Radial neuropathy is a type of mononeuropathy which results from acute trauma to the

radial nerve The radial nerve is a nerve in the human body that supplies the posterior portion of the upper limb. It innervates the medial and lateral heads of the triceps brachii muscle of the arm, as well as all 12 muscles in the posterior osteofascial comp ...

that extends the length of the arm. It is known as transient paresthesia when sensation is temporarily abnormal.

Signs and symptoms

Symptoms of radial neuropathy vary depending on the severity of the trauma; however, common symptoms may include wrist drop,

numbness Hypoesthesia or numbness is a common side effect of various medical conditions that manifests as a reduced sense of touch or sensation, or a partial loss of sensitivity to sensory stimuli. In everyday speech this is generally referred to as nu ...

on the back of the hand and wrist, and inability to voluntarily straighten the fingers. Loss of wrist extension is due to loss of the ability to move of the posterior compartment of

forearm The forearm is the region of the upper limb between the elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb, but which in ...

muscles. In the event of lacerations to the wrist area the symptom would therefore be sensory. Additionally, depending on the type of trauma, other nerves may be affected such as the

median nerve The median nerve is a nerve in humans and other animals in the upper limb. It is one of the five main nerves originating from the brachial plexus. The median nerve originates from the lateral and medial cords of the brachial plexus, and has contr ...

and axillary nerves.

Causes

There are many ways to acquire radial nerve neuropathy, including: :::::::::::*Upper arm - a fracture of the bone :::::::::::*Elbow - entrapment of the nerve :::::::::::*Wrist -

elbow The elbow is the region between the arm and the forearm that surrounds the elbow joint. The elbow includes prominent landmarks such as the olecranon, the cubital fossa (also called the chelidon, or the elbow pit), and the lateral and the m ...

deformity and soft-tissue masses :::::::::::*Axilla - here the most common cause is compression. However, a dislocation of the

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

is a possible factor as well. It could also be due to

brachial plexus The brachial plexus is a network () of nerves formed by the anterior rami of the lower four cervical nerves and first thoracic nerve ( C5, C6, C7, C8, and T1). This plexus extends from the spinal cord, through the cervicoaxillary canal in th ...

compression.

Mechanism

The mechanism of radial neuropathy is such that it can cause focal

demyelination A demyelinating disease is any disease of the nervous system in which the myelin sheath of neurons is damaged. This damage impairs the conduction of signals in the affected nerves. In turn, the reduction in conduction ability causes deficiency i ...

and axonal degeneration. These would be caused via laceration or compression of the nerve in question.

Diagnosis

Radial neuropathy may be diagnosed using MRI,

ultrasound Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies fr ...

nerve conduction study A nerve conduction study (NCS) is a medical diagnostic test commonly used to evaluate the function, especially the ability of electrical conduction, of the motor and sensory nerves of the human body. These tests may be performed by medical speci ...

electromyography Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyo ...

(EMG).

Treatment

The treatment and management of radial neuropathy can be achieved via the following methods: *

Physical therapy Physical therapy (PT), also known as physiotherapy, is one of the allied health professions. It is provided by physical therapists who promote, maintain, or restore health through physical examination, diagnosis, management, prognosis, patie ...

or occupational therapy * Surgery (depending on the specific area and extent of damage) :*

Tendon A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability ...

transfer (the origin remains the same but insertion is moved) * Splinting

Prognosis

Radial neuropathy is not necessarily permanent, though there could be partial loss of movement or

sensation Sensation (psychology) refers to the processing of the senses by the sensory system. Sensation or sensations may also refer to: In arts and entertainment In literature *Sensation (fiction), a fiction writing mode * Sensation novel, a Britis ...

. Complications include deformity of the hand in some individuals. If the injury is axonal (the underlying nerve fiber itself is damaged), recovery may take months or years and full recovery 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.

Culture and society

There are a number of terms used to describe radial nerve injuries, which are dependent on the causation factor such as: * ''Honeymoon palsy'' from another individual sleeping on and compressing one's arm overnight. * ''Saturday night palsy'' from falling asleep with one's arm hanging over the arm rest of a chair, compressing the radial nerve. * ''Squash palsy'', from traction forces associated with the sport squash, happens to squash players during periods between matches.

References

External links

{{Medicine Peripheral nervous system disorders Symptoms and signs: Nervous system Mononeuropathies of upper limb