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.

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.

In order to diagnose radial nerve dysfunction, a doctor will conduct a physical examination. During the exam of the arm, wrist, and hand, the doctor will look for: difficulty straightening the arm at the elbow; trouble turning the arm outward; difficulty lifting the wrist; muscle loss or atrophy in the forearm; weakness of the wrist and/or fingers. In addition, tests may need to be conducted to confirm the doctors findings. These tests include: blood tests; MRI of the neck and shoulders to screen for other problems; nerve biopsy; nerve conduction tests; ultrasound of the elbow.

Radial neuropathy is not necessarily permanent. The majority of radial neuropathies due to an acute compressive event (Saturday night palsy) do recover without intervention. If the injury is demyelinating (meaning only the myelin sheath surrounding the nerve is damaged), then full recovery typically occurs within 2–4 weeks. If the injury is axonal (meaning the underlying nerve fiber itself is damaged) then full recovery may take months or years, or may never occur. EMG and nerve conduction studies are typically performed to diagnose the extent and distribution of the damage, and to help with prognosis for recovery.

In terms of the diagnosis of radial neuropathy the following tests/exams can be done to ascertain the condition:

The severity of brachial plexus injury is determined by the type of nerve damage. There are several different classification systems for grading the severity of nerve and brachial plexus injuries. Most systems attempt to correlate the degree of injury with symptoms, pathology and prognosis. Seddon's classification, devised in 1943, continues to be used, and is based on three main types of nerve fiber injury, and whether there is continuity of the nerve.

1. Neurapraxia: The mildest form of nerve injury. It involves an interruption of the nerve conduction without loss of continuity of the axon. Recovery takes place without wallerian degeneration.

2. Axonotmesis: Involves axonal degeneration, with loss of the relative continuity of the axon and its covering of myelin, but preservation of the connective tissue framework of the nerve (the encapsulating tissue, the epineurium and perineurium, are preserved).

3. Neurotmesis: The most severe form of nerve injury, in which the nerve is completely disrupted by contusion, traction or laceration. Not only the axon, but the encapsulating connective tissue lose their continuity. The most extreme degree of neurotmesis is transsection, although most neurotmetic injuries do not produce gross loss of continuity of the nerve but rather, internal disruption of the nerve architecture sufficient to involve perineurium and endoneurium as well as axons and their covering. It requires surgery, with unpredictable recovery.

A more recent and commonly used system described by the late Sir Sydney Sunderland, divides nerve injuries into five degrees: first degree or neurapraxia, following on from Seddon, in which the insulation around the nerve called myelin is damaged but the nerve itself is spared, and second through fifth degree, which denotes increasing severity of injury. With fifth degree injuries, the nerve is completely divided.

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.

The function of the spinal accessory nerve is measured in the neurological examination. How the examination is administered varies by practitioner, but it frequently involves three components: inspection, range of motion testing, and strength testing.

During inspection, the examiner observes the sternocleidomastoid and trapezius muscles, looking for signs of lower motor neuron disease, such as muscle atrophy and fasciculation. A winged scapula may also be suggestive of abnormal spinal accessory nerve function, as described above.

In assessing range of motion, the examiner observes while the patient tilts and rotates the head, shrugs both shoulders, and abducts both arms. A winged scapula due to spinal accessory nerve damage will often be exaggerated on arm abduction.

Strength testing is similar to range of motion testing, except that the patient performs the actions against the examiner's resistance. The examiner measures sternocleidomastoid muscle function by asking the patient to turn his or her head against resistance. Simultaneously, the examiner observes the action of the contralateral sternocleidomastoid muscle. For example, if the patient turns his or her head to the right, the left sternocleidomastoid muscle normally will tighten.

To assess the strength of the trapezius muscle, the examiner asks the patient to shrug his or her shoulders against resistance. In patients with damage to the spinal accessory nerve, shoulder elevation will be diminished, and the patient will be incapable of raising the shoulders against the examiner's resistance.

In terms of prognosis radial neuropathy is not necessarily permanent, though sometimes there could be partial loss of movement/sensation.Complications may be possible deformity of the hand in some individuals.

If the injury is axonal (the underlying nerve fiber itself is damaged) then full recovery may take months or years ( or could be permanent). EMG and nerve conduction studies are typically performed to diagnose the extent and distribution of the damage, and to help with prognosis for recovery.

One way to prevent this injury from occurring is to be informed and educated about the risks involved in hurting your wrist and hand. If patients do suffer from median nerve palsy, occupational therapy or wearing a splint can help reduce the pain and further damage. Wearing a dynamic splint, which pulls the thumb into opposition, will help prevent an excess in deformity. This splint can also assist in function and help the fingers flex towards the thumb. Stretching and the use of C-splints can also assist in prevention of further damage and deformity. These two methods can help in the degree of movement the thumb can have. While it is impossible to prevent trauma to your arms and wrist, patients can reduce the amount of compression by maintaining proper form during repetitive activities. Furthermore, strengthening and increasing flexibility reduces the risk of nerve compression.

A thorough medical history and physical examination, including a neurological examination, are the first steps in making a diagnosis. This alone may be sufficient to diagnose Bell's Palsy, in the absence of other findings. Additional investigations may be pursued, including blood tests such as ESR for inflammation, and blood sugar levels for diabetes. If other specific causes, such as sarcoidosis or Lyme disease are suspected, specific tests such as angiotensin converting enzyme levels, chest x-ray or Lyme titer may be pursued. If there is a history of trauma, or a tumour is suspected, a CT scan may be used.

Because lesions to different areas of the median nerve produce similar symptoms, clinicians perform a complete motor and sensory diagnosis along the nerve course. Decreased values of nerve conduction studies are used as indicators of nerve compression and may aid in determining the localization of compression.

Palpation above the elbow joint may reveal a bony consistency. Radiography images may show an abnormal bony spur outgrowth (supracondyloid process) just proximal to the elbow joint. Attached fibrous tissue (Struthers' ligament) may compress the median nerve as it passes underneath the process. This is also known as supracondylar process syndrome. Compression at this point may also occur without the bony spur; in this case, aponeurotic tissue found at the location of where Struthers' ligament should be is responsible for the compression.

If patients mention reproduction of symptoms to the forearm during elbow flexion of 120–130 degrees with the forearm in maximal supination, then the lesion may be localized to the area underneath the lacertus fibrosus (also known as bicipital aponeurosis). This is sometimes misdiagnosed as elbow strain and medial or lateral epicondylitis.

A lesion to the upper arm area, just proximal to where motor branches of forearm flexors originate, is diagnosed if the patient is unable to make a fist. More specifically, the patient's index and middle finger cannot flex at the MCP joint, while the thumb usually is unable to oppose. This is known as hand of benediction or Pope’s blessing hand. Another test is the bottle sign—the patient is unable to close all their fingers around a cylindrical object.

Carpal tunnel syndrome (CTS) is caused by compression of the median nerve as it passes under the carpal tunnel. Nerve conduction velocity tests through the hand are used to diagnosis CTS. Physical diagnostic tests include the Phalen maneuver or Phalen test and Tinel's sign. To relieve symptoms, patients may describe a motion similar to "shaking a thermometer", another indication of CTS.

Pronator teres syndrome (also known as pronator syndrome) is compression of the median nerve between the two heads of the pronator teres muscle. The Pronator teres test is an indication of the syndrome—the patient reports pain when attempting to pronate the forearm against resistance while extending the elbow simultaneously. The physician may notice an enlarged pronator teres muscle. Tinel's sign the area around the pronator teres heads should be positive. The key to discerning this syndrome from carpal tunnel syndrome is the absence of pain while sleeping. More recent literature collectively diagnose median nerve palsy occurring from the elbow to the forearm as pronator teres syndrome.

In uncooperative patients, the skin wrinkle test offers a pain-free way to identify denervation of the fingers. After submersion in water for 5 minutes, normal fingers will become wrinkled, whereas denervated fingers will not.

In "Ape hand deformity", the thenar muscles become paralyzed due to impingement and are subsequently flattened. This hand deformity is not by itself an individual diagnosis; it is seen only after the thenar muscles have atrophied. While the adductor pollicis remains intact, the flattening of the muscles causes the thumb to become adducted and laterally rotated. The opponens pollicis causes the thumb to flex and rotate medially, leaving the thumb unable to oppose. Carpal tunnel syndrome can result in thenar muscle paralysis which can then lead to ape hand deformity if left untreated. Ape hand deformity can also be seen in the hand of benediction deformity.

The Anterior Interosseus Nerve (AIN), a branch of the median nerve, only accounts for the movement of the fingers in hand and does not have any sensory capabilities. Therefore, the AIN syndrome is purely neuropathic. AINS is considered as an extremely rare condition because it accounts for less than 1% of neuropathies in the upper limb. Patients suffering from this syndrome have impaired distal interphalangeal joint, because of which they are unable to pinch anything or make and "OK" sign with their index finger and thumb. The syndrome can either happen from pinched nerve, or even dislocation of the elbow.

There are several options of treatment when iatrogenic (i.e., caused by the surgeon) spinal accessory nerve damage is noted during surgery. For example, during a functional neck dissection that injures the spinal accessory nerve, injury prompts the surgeon to cautiously preserve branches of C2, C3, and C4 spinal nerves that provide supplemental innervation to the trapezius muscle. Alternatively, or in addition to intraoperative procedures, postoperative procedures can also help in recovering the function of a damaged spinal accessory nerve. For example, the Eden-Lange procedure, in which remaining functional shoulder muscles are surgically repositioned, may be useful for treating trapezius muscle palsy.

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.

In addition to history and exam, it has been recommended to perform projectional radiography of the neck, chest, shoulder, and thoracic inlet to rule out structural abnormalities such as malunited or greenstick fractures. Computed tomography (CT) or magnetic resonance imaging (MRI) are rarely indicated, but may be useful to rule out certain diagnoses if suspected, such as neurofibromatosis-related injury, intervertebral disc disorder, radiculopathy, and tumors.

Stingers are best diagnosed by a medical professional. This person will assess the athlete's pain, range of head and neck motion, arm numbness, and muscle strength. Often, the affected athlete is allowed to return to play within a short time, but persistent symptoms will result in removal. Athletes are also advised to receive

regular evaluations until symptoms have ceased. If they have not after two weeks, or increase, additional tests such as magnetic resonance imaging (MRI) can be performed to detect a more serious injury, such as a herniated disc.

The order of treatments applied depends on whether the athlete's main complaint is pain or weakness. Both can be treated with an analgesic, anti-inflammatory medication, ice and heat, restriction of movement, and if necessary, cervical collar or traction. Surgery is only necessary in the most severe cases.

Facial nerve paralysis may be divided into supranuclear and infranuclear lesions.

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."

Initial line of treatment is with anti-inflammatory drugs or cortisone injections. There have been trials with gloves which help protect the ulnar nerve from compression. The most radical treatment option is surgery to relieve tension in the volar carpal ligament which forms the roof of Guyon's canal, thereby reducing compression on the ulnar nerve.

The place of chiropractic-, physical-, occupational-, massage- and osteopathic therapy was not confirmed in scientific studies. These treatments can be both expensive as well as dangerous (causing permanent damage when performed wrongly).

It is advised to consult a physician beforehand starting any therapy, albeit an alternative approach, to avoid any permanent nerve damage.

The appearance of the affected arm (or arms) depends on the individual case. In some cases the arm may lack the ability to straighten or rotate but otherwise function normally giving the overall appearance of the arm to be stiff and crooked. Whereas in other circumstances the arm has little to no control and has a "loose" appearance. Treatment such as physiotherapy, massage and electrical stimulation can help to prevent this early on (or throughout) the patient's life by strengthening the arm.

In some cases, again, individuals may suffer a great deal of discomfort. For example, they may experience a severe cramping pain that lasts for some time and is particularly painful after they have slept, running from the shoulder all the way down to the wrist. Although pain does not affect everyone with Erb's Palsy, it can be extremely uncomfortable to those that it does and can even cause patients to be physically sick or faint. This extreme nerve pain is mostly common during the final stages of growth and almost always eases off in time. Other pains that Erb's Palsy sufferers might endure include strained muscle, stiffness, circulatory problems and cramp. Different factors are dependent on the severity of the condition and can vary, so whilst some patient experience a lot of pain, some patients may experience no pain at all and for their affected arm to simply be visually crooked.

Discomfort with the shoulder blade is also extremely common in Erb's palsy as the shoulder is often at risk of dislocation. This can result, again, in sickness or lack of sleep.

In terms of diagnosis of HNPP measuring nerve conduction velocity may give an indication of the presence of the disease.Other methods via which to ascertain the diagnosis of hereditary neuropathy with liability to pressure palsy are:

- Family history

- Genetic test

- Physical exam(lack of ankle reflex)

There are several tests done to diagnose hemifacial spasm. Diagnosing a case of hemifacial spasm begins with a complete neurological exam, including an Electromyography (EMG – a test that measures and records electrical activity generated in muscle at rest and in response to muscle contraction), Magnetic resonance imaging (MRI – a test that uses magnetic waves to make pictures of structures inside the head), Computed tomography (CT scan – a type of x-ray that uses a computer to make pictures of structures inside the head), and Angiography (an x-ray exam of the blood vessels when they are filled with a contrast material).

Studies have shown that the most effective method of hemifacial spasm screening is MRI. In one study only 25% of the CT scans showed the abnormality in hemifacial spasm patients, whilst more than half of the MRI imaging demonstrated a vascular anomaly. MRI imaging should be the initial screening procedure in the assessment of patients with hemifacial spasm.

Since there is a variety of classifications of winged scapula, there is also more than one type of treatment. Massage Therapy is an effective initial approach to relax the damaged muscles. In more severe cases, Physical Therapy can help by strengthening affected and surrounding muscles. Physical therapy constitutes treatment options if there is weakness of the glenohumeral joint muscles, but if the muscles do not contract clinically and symptoms continue to be severe for more than 3–6 months, surgery may be the next choice. Surgery by fixation of the scapula to the rib cage can be done for those with isolated scapular winging. Some options are neurolysis (chordotomy), intercostal nerve transfer, scapulothoracic fusion, arthrodesis (scapulodesis), or scapulothoracis fixation without arthrodesis (scapulopexy).

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.

Bell's palsy is a diagnosis of exclusion, meaning it is diagnosed by elimination of other reasonable possibilities. By definition, no specific cause can be determined. There are no routine lab or imaging tests required to make the diagnosis. The degree of nerve damage can be assessed using the House-Brackmann score.

One study found that 45% of patients are not referred to a specialist, which suggests that Bell’s palsy is considered by physicians to be a straightforward diagnosis that is easy to manage.

Other conditions that can cause similar symptoms include: herpes zoster, Lyme disease, sarcoidosis, stroke, and brain tumors.