Anterior interosseous nerve

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Anterior interosseous nerve
Nerves of the left upper extremity.gif
Nerves of the left upper extremity. (Volar interosseus labeled at center right.)
Gray817.png
Deep palmar nerves. (Volar interosseous labeled at center top.)
Details
From Median nerve
Identifiers
Latin nervus interosseus antebrachii anterior
TA98 A14.2.03.034
TA2 6460
FMA 44822
Anatomical terms of neuroanatomy

The anterior interosseous nerve (volar interosseous nerve) is a branch of the median nerve that supplies the deep muscles on the anterior of the forearm, except the ulnar (medial) half of the flexor digitorum profundus. Its nerve roots come from C8 and T1.

Contents

It accompanies the anterior interosseous artery along the anterior of the interosseous membrane of the forearm, in the interval between the flexor pollicis longus and flexor digitorum profundus, supplying the whole of the former and (most commonly) the radial half of the latter, and ending below in the pronator quadratus and wrist joint.

Note that the median nerve supplies all flexor muscles of the forearm except for the ulnar half of flexor digitorum profundus and the flexor carpi ulnaris, which is a superficial muscle of the forearm.

Innervation

The anterior interosseous nerve classically innervates 2.5 muscles:

which are deep muscles of the forearm

and the inferior radioulnar, wrist and carpal joints.

Injury

A branch of the median nerve, the anterior interosseous nerve (AIN) can be affected by either direct penetrating injury, possibly compression in a fashion similar to carpal tunnel syndrome, but most commonly an idiopathic inflammatory process (referred to an Anterior Interosseous Syndrome). As might be expected, the symptoms involve weakness in the muscle innervated by the AIN including the flexor digitorum profundus muscle to the index (and sometimes the middle) finger, the flexor pollicis longus muscle to the thumb and the pronator quadratus of the distal forearm. AIN also has large sensory nerve to the volar wrist bones and compression of the AIN branch of the median nerve at the elbow can cause referred pain in the volar wrist/distal volar forearm. Non-surgical treatment consists of splinting, proximal tissue massage and anti-inflammatory drugs. Surgical treatment consists of releasing the compression on the nerve from surrounding structures. Pronator Syndrome is similar, but involves both the AIN as well as the median nerve proper.

Clinical significance

Following peripheral nerve injury to the ulnar nerve, the AIN is often used as a donor branch to reinnervate the paralysed muscles innervated by the ulnar nerve. [1]

See also

Related Research Articles

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The carpal bones are the eight small bones that make up the wrist (carpus) that connects the hand to the forearm. The term "carpus" and "carpal" is derived from the Latin carpus and the Greek καρπός (karpós), meaning "wrist". In human anatomy, the main role of the carpal bones is to articulate with the radial and ulnar heads to form a highly mobile condyloid joint, to provide attachments for thenar and hypothenar muscles, and to form part of the rigid carpal tunnel which allows the median nerve and tendons of the anterior forearm muscles to be transmitted to the hand and fingers.

<span class="mw-page-title-main">Ulna</span> Medial bone from forearm

The ulna or ulnar bone is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the radius, the forearm's other long bone. Longer and thinner than the radius, the ulna is considered to be the smaller long bone of the lower arm. The corresponding bone in the lower leg is the fibula.

<span class="mw-page-title-main">Median nerve</span> Nerve of the upper limb

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.

<span class="mw-page-title-main">Wrist</span> Part of the arm between the lower arm and the hand

In human anatomy, the wrist is variously defined as (1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; (2) the wrist joint or radiocarpal joint, the joint between the radius and the carpus and; (3) the anatomical region surrounding the carpus including the distal parts of the bones of the forearm and the proximal parts of the metacarpus or five metacarpal bones and the series of joints between these bones, thus referred to as wrist joints. This region also includes the carpal tunnel, the anatomical snuff box, bracelet lines, the flexor retinaculum, and the extensor retinaculum.

The flexor digitorum profundus or flexor digitorum communis profundus is a muscle in the forearm of humans that flexes the fingers. It is considered an extrinsic hand muscle because it acts on the hand while its muscle belly is located in the forearm.

<span class="mw-page-title-main">Ulnar nerve</span> Nerve which runs near the ulna bone

The ulnar nerve is a nerve that runs near the ulna, one of the two long bones in the forearm. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest in the human body unprotected by muscle or bone, so injury is common. This nerve is directly connected to the little finger, and the adjacent half of the ring finger, innervating the palmar aspect of these fingers, including both front and back of the tips, perhaps as far back as the fingernail beds.

<span class="mw-page-title-main">Radius (bone)</span> One of the two long bones of the forearm

The radius or radial bone is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna. The ulna is longer than the radius, but the radius is thicker. The radius is a long bone, prism-shaped and slightly curved longitudinally.

<span class="mw-page-title-main">Upper limb</span> Consists of the arm, forearm, and hand

The upper limbs or upper extremities are the forelimbs of an upright-postured tetrapod vertebrate, extending from the scapulae and clavicles down to and including the digits, including all the musculatures and ligaments involved with the shoulder, elbow, wrist and knuckle joints. In humans, each upper limb is divided into the shoulder, arm, elbow, forearm, wrist and hand, and is primarily used for climbing, lifting and manipulating objects. In anatomy, just as arm refers to the upper arm, leg refers to the lower leg.

<span class="mw-page-title-main">Ulnar artery</span> Artery of the forearm

The ulnar artery is the main blood vessel, with oxygenated blood, of the medial aspects of the forearm. It arises from the brachial artery and terminates in the superficial palmar arch, which joins with the superficial branch of the radial artery. It is palpable on the anterior and medial aspect of the wrist.

The flexor pollicis longus is a muscle in the forearm and hand that flexes the thumb. It lies in the same plane as the flexor digitorum profundus. This muscle is unique to humans, being either rudimentary or absent in other primates. A meta-analysis indicated accessory flexor pollicis longus is present in around 48% of the population.

The pronator teres is a muscle that, along with the pronator quadratus, serves to pronate the forearm. It has two origins, at the medial humeral supracondylar ridge and the medial side of the coronoid process of the ulna and inserts near the middle of the radius.

<span class="mw-page-title-main">Galeazzi fracture</span> Medical condition

The Galeazzi fracture is a fracture of the distal third of the radius with dislocation of the distal radioulnar joint. It classically involves an isolated fracture of the junction of the distal third and middle third of the radius with associated subluxation or dislocation of the distal radio-ulnar joint; the injury disrupts the forearm axis joint.

<span class="mw-page-title-main">Anterior interosseous artery</span>

The anterior interosseous artery is an artery in the forearm. It is a branch of the common interosseous artery.

<span class="mw-page-title-main">Carpal tunnel</span> Structure of human wrist

In the human body, the carpal tunnel or carpal canal is a flattened body cavity on the flexor (palmar/volar) side of the wrist, bounded by the carpal bones and flexor retinaculum. It forms the passageway that transmits the median nerve and the tendons of the extrinsic flexor muscles of the hand from the forearm to the hand. The median artery is an anatomical variant. When present it lies between the radial artery, and the ulnar artery and runs with the median nerve supplying the same structures innervated.

<span class="mw-page-title-main">Cervical spinal nerve 8</span> Spinal nerve of the cervical segment

The cervical spinal nerve 8 (C8) is a spinal nerve of the cervical segment.

Anterior interosseous syndrome is a medical condition in which damage to the anterior interosseous nerve (AIN), a distal motor and sensory branch of the median nerve, classically with severe weakness of the pincer movement of the thumb and index finger, and can cause transient pain in the wrist.

<span class="mw-page-title-main">Pronator teres syndrome</span> Medical condition

Pronator teres syndrome is a compression neuropathy of the median nerve at the elbow. It is rare compared to compression at the wrist or isolated injury of the anterior interosseous branch of the median nerve.

<span class="mw-page-title-main">Median nerve palsy</span> Medical condition

Injuries to the arm, forearm or wrist area can lead to various nerve disorders. One such disorder is median nerve palsy. The median nerve controls the majority of the muscles in the forearm. It controls abduction of the thumb, flexion of hand at wrist, flexion of digital phalanx of the fingers, is the sensory nerve for the first three fingers, etc. Because of this major role of the median nerve, it is also called the eye of the hand. If the median nerve is damaged, the ability to abduct and oppose the thumb may be lost due to paralysis of the thenar muscles. Various other symptoms can occur which may be repaired through surgery and tendon transfers. Tendon transfers have been very successful in restoring motor function and improving functional outcomes in patients with median nerve palsy.

<span class="mw-page-title-main">Muscles of the thumb</span> Set of nine human skeletal muscles

The muscles of the thumb are nine skeletal muscles located in the hand and forearm. The muscles allow for flexion, extension, adduction, abduction and opposition of the thumb. The muscles acting on the thumb can be divided into two groups: The extrinsic hand muscles, with their muscle bellies located in the forearm, and the intrinsic hand muscles, with their muscles bellies located in the hand proper.

<span class="mw-page-title-main">Palmaris profundus muscle</span>

Palmaris profundus is a rare anatomical variant in the anterior compartment of forearm. It was first described in 1908. It is usually found incidentally in cadaveric dissection or surgery.

References

  1. Sukegawa, K.; Kuniyoshi, K.; Suzuki, T.; Ogawa, Y.; Okamoto, S.; Shibayama, M.; Kobayashi, T.; Takahashi, K. (2014-06-01). "An anatomical study of transfer of the anterior interosseous nerve for the treatment of proximal ulnar nerve injuries". Bone Joint J. 96-B (6): 789–794. doi:10.1302/0301-620X.96B6.33656. ISSN   2049-4394. PMID   24891580. Archived from the original on 2017-09-14. Retrieved 2016-10-17.

PD-icon.svgThis article incorporates text in the public domain from page 938 of the 20th edition of Gray's Anatomy (1918)

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