The Axillary nerve is formed within the axilla area of the upper limb. It is a direct continuation of the posterior cord from the brachial plexus, and therefore contains from the C5 and C6 nerve roots. In the axilla, the Axillary nerve is located posterior to the Axillary artery and anterior to the subscapularis muscle. It exits the axilla at the inferior border of the subscapularis which is often accompanied by the posterior circumflex humeral artery and vein.
Additionally, the Axillary nerve passes medically to the surgical neck of the humerus, where it divides into three terminal branches, including:
- Posterior terminal branch – This provides motor inner at ion to the posterior aspect of the deltoid muscle and teres minor. It also innervates the skin over the inferior part of the deltoid as the upper lateral cutaneous nerve of the arm.
- Anterior terminal branch – The anterior terminal branch winds around the surgical neck of the humerus and provides motor inner at ion to the anterior aspect of the deltoid muscle. It terminates with cutaneous branches to the anterior and anterolateral shoulder.
- Articular branch – The articular branch supplies the glenohumeral joint.
The Axillary nerve usually travels through the quadrangular space together with the posterior circumflex artery and vein. The quadrangular space is a gap in the muscles of the posterior scapular region. It is a pathway for neuromuscular structures to move from the axilla anteriorly to the posterior shoulder and arm. It is bounded by the inferior, superior, lateral, medial, and anterior.
Axillary nerve injuries are one of the most common peripheral nerve injuries that are known to affect athletes who participate in contact sports. It can occur from glenohumeral dislocation, proximal humerus fracture or from a direct blow to the anterolateral deltoid muscle. Axillary nerve injuries after a fracture or dislocation of the shoulder are some common causes. Therefore, injuries to the bones, joints, or other muscles of the rotator cuff may compromise shoulder motion by itself and Axillary nerve injury particularly if they are mild, may occur.
Causes & Symptoms of an Axillary Nerve Injury
Axillary nerve injury can be caused due to three main roles that associate with this condition, such as:
Nerve compression
The Axillary nerve may be compressed. This causes more temporary symptoms, rather than permanent damage.
Traumatic injury
Injury directly to the Axillary nerve can be caused due to traumatic injury such as a shoulder dislocation or direct impact to the outside of the upper arm. In this case, damage is done to the nerve, which the myelin sheath (which surrounds the nerve) or the axon (the nerve itself) are two of the most common nerves to be injured. The injured nerves can heal, but also may cause permanent disability, depending on the extent of the damage.
Quadrilateral space syndrome
This is a condition that occurs when the Axillary nerve is suddenly compressed within the quadrilateral space at the back of the shoulder. This is often seen in throwers, such as baseball pitchers. In addition, patients also report a great amount of pain at the back of their shoulder.
Certain symptoms depend on where the nerve injuries can occur and how severe they are. The following below are some common symptoms that may lead to an Axillary nerve injury:
- Numbness or loss of feeling in the hand or arm.
- An arm that hangs limply.
- Burning, stinging, or severe and sudden pain in the shoulder or arm.
- Less range of motion of the shoulder, arm, wrist, or hand.
- Having problems with regular physical activities, such as lifting your arms above your head.
- Having difficulty lifting certain objects.
Axillary nerve injury pain can be mild to severe, depending on the type of extent of the injury. For instance, a simple stretched nerve may hurt for a week or so, however, a ruptured nerve can cause longer-term pain that may require physiotherapy and potentially surgery to the affected shoulder.
Who gets an Axillary Nerve Injury?
The following are a few of the risk factors for an Axillary nerve injury:
- Sports – Athletes who participates in high-impact sports that involve repetitive upper body movement (such as basketball, football, tennis and lacrosse) are at a higher risk of experiencing Axillary nerve damage, thus leading to disorders such as Axillary nerve dysfunction.
- Repetitive shoulder use – If you perform repetitive tasks using your shoulder, you are at an increased risk of Axillary nerve injuries.
- Bone fractures – Patients who have had previous fractures in their shoulders may have a chance of experiencing this condition more than those who have not had a fracture in the past.
- Unsupportive equipment – Improper use of supportive equipment such as crutches may eventually lead you to developing a disorder known as Axillary nerve dysfunction.
How Does an Axillary Nerve Injury Affect You? How Serious is it?
As mentioned earlier, the axillary nerve is one of the many nerves that is included within the brachial plexus which include musculocutaneous nerve, median nerve, axillary nerve, radial nerve, and ulnar nerve. All of the nerves mentioned are attached at the ends of the brachial plexus. However, brachial plexus injury at birth can lead to two different disorders, which are Erb’s palsy and Klumpke’s palsy:
Erb’s palsy
Erb’s palsy is a condition characterized by arm weakness and loss of motion. It can occur in both infants and adults. It is typically caused by a physical injury during newborn delivery or by traumatic force downward on the upper arm and shoulder, damaging the brachial plexus.
Klumpke’s palsy
Also known as Klumpke’s paralysis, is a condition that occurs from damage to the brachial plexus nerves. It is also sometimes referred to as Dejerine-Klumpke palsy.
Recommended Treatment & Rehabilitation for an Axillary Nerve Injury
During a diagnosis of an axillary nerve injury, a healthcare provider will first examine your neck, arm, and shoulder. This will help your doctor get a clear view of what caused your damaged nerve. Additional tests that may be used to check axillary nerve injuries include:
- X-rays – This can be used to show any broken bones or damaged to the tissues around your axillary nerve.
- Magnetic resonance imaging (MRI) – MRI may be ordered to visualize a clearer view of the shoulder injury within the brachial plexus.
Generally, the recovery time for an axillary nerve injury may take several months. However, if a severe axillary nerve injury has been suspected, surgery through the brachial plexus may be required to release the damaged nerve. Therefore, before recommending this type of procedure, your surgeon needs to understand which nerves are affected and the injury’s location.
If this is required, a neurosurgeon, plastic surgeons, and neurologists will be able to work with you to determine the best treatment approach based on the injury and your treatment goals. Certain surgical procedures your surgeon might recommend include:
Nerve repair
When a nerve has been cut or torn, your surgeon may be able to re-connect it by sewing the ends back together. This is performed with the help of a microscope and small, specialized instruments.
Decompression and neurolysis
When your axillary nerve is compressed but otherwise intact, a decompression surgery can help relieve the pressure on the nerve and address related symptoms and loss of function.
Nerve transfer surgery
During a nerve transfer, a nearby functioning nerve that is performing a noncritical function is connected to the injured nerve. This creates a framework for new growth and a pathway for signals.
Recovery after a brachial plexus surgery includes healing of the tissues that were operated on and regain any lost function. While healing of the tissues is relatively quick, function recovery may take months depending on the procedure you had and the extent of the injury.
Physiotherapy should begin as soon as possible after diagnosis or surgery has been done. Your physiotherapist will begin by identifying your muscle weakness, help reduce or prevent muscle / joint contractures, and encourage movement and function. Even when surgery isn’t required, physiotherapy may need to continue for weeks and/or months, as the nerves slowly grow again or recover from damage. Therefore, several treatment plans your physiotherapist may work with you include the following:
Prevention of injury
Your physiotherapist will explain possible injuries that could occur without recurrence to help prevent further injuries.
Passive and active stretching
Your physiotherapist will assist you in performing gentle stretches to increase joint flexibility, and prevent or delay contractures in the arm.
Improving your strength
He or she will teach you exercises and activities to maintain or increase arm strength. Then, your therapist will identify certain simple tasks that promote strength without the need to put extra strength.
Modalities
Your physiotherapist may use a variety of modalities to help improve muscle function and movement. Electrical stimulation is sometimes applied to gently stimulate the axillary nerve signal to the muscle. Flexible tape can be applied over specific muscle areas to help guide proper muscle movement, or promote relaxation. Constraint-induced movement therapy (CIMT) may also be used to the non-affected arm to limit and encourage use of the affected arm.
The following exercises listed below will help boost that specific muscle and improve symptoms associating with your axillary nerve:
Lateral raises
Stand up straight and squeeze your shoulder blades together. Next, holding a dumbbell in your hand, turn your thumb toward the ceiling. Lift your arm out to the side until it is parallel to the ground. Hold for 2-3 seconds, then slowly lower back down before repeating 3-4 times a day.
Grip strengthening
Squeeze a small ball for 30 seconds to one minute. Repeat this simple method several times a day.
Rubber band
Muscles that abduct your fingers, or move them apart, can become weak with damage to the lower brachial plexus. Therefore, it is essential to perform this specific exercise. Begin by wrapping a rubber band around your fingers, with the exception of your thumb. Next, spread your fingers apart and hold for 2-3 seconds. Slowly bring them back together and repeat for 10 repetitions, 3-4 sets a day.
Biceps curls
Hold a dumbbell and being with your arm straight, resting by your side. Bend your elbow as far as possible. Hold for 2-3 seconds at the top of the movement, then slowly lower back down. Repeat this exercise 2-3 times a day.
Alternative & Homeopathic Treatment for Axillary Nerve Injury
Mild graded axillary nerve injuries respond very well to a combination of homeopathic treatments. Some of them include:
- Non-steroidal anti-inflmmatory drugs (NSAIDs) – Anti-inflammatory medications such as ibuprofen or naproxen can help reduce swelling and inflammation located in your shoulder where your axillary nerve is affected.
- Supporting equipment – Certain equipment, such as braces, splints, and compression sleeves can help immobilize and lessen symptoms linked to your axillary nerve injury.
- Pain-relieving cream – Over-the-counter pain-relieving cream are a great help due to its inflammatory properties when absorbed in the skin where your nerve is affected. Most patients tend to use these types of creams instead of taking oral medications.
- Massage – Getting a massage by a professional massage therapist can help boost your recovery from your nerve injury and improve blood flow once a massage session has been done.