EMG test is often performed together with another test called nerve conduction study, which measures the conducting function of nerves. NCV study shows loss of nerve conduction in the distal segment (3 to 4 days after injury). According to NCV study, in axonotmesis there is an absence of distal sensory-motor responses.

Electromyography (EMG) is a medical test performed to evaluate and record the electrical activity (electromyogram) produced by skeletal muscles using an instrument called electromyograph. In axonotmesis, EMG changes (2 to 3 weeks after injury) in the denervated muscles include:

1. Fibrillation potentials (FP)

2. Positive sharp waves

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. Furthermore, a patient can also be tested for weakness when asked to raise the arm. 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.

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. An MRI (magnetic resonance imaging) or X-Ray may also be done by a doctor.

Peripheral neuropathy may first be considered when an individual reports symptoms of numbness, tingling, and pain in feet. After ruling out a lesion in the central nervous system as a cause, diagnosis may be made on the basis of symptoms, laboratory and additional testing, clinical history, and a detailed examination.

During physical examination, specifically a neurological examination, those with generalized peripheral neuropathies most commonly have distal sensory or motor and sensory loss, although those with a pathology (problem) of the nerves may be perfectly normal; may show proximal weakness, as in some inflammatory neuropathies, such as Guillain–Barré syndrome; or may show focal sensory disturbance or weakness, such as in mononeuropathies. Classically, ankle jerk reflex is absent in peripheral neuropathy.

A physical examination will involve testing the deep ankle reflex as well as examining the feet for any ulceration. For large fiber neuropathy, an exam will usually show an abnormally decreased sensation to vibration, which is tested with a 128-Hz tuning fork, and decreased sensation of light touch when touched by a nylon monofilament.

Diagnostic tests include electromyography (EMG) and nerve conduction studies (NCSs), which assess large myelinated nerve fibers. Testing for small-fiber peripheral neuropathies often relates to the autonomic nervous system function of small thinly- and unmyelinated fibers. These tests include a sweat test and a tilt table test. Diagnosis of small fiber involvement in peripheral neuropathy may also involve a skin biopsy in which a 3 mm-thick section of skin is removed from the calf by a punch biopsy, and is used to measure the skin intraepidermal nerve fiber density (IENFD), the density of nerves in the outer layer of the skin. Reduced density of the small nerves in the epidermis supports a diagnosis of small-fiber peripheral neuropathy.

Laboratory tests include blood tests for vitamin B-12 levels, a complete blood count, measurement of thyroid stimulating hormone levels, a comprehensive metabolic panel screening for diabetes and pre-diabetes, and a serum immunofixation test, which tests for antibodies in the blood.

Plexopathy symptoms often resemble spinal cord disorders. A neurosurgical consultation is usually undertaken to ensure proper diagnosis, management, and treatment. Patients with chronic symptoms will likely be advised to follow up with outpatient care from either their health care provider or specialist.

The first steps in the evaluation and later management of plexopathy would consist of gathering a medical history and conducting a physical examination by a healthcare clinician. Motor function defect patterns detected within either the upper or lower extremities help with diagnosis of the disorder.

X-rays of the cervical spine, chest, and shoulder are usually ordered if symptoms point to acute Brachial plexopathy. If the physical history reveals a history of diabetes, collagen vascular disease, or symptoms of infection, the physician may order a series of blood tests including a complete blood count (CBC) and a comprehensive metabolic panel (CMP).

EMG &NCV can help to treatment with the diagnosis of the location and severity of the lesion.

The severe pain of HNA can be controlled with an anti-inflammatory drug such as prednisone, although it is unknown whether these anti-inflammatory drugs actually slow or stop the nerve degeneration process.

Nerve regeneration after an episode is normal, and in less severe cases a full recovery of the nerves and muscles can be expected. However, in a severe case permanent nerve damage may occur.

The distinct innervation of the hand usually enables diagnosis of an ulnar nerve impingement by symptoms alone. Ulnar nerve damage that causes paralysis to these muscles will result in a characteristic ulnar claw position of the hand at rest. Clinical tests such as the card test for Froment's sign, can be easily performed for assessment of ulnar nerve. However, a complete diagnosis should identify the source of the impingement, and radiographic imaging may be necessary to determine or rule-out an underlying cause.

Imaging studies, such as ultrasound or MRI, may reveal anatomic abnormalities or masses responsible for the impingement. Additionally, imaging may show secondary signs of nerve damage that further confirm the diagnosis of impingement. Signs of nerve damage include flattening of the nerve, swelling of the nerve proximal to site of injury, abnormal appearance of nerve, or characteristic changes to the muscles innervated by the nerve.

Electrophysiologic testing is an essential part of the evaluation of Anterior interosseous nerve syndromes. Nerve conduction studies may be normal or show pronator quadratus latency.⁠⁠

Electromyography (EMG) is generally most useful and will reveal abnormalities in the flexor pollicis longus, flexor digitorum profundus I and II and pronator quadratus muscles.⁠⁠

The role or MRI and ultrasound imaging in the diagnosis of Kiloh-Nevin syndrome is unclear.⁠

If asked to make the "OK" sign, patients will make a triangle sign instead.

This 'Pinch-Test' exposes the weakness of the Flexor pollicis longus muscle and the flexor digitorum profundus I leading to weakness of the flexion of the distal phalanges of the thumb and index finger. This results in impairment of the pincer movement and the patient will have difficulty picking up a small item, such as a coin, from a flat surface.

The treatment of peripheral neuropathy varies based on the cause of the condition, and treating the underlying condition can aid in the management of neuropathy. When peripheral neuropathy results from diabetes mellitus or prediabetes, blood sugar management is key to treatment. In prediabetes in particular, strict blood sugar control can significantly alter the course of neuropathy. In peripheral neuropathy that stems from immune-mediated diseases, the underlying condition is treated with intravenous immunoglobulin or steroids. When peripheral neuropathy results from vitamin deficiencies or other disorders, those are treated as well.

In many cases recovery happens spontaneously and no treatment is needed. This spontaneous recovery can occur because distance between the injury location and the deltoid muscle is small. Spontaneous recovery may take as long as 12 months.

In order to combat pain and inflammation of nerves, medication may be prescribed.

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. Some suggest that surgical exploration should be considered if no recovery occurs after 3 to 6 months. Some surgical options include nerve grafting, neurolysis, or nerve reconstruction. Surgery results are typically better for younger patients (under 25) and for nerve grafts less than six centimeters.

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. Physical therapy or Occupational therapy will help retrain and gain muscle tone back.

HNA is an episodic disorder; it is characterized by episodes generally lasting 1–6 weeks. During an episode, the nerves of the brachial plexus are targeted by the body as antigens, and the body's immune system begins to degenerate the nerves of the brachial plexus. The exact order or location of the nerve degeneration cannot be predicted before an episode. Other areas of the nervous system that have been affected are the phrenic nerves and the recurrent laryngeal. As the nerves lose function, the muscles associated with those nerves begin to atrophy. In brachial plexus degeneration, atrophy may occur in the deltoid muscles. In phrenic nerve degeneration, the diaphragm may be affected. In this case, breathing can be impaired due to a lack of muscle control of the diaphragm. If the recurrent larangyl nerve is targeted, the pharynx will begin to atrophy and voice function may be lost.

Most patients diagnosed with cubital tunnel syndrome have advanced disease (atrophy, static numbness, weakness) that might reflect permanent nerve damage that will not recover after surgery. When diagnosed prior to atrophy, weakness or static numbness, the disease can be arrested with treatment. Mild and intermittent symptoms often resolve spontaneously.

The diagnosis is based on symptoms and signs alone and objective testing is expected to be normal. This syndrome may be clinically tested by flexing the patients long finger while the patient extends the wrist and fingers. Pain is a positive finding.

The chief complaint of this disease is usually pain in the dorsal aspect of the upper forearm, and any weakness described is secondary to the pain. Tenderness to palpation occurs over the area of the radial neck. Also, the disease can be diagnosed by a positive "middle finger test", where resisted middle finger extension produces pain. Radiographic evaluation of the elbow should be performed to rule out other diagnoses.

Physiotherapy

To increase strength of muscle

To improve muscle functions

Electrical modalities =Electric stimulation.etc.

Occupational Therapy

Positioning, ROM, Sensory, Splinting

The diagnosis may be confirmed by an EMG examination in 5 to 7 days. The evidence of denervation will be evident. If there is no nerve conduction 72 hours after the injury, then avulsion is most likely..

The most advanced diagnostic method is MR imaging of the brachial plexus using a high Tesla MRI scanner like 1.5 T or more. MR helps aid in the assessment of the injuries in specific context of site, extent and the nerve roots involved. In addition, assessment of the cervical cord and post traumatic changes in soft tissues may also be visualised.

Patients with diabetes and proximal (hip, thigh) pain and weakness are often suspected of having diabetic amyotrophy. More definitive diagnosis is commonly made with electrodiagnostic studies including nerve conduction studies (NCS) and electromyogram (EMG). Diabetic amyotrophy is often a diagnosis of exclusion in diabetic patients with a lumbosacral plexopathy for whom no other cause of lumbosacral plexopathy can be determined.

Surgical decompression can give excellent results if the clinical picture and the EMG suggest a compression neuropathy.

In brachial plexus neuritis, conservative management may be more appropriate.

Spontaneous recovery has been reported, but is said to be delayed and incomplete.

There is a role for physiotherapy and this should be directed specifically towards the pattern of pain and symptoms. Soft tissue massage, stretches and exercises to directly mobilise the nerve tissue may be used.⁠

Bernese periacetabular osteotomy resulted in major nerve deficits in the sciatic or femoral nerves in 2.1% of 1760 patients, of whom approximately half experienced complete recovery within a mean of 5.5 months.

Sciatic nerve exploration can be done by endoscopy in a minimally invasive procedure to assess lesions of the nerve. Endoscopic treatment for sciatic nerve entrapment has been investigated in deep gluteal syndrome; "Patients were treated with sciatic nerve decompression by resection of fibrovascular scar bands, piriformis tendon release, obturator internus, or quadratus femoris or by hamstring tendon scarring."

Non-surgical treatment of radial tunnel syndrome includes rest, NSAID, therapy with modalities, work modification, ergonomic modification, injection if associated with lateral epicondylitis.

Patients whose conditions are more adapted to surgical intervention are those who do not respond to prolonged conservative treatment. The patient must have pain with resisted supination, positive middle finger test, positive electrodiagnostic findings, and pain relief after anesthetic injection into the radial tunnel. Based on 2002 data, surgical decompression leads to 60-70% good or excellent results.

The site and type of brachial plexus injury determine the prognosis. Avulsion and rupture injuries require timely surgical intervention for any chance of recovery. For milder injuries involving buildup of scar tissue and for neurapraxia, the potential for improvement varies, but there is a fair prognosis for spontaneous recovery, with a 90–100% return of function.

Some babies recover on their own; however, some may require specialist intervention.

Neonatal/pediatric neurosurgery is often required for avulsion fracture repair. Lesions may heal over time and function return. Physiotherapeutic care is often required to regain muscle usage.

Although range of motion is recovered in many children under one year in age, individuals who have not yet healed after this point will rarely gain full function in their arm and may develop arthritis.

The three most common treatments for Erb's Palsy are: Nerve transfers (usually from the opposite arm or limb), Sub Scapularis releases and Latissimus Dorsi Tendon Transfers.

Nerve transfers are usually performed on babies under the age of 9 months since the fast development of younger babies increases the effectiveness of the procedure. They are not usually carried out on patients older than this because when the procedure is done on older infants, more harm than good is done and can result in nerve damage in the area where the nerves were taken from. Scarring can vary from faint scars along the lines of the neck to full "T" shapes across the whole shoulder depending on the training of the surgeon and the nature of the transplant.

Subscapularis releases, however, are not time limited. Since it is merely cutting a "Z" shape into the subscapularis muscle to provide stretch within the arm, it can be carried out at almost any age and can be carried out repeatedly on the same arm; however, this will compromise the integrity of the muscle.

Latissimus Dorsi Tendon Transfers involve cutting the Latissimus Dorsi in half horizontally in order to 'pull' part of the muscle around and attach it to the outside of the biceps. This procedure provides external rotation with varying degrees of success. A side effect may be increased sensitivity of the part of the biceps where the muscle will now lie, since the Latissimus Dorsi has roughly twice the number of nerve endings per square inch of other muscles.

Signals from the sciatic nerve and it branches can be blocked, in order to interrupted transmission of pain signal from the innervation area, by performing a regional nerve blockade called a sciatic nerve block.

Crutch paralysis is a form of paralysis which can occur when either the radial nerve or part of the brachial plexus, containing various nerves that innervate sense and motor function to the arm and hand, is under constant pressure, such as by the use of a crutch. This can lead to paralysis of the muscles innervated by the compressed nerve. Generally, crutches that are not adjusted to the correct height can cause the radial nerve to be constantly pushed against the humerus. This can cause any muscle that is innervated by the radial nerve to become partially or fully paralyzed. An example of this is wrist drop, in which the fingers, hand, or wrist is chronically in a flexed position because the radial nerve cannot innervate the extensor muscles due to paralysis. This condition, like other injuries from compressed nerves, normally improves quickly through therapy.