Many patients with neck and shoulder pain and shoulder and back pain are encountered in the clinic. One of them is often overlooked with interstitial pain and numbness in the shoulder and arm, which gradually spreads to the upper arm, forearm and hand, quadrilateral foramen syndrome.
Quadrilateral foramen syndrome is a group of symptoms and signs caused by the axillary nerve being embedded at the quadrilateral foramen of the shoulder.
Causes
When the shoulder joint is abducted and externally rotated. The muscles that make up the quadrilateral foramen are all stretched. This is caused by the compression of the quadrilateral foramen from three directions.
Anatomy
The quadrilateral foramen, also known as the quadrilateral space, is located between the medial humerus and the outer edge of the scapula.
Superior border: small round muscle; inferior border: large round muscle; medial border: long head of triceps; lateral border: lateral head of triceps and surgical neck of humerus.
The axillary nerve originates from the posterior bundle of the brachial plexus nerve to the anterior border of the subscapularis muscle, penetrates through the quadrilateral foramen in conjunction with the posterior humeral vessels, and passes around the posterior aspect of the surgical neck of the humerus, directly below the inferior border of the lesser round muscle tendon and at the midpoint of the posterior border of the deltoid muscle, the nerve vessels migrate from the quadrilateral foramen to the subdeltoid space and innervate the lesser round muscle, deltoid muscle and lateral shoulder skin.
Due to the above anatomical features, lesions of the bones and tendons around the quadrilateral foramen can reduce the gap and constitute a factor for axillary nerve impingement.
Etiology and pathogenesis
Congestion, edema, hyperplasia or crust formation in the soft tissues within and around the quadrilateral foramen are all possible causes of axillary nerve impingement.
The main etiological factors are.
(1) Scapular impingement injury may cause contusion of bones, muscles and tendons around the quadrilateral foramen, resulting in congestion, edema, hyperplasia and scar formation in the damaged tissues and direct axillary nerve impingement;
(2) The shoulder joint is suddenly and excessively abducted, the tissues around the quadrilateral foramen are damaged by sudden traction, and the scar formation during the repair process makes the quadrilateral foramen relatively smaller and the axillary nerve is compressed;
(3) Repeated movement of the shoulder joint causes chronic injury to the axillary nerve by repeated friction in the muscles around the rotator cuff, and the pathological change is local tissue congestion and edema, which in turn produces axillary nerve compression symptoms.
④Humeral surgical neck fracture, late bone scab formation, direct or indirect compression of the axillary nerve.
Diagnostic points
①History of trauma to the shoulder or posterior axillary area or history of repeated activity.
② Paralysis of deltoid and triceps muscle.
③Sensory impairment of the lateral shoulder skin.
④Electromyography suggests nerve injury in the shoulder.
Treatment and prevention
①There should be electrical stimulation of the deltoid muscle;
②Take vitamin B1, vitamin B12 and other neurotrophic drugs;
(3) Cooperate with appropriate functional exercises for shoulder abduction. If conservative treatment is not effective, axillary nerve exploration and release can be performed.