Quadrilateral foraminal syndrome is a quadrilateral foraminal structure consisting of the long head of the triceps tendon, the lesser trochanter above the humerus, and the greater trochanter below, with the axillary nerve and posterior rotator humeral artery passing through it. When muscle injury, strain, spasm, scarring, or adhesions occur in this location, the axillary nerve and posterior rotator humeral artery will be compressed, resulting in neurological and vascular symptoms, mainly numbness and decreased normal muscle contraction of the deltoid muscle in the lateral shoulder joint. For example, when the shoulder joint is flexed, abducted and rotated, the numbness and unfavorable muscle movement will be aggravated.