Table of Contents
What is extensor Indicis proprius?
Abstract. Purpose: The extensor indicis proprius (EIP) is a muscle of the forearm that originates from the posterior surface of the ulna and the adjacent interosseous membrane and attaches to the index finger. Many anatomical variations of this muscle have been reported in the literature.
What is EPL tendon?
The long extensor tendon to the thumb is called the Extensor Pollicis Longus (EPL). This tendon straightens the end joint of the thumb and also helps pull the thumb in towards the index finger. The tendon runs around a bony prominence on the back of the wrist called Lister’s tubercle.
Where is the extensor pollicis longus?
forearm
Extensor pollicis longus (EPL) is a long muscle located at the deep layer with extensor pollicis brevis, abductor pollicis longus, extensor indicis, and supinator muscle in the posterior compartment of the forearm.
Where does extensor indicis insert?
index finger
It is known that the extensor indicis proprius inserts to the index finger on the ulnar side of the extensor digitorum. However, the insertion on the radial side of the common extensor digitorum infrequently seen, namely the extensor indicis radialis.
What Innervates the extensor Indicis?
Innervation. Extensor indicis receives its nervous supply from posterior interosseous nerve, a branch of the radial nerve derived from spinal roots C7 and C8. The skin overlying the muscle is supplied by the same nerve, with fibers that stem from the spinal roots C6 and C7.
Which is the insertion of the extensor Indicis?
Extensor expansion of index finger
Extensor indicis muscle
| Origin | Posterior surface of distal third of ulna and interosseus membrane |
|---|---|
| Insertion | Extensor expansion of index finger |
| Action | Wrist joints: Weak hand extension Metacarpophalangeal and interphalangeal joints of index finger: Finger extension |
| Innervation | Posterior interosseous nerve (C7, C8) |
What activities use the extensor pollicis longus?
The main action of extensor pollicis longus is extension of the thumb at the metacarpophalangeal and interphalangeal joints. Extension at the metacarpophalangeal joint occurs in synergy with extensor pollicis brevis muscle.
What are two actions of the extensor indicis muscle?
Function. The extensor indicis extends the index finger, and by its continued action assists in extending (dorsiflexion) the wrist and the midcarpal joints.
What is the extensor expansion?
The extensor expansions (also known as the extensor hood or dorsal digital expansion) are triangular aponeuroses by which the extensor tendons insert onto the phalanges.
What are two actions of the extensor Indicis muscle?
Which is the insertion of the extensor indicis?
The extensor indicis is a muscle that extends the 2nd digit (index finger) and the wrist. It originates at the posterior surface of the ulna and the interosseous membrane, a collagenous tissue that connects the radius and ulna, the two bones of the forearm. It inserts on the extensor expansion of the 2nd digit.
What is extensor Retinaculum?
The extensor retinaculum (dorsal carpal ligament, or posterior annular ligament) is an anatomical term for the thickened part of the antebrachial fascia that holds the tendons of the extensor muscles in place. It is located on the back of the forearm, just proximal to the hand.
What is the action of the extensor Indicis?
The primary function of Extensor Indicis Propius is the extension of second digit at metacarpophalangeal and interphalangeal joints. It may assist in wrist extension. It assists in abducting the index finger. It may assist in slight supination of forearm.
What is the origin of the extensor Indicis muscle?
Extensor indicis muscle
| Origin | Posterior surface of distal third of ulna and interosseus membrane |
|---|---|
| Insertion | Extensor expansion of index finger |
| Action | Wrist joints: Weak hand extension Metacarpophalangeal and interphalangeal joints of index finger: Finger extension |
| Innervation | Posterior interosseous nerve (C7, C8) |
How does the extensor mechanism work?
The extensor hood spreads out further distally into a median band which attaches to the middle phalanx and two lateral bands which attach to the distal phalanx. Contraction of the extensor digitorum muscle tightens this tendon which acts on these attachments and extends the fingers.
How is extensor retinaculum formed?
The tendon of the extensor carpi ulnaris is enclosed in an independent fibrous tunnel formed by the supratendinous retinaculum superiorly, the infratendinous retinaculum inferiorly, the sixth septum laterally, and the ulnar insertion of the retinaculum reinforced by longitudinal fibers called the “linea jugata” …
What is the function of the extensor retinaculum quizlet?
Thickening of fascia on the dorsal side of hand. Functions to keep extensor tendons in position to prevent bowstringing.
What is the function of the extensor expansion?
The extensor expansion surrounds the distal metacarpal head and proximal phalanx and serves to hold the extensor tendons in place and allow the extensors, lumbricals, and interossei to effect extension at the proximal and distal interphalangeal joints.
What is the function of the extensor indicis?
The main function of extensor indicis involves the extension of the index finger at the metacarpophalangeal and interphalangeal joints. As the index finger is one of the few fingers that have their own separate extensor muscle, it is able to extend independently from other fingers.
How do you palpate the extensor indicis?
Extensor indicis can be palpated by applying deep pressure over the lower part of the ulna while the index finger is extended. The main function of extensor indicis involves the extension of the index finger at the metacarpophalangeal and interphalangeal joints.
Where is the musculus extensor indicis located?
Extensor indicis muscle (Musculus extensor indicis) Extensor indicis is a narrow, elongated muscle found in the posterior compartment of the forearm. It belongs to the deep extensors of the forearm, together with supinator, abductor pollicis longus, extensor pollicis longus, and extensor pollicis brevis muscles.