What You Need to Know About Axillary Neuropathy
What is Axillary Neuropathy?
The axillary nerve is the direct continuation of the brachial plexus. It’s fibers arise from the C5 and C6 spinal nerve roots. The nerve lies in front of the subscapularis muscle (of the rotator cuff), then descends down, exiting the arm pit area through the "Quadrangular space". After exiting the quadrangular space along with the posterior circumflex artery, the nerve supplies a motor branch to the teres minor muscle (of the rotator cuff) and another that courses around the head of the shoulder to innervate the deltoid muscle of the shoulder. A sensory branch of the nerve supplies innervation to the skin along the lower portion of the deltoid muscle region. Axillary nerve injury may result in loss of shoulder abduction (reaching out to the side) or external rotation.
Axillary neuropathy may begin from blunt trauma to the anterior shoulder, particularly in sports such as skiing, football, rugby, baseball, hockey, soccer, weightlifting, and wrestling. Axillary nerve injury symptoms frequently accompany shoulder dislocation. In fact, the reported incidence of axillary nerve injury evaluation and assessments following anterior shoulder dislocation ranges between 9 and 18%. Traumatic axillary nerve injuries may present as part of a larger brachial plexus nerve injury.
Chronic compression or traction is a more common mechanism of axillary neuropathy termed Quadrangular Space Syndrome, aka, Quadrilateral Space Syndrome (QSS). QSS is more common in young active adults, particularly overhead athletes, i.e. throwers and swimmers. QSS is often caused by nerve compression from fibrous bands within the quadrangular space, particularly at the inferior margin of the teres minor (of the rotator cuff). This presentation is common for throwing athletes. QSS may also result from carrying a heavy backpack, the misuse of crutches, overdevelopment/ hypertrophy of the muscles forming the quadrangular space, or a cyst. The condition is more common in the dominant shoulder.
What Will Axillary Neuropathy Look and Feel Like?
The clinical presentation typically consists of dull, poorly localized shoulder aching with possible vague shoulder numbness or tingling. However, pain is not always prominent. Sensory symptoms, when present, are often worse at night. One of the axillary nerve injury symptoms is when patients complain of shoulder weakness, including rapid fatigue with overhead activity or overhead lifting. Compressive symptoms are exacerbated during activity, especially those involving lifting the arm out to the side and external rotation. QSS is difficult to diagnosis and is frequently misidentified as shoulder impingement syndrome. Resisted muscle testing may demonstrate weakness in reaching out to the side or external rotation. Clinicians should be cognizant that weakness may be masked by compensatory muscle recruitment into the neck or muscles of the back. Long-standing compression may result in muscle atrophy.
How Do We Treat Axillary Neuropathy?
Conservative management affords good outcomes for the majority of patients. Overhead athletes may benefit from physical therapy like selective rest and activity modification. Range of motion exercises may be implemented to prevent joint contracture. Conservative care may include cross friction massage therapy or myofascial release techniques to the muscles of the quadrangular space, mobilization to the shoulder joint, cross body and posterior capsule/internal rotation stretching, and rotator cuff strengthening. One should be cautious to avoid positions that place the axillary nerve in a state of sustained traction (i.e. overhead reaching with rotation). Anti-inflammatory modalities and/or NSAID’s may be beneficial to manage painful symptoms.
Axillary neuropathy heal slowly, and surgical intervention is generally not considered until conservative management fails to restore muscle function in three to six months. Surgical intervention includes neurolysis and release of fibrous bands. A nerve graft may be considered in severe cases. Surgical outcomes are typically good when they are indicated.
If you have been suffering from shoulder pain or symptoms of axillary neuropathy, make an appointment to see what our doctors can do for you.