Sciatic nerve injury occurs between 0.5% and 2.0% of the time during total hip arthroplasty. Sciatic nerve palsy is a complication of total hip arthroplasty with an incidence of 0.2% to 2.8% of the time, or with an incidence of 1.7% to 7.6% following revision. Following the procedure, in rare cases, a screw, broken piece of trochanteric wire, fragment of methyl methacrylate bone cement, or Burch-Schneider metal cage can impinge on the nerve; this can cause sciatic nerve palsy which may resolve after the fragment is removed and the nerve freed. The nerve can be surrounded in oxidized regenerated cellulose to prevent further scarring. Sciatic nerve palsy can also result from severe spinal stenosis following the procedure, which can be addressed by spinal decompression surgery. It is unclear if inversion therapy is able to decompress the sacral vertebrae, it may only work on the lumbar aspects of the sciatic nerves.

Sciatic nerve injury may also occur from improperly performed injections into the buttock, and may result in sensory loss.

Most often the radiculopathy found in the patients are located in the cervical spine, most commonly affecting C6-C8 spinal nerves.

Certain injuries can also lead to radiculopathy. These injuries include lifting heavy objects improperly or suffering from a minor trauma such as a car accident. Less common causes of radiculopathy include injury caused by tumor (which can compress nerve roots locally) and diabetes (which can effectively cause ischemia or lack of blood flow to nerves).

Various etiologies of CES include fractures, abscesses, hematomas, and any compression of the relevant nerve roots. Injuries to the thoracolumbar spine will not necessarily result in a clinical diagnosis of CES, but in all such cases it is necessary to consider. Few epidemiological studies of CES have been done in the United States, owing to difficulties such as amassing sufficient cases as well as defining the affected population, therefore this is an area deserving of additional scrutiny.

Traumatic spinal cord injuries occur in approximately 40 people per million annually in the United States, resulting from traumas due to motor vehicle accidents, sporting injuries, falls, and other factors. An estimated 10 to 25% of vertebral fractures will result in injury to the spinal cord. Thorough physical examinations are required, as 5 to 15% of trauma patients have fractures that initially go undiagnosed.

The most frequent injuries of the thoracolumbar region are to the conus medullaris and the cauda equina, particularly between T12 and L2. Of these two syndromes, CES is the more common. CES mainly affects middle-aged individuals, particularly those in their forties and fifties, and presents more often in men. It is not a typical diagnosis, developing in only 4 to 7 out of every 10,000 to 100,000 patients, and is more likely to occur proximally. Disc herniation is reportedly the most common cause of CES, and it is thought that 1 to 2% of all surgical disc herniation cases result in CES.

No set risk factors have been clearly defined for CES at this point in time. Individuals most at risk for disc herniation are the most likely to develop CES. Race has little influence with the notable exception that African Americans appear slightly less likely to develop CES than other groups; similarly, men are slightly more likely to develop CES than women. Middle age also appears to be a notable risk factor, as those populations are more likely to develop a herniated disc; heavy lifting can also be inferred as a risk factor for CES.

Radiculopathy is a mechanical compression of a nerve root usually at the exit foramen or lateral recess. It may be secondary to degenerative disc disease, osteoarthritis, facet joint degeneration/hypertrophy, ligamentous hypertrophy, spondylolisthesis, or a combination of these factors. Rarer causes of radiculopathy may include radiation, diabetes mellitus, neoplastic disease, or any meningeal-based disease process. Second-stage Lyme meningitis resembles aseptic meningitis and is often associated with radiculopathies.

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."

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.

Surgery may be useful in those with a herniated disc that is causing significant pain radiating into the leg, significant leg weakness, bladder problems, or loss of bowel control. Discectomy (the partial removal of a disc that is causing leg pain) can provide pain relief sooner than nonsurgical treatments. Discectomy has better outcomes at one year but not at four to ten years. The less invasive microdiscectomy has not been shown to result in a significantly different outcome than regular discectomy with respect to pain. It might however have less risk of infection.

The presence of cauda equina syndrome (in which there is incontinence, weakness and genital numbness) is considered a medical emergency requiring immediate attention and possibly surgical decompression. Regarding the role of surgery for failed medical therapy in people without a significant neurological deficit, a Cochrane review concluded that "limited evidence is now available to support some aspects of surgical practice".

People with diabetes mellitus are at higher risk for any kind of peripheral neuropathy, including ulnar nerve entrapments.

Cubital tunnel syndrome is more common in people who spend long periods of time with their elbows bent, such as when holding a telephone to the head. Flexing the elbow while the arm is pressed against a hard surface, such as leaning against the edge of a table, is a significant risk factor. The use of vibrating tools at work or other causes of repetitive activities increase the risk, including throwing a baseball.

Damage to or deformity of the elbow joint increases the risk of cubital tunnel syndrome. Additionally, people who have other nerve entrapments elsewhere in the arm and shoulder are at higher risk for ulnar nerve entrapment. There is some evidence that soft tissue compression of the nerve pathway in the shoulder by a bra strap over many years can cause symptoms of ulnar neuropathy, especially in very large-breasted women.

Disc herniation can occur in any disc in the spine, but the two most common forms are lumbar disc herniation and cervical disc herniation. The former is the most common, causing lower back pain (lumbago) and often leg pain as well, in which case it is commonly referred to as sciatica. Lumbar disc herniation occurs 15 times more often than cervical (neck) disc herniation, and it is one of the most common causes of lower back pain. The cervical discs are affected 8% of the time and the upper-to-mid-back (thoracic) discs only 1–2% of the time.

The following locations have no discs and are therefore exempt from the risk of disc herniation: the upper two cervical intervertebral spaces, the sacrum, and the coccyx. Most disc herniations occur when a person is in their thirties or forties when the nucleus pulposus is still a gelatin-like substance. With age the nucleus pulposus changes ("dries out") and the risk of herniation is greatly reduced. After age 50 or 60, osteoarthritic degeneration (spondylosis) or spinal stenosis are more likely causes of low back pain or leg pain.

- 4.8% males and 2.5% females older than 35 experience sciatica during their lifetime.

- Of all individuals, 60% to 80% experience back pain during their lifetime.

- In 14%, pain lasts more than 2 weeks.

- Generally, males have a slightly higher incidence than females.

Brachial plexus injury is found in both children and adults, but there is a difference between children and adults with BPI.

Anatomically, damage to the axillary nerve or suppression of it causes the palsy. This suppression, referred to as entrapment, causes the nerve pathway to become smaller and impulses cannot move through the nerve as easily. 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.

Usually, an outside force is acting to suppress the nerve, or cause nerve damage. Most commonly, shoulder dislocation or fractions in the shoulder can cause the palsy. Contact sports such as football and hockey can cause the injury Other cases have been caused by repeated crutch pressure or injuries accidentally caused by health professionals (iatrogenesis). 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. 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.

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. 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. 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. Some patients who are diagnosed with nodular fasciitis may develop axillary nerve palsy if the location of the rapid growth is near the axilla. 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.

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.)

Radicular pain, or radiculitis, is pain "radiated" along the dermatome (sensory distribution) of a nerve due to inflammation or other irritation of the nerve root (radiculopathy) at its connection to the spinal column. A common form of radiculitis is sciatica – radicular pain that radiates along the sciatic nerve from the lower spine to the lower back, gluteal muscles, back of the upper thigh, calf, and foot as often secondary to nerve root irritation from a spinal disc herniation or from osteophytes in the lumbar region of the spine.

A nerve may be compressed by prolonged or repeated external force, such as sitting with one's arm over the back of a chair (radial nerve), frequently resting one's elbows on a table (ulnar nerve), or an ill-fitting cast or brace on the leg (peroneal nerve). Part of the patient's body can cause the compression and the term "entrapment neuropathy" is used particularly in this situation. The offending structure may be a well-defined lesion such as a tumour (for example a lipoma, neurofibroma or metastasis), a ganglion cyst or a haematoma. Alternatively, there may be expansion of the tissues around a nerve in a space where there is little room for this to occur, as is often the case in carpal tunnel syndrome. This may be due to weight gain or peripheral oedema (especially in pregnancy), or to a specific condition such as acromegaly, hypothyroidism or scleroderma and psoriasis.

Some conditions cause nerves to be particularly susceptible to compression. These include diabetes, in which the blood supply to the nerves is already compromised, rendering the nerve more sensitive to minor degrees of compression. The genetic condition HNPP is a much rarer cause.

The lateral femoral cutaneous nerve most often becomes injured by entrapment or compression where it passes between the upper front hip bone (ilium) and the inguinal ligament near the attachment at the anterior superior iliac spine (the upper point of the hip bone). Less commonly, the nerve may be entrapped by other anatomical or abnormal structures, or damaged by diabetic or other neuropathy or trauma such as from seat belt injury in an accident.

The nerve may become painful over a period of time as weight gain makes underwear, belting or the waistband of pants gradually exert higher levels of pressure. Pain may be acute and radiate into the rib cage, and into the groin, thigh, and knee. Alternately, weight loss or aging may remove protective fat layers under the skin, so the nerve can compress against underwear, outer clothing, and—most commonly— by belting. Long periods of standing or leg exercise that increases tension on the inguinal ligament may also cause pressure.

Trauma is the most frequent cause of peripheral nerve lesions. There are two classifications of trauma which include civilian trauma and military trauma. Civilian trauma is most commonly caused by motor vehicle accidents but also by lacerations caused by glass, knives, fans, saw blades or fractures and occasionally sports injuries. Of the civilian injuries, stretch injuries are the most common types and are considered to be a closed injury, where the tissue is unexposed. Stretch injures are commonly the result of dislocation, such as a shoulder dislocation that stretches nerves. Opposite of civilian trauma, there is military trauma which most commonly results in open injuries from blasts often by bombs or improvised explosive devices. Other mechanisms of injury are less common but include ischemia, thermal, electric shock, radiation, adverse reactions to certain chemotherapy medications, percussion and vibration.

Ulnar nerve entrapment is classified by location of entrapment. The ulnar nerve passes through several small spaces as it courses through the medial side of the upper extremity, and at these points the nerve is vulnerable to compression or entrapment—a so-called "pinched nerve". The nerve is particularly vulnerable to injury when there has been a disruption in the normal anatomy. The most common site of ulnar nerve entrapment is at the elbow, followed by the wrist.

Causes or structures which have been reported to cause ulnar nerve entrapment include:

- Problems originating at the neck: thoracic outlet syndrome, cervical spine pathology, compression by anterior scalene muscles

- Problems originating in the chest: compression by pectoralis minor muscles

- Brachial plexus abnormalities

- Elbow: fractures, growth plate injuries, cubital tunnel syndrome, flexorpronator aponeurosis, arcade of Struthers

- Forearm: tight flexor carpi ulnaris muscles

- Wrist: fractures, ulnar tunnel syndrome, hypothenar hammer syndrome

- Artery aneurysms or thrombosis

- "Other": Infections, tumors, diabetes, hypothyroidism, rheumatism, and alcoholism

External pressure reduces flow in the vessels supplying the nerve with blood (the vasa nervorum). This causes local ischaemia, which has an immediate effect on the ability of the nerve axons to transmit action potentials. As the compression becomes more severe over time, focal demyelination occurs, followed by axonal damage and finally scarring.

The entire distribution of the nerve is rarely affected. Usually, the unpleasant sensation(s) affect only part of the skin supplied by the nerve.

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.

Medical procedures are the most common cause of injury to the spinal accessory nerve. In particular, radical neck dissection and cervical lymph node biopsy are among the most common surgical procedures that result in spinal accessory nerve damage. London notes that a failure to rapidly identify spinal accessory nerve damage may exacerbate the problem, as early intervention leads to improved outcomes.

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. Since this is a problem with just one nerve, it is a type of Peripheral neuropathy called mononeuropathy. Of all brachial plexus injuries, axillary nerve palsy represents only .3% to 6% of them.

The root cause of the condition is not entirely clear, and it appears to have multiple causes, including iatrogenic cause from misplaced epidural steroid injection therapy when accidentally administered intrathecally (inside the dura mater, the sac enveloping the arachnoid mater), or from contrast media used in myelography prior to the introduction of Metrizamide. Other noninfectious inflammatory processes include surgery, intrathecal hemorrhage, and the administration of anesthetics (e.g. chloroprocaine), and steroids (e.g. prednisolone, triamcinolone acetonide). A variety of other causes exist, including infectious, inflammatory, and neoplastic processes. Infectious causes include bacterial, viral, fungal, and parasitic agents. Prior spinal surgery has been documented as a cause of "arachnoiditis ossificans", as well as for the adhesive form. It can also be caused by long term pressure from either a severe disc herniation or spinal stenosis.

Neurotmesis (in Greek tmesis signifies "to cut") 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.

Workers in certain fields are at risk of repetitive strains. Most occupational injuries are musculoskeletal disorders, and many of these are caused by cumulative trauma rather than a single event. Miners and poultry workers, for example, must make repeated motions which can cause tendon, muscular, and skeletal injuries.