Radial nerve

Radial nerve
Nerve: Radial nerve
The suprascapular, axillary, and radial nerves.
Latin nervus radialis
Gray's subject #210 943
Innervates posterior compartment of the arm, posterior compartment of the forearm
From posterior cord
To posterior interosseous nerve
MeSH Radial+Nerve

The radial nerve is a nerve in the human body that supplies the upper limb. It supplies the medial and lateral heads of the triceps brachii muscle of the arm, as well as all 12 muscles in the posterior osteofascial compartment of the forearm and the associated joints and overlying skin.

It originates from the posterior cord of the brachial plexus, carrying fibers from the ventral roots of spinal nerves C5, C6, C7, C8 & T1.

The radial nerve and its branches provide motor innervation to the dorsal arm muscles (the triceps brachii and the anconeus) and the extrinsic extensors of the wrists and hands; it also provides cutaneous sensory innervation to most of the back of the hand. The ulnar nerve provides cutaneous sensory innervation to the back of the little finger and adjacent half of the ring finger.

The radial nerve divides into a deep branch, which becomes the posterior interosseous nerve, and a superficial branch, which goes on to innervate the dorsum (back) of the hand.

Contents

Course

The radial nerve originates as a terminal branch of the posterior cord of the brachial plexus. It goes through the arm, first in the posterior compartment of the arm, and later in the anterior compartment of the arm, and continues in the posterior compartment of the forearm.

In arm

From the brachial plexus, it travels posteriorly through what is often called the triangular interval (US), the lower triangular space of the axilla (UK) or the triceps hiatus (medical terminology).

Radial nerve

Having passed through this inter muscular gap, the radial nerve continues posteriorly in a medial to lateral fashion on the arm while in conjunction with the axillary artery/brachial artery.

The nerve will first give off branches to the medial head of the triceps brachii and then enter a groove on the humerus, the radial sulcus (AKA spiral groove), where it innervates the lateral head of the triceps. It is commonly believed that the radial nerve also provided motor innervation to the long head of the triceps. However, a study conducted in 2004 determined that, in 20 cadaveric specimens and 15 surgical dissections on participants, the long head was innervated by a branch of the axillary nerve in all cases. [1]

With the lateral and medial heads of the triceps intervated, the radial nerve emerges from the radial groove on the lateral aspect of the humerus.

At this point, it pierces the lateral intermuscular septum and enters the anterior compartment of the arm.

It continues its journey inferiorly between the brachialis and brachioradialis muscles.

When the radial nerve reaches the distal part of the humerus, it passes anterior to the lateral epicondyle and continues in the forearm.

In forearm

In the forearm, it branches into a superficial branch (primarily sensory) and a deep branch (primarily motor).

Branches/Innervations

The following are branches/innervations of the radial nerve (including the superficial branch of the radial nerve and the deep branch of the radial nerve/posterior interosseous nerve).

Cutaneous

Cutaneous innervation of the right upper extremity. Areas innervated by the radial nerve are colored in pink.

Cutaneous innervation by the radial nerve is provided by the following nerve branches:

The superficial branch of the radial nerve provides sensory innervation to much of the back of the hand, including the web of skin between the thumb and index finger.

Motor

Muscles of the posterior forearm. All the labeled muscles (that is, all the visible muscles except the ones one the dorsal hand and one at top left) are innervated by the radial nerve, and represent all muscles innervated by the radial nerve except for the supinator.

Muscular branches of the radial nerve:

  • Triceps brachii (lateral and medial heads)
  • Anconeus
  • Brachioradialis
  • Extensor carpi radialis longus

Deep branch of the radial nerve:

  • Extensor carpi radialis brevis
  • Supinator

Posterior interosseous nerve (a continuation of the deep branch after the supinator):

  • Extensor digitorum
  • Extensor digiti minimi
  • Extensor carpi ulnaris
  • Abductor pollicis longus
  • Extensor pollicis brevis
  • Extensor pollicis longus
  • Extensor indicis

The radial nerve (and its deep branch) provides motor innervation to the muscles in the posterior compartment of the arm and forearm, which are mostly extensors.

Additional images

References

  1. ^ de Se`ze MP, Rezzouk J, de Se`ze M, Uzel M, Lavignolle B, Midy D, Durandeau A (2004). "Does the motor branch of the long head of the triceps brachii arise from the radial nerve?". Surg Radiol Anat 26 (6): 459–461. doi:10.1007/s00276-004-0253-z. PMID 15365769. 

See also

External links


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • radial nerve — n a large nerve that arises from the posterior cord of the brachial plexus and passes spirally down the humerus to the front of the lateral epicondyle where it divides into a superficial branch distributed to the skin of the back of the hand and… …   Medical dictionary

  • radial nerve — noun largest branch of the brachial plexus; extends down the humerus to the lateral epicondyle where it divides into one branch that goes to the skin on the back of the hand and another that goes to the underlying extensor muscles • Syn: ↑nervus… …   Useful english dictionary

  • radial nerve — noun A large nerve, carrying both sensory and motor neurones, that supplies the dorsal aspect of the forearm and arm …   Wiktionary

  • radial nerve — an important mixed sensory and motor nerve of the arm, forming the largest branch of the brachial plexus. It extends downwards behind the humerus, supplying muscles of the upper arm, to the elbow, which it supplies with branches, and then runs… …   The new mediacal dictionary

  • radial nerve deep — ramus profundus nervi radialis …   Medical dictionary

  • radial nerve superficial — ramus superficialis nervi radialis …   Medical dictionary

  • Deep branch of radial nerve — Nerve: Deep branch of radial nerve The suprascapular, axillary, and radial nerves. (Deep branch of radial labeled at right.) Latin ramus profundus nervi radialis, nervus interosseus dorsalis Gray s …   Wikipedia

  • Muscular branches of the radial nerve — Nerve: Muscular branches of the radial nerve The suprascapular, axillary, and radial nerves. Superficial palmar nerves …   Wikipedia

  • Dorsal digital nerves of radial nerve — Nerve: Dorsal digital nerves of radial nerve Diagram of segmental distribution of the cutaneous nerves of the right upper extremity. (Dorsal digital nerves of radial nerve at bottom right, in yellow.) Latin nervi digitales dorsales nervi radialis …   Wikipedia

  • Superficial branch of the radial nerve — Infobox Nerve Name = Superficial branch of the radial nerve Latin = ramus superficialis nervi radialis GraySubject = 210 GrayPage = 944 Caption = Diagram of segmental distribution of the cutaneous nerves of the right upper extremity. Caption2 =… …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.