The brachial plexus refers to a network of nerves that start out in the neck and move through the upper limbs. This covers the shoulders, arms, elbows, forearms, wrist as well as the hand. All five of the nerves originate in the spinal cord. These nerves are responsible for the sensations and motor movements of the upper extremity. In medical terms, the brachial plexus is the somatic nerve plexus between the ventral rami of the lower four cervical and first thoracic nerve.
Nerves of the brachial plexus labeled. - Image Copyright: Alila Medical Media / Shutterstock
What Does Pain in the Neck and Shoulders Indicate?
The pain that radiates from the neck down the shoulders is usually associated with an injury to the brachial plexus. The nerves of the brachial plexus may have been damaged by stretching, pressure, or cutting. The jerk of the head away from the shoulder can cause the nerves to stretch suddenly beyond their usual capacity. This is called neurapraxia.
A fracture or dislocation of the shoulder or arm bones may put enough pressure on the brachial plexus nerves to cause damage, also called rupture. If the pressure is too much during an accident the nerves may be torn right out of the spinal cord, or they may be cut when the soft tissue is injured. This is known as avulsion. It is the most severe injury to the brachial plexus.
In axonotemesis, the axons of the nerve are severed. When the entire nerve is divided the condition is referred to as neurotemesis. If a tumour grows from the divided axons that fail to regenerate, it is called neuroma. Minor brachial plexus injuries are called stingers or burners and are common in contact sports.
How is Brachial Plexus Injury Diagnosed?
The pain is the first clinical feature that the physician will consider during a physical exam. In order to confirm the severity of the injury, the physician will prescribe some of these tests:
An angiogram may be conducted by injecting a contrast material into an artery or vein to check the condition of the blood vessels before surgery.
Nerve conduction test is also done as part of the EMG wherein a small current is passed through the nerve and speed of conduction is measured. This test provides information about the health of the nerve.
Electromyography or EMG is a procedure in which an electrode is inserted into different muscles through the skin. The electrical activity of the muscle is checked at rest and when contracted. There may be little pain and some discomfort caused by the electrodes passing through the skin.
Magnetic resonance imaging or MRI uses magnets as well as radio waves to view the body. The imaging allows the physician to know the amount of damage caused to the nerve due to an injury to the brachial plexus. MRI also provides valuable information about the state of the arteries when the patient may need to undergo reconstructive surgery for the upper limbs.
Computerized tomography or CT myelography may be used to provide information about the nerve roots and spinal cord. A CT scan is prescribed if the MRI information is inadequate.
What Treatments Exist for Brachial Plexus Injuries?
A broad spectrum of injuries can affect the brachial plexus and treatment will depend on the severity and nature of injury. Broadly speaking treatment options fall under two types:
Non-surgical treatment is usually considered when the injury is not too severe and is likely to heal on its own. Pain management is done through medication and massages. Physiotherapy is recommended as part of the individual’s rehabilitation routine. This will enable the muscles and joints to maintain their range of motion even as the nerves heal. If the nerve injury related pain does not reduce within a couple of months, surgical intervention may be needed.
Surgery needs to be conducted within six months from the time of injury, as the nerves may not respond to reconnection after that period of time. The most critical decision for the doctor is fixing the time of the surgery. Surgical treatments will include nerve graft, nerve transfer, tendon transfer, and muscle transfer.
In a nerve graft, the damaged portion of the brachial plexus is taken out and replaced with healthy nerves taken from some other part of the patient’s body. A nerve transfer is done when the root of the nerve has been completely removed from the spinal cord. The surgery consists of attaching a relatively less important nerve connected to the spinal cord, to the damaged nerve.
The surgeon may consider a blend of both nerve transfer and graft. In muscle and tendon transfers, healthy replacements are surgically removed from other parts of the body and reconnected with nerves and blood vessels supplying the muscles. The attending doctor will make decisions based on the nerve injury.
Reviewed by Susha Cheriyedath, MSc