include throwing a powerful pitch, holding a fast moving rope during water sports, falling over onto an outstretched hand at speed, or making a sudden thrust with the paddle in kayaking. A chronic tear develops over a period of time. They usually occur at or near the tendon, as a result of the tendon rubbing against the underlying bone. The teres minor is typically normal following a rotator cuff tear. Imaging Atrophy of the teres minor muscle is often a consequence of a rotator cuff tear, but common isolated teres minor atrophies have also been found. A quadrangular space syndrome causes excessive and or chronically compression of the structures which pass through this anatomical tunnel. The axillary nerve and the posterior humeral circumflex artery pass through the space. People affected note shoulder pain and paresthesia down the arm first and foremost in abduction, extension, external rotation and overhead activity. Selective atrophy of the teres minor muscle has been seen and pulled together directly with compression of the corresponding axillary nerve branch or posterior humeral circumflex artery. Fibrous bands, cysts of the glenoid labrum, lipoma or dilated veins can occupy the quadrilateral space pathologically. Similar symptoms are common with anterior shoulder dislocation, humeral neck fracture, brachial plexus injury and thoracic outlet and inlet syndrome. It is important to include those pathologies for a complete as possible differential diagnosis. Ultrasonography is a tool to detect a fatty degenerative atrophy of the teres minor and shows in affected muscles increased echogenicity and betimes a slight reduction in muscle bulk. MR imaging helps to consolidate the diagnosis of neurogenic muscle atrophy. Extracellular edema after traumatic events causing neural damage show an increased signal intensity on T2-weighted MRI sequences and normal intensity on T1-weighted sequences. Posterior humeral circumflex artery compression and reduced blood flow in stressful arm positions and or maneuvers can be diagnosed by a Doppler ultrasonography. The nerve should be detected adjacent to the vessel. In an elevated arm position the axillary neurovascular bundle can be seen at the posterior axillary fold just before it perforates the deltoideus, while the posterior course is well visible in the neutral position. For a detailed assessment of the artery, a MR angiography is required. The major task of an ultrasonographic examination is to rule out any space occupying mass. Additional electromyography is helpful to reveal any decelerated nerve conduction velocity, and thus denervation of the concerned