Extensor carpi ulnaris muscle

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Extensor carpi ulnaris
Extensor carpi ulnaris muscle.png
Posterior surface of the forearm. Extensor carpi ulnaris labeled in purple at center right.
Details
Origin Humeral head: Lateral epicondyle of the Humerus.Ulnar head: Olecranon, Posterior surface of ulna, antebrachial fascia
Insertion 5th metacarpal
Artery ulnar artery
Nerve Posterior interosseous nerve
Actions extends and adducts the wrist
Antagonist Flexor carpi radialis
Identifiers
Latin musculus extensor carpi ulnaris
TA98 A04.6.02.045
TA2 2507
FMA 38506
Anatomical terms of muscle

In human anatomy, the extensor carpi ulnaris is a skeletal muscle located on the ulnar side of the forearm. It acts to extend and adduct at the carpus/wrist from anatomical position.

Contents

Being an extensor muscle, extensor carpi ulnaris is on the posterior side of the forearm.

Origin and insertion

It originates from the lateral epicondyle of the humerus and the posterior border of the ulna, and crosses the forearm to the ulnar (medial) side to insert at the base of the 5th metacarpal.

Action

The extensor carpi ulnaris extends the wrist, but when acting alone inclines the hand toward the ulnar side; by its continued action it extends the elbow-joint.

The muscle is a minor extensor of the carpus in carnivores, but has become a flexor in ungulates. In this case it is described as ulnaris lateralis.

Innervation

Despite its name, the extensor carpi ulnaris is innervated by the posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve. [1] It would therefore be paralyzed in an injury to the posterior cord of the brachial plexus. [2] [3]

Injuries

A common injury to the extensor carpi ulnaris is tennis elbow. This injury occurs in people that participate in activities requiring repetitive arm, elbow, and wrist, especially when they are tightly gripping an object. Some symptoms include pain when shaking hands or when squeezing/gripping an object. The pain worsens when a person moves their wrist with force. The pain intensifies because the extensor carpi ulnaris has an injury near the elbow area and as a person moves their arm, the muscle contracts, thus causing it to move over the medial epicondyle of the humerus. This causes irritation to the already existing injury. Some treatments for tennis elbow include occupational therapy, physical therapy, anti-inflammatory medication, and rest from the activity that caused the injury. A similar injury involving the medial elbow is known as golfer's elbow. [4] [5]

Injury treatment and diagnosis

An ECU injury most often requires imaging (CT, MRI, ultrasound) for diagnosis. [6] After the ECU injury is diagnosed, a physician will choose a course of treatment, which depends upon the severity of the injury. Conservative treatments include immobilization and stabilization of the affected wrist by placing it in a cast. [7] A long arm cast may be required in order to ensure that all wrist movement has been stopped. The duration of the immobilization is at the treating physician's discretion. After the immobilization period has ended, the cast will be removed and further analysis of the injury will be required. If the injury did not improve with the conservative courses of treatment, or if the injury was initially too severe for conservative treatment, invasive procedures may become necessary. Steroid injections and surgical procedures are the most prominent invasive procedures. [6] Surgical repair or reconstruction of the ECU is not often required, yet a severe ECU injury may cause these approaches to be necessary. [6]

Additional images

Related Research Articles

Ulna

The ulna is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. It runs parallel to the radius, the other long bone in the forearm. The ulna is usually slightly longer than the radius, but the radius is thicker. Therefore, the radius is considered to be the larger of the two.

Humerus Long bone of the upper arm

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 rounded head, a narrow neck, and two short processes. The body is cylindrical in its upper portion, and more prismatic below. The lower extremity consists of 2 epicondyles, 2 processes, and 3 fossae. As well as its true anatomical neck, the constriction below the greater and lesser tubercles of the humerus is referred to as its surgical neck due to its tendency to fracture, thus often becoming the focus of surgeons.

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 anatomy, technically, means only the region of the upper arm, whereas the lower "arm" is called the forearm. It is homologous to the region of the leg that lies between the knee and the ankle joints, the crus.

In human anatomy, extensor carpi radialis brevis is a muscle in the forearm that acts to extend and abduct the wrist. It is shorter and thicker than its namesake extensor carpi radialis longus which can be found above the proximal end of the extensor carpi radialis brevis.

Flexor carpi radialis muscle

In anatomy, flexor carpi radialis is a muscle of the human forearm that acts to flex and (radially) abduct the hand. The Latin carpus means wrist; hence flexor carpi is a flexor of the wrist.

Ulnar nerve

In human anatomy, the ulnar nerve is a nerve that runs near the ulna bone. 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.

Wrist drop Medical condition

Wrist drop, is a medical condition in which the wrist and the fingers cannot extend at the metacarpophalangeal joints. The wrist remains partially flexed due to an opposing action of flexor muscles of the forearm. As a result, the extensor muscles in the posterior compartment remain paralyzed.

Radius (bone) 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 usually slightly longer than the radius, but the radius is thicker. Therefore the radius is considered to be the larger of the two. It is a long bone, prism-shaped and slightly curved longitudinally.

Upper limb

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 arm, forearm and hand, and is primarily used for climbing, lifting and manipulating objects.

Ulnar collateral ligament of elbow joint

The ulnar collateral ligament is a thick triangular band at the medial aspect of the elbow uniting the distal aspect of the humerus to the proximal aspect of the ulna.

Flexor carpi ulnaris muscle

The flexor carpi ulnaris (FCU) is a muscle of the forearm that flexes and adducts at the wrist joint.

Lateral epicondyle of the humerus Structure of humerus

The lateral epicondyle of the humerus is a large, tuberculated eminence, curved a little forward, and giving attachment to the radial collateral ligament of the elbow joint, and to a tendon common to the origin of the supinator and some of the extensor muscles. Specifically, these extensor muscles include the anconeus muscle, the supinator, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris. In birds, where the arm is somewhat rotated compared to other tetrapods, it is termed dorsal epicondyle of the humerus. In comparative anatomy, the term ectepicondyle is sometimes used.

The pronator teres is a muscle that, along with the pronator quadratus, serves to pronate the forearm. It has two attachments, to the medial humeral supracondylar ridge and the ulnar tuberosity, and inserts near the middle of the radius.

Medial epicondyle of the humerus A rounded eminence on the medial side of the humerus

The medial epicondyle of the humerus is an epicondyle of the humerus bone of the upper arm in humans. It is larger and more prominent than the lateral epicondyle and is directed slightly more posteriorly in the anatomical position. In birds, where the arm is somewhat rotated compared to other tetrapods, it is called the ventral epicondyle of the humerus. In comparative anatomy, the more neutral term entepicondyle is used.

Golfers elbow Tendon inflammation disease of the elbow

Golfer's elbow, or medial epicondylitis, is tendinosis of the medial epicondyle on the inside of the elbow. It is in some ways similar to tennis elbow, which affects the outside at the lateral epicondyle.

Ulnar styloid process

The styloid process of the ulna is a bony prominence found at distal end of the ulna in the forearm.

Fascial compartments of arm

The fascial compartments of arm refers to the specific anatomical term of the compartments within the upper segment of the upper limb(the arm) of the body. The upper limb is divided into two segments, the arm and the forearm. Each of these segments is further divided into two compartments which are formed by deep fascia – tough connective tissue septa (walls). Each compartment encloses specific muscles and nerves.

The posterior compartment of the forearm contains twelve muscles which are chiefly responsible for extension of the wrist and digits, and supination of the forearm. It is separated from the anterior compartment by the interosseous membrane between the radius and ulna.

Elbow Joint between the upper and lower parts of the arm

The elbow is the visible joint between the upper and lower parts of the arm. It includes prominent landmarks such as the olecranon, the elbow pit, the lateral and medial epicondyles, and the elbow joint. The elbow joint is the synovial hinge joint between the humerus in the upper arm and the radius and ulna in the forearm which allows the forearm and hand to be moved towards and away from the body.

Extrinsic extensor muscles of the hand

The extrinsic extensor muscles of the hand are located in the back of the forearm and have long tendons connecting them to bones in the hand, where they exert their action. Extrinsic denotes their location outside the hand. Extensor denotes their action which is to extend, or open flat, joints in the hand. They include the extensor carpi radialis longus (ECRL), extensor carpi radialis brevis (ECRB), extensor digitorum (ED), extensor digiti minimi (EDM), extensor carpi ulnaris (ECU), abductor pollicis longus (APL), extensor pollicis brevis (EPB), extensor pollicis longus (EPL), and extensor indicis (EI).

References

  1. Clinically oriented anatomy. [S.l.]: Lippincott Williams & Wil. 2009. p. 751. ISBN   978-1-6083-1181-1.
  2. Chung, K (1995). BRS: Gross Anatomy.
  3. Moore, K; Agar, A (2002). Essential Clinical Anatomy (2nd ed.). Lippincott.
  4. Nirschl, RP (October 1992). "Elbow Tendinosis/tennis Elbow". Clin Sports Med. 11 (4): 851–70. PMID   1423702.
  5. Saladin, Kenneth S. Anatomy and Physiology: The Unity and Form of Function (5th ed.). ISBN   9780077396336.[ page needed ]
  6. 1 2 3 Campbell, Doug; Campbell, Rob; O'Connor, Phil; Hawkes, Roger (4 October 2013). "Sports-Related Extensor Carpi Ulnaris Pathology: A Review of Functional Anatomy, Sports Injury and Management". British Journal of Sports Medicine. 47 (17): 1105–1111. doi:10.1136/bjsports-2013-092835. PMC   3812850 . PMID   24096897.
  7. Patterson, Steve M.; Picconatto, William J.; Alexander, Julie A.; Johnson, Rachel L. (September–October 2011). "Conservative Treatment of an Acute Traumatic Extensor Carpi Ulnaris Tendon Sublaxation in a Collegiate Basketball Player: A Case Report". Journal of Athletic Training. 46 (5): 574–576. doi:10.4085/1062-6050-46.5.574. PMC   3418964 . PMID   22488145.