Quadrilateral Space Syndrome
What is it?
What is the cause?
Signs and Symptoms:
Pain referral pattern:
Diagnostic tool to rule in/out:
Presentation of the disease:
What is it?
- A clinical syndrome resulting from compression of the axillary nerve and posterior circumflex artery in the quadrilateral space.
- The quadrilateral space is the anatomic space in the upper arm bounded by the long head of the triceps, the teres minor and teres major muscles, and the cortex of the humerus.
What is the cause?
- Symptoms are caused by entrapment of the axillary nerve within the quadrilateral space.
- Repetitive stress or overuse is a major cause of quadrilateral space syndrome.
- Some of the more common causes of overuse are seen in overhead sports like throwing and swimming.
Signs and Symptoms:
- Symptoms typically occur with the arm in an over head position, e.g., the late cocking or early acceleration phase of the throwing motion.
- Four cardinal features of QSS: poorly localized shoulder pain, nondermatomal distribution of parasthesia, discrete point tenderness in the quadrilateral space, and a positive arteriogram finding with the affected shoulder in a position of abduction and external rotation.
Pain referral pattern:
- There is pain over the posterior aspect of the shoulder that may radiate into the arm and forearm with a non-dermatomal distribution.
Diagnostic tool to rule in/out:
- Definitive diagnosis may require an angiogram to identify an occlusion of the circumflex scapular artery, which accompanies the axillary nerve through the quadrilateral space.
Presentation of the disease:
- The athlete will typically complain of vague pain in the shoulder and around the shoulder that can radiate as far distally as the forearm in a nondermatomal pattern.
- This may be experienced before, during, and after physical exertion. Often isolated tenderness in response to palpation over the quadrilateral space.