Muscular branches of the radial nerve: Difference between revisions

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== Muscular Branches of the Radial Nerve ==
{{Infobox nerve
| Name = Muscular branches of the radial nerve
| Latin = rami musculares nervi radialis
| Image = Gray818.png
| Caption = The suprascapular, axillary, and radial nerves. (Muscular branches of the radial nerve are not labeled, but the radial nerve is visible.)
| Innervates = [[Triceps brachii]], [[Anconeus]], [[Brachioradialis]], [[Extensor carpi radialis longus]]
| BranchFrom = [[Radial nerve]]
}}


The radial nerve is one of the major nerves in the upper limb, originating from the brachial plexus. It provides innervation to various muscles in the arm and forearm, allowing for movement and sensation. In this article, we will focus on the muscular branches of the radial nerve and their functions.
The '''muscular branches of the radial nerve''' are branches of the [[radial nerve]] that supply motor innervation to several muscles in the posterior compartment of the arm and forearm. These branches are crucial for the extension of the elbow, wrist, and fingers, as well as for the supination of the forearm.


=== Triceps Brachii ===
==Anatomy==
The radial nerve originates from the posterior cord of the [[brachial plexus]] and travels down the arm. As it descends, it gives off several muscular branches:


The triceps brachii is a large muscle located on the posterior aspect of the upper arm. It consists of three heads: the long head, lateral head, and medial head. The radial nerve gives off a branch known as the posterior branch, which innervates the triceps brachii muscle. This branch provides motor innervation, allowing for extension of the elbow joint.
* '''Triceps brachii''': The radial nerve innervates all three heads of the triceps brachii muscle, which is responsible for the extension of the elbow joint.
* '''Anconeus''': This small muscle assists in elbow extension and is also innervated by a branch of the radial nerve.
* '''Brachioradialis''': Although primarily a flexor of the elbow, the brachioradialis is innervated by the radial nerve, which is unusual as most flexors are innervated by the [[musculocutaneous nerve]].
* '''Extensor carpi radialis longus''': This muscle extends and abducts the wrist and is innervated by the radial nerve.


=== Anconeus ===
==Function==
The muscular branches of the radial nerve are primarily responsible for the extension movements of the upper limb. They enable the extension of the elbow via the triceps brachii, and the extension and abduction of the wrist through the extensor carpi radialis longus. The brachioradialis, although a flexor, is also innervated by the radial nerve and plays a role in flexing the elbow when the forearm is in a mid-pronated position.


The anconeus muscle is a small triangular muscle located on the posterior aspect of the elbow joint. It assists in extension of the forearm and stabilizes the elbow during movements. The radial nerve gives off a branch known as the posterior branch, which innervates the anconeus muscle. This branch provides motor innervation, allowing for the contraction of the anconeus muscle.
==Clinical significance==
Injury to the radial nerve or its muscular branches can lead to a condition known as "[[wrist drop]]", where the patient is unable to extend the wrist and fingers. This can occur due to fractures of the humerus, compression injuries, or prolonged pressure on the nerve.


=== Brachioradialis ===
==Also see==
* [[Radial nerve]]
* [[Brachial plexus]]
* [[Wrist drop]]
* [[Triceps brachii]]
* [[Brachioradialis]]


The brachioradialis muscle is a long muscle located on the lateral aspect of the forearm. It spans from the distal end of the humerus to the styloid process of the radius. The radial nerve gives off a branch known as the posterior interosseous nerve, which innervates the brachioradialis muscle. This branch provides motor innervation, allowing for flexion and pronation of the forearm.
{{Nerves of the upper limb}}


=== Extensor Carpi Radialis Longus ===
[[Category:Peripheral nervous system]]
 
[[Category:Upper limb anatomy]]
The extensor carpi radialis longus muscle is located on the lateral aspect of the forearm, next to the brachioradialis muscle. It spans from the lateral supracondylar ridge of the humerus to the base of the second metacarpal bone. The radial nerve gives off a branch known as the posterior interosseous nerve, which innervates the extensor carpi radialis longus muscle. This branch provides motor innervation, allowing for extension and abduction of the wrist joint.
 
=== Extensor Carpi Radialis Brevis ===
 
The extensor carpi radialis brevis muscle is located on the lateral aspect of the forearm, next to the extensor carpi radialis longus muscle. It spans from the lateral epicondyle of the humerus to the base of the third metacarpal bone. The radial nerve gives off a branch known as the posterior interosseous nerve, which innervates the extensor carpi radialis brevis muscle. This branch provides motor innervation, allowing for extension and abduction of the wrist joint.
 
=== Supinator ===
 
The supinator muscle is located on the lateral aspect of the forearm, deep to the brachioradialis muscle. It spans from the lateral epicondyle of the humerus to the proximal part of the radius. The radial nerve gives off a branch known as the posterior interosseous nerve, which innervates the supinator muscle. This branch provides motor innervation, allowing for supination of the forearm.
 
=== Extensor Digitorum ===
 
The extensor digitorum muscle is located on the posterior aspect of the forearm, deep to the extensor carpi radialis brevis muscle. It spans from the lateral epicondyle of the humerus to the distal phalanges of the fingers. The radial nerve gives off a branch known as the posterior interosseous nerve, which innervates the extensor digitorum muscle. This branch provides motor innervation, allowing for extension of the fingers.
 
=== Extensor Digiti Minimi ===
 
The extensor digiti minimi muscle is located on the posterior aspect of the forearm, next to the extensor digitorum muscle. It spans from the lateral epicondyle of the humerus to the fifth digit. The radial nerve gives off a branch known as the posterior interosseous nerve, which innervates the extensor digiti minimi muscle. This branch provides motor innervation, allowing for extension of the fifth digit.
 
In conclusion, the radial nerve gives off various muscular branches that innervate important muscles in the arm and forearm. These branches play a crucial role in allowing for movement and stability of the upper limb. Understanding the innervation of these muscles is essential for diagnosing and treating any radial nerve-related conditions or injuries.<br>{{stub}}
{{dictionary-stub1}}

Latest revision as of 02:58, 11 December 2024


The muscular branches of the radial nerve are branches of the radial nerve that supply motor innervation to several muscles in the posterior compartment of the arm and forearm. These branches are crucial for the extension of the elbow, wrist, and fingers, as well as for the supination of the forearm.

Anatomy[edit]

The radial nerve originates from the posterior cord of the brachial plexus and travels down the arm. As it descends, it gives off several muscular branches:

  • Triceps brachii: The radial nerve innervates all three heads of the triceps brachii muscle, which is responsible for the extension of the elbow joint.
  • Anconeus: This small muscle assists in elbow extension and is also innervated by a branch of the radial nerve.
  • Brachioradialis: Although primarily a flexor of the elbow, the brachioradialis is innervated by the radial nerve, which is unusual as most flexors are innervated by the musculocutaneous nerve.
  • Extensor carpi radialis longus: This muscle extends and abducts the wrist and is innervated by the radial nerve.

Function[edit]

The muscular branches of the radial nerve are primarily responsible for the extension movements of the upper limb. They enable the extension of the elbow via the triceps brachii, and the extension and abduction of the wrist through the extensor carpi radialis longus. The brachioradialis, although a flexor, is also innervated by the radial nerve and plays a role in flexing the elbow when the forearm is in a mid-pronated position.

Clinical significance[edit]

Injury to the radial nerve or its muscular branches can lead to a condition known as "wrist drop", where the patient is unable to extend the wrist and fingers. This can occur due to fractures of the humerus, compression injuries, or prolonged pressure on the nerve.

Also see[edit]

Template:Nerves of the upper limb

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