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Forearm Flexors
Compartments, Anatomical significance, veins, arteries, muscles of the forearm
11
Anatomy
Graduate
09/22/2013

Additional Anatomy Flashcards

 


 

Cards

Term
Compartments of the Forearm
Definition

The fascial compartments of the limbs generally end at the joints; therefore, fluids and infections in compartments are usually contained and cannot readily spread to other compartments. 


The anterior compartment is exceptional in this regard because it communicates with the central compartment of the palm through the carpal tunnel 

Term
flexor muscles of the forearm structure
Definition

The tendons of most flexor muscles are located on the anterior surface of the wrist and are held in place by the palmar carpal ligament and the flexor retinaculumtransverse carpal ligament), thickenings of the antebrachial fascia 


superficial layer or group of four muscles (pronator teres, flexor carpi radialis, palmaris longus, and flexor carpi ulnaris). These muscles are all attached proximally by a common flexor tendon to the medial epicondyle of the humerus, the common flexor attachment.
An intermediate layer, consisting of one muscle (flexor digitorum superficialis).
deep layer or group of three muscles (flexor digitorum profundus, flexor pollicis longus, and pronator quadratus).
Term
Forearm muscle structure part 2
Definition

the five superficial and intermediate muscles cross the elbow jointthe three deep muscles do not.


All muscles in the anterior compartment of the forearm are supplied by the median and/or ulnar nerves (most by the median; only one and a half exceptions are supplied by the ulnar).


Functionally, the brachioradialis is a flexor of the forearm, but it is located in the posterior (posterolateral) or extensor compartment and is thus supplied by the radial nerve.


Therefore, the brachioradialis is a major exception to the rule that (1) the radial nerve supplies only extensor muscles and (2) that all flexors lie in the anterior (flexor) compartment.


 long flexors of the digits (flexor digitorum superficialis and flexor digitorum profundus) also flex the metacarpophalangeal and wrist joints.

Term
Pronator Teres
Definition

 

Origin Medial epicondyle of humerus and coronoid process of ulna
Insertion Middle of lateral surface of radius
Action Pronates and flexes forearm (at elbow)
Innervation Median nerve (C6 and C7) (C6, C7)
Arterial Supply Ulnar artery, anterior recurrent ulnar artery

 

[image]

Is the most lateral of the superficial forearm flexors. Its lateral border forms the medial boundary of the cubital fossa.


 along with the Pronator Quadratus muscle, serves to pronate the forearm (turning it so that the palm faces posteriorly when the body is in the anatomical position).


The pronator teres has two heads—humeral and ulnar. Humeral connects to the medial epicondyle


Median Nerve innervation

Positive tinel sign on forearm, not the wrist

Term
Flexor Carpi Radialis
Definition

 

Origin Medial epicondyle of humerus
Insertion Base of 2nd metacarpal
Action Flexes and abducts hand (at wrist)
Innervation Median nerve (C6 and C7) (C6, C7)
Arterial Supply Ulnar artery


is a long fusiform muscle located medial to the pronator teres


The FCR produces flexion (when acting with the flexor carpi ulnaris) and abduction of the wrist (when acting with the extensors carpi radialis longus and brevis).


To test the flexor carpi radialis, the person is asked to flex the wrist against resistance. If acting normally, its tendon can be easily seen and palpated.


Good guide to radial nerve as it passes lateraly to it.It gets its blood from the Ulnar artery 


[image]


Term
Palmaris Longus
Definition
Origin Medial epicondyle of humerus
Insertion Distal half of flexor retinaculum and palmar aponeurosis
Action Flexes hand (at wrist) and tightens palmar aponeurosis
Innervation Median nerve (C7 and C8) (C7, C8)
Arterial Supply Ulnar artery


passes superficial to the flexor retinaculum and attaches to it and the apex of the palmar aponeurosis


Dupuytrens Contracture produces the same position with the hand tightly contracted in a claw and flexed at the wrist.


When the muscle is tense, it’s tendon can put pressure on the ligament reproducing some of the symptoms of Carpal Tunnel Syndrome.


 [image]

Term
Flexor Carpi Ulnaris
Definition

 

Origin Humeral head: medial epicondyle of humerus; Ulnar head: olecranon and posterior border of ulna
Insertion Pisiform bone, hook of hamate bone, and 5th metacarpal bone
Action Flexes and adducts hand (at wrist)
Innervation Ulnar nerve (C7 and C8) (C7, C8)
Arterial Supply

Ulnar artery

 

is the most medial of the superficial flexor muscles. 


The FCU simultaneously flexes and adducts the hand at the wrist if acting alone. 


This muscle is exceptional among muscles of the anterior compartment, being fully innervated by the ulnar nerve.

[image]

 

Term
Flexor Digitorum Superficialis
Definition

 

Origin Humeroulnar head: medial epicondyle of humerus, ulnar collateral ligament, and coronoid process of ulna; Radial head: superior half of anterior border of radius
Insertion Bodies of middle phalanges of digits 2 - 5
Action Flexes middle phalanges at proximal interphalangeal joints of medial four digits; acting more strongly, it also flexes proximal phalanges at metacarpophalangeal joints and hand
Innervation Median nerve (C7, C8 and T1) (C7, C8, T1)
Arterial Supply Ulnar artery

 

the FDS actually forms an intermediate layer between the superficial and the deep groups of forearm muscles

 

Near the wrist, the FDS gives rise to four tendons, which pass deep to the flexor retinaculum through the carpal tunnel to the fingers.


The four tendons are enclosed (along with the four tendons of the flexor digitorum profundus) in a synovial common flexor sheath


The FDS is capable of flexing each finger it serves independently.



Term
Flexor Digitorum Profundus
Definition

 

Origin Proximal 3/4 of medial and anterior surfaces of ulna and interosseous membrane
Insertion Base of the distal phalanx of digits 2 - 5
Action Flexes distal phalanges at distal interphalangeal joints of medial four digits; assists with flexion of hand
Innervation Medial part: ulnar nerve (C8 and T1); Lateral part: anterior interosseous branch of median nerve (C8 and T1) (C8, T1)
Arterial Supply Ulnar and anterior interosseous arteries

 

flexor digitorum profundus (FDP) is the only muscle that can flex the distal interphalangeal joints of the fingers


(i.e., it curls the fingers and assists with flexion of the hand, making a fist).


. The part of the muscle going to the index finger usually separates from the rest of the muscle relatively early in the distal part of the forearm and is capable of independent contraction.


[image]

Term
Flexor Pollicis Longus
Definition

 

Origin Anterior surface of radius and adjacent interosseous membrane
Insertion Base of distal phalanx of thumb
Action Flexes phalanges of 1st digit (thumb)
Innervation Anterior interosseous nerve from median nerve (C8 and T1) (C8, T1)
Arterial Supply Anterior interosseous artery

 

the long flexor of the thumb


The FPL is the only muscle that flexes the interphalangeal joint of the thumb.


[image]

Term
Pronator Quadratus
Definition

 

 

Origin

Distal 1/4 of anterior surface of ulna
Insertion Distal 1/4 of anterior surface of radius
Action Pronates forearm; deep fibers bind radius and ulna together
Innervation Anterior interosseous nerve from median nerve (C8 and T1) (C8, T1)
Arterial Supply Anterior interosseous artery

 

The pronator quadratus is the prime mover for pronation. The muscle initiates pronation; it is assisted by the pronator teres when more speed and power are needed.


[image]

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