Pinching of the brachial nerve plexus

Pinching of the brachial plexus root, or, as it is often said, pinching of the brachial nerve, is a rather serious neurological lesion, since the network of intersecting nerves of this anatomical region transmits signals from the spinal cord to the upper limbs, being responsible for motor (motor or muscle) and sensory (i.e., skin sensitive) innervation of the shoulder, arm and hand.

Epidemiology

Cases of damage to the brachial plexus in road traffic-related injuries, according to some reports, exceed 40%.

Postoperative damage to the brachial plexus occurs in 12-15% of cases.

The prevalence of the compression effect of tumors on the roots of the plexus brachialis is estimated at 0.4-1.2%.

And the statistics of the development of paralysis of the brachial plexus in newborns: 0.4-5% of cases for every thousand live births.[1]

Causes of the pinched shoulder nerve

Considering the etiology of pinching the nerve root  of the brachial plexus  (plexus brachialis) - without touching the short and long lateral branches emerging from it at various points, it should be recalled that this peripheral plexus is formed by the ventral (anterior) branches of the  spinal nerves  (cervical C5-C8 and the first thoracic T1 ) and extends from the base of the neck to the armpit, passing between the anterior and medial scalene muscles (musculus scalenus). And its motor and sensory roots are precisely these paired spinal nerves that exit the spinal cord through the intervertebral foramina at the level of the lower cervical and upper thoracic vertebrae.[2]

The key causes of compression lesions of the roots - pinching or compression - may be due to:

• trauma of the brachial plexus and damage to the joint and / or bone and ligamentous apparatus, including birth injuries (obstetric trauma of the brachial plexus);[3]
• habitual dislocation of the shoulder joint;
• increased physical stress on the shoulder girdle;
• osteochondrosis of the vertebrae of the cervicothoracic spine with the development  of the syndrome of the anterior scalene muscle ;[4]
• elongated (hypertrophied) spinous process of the seventh cervical vertebra (C7) - the most protruding in the neck;
• thoracic outlet syndrome (compression of the nerve roots between the clavicle and the first rib);[5], [6]
• a growing tumor of the brachial plexus, in particular, schwannoma, neurofibroma, neurosarcoma, as well as metastases of primary lung carcinoma.

Risk factors

Risk factors for pinched brachial nerve (brachial plexus roots) include:

• traffic accidents;
• falls with bruises, dislocations and fractures of the shoulder joint, lower cervical vertebral joints or collarbone;
• frequent carrying of weights, including in a bag on the shoulder strap or in a backpack;
• engaging in contact sports, in particular football and wrestling;
• surgical interventions in the brachial plexus.

In infants, the risk of pinching is increased during difficult labor, which may be due to heavy weight, malposition or dystocia of the fetus's shoulders, and a narrow pelvis of the mother.

Pathogenesis

Experts note the vulnerability of the nerve roots to compression, since their epineurium (outer layer) is poorly developed, and the connective tissue sheath (perineurium) is absent.[7]

Compression neuropathies are caused by direct pressure on the nerves. In fact, pinching of the nerve roots (including the brachial plexus) leads to the development of compressive  ischemic neuropathy  with a deterioration in the nutrition of the nerve fiber tissue, which negatively affects their functions. And the pathogenesis of neuropathic pain caused by pinching  , muscle (motor) and sensory disorders lies in the partial or complete blockade of nerve conduction.[8], [9]

Symptoms of the pinched shoulder nerve

The first signs of pinching in the form of radicular syndrome depend on which particular root is subjected to compression and its innervation zone (muscles and dermatomes).

So, pinching the C5 root, which is responsible for the innervation of the muscles of the shoulder girdle and part of the muscles of the shoulder, weakens the deltoid muscle of the shoulder and part of the biceps (flexing and extending the arm with the elbow joint) and reduces the sensitivity of the skin of its outer surface to the elbow, causing tingling or burning, as well as loss skin sensitivity - numbness. The pain may radiate to the shoulder.

With compression of the C6 root of the brachial plexus, symptoms are manifested by pain in the shoulder and forearm (which is aggravated by movements of the arms or neck); paresthesia or numbness of the outer side of the forearm, thumb and forefinger; decrease in strength or complete loss of muscle reflexes of the biceps of the shoulder.

If the C7 root is pinched, then there is a loss of skin sensitivity down the back of the hand to the index and middle fingers; a decrease in the triceps reflex (the triceps muscle of the shoulder that straightens the elbow), as well as pain in the shoulder and forearm (on the back surface), which can give under the shoulder blade.

Symptoms of root pinching C8 and T1 include pain in parts of the shoulder, forearm, hand and little finger; progressive weakness in the wrist, hand, or fingers; numbness of the forearm or hand.

A pinched nerve in the shoulder joint is accompanied by pain in the shoulder and neck (especially when turning the head from side to side), numbness and muscle weakness of the arm and hand (thenar muscles of the palm), leading to difficulty with raising the arm and fine motor skills.

See also -  Syndromes of lesions of the brachial plexus

Complications and consequences

Complications of a pinched brachial nerve (brachial plexus root) can be very serious, and some of the consequences are irreversible.

For example, pain as a result of damage to the nerve roots can become chronic and reach causalgia, and the limitation of the mobility of the arm or hand leads to the so-called stiffness of the joints, which exacerbates the difficulty in moving the limb.

Compression of nerve fibers is due not only to muscle denervation, but also to their gradual atrophy.

Severe injuries of the brachial plexus with pinching of its roots can lead to  paralysis of the arm  and disability.

Diagnostics of the pinched shoulder nerve

A physical examination by a neuropathologist (with an assessment of the range of motion on the side of the lesion) and anamnesis are supplemented by mandatory instrumental diagnostics, including x-rays of the shoulder joint and shoulder girdle, x-rays of the cervical spine, ultrasound of the brachial plexus, electromyography and electroneuromyography (nerve conduction study). If necessary, CT or MRI is performed.[10]

Differential diagnosis

Differential diagnosis should exclude shoulder plexitis, inflammatory diseases of the shoulder joint, pinching of the C1-C4 roots of the cervical plexus (cervical radiculopathy), cervical facet joint syndrome,  carpal tunnel syndrome , myofascial syndrome, chest outlet compression syndromes, endocrine peripheral neuropathies, autoimmune motor neuron diseases and others

Treatment of the pinched shoulder nerve

After the diagnosis is made, in most cases, a pinched brachial nerve is treated at home.

The main pharmacological drugs are symptomatic: pain pills - non-steroidal anti-inflammatory drugs (NSAIDs) with an analgesic effect, for example, Paracetamol, Ibuprofen and other  neuralgia pills

Corticosteroid injections may also be given to relieve pain.

To restore motor functions and expand the range of motion of the arms and hands, physiotherapy is used: physiotherapy exercises and massage for pinched shoulder nerves.

Read more in the publications:

• Treatment of neuropathy of the upper extremities
• Treatment of neuropathic pain
• Hand numbness treatment

Additionally, herbal treatment can be carried out using: calamus root extract (Acorus calamus) - as an analgesic; ginkgo biloba (Ginkgo biloba) - to improve tissue trophism and reduce oxidative stress, as well as increase the conduction of nerve impulses in the central nervous system; sage officinalis (Salvia officinalis) - as a means of strengthening the nervous system.

Prevention

Most often, damage to the brachial plexus cannot be prevented, except to limit physical activity on the shoulder girdle.

Forecast

With relatively minor damage to the brachial plexus, the prognosis is more favorable, since in such cases, in 90% of patients, the mobility and sensitivity of the upper limbs - with proper treatment - can be normalized. Severe injuries are characterized by chronic dysfunction of the roots of the brachial plexus.