Synonyms
radial nerve Medical: radial nerve
Definition
The radial nerve is an important arm nerve. It is called the radial nerve because it is oriented along the radius, one of the two bones of the forearm (ulna and radius). Like the other two main arm nerves (ulnar nerve and median nerve), it consists of fibers that transport sensitive information from the skin and joints to the spinal cord and brain (sensitive afferences) and of motor fibers that send impulses from the brain to the arm muscles (motor effects).
Origin
The radial nerve is one of many nerves that make up the brachial plexus. The spinal nerves from the cervical medulla of the spinal cord (C5-C8) join together immediately after exiting the spinal cord to form this nerve bundle, which is called the brachial plexus. All nerves supplying the arm emerge from this nerve bundle.
The nerves of the brachial plexus are called brachial plexus nerve bundle:
- Short branches:N. subscapularis, N. thoracodorsalis, Nn. pectoralis medialis and lateralis, N. cutaneus antebrachii medialis, Nn. intercostobrachiales;
- Long branches:N. musculocutanes, N. axillaris, N. radialis, N. medianus, N. ulnaris
Overview and classification
A nerve contains fibers that transport sensitive impulses from the skin and joints back to the brain (afferences) and at the same time fibers through which impulses are sent from the brain to the muscles (efferences). A special feature of the radial nerve, in comparison to its siblings, the median nerve and the ulnar nerve, is that it supplies muscles in both the upper and lower arm.
Anatomy and course
The radial nerve runs from the armpit, where it emerges from the plexus of the arm nerve root, to the back of the humerus. There, during development, it makes a notch in the bone, the radial nerve pit (sulcus nervus radialis). It passes over the back of the elbow in the radialis tunnel.
Below the elbow, the nerve divides into two branches: one deep and one superficial branch (ramus profundus, ramus superficialis). The deep branch runs through a muscle canal (supinator canal) formed by the supinator muscle. The superficial branch runs along the radius (hence the name) protected by the muscles of the lower arm to the thumb and the back of the hand. On the long way from the root to the back of the hand, the spoke nerve repeatedly releases fibres/branches to muscles (motor branches) or to the skin (sensitive branches).
