Klumpke's paralysis is a form of paralysis involving the muscles of the forearm and hand, resulting from a brachial plexus injury in which the eighth cervical (C8) and first thoracic (T1) nerves are injured either before or after they have joined to form the lower trunk. The subsequent paralysis affects, principally, the intrinsic muscles of the hand (notably the interossei, thenar and hypothenar muscles) and the flexors of the wrist and fingers (notably flexor carpi ulnaris and ulnar half of the flexor digitorum profundus). Forearm pronators and wrist flexors may be involved, as may dilators of the iris and elevators of the eyelid (both of which may be seen in the case of associated Horner's syndrome). The classic presentation of Klumpke's palsy is the “claw hand” where the forearm is supinated and the wrist and fingers are flexed. If Horner syndrome is present, there is miosis (constriction of the pupils) in the affected eye.

The injury can result from difficulties in childbirth. The most common aetiological mechanism is caused by a traumatic vaginal delivery. The risk is greater when the mother is small or when the infant is of large weight. Risk of injury to the lower brachial plexus results from traction on an abducted arm, as with an infant being pulled from the birth canal by an extended arm above the head or with someone catching himself by a branch as he falls from a tree. Lower brachial plexus injuries should be distinguished from upper brachial plexus injuries, which can also result from birth trauma but give a different syndrome of weakness known as Erb's palsy.

Other trauma, such as motorcycle accidents, that have similar spinal cord injuries to C-8 & T-1, also show the same symptom's of Klumpke's paralysis.

Klumpke Palsy is listed as a 'rare disease' by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that Klumpke palsy, or a subtype of Klumpke palsy, affects fewer than 200,000 people in the US population.

The most common cause of Erb's palsy is dystocia, an abnormal or difficult childbirth or labor. For example, it can occur if the infant's head and neck are pulled toward the side at the same time as the shoulders pass through the birth canal. The condition can also be caused by excessive pulling on the shoulders during a cephalic presentation (head first delivery), or by pressure on the raised arms during a breech (feet first) delivery. Erb's palsy can also affect neonates affected by a clavicle fracture unrelated to dystocia.

A similar injury may be observed at any age following trauma to the head and shoulder, which cause the nerves of the plexus to violently stretch, with the upper trunk of the plexus sustaining the greatest injury. Injury may also occur as the result of direct violence, including gunshot wounds and traction on the arm, or attempting to diminish shoulder joint dislocation. The level of damage to the constituent nerves is related to the amount of paralysis.

Upper limb paralysis refers to the loss of function of the elbow and hand. When upper limb function is absent as a result of a spinal cord injury it is a major barrier to regain autonomy. People with tetraplegia should be examined and informed concerning the options for reconstructive surgery of the tetraplegic arms and hands.

Delayed diagnosis of cervical spine injury has grave consequences for the victim. About one in 20 cervical fractures are missed and about two-thirds of these patients have further spinal-cord damage as a result. About 30% of cases of delayed diagnosis of cervical spine injury develop permanent neurological deficits. In high-level cervical injuries, total paralysis from the neck can result. High-level tetraplegics (C4 and higher) will likely need constant care and assistance in activities of daily living, such as getting dressed, eating and bowel and bladder care. Low-level tetraplegics (C5 to C7) can often live independently.

Even with "complete" injuries, in some rare cases, through intensive rehabilitation, slight movement can be regained through "rewiring" neural connections, as in the case of the late actor Christopher Reeve.

In the case of cerebral palsy, which is caused by damage to the motor cortex either before, during (10%), or after birth, some people with tetraplegia are gradually able to learn to stand or walk through physical therapy.

Quadriplegics can improve muscle strength by performing resistance training at least three times per week. Combining resistance training with proper nutrition intake can greatly reduce co-morbidities such as obesity and type 2 diabetes.

Triplegia is a medical condition characterized by the paralysis of three limbs (Triplegia Muscle Anatomy) . A person with triplegia can be referred to as triplegic. While there is no typical pattern of involvement, it is usually associated with paralysis of both legs and one arm — but can also involve both arms and one leg. Triplegia can sometimes by considered a combination of hemiplegia (paralysis of arm and leg of one side of the body) overlaying diplegia (paralysis of both legs), or as quadriplegia (paralysis of four limbs) with less involvement in one extremity.

The condition is commonly associated with cerebral palsy, although conditions such as stroke can also lead to it. Triplegia has also been found to be due to an increase in intracranial pressure associated with hydrocephalus resulting from traumatic brain injury.

A similar condition is triparesis, in which the patient suffers from paresis in three limbs, meaning that the limbs are very weak, but not completely paralyzed.

In a case reported only due to its rarity, triplegia was reported following a tonsillectomy (surgical removal of the tonsils). An eight-year-old male patient was sent to Willard Parker Hospital on August 12, 1929 and had been diagnosed with poliomyelitis. After an unrelated, and routine, tonsillectomy there was complete flaccid paralysis and loss of feeling in both the legs, right arm, and muscles in the trunk.

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.

Other causes may include:

- Diabetes mellitus

- Facial nerve paralysis, sometimes bilateral, is a common manifestation of sarcoidosis of the nervous system, neurosarcoidosis.

- Bilateral facial nerve paralysis may occur in Guillain–Barré syndrome, an autoimmune condition of the peripheral nervous system.

- Moebius syndrome is a bilateral facial paralysis resulting from the underdevelopment of the VII cranial nerve (facial nerve), which is present at birth. The VI cranial nerve, which controls lateral eye movement, is also affected, so people with Moebius syndrome cannot form facial expression or move their eyes from side to side. Moebius syndrome is extremely rare, and its cause or causes are not known.

Brown-Séquard syndrome is rare as the trauma would have to be something that damaged the nerve fibres on just one half of the spinal cord.

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.

Central facial palsy can be caused by a lacunar infarct affecting fibers in the internal capsule going to the nucleus. The facial nucleus itself can be affected by infarcts of the pontine arteries.

Most common causes of lower motor neuron injuries are trauma to peripheral nerves that serve the axons – a virus that selectively attacks ventral horn cells.

Disuse atrophy of the muscle occurs i.e., shrinkage of muscle fibre finally replaced by fibrous tissue (fibrous muscle)

Other causes include Guillain–Barré syndrome, "C. botulism", polio, and cauda equina syndrome; another common cause of lower motor neuron degeneration is amyotrophic lateral sclerosis.

Brown-Séquard syndrome may be caused by a spinal cord tumour, trauma [such as a gunshot wound or puncture wound to the cervical (neck) or thoracic spine (back)], ischemia (obstruction of a blood vessel), or infectious or inflammatory diseases such as tuberculosis, or multiple sclerosis. In its pure form, it is rarely seen. The most common cause is penetrating trauma such as a gunshot wound or stab wound to the spinal cord. Decompression sickness may also be a cause of Brown-Séquard syndrome.

The presentation can be progressive and incomplete. It can advance from a typical Brown-Séquard syndrome to complete paralysis. It is not always permanent and progression or resolution depends on the severity of the original spinal cord injury and the underlying pathology that caused it in the first place.

Flaccid dysarthria is caused when damage occurs to the motor unit (one or more cranial or spinal nerves). Processes that can cause this include:

- Congenital disorders

- Demyelinating disorders

- Infectious/Inflammatory

- Degenerative disorders

- Metabolic

- Neoplastic

- Traumatic

- Vascular Diseases

- Flaccid Paralysis

The most common cause of diplegia in the legs is Cerebral Palsy. Paralysis of the legs may also be caused by trauma, injury, or genetics but this is very rare

A lower motor neuron lesion is a lesion which affects nerve fibers traveling from the ventral horn or anterior grey column of the spinal cord to the relevant muscle(s) – the lower motor neuron.

One major characteristic used to identify a lower motor neuron lesion is flaccid paralysis – paralysis accompanied by loss of muscle tone. This is in contrast to an upper motor neuron lesion, which often presents with spastic paralysis – paralysis accompanied by severe hypertonia.

Besides complications of surgery and anesthesia in general, there may be drainage, swelling, or redness of the incision, gagging or coughing during eating or drinking, or pneumonia due to aspiration of food or liquids. Undesirable complications are estimated to occur in 10-30% of cases. If medical therapy is unsuccessful and surgery cannot be performed due to concurrent disease (such as heart or lung problems) or cost, euthanasia may be necessary if the animal's quality of life is considered unacceptable due to the disease.

There are several ways of getting diplegia in the arms. It is very common for people with Cerebral Palsy to have diplegia of the arms. Although most people with Cerebral Palsy have diplegia in their legs, some people have diplegia in their arms. Other ways of getting paralysis of both arms is through a traumatic event or injury.

Some viruses are thought to establish a persistent (or latent) infection without symptoms, e.g., the varicella-zoster virus and Epstein-Barr viruses, both of the herpes family. Reactivation of an existing (dormant) viral infection has been suggested as a cause of acute Bell's palsy. Studies suggest that this new activation could be preceded by trauma, environmental factors, and metabolic or emotional disorders, thus suggesting that a host of different conditions may trigger reactivation.

Familial inheritance has been found in 4–14% of cases. Bell's palsy is three times more likely to occur in pregnant women than non-pregnant women. It is also considered to be four times more likely to occur in diabetics than the general population.

Bell's palsy is a type of facial paralysis that results in an inability to control the facial muscles on the affected side. Symptoms can vary from mild to severe. They may include muscle twitching, weakness, or total loss of the ability to move one or rarely both sides of the face. Other symptoms include drooping of the eyelid, a change in taste, pain around the ear, and increased sensitivity to sound. Typically symptoms come on over 48 hours.

The cause of Bell's palsy is unknown. Risk factors include diabetes and a recent upper respiratory tract infection. It results from a dysfunction of cranial nerve VII (the facial nerve). Many believe that this is due to a viral infection that results in swelling. Diagnosis is based on a person's appearance and ruling out other possible causes. Other conditions that can cause facial weakness include brain tumor, stroke, Ramsay Hunt syndrome, and Lyme disease.

The condition normally gets better by itself with most achieving normal or near-normal function. Corticosteroids have been found to improve outcomes, while antiviral medications may be of a small additional benefit. The eye should be protected from drying up with the use of eye drops or an eyepatch. Surgery is generally not recommended. Often signs of improvement begin within 14 days, with complete recovery within six months. A few may not recover completely or have a recurrence of symptoms.

Bell's palsy is the most common cause of one sided facial nerve paralysis (70%). It occurs in 1 to 4 per 10,000 people per year. About 1.5% of people are affected at some point in their life. It most commonly occurs in people between ages 15 and 60. Males and females are affected equally. It is named after Scottish surgeon Charles Bell (1774–1842), who first described the connection of the facial nerve to the condition.

Abasia (from Greek: "a-", without and "basis", step) is the inability to walk owing to impairment in motor coordination.

The term covers a spectrum of medical disorders such as:

- choreic abasia: caused by chorea of the legs

- paralytic abasia: caused by paralysis of the leg muscles

- spastic abasia: caused by spastic stiffening of the leg muscles

- trembling abasia: caused by trembling of the legs

Abasia is frequently accompanied by astasis, an inability to stand, see Astasia-abasia.

Flaccid dysarthria is a motor speech disorder resulting from damage to peripheral nervous system (cranial or spinal nerves) or lower motor neuron system. Depending on which nerves are damaged, flaccid dysarthria affects respiration, phonation, resonance, and articulation. It also causes weakness, hypotonia (low-muscle tone), and diminished reflexes., Perceptual effects of flaccid dysarthria can include hypernasality, imprecise consonant productions, breathiness of voice, and affected nasal emission.

Foot drop is a gait abnormality in which the dropping of the forefoot happens due to weakness, irritation or damage to the common fibular nerve including the sciatic nerve, or paralysis of the muscles in the anterior portion of the lower leg. It is usually a symptom of a greater problem, not a disease in itself. Foot drop is characterized by inability or impaired ability to raise the toes or raise the foot from the ankle (dorsiflexion). Foot drop may be temporary or permanent, depending on the extent of muscle weakness or paralysis and it can occur in one or both feet. In walking, the raised leg is slightly bent at the knee to prevent the foot from dragging along the ground.

Foot drop can be caused by nerve damage alone or by muscle or spinal cord trauma, abnormal anatomy, toxins, or disease. Toxins include organophosphate compounds which have been used as pesticides and as chemical agents in warfare. The poison can lead to further damage to the body such as a neurodegenerative disorder called organophosphorus induced delayed polyneuropathy. This disorder causes loss of function of the motor and sensory neural pathways. In this case, foot drop could be the result of paralysis due to neurological dysfunction. Diseases that can cause foot drop include trauma to the posterolateral neck of fibula, stroke, amyotrophic lateral sclerosis, muscular dystrophy, poliomyelitis, Charcot Marie Tooth disease, multiple sclerosis, cerebral palsy, hereditary spastic paraplegia, Guillain–Barré syndrome, and Friedreich's ataxia. It may also occur as a result of hip replacement surgery or knee ligament reconstruction surgery.

The causes of foot drop, as for all causes of neurological lesions, should be approached using a localization-focused approach before etiologies are considered. Most of the time, foot drop is the result of neurological disorder; only rarely is the muscle diseased or nonfunctional. The source for the neurological impairment can be central (spinal cord or brain) or peripheral (nerves located connecting from the spinal cord to an end-site muscle or sensory receptor). Foot drop is rarely the result of a pathology involving the muscles or bones that make up the lower leg. The anterior tibialis is the muscle that picks up the foot. Although the anterior tibialis plays a major role in dorsiflexion, it is assisted by the fibularis tertius, extensor digitorum longus and the extensor halluces longus. If the drop foot is caused by neurological disorder all of these muscles could be affected because they are all innervated by the deep fibular (peroneal) nerve, which branches from the sciatic nerve. The sciatic nerve exits the lumbar plexus with its root arising from the fifth lumbar nerve space. Occasionally, spasticity in the muscles opposite the anterior tibialis, the gastrocnemius and soleus, exists in the presence of foot drop, making the pathology much more complex than foot drop. Isolated foot drop is usually a flaccid condition. There are gradations of weakness that can be seen with foot drop, as follows: 0=complete paralysis, 1=flicker of contraction, 2=contraction with gravity eliminated alone, 3=contraction against gravity alone, 4=contraction against gravity and some resistance, and 5=contraction against powerful resistance (normal power). Foot drop is different from foot slap, which is the audible slapping of the foot to the floor with each step that occurs when the foot first hits the floor on each step, although they often are concurrent.

Treated systematically, possible lesion sites causing foot drop include (going from peripheral to central):

1. Neuromuscular disease;

2. Peroneal nerve (common, i.e., frequent) —chemical, mechanical, disease;

3. Sciatic nerve—direct trauma, iatrogenic;

4. Lumbosacral plexus;

5. L5 nerve root (common, especially in association with pain in back radiating down leg);

6. Cauda equina syndrome, which is cause by impingement of the nerve roots within the spinal canal distal to the end of the spinal cord;

7. Spinal cord (rarely causes isolated foot drop) —poliomyelitis, tumor;

8. Brain (uncommon, but often overlooked) —stroke, TIA, tumor;

9. Genetic (as in Charcot-Marie-Tooth Disease and hereditary neuropathy with liability to pressure palsies);

10. Nonorganic causes.

If the L5 nerve root is involved, the most common cause is a herniated disc. Other causes of foot drop are diabetes (due to generalized peripheral neuropathy), trauma, motor neuron disease (MND), adverse reaction to a drug or alcohol, and multiple sclerosis.

In most cases, the cause of laryngeal paralysis is unknown or idiopathic. However, the disorder may arise secondary to general neuropathies, generalized neuromuscular diseases, muscular diseases, neoplasia either in the cervical (neck) region or the cranial mediastinum, or trauma. This acquired form occurs predominantly in middle-aged to old large breed or giant breed dogs such as the Labrador Retriever, golden retriever, Siberian Husky, Newfoundland, and St. Bernard. Usually these dogs are born with a normal larynx, but over time the nerves and muscles that control the laryngeal cartilages lose function.

Laryngeal paralysis may also be congenital in some breeds (e.g. Bouvier des Flandres, Dalmatians, Siberian huskies, and bulldogs), appearing in dogs between two and six months of age. Affected puppies may have difficulty swallowing and breathing, they may gag frequently, and their bark often sounds abnormal. In Dalmatians it is part of another condition called 'laryngeal paralysis-polyneuropathy complex.' Affected puppies should not be used for breeding.

Choke collars are not thought to be a significant risk factor for this disorder. However, after LP is diagnosed it is usually recommended to stop using a collar or anything else around the dog's neck and to switch to a harness instead.