| Axillary nerve palsy | |
|---|---|
| Specialty | Emergency medicine  |
Axillary nerve palsy is a neurological condition in which the axillary (also called circumflex) nerve has been damaged by shoulder dislocation. It can cause weak deltoid and sensory loss below the shoulder. [1] Since this is a problem with just one nerve, it is a type of Peripheral neuropathy called mononeuropathy. [2] Of all brachial plexus injuries, axillary nerve palsy represents only .3% to 6% of them. [3]
Axillary nerve palsy patients present themselves with differing symptoms. For instance, some axillary nerve palsy patients complain that they cannot bend their arm at the elbow, however no other pain or discomfort exists. [4] To further complicate diagnosis, onset of palsy can be delayed and may not be noticed until 12-24 hours after the trauma of shoulder region occurred. [5]
Symptoms include:
Anatomically, damage to the axillary nerve or suppression of it causes the palsy. [5] This suppression, referred to as entrapment, causes the nerve pathway to become smaller and impulses cannot move through the nerve as easily. [2] Furthermore, if trauma causes damage to the myelin sheath, or injures the nerve another way, this will also reduce the ability of nerve impulse flow. [2]
Usually, an outside force is acting to suppress the nerve, or cause nerve damage. [2] Most commonly, shoulder dislocation or fractions in the shoulder can cause the palsy. [8] Contact sports such as football and hockey can cause the injury [9] Other cases have been caused by repeated crutch pressure or injuries accidentally caused by health professionals (iatrogenesis). [7] Furthermore, following an anterior shoulder operation; damage to the axillary nerve is possible and has been documented by various surgeons, thus causing axillary nerve palsy. [10] Other possible causes include: deep infection, pressure from a cast or splint, fracture of the humerus, or nerve disorders in which the nerves become inflamed. [2]
There are rare causes of axillary nerve palsy that do occur. For instance, axillary nerve palsy can occur after there is blunt trauma in the shoulder area without any sort of dislocation or fracture. [5] Examples of this blunt trauma may include: being hit by heavy an object, falling on shoulder, a strong blow while participating in boxing, or motor vehicle accidents. [5] Another rare cause of axillary nerve palsy can occur after utilizing a side birthing position. When the patient lies on their side for a strenuous amount of time, they can develop axillary nerve palsy. This rare complication of labor can occur due to the prolonged pressure on the axillary nerve while in a side-birth position. [4] Some patients who are diagnosed with nodular fasciitis may develop axillary nerve palsy if the location of the rapid growth is near the axilla. [11] In the case of Nodular Fasciitis, a fibrous band or the growth of a schwannoma can both press against the nerve, causing axillary nerve palsy. [11] An injury to the axillary nerve normally occurs from a direct impact of some sort to the outer arm, though it can result from injuring a shoulder via dislocation or compression of the nerve. The axillary nerve comes from the posterior cord of the brachial plexus at the coracoid process and provides the motor function to the deltoid and teres minor muscles. An EMG can be useful in determining if there is an injury to the axillary nerve. The largest numbers of axillary nerve palsies arise due to stretch injuries which are caused by blunt trauma or iatrogenesis. Axillary nerve palsy is characterized by the lack of shoulder abduction greater than 30 degrees with or without the loss of sense in the low two thirds of the shoulder. Normally the patients that have axillary nerve palsy are involved in blunt trauma and have a number of shoulder injuries. Surgery is not always required to solve the problem (information from: Midha, Rajiv, Zager, Eric. Surgery of Peripheral Nerves: A Case-Based Approach. Thieme Medical Publishers, Inc. 2008.)
A variety of methods may be used to diagnose axillary nerve palsy. The health practitioner may examine the shoulder for muscle atrophy of the deltoid muscle. [2] Furthermore, a patient can also be tested for weakness when asked to raise the arm. [2] The deltoid extension lag sign test is one way to evaluate the severity of the muscle weakness. During this test, the physician stands behind the patient and uses the patient's wrist to elevate the arm. Then, the patient is told to hold this position without the doctor's assistance. If the patient cannot hold this position on their own and an angular drop occurs, the angular lag is observed as an indicator of axillary nerve palsy. When the shoulder is at its maximum extension, only the posterior area of the deltoid muscle and the axillary nerve are working to raise the arm. Therefore, no other muscles can provide compensation, which allows the test to be an accurate measure of the axillary nerve’s dysfunction. [6]
Additional testing includes electromyography (EMG) and nerve conduction tests. However, these should not be done right after the injury because results will be normal. These tests must be executed weeks after the initial injury and onset of symptoms. [2] An MRI (magnetic resonance imaging) or X-ray may also be done by a doctor. [2]
In many cases recovery happens spontaneously and no treatment is needed. [2] This spontaneous recovery can occur because distance between the injury location and the deltoid muscle is small. [7] Spontaneous recovery may take as long as 12 months. [5]
In order to combat pain and inflammation of nerves, medication may be prescribed. [2]
Surgery is an option, but it has mixed results within the literature and is usually avoided because only about half of people who undergo surgery see any positive results from it. [3] Some suggest that surgical exploration should be considered if no recovery occurs after 3 to 6 months. [9] Some surgical options include nerve grafting, neurolysis, or nerve reconstruction. [12] Surgery results are typically better for younger patients (under 25) and for nerve grafts less than six centimeters. [13]
For some, recovery does not occur and surgery is not possible. In these cases, most patients’ surrounding muscles can compensate, allowing them to gain a satisfactory range of motion back. [8] Physical therapy or Occupational therapy will help retrain and gain muscle tone back. [2]
The brachial plexus is a network of nerves formed by the anterior rami of the lower four cervical nerves and first thoracic nerve. This plexus extends from the spinal cord, through the cervicoaxillary canal in the neck, over the first rib, and into the armpit, it supplies afferent and efferent nerve fibers to the chest, shoulder, arm, forearm, and hand.
The axillary nerve or the circumflex nerve is a nerve of the human body, that originates from the brachial plexus at the level of the axilla (armpit) and carries nerve fibers from C5 and C6. The axillary nerve travels through the quadrangular space with the posterior circumflex humeral artery and vein to innervate the deltoid and teres minor.
The long thoracic nerve is a branch of the brachial plexus derived from cervical nerves C5-C7 that innervates the serratus anterior muscle.
Wrist drop is a medical condition in which the wrist and the fingers cannot extend at the metacarpophalangeal joints. The wrist remains partially flexed due to an opposing action of flexor muscles of the forearm. As a result, the extensor muscles in the posterior compartment remain paralyzed.
The deltoid muscle is the muscle forming the rounded contour of the human shoulder. It is also known as the 'common shoulder muscle', particularly in other animals such as the domestic cat. Anatomically, the deltoid muscle appears to be made up of three distinct sets of muscle fibers, namely the
A joint dislocation, also called luxation, occurs when there is an abnormal separation in the joint, where two or more bones meet. A partial dislocation is referred to as a subluxation. Dislocations are often caused by sudden trauma on the joint like an impact or fall. A joint dislocation can cause damage to the surrounding ligaments, tendons, muscles, and nerves. Dislocations can occur in any major joint or minor joint. The most common joint dislocation is a shoulder dislocation.
Neurotmesis is part of Seddon's classification scheme used to classify nerve damage. It is the most serious nerve injury in the scheme. In this type of injury, both the nerve and the nerve sheath are disrupted. While partial recovery may occur, complete recovery is impossible.
The musculocutaneous nerve is a mixed branch of the lateral cord of the brachial plexus derived from cervical spinal nerves C5-C7. It arises opposite the lower border of the pectoralis major. It provides motor innervation to the muscles of the anterior compartment of the arm: the coracobrachialis, biceps brachii, and brachialis. It provides sensory innervation to the lateral forearm. It courses through the anterior part of the arm, terminating 2 cm above elbow; after passing the lateral edge of the tendon of biceps brachii it is becomes known as the lateral cutaneous nerve of the forearm.
Erb's palsy is a paralysis of the arm caused by injury to the upper group of the arm's main nerves, specifically the severing of the upper trunk C5–C6 nerves. These form part of the brachial plexus, comprising the ventral rami of spinal nerves C5–C8 and thoracic nerve T1. These injuries arise most commonly, but not exclusively, from shoulder dystocia during a difficult birth. Depending on the nature of the damage, the paralysis can either resolve on its own over a period of months, necessitate rehabilitative therapy, or require surgery.
In medicine, a stinger, also called a burner or nerve pinch injury, is a neurological injury suffered by athletes, mostly in high-contact sports such as ice hockey, rugby, American football, and wrestling. The spine injury is characterized by a shooting or stinging pain that travels down one arm, followed by numbness and weakness in the parts of the arms, including the biceps, deltoid, and spinati muscles. Many athletes in contact sports have suffered stingers, but they are often unreported to medical professionals.
The shoulder joint is structurally classified as a synovial ball-and-socket joint and functionally as a diarthrosis and multiaxial joint. It involves an articulation between the glenoid fossa of the scapula and the head of the humerus. Due to the very loose joint capsule that gives a limited interface of the humerus and scapula, it is the most mobile joint of the human body.
A brachial plexus injury (BPI), also known as brachial plexus lesion, is an injury to the brachial plexus, the network of nerves that conducts signals from the spinal cord to the shoulder, arm and hand. These nerves originate in the fifth, sixth, seventh and eighth cervical (C5–C8), and first thoracic (T1) spinal nerves, and innervate the muscles and skin of the chest, shoulder, arm and hand.
Radial neuropathy is a type of mononeuropathy which results from acute trauma to the radial nerve that extends the length of the arm. It is known as transient paresthesia when sensation is temporarily abnormal.
A dislocated shoulder is a condition in which the head of the humerus is detached from the glenoid fossa. Symptoms include shoulder pain and instability. Complications may include a Bankart lesion, Hill-Sachs lesion, rotator cuff tear, or injury to the axillary nerve.
A winged scapula is a skeletal medical condition in which the shoulder blade protrudes from a person's back in an abnormal position.
Idiopathic ulnar neuropathy at the elbow is a condition where pressure on the ulnar nerve as it passes through the cubital tunnel causes ulnar neuropathy. The symptoms of neuropathy are paresthesia (tingling) and numbness primarily affecting the little finger and ring finger of the hand. Ulnar neuropathy can progress to weakness and atrophy of the muscles in the hand. Symptoms can be alleviated by the use of a splint to prevent the elbow from flexing while sleeping.
Injury of axillary nerve is a condition that can be associated with a surgical neck of the humerus fracture.
Injuries to the arm, forearm or wrist area can lead to various nerve disorders. One such disorder is median nerve palsy. The median nerve controls the majority of the muscles in the forearm. It controls abduction of the thumb, flexion of hand at wrist, flexion of digital phalanx of the fingers, is the sensory nerve for the first three fingers, etc. Because of this major role of the median nerve, it is also called the eye of the hand. If the median nerve is damaged, the ability to abduct and oppose the thumb may be lost due to paralysis of the thenar muscles. Various other symptoms can occur which may be repaired through surgery and tendon transfers. Tendon transfers have been very successful in restoring motor function and improving functional outcomes in patients with median nerve palsy.
Radial nerve dysfunction is a problem associated with the radial nerve resulting from injury consisting of acute trauma to the radial nerve. The damage has sensory consequences, as it interferes with the radial nerve's innervation of the skin of the posterior forearm, lateral three digits, and the dorsal surface of the lateral side of the palm. The damage also has motor consequences, as it interferes with the radial nerve's innervation of the muscles associated with the extension at the elbow, wrist, and fingers, as well the supination of the forearm. This type of injury can be difficult to localize, but relatively common, as many ordinary occurrences can lead to the injury and resulting mononeuropathy. One out of every ten patients with radial nerve dysfunction do so because of a fractured humerus.
A proximal humerus fracture is a break of the upper part of the bone of the arm (humerus). Symptoms include pain, swelling, and a decreased ability to move the shoulder. Complications may include axillary nerve or axillary artery injury.