Extensor digitorum reflex

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The Extensor digitorum reflex is tested as part of the neurological examination to assess the sensory and motor pathways within the C6 and C7 spinal nerves. It is also known as Braunecker-Effenberg reflex, or BER.

Contents

Testing

The test is performed by tapping the extensor digitorum muscle while the fingers are light or half flexed. A sudden contraction of the musculus extensor digitorum and extension of the fingers indicate a normal reflex. [1]

Absence of reflex

An absence of reflex can be an indicator for radiculopathy within the C6 and C7 or neuropathy within the deep branch of the radial nerve.

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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.

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Plantar reflex

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Phalen maneuver

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Extensor digiti minimi muscle muscle of the forearm

The extensor digiti minimi is a slender muscle of the forearm, placed on the ulnar side of the extensor digitorum communis, with which it is generally connected.

Extensor digitorum muscle

The extensor digitorum muscle is a muscle of the posterior forearm present in humans and other animals. It extends the medial four digits of the hand. Extensor digitorum is innervated by the posterior interosseous nerve, which is a branch of the radial nerve.

Posterior interosseous nerve

The posterior interosseous nerve is a nerve in the forearm. It is the continuation of the deep branch of the radial nerve, after this has crossed the supinator muscle. It is considerably diminished in size compared to the deep branch of the radial nerve. The nerve fibers originate from cervical segments C7 and C8.

Finkelsteins test


Finkelstein's test is a test used to diagnose de Quervain's tenosynovitis in people who have wrist pain.

The stretch reflex is a muscle contraction in response to stretching within the muscle. It is a monosynaptic reflex which provides automatic regulation of skeletal muscle length.

Extensor indicis muscle

In human anatomy, the extensor indicis [proprius] is a narrow, elongated skeletal muscle in the deep layer of the dorsal forearm, placed medial to, and parallel with, the extensor pollicis longus. Its tendon goes to the index finger, which it extends.

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.

Cervical spinal nerve 8

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

Ulnar claw

An ulnar claw, also known as claw hand, or 'Spinster's Claw' is a deformity or an abnormal attitude of the hand that develops due to ulnar nerve damage causing paralysis of the lumbricals. A claw hand presents with a hyper-extension at the metacarpophalangeal joints and flexion at the proximal and distal interphalangeal joints of the 4th and 5th fingers. The patients with this condition can make a full fist but when they extend their fingers, the hand posture is referred to as claw hand. The ring- and little finger can usually not fully extend at the proximal interphalangeal joint (PIP).

Extensor digitorum brevis manus is an extra or accessory muscle on the backside (dorsum) of the hand. It was first described by Albinus in 1758. The muscles lies in the fourth extensor compartment of the wrist, and is relatively rare. It has a prevalence of 4% in the general population according to a meta-analysis. This muscle is commonly misdiagnosed as a ganglion cysta, synovial nodule or cyst.

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).

Extensor medii proprius muscle

The extensor medii proprius is a rare anatomical variant in the extensor compartment of the forearm. The aberrant muscle is analogous to the extensor indicis with the insertion being the middle finger instead of the index finger.

Juncturae tendinum

In human anatomy, juncturae tendinum or connexus intertendinei refers to the connective tissues that link the tendons of the extensor digitorum communis, and sometimes, to the tendon of the extensor digiti minimi. Juncturae tendinum are located on the dorsal aspect of the hand in the first, second and third inter-metacarpal spaces proximal to the metacarpophalangeal joint.

References

  1. Extensor Carpi Radialis Longus, Extensor Digitorum Communis Reflex DTR MSR on YouTube