Extensor digiti minimi muscle

Extensor digiti minimi
The mucous sheaths of the tendons on the back of the wrist. (Extensor digiti quinti proprius labeled at center left.)
Details
Latin	musculus extensor digiti minimi
Origin	the anterior portion of the lateral epicondyle of the humerus (common extensor tendon)
Insertion	at the extensor expansion, located at the base of the proximal phalanx of digit V on the dorsal side
Artery	posterior interosseous artery
Nerve	posterior interosseous nerve (C7, 8)
Actions	extends the wrist and the little finger at all joints
Antagonist	Flexor digiti minimi brevis
Identifiers
Dorlands /Elsevier	m_22/12548878
TA
TH	{{#property:P1694}}
TE	{{#property:P1693}}
FMA	{{#property:P1402}}
Anatomical terms of muscle [[[d:|edit on Wikidata]]]

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

It arises from the common Extensor tendon by a thin tendinous slip, from the intermuscular septa between it and the adjacent muscles.

Its tendon runs through a compartment of the dorsal carpal ligament behind the distal radio-ulnar joint, then divides into two as it crosses the hand, and finally joins the expansion of the Extensor digitorum communis tendon on the dorsum of the first phalanx of the little finger.

Structure

The extensor digiti minimi originates from the lateral epicondyle of the humerus, or the outer edge of the elbow if the palm is facing up, in the anatomical position. It runs along the back of the back of the arm to the wrist and past the wrist to the proximal phalanx V, or the bone between the genital knuckle and first bend of the finger of the little finger.

Variations

An additional fibrous slip from the lateral epicondyle; the tendon of insertion may not divide or may send a slip to the ring finger.

Absence of muscle rare; fusion of the belly with the Extensor digitorum communis not uncommon.

Variations to the 5th extensor compartment, which the extensor digiti minimi runs through, may cause tenosynovitis and can limit the use of the extensor digiti minimi.

Extensor digiti minimi can also be bifurcated, which means split, at many different points in the muscle.

Functions

The extensor digiti minimi is a two joint muscle. It acts as an extensor in both joints. It extends the wrist, which means it moves the back of the hand toward the back of the forearm. It also extends the little finger, which means it straightens the little finger from a fist.

Additional images

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  Bones of left forearm. Posterior aspect.

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  Posterior surface of the forearm. Superficial muscles.

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  Transverse section across distal ends of radius and ulna.

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  Transverse section across the wrist and digits.

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  Extensor digiti minimi muscle

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  Extensor digiti minimi muscle '

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  Extensor digiti minimi muscle

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  Muscles of hand. Posterior view.

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  Muscles of hand. Posterior view.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

External links

• Hand kinesiology at the University of Kansas Medical Center