mechanical injury of the posterior circumflex humeral artery. This is reported to occur more often in younger individuals who participate in overhead sports (such as volleyball or tennis) 5…”