Muscles in Forearm Flashcards
Origin and Insertion of Brachioradialis
O: Lateral supracondylar ridge of humerus
I: Distal end of radius
Action of Brachioradialis
Flexion of elbow when the forearm is in the neutral position
Assisting flexion in the supinated position
Innervation of the posterior arm
Radial nerve
Origin and Insertion of Extensor Carpi Radialis Longus
O: Lateral supracondylar ridge of humerus
Insertion: Dorsal surface of the base of the 2’nd metacarpal bone
Origin and Insertion of Extensor carpi digitorum brevis
O: CEO
I: Dorsal surface of the base of the 3’rd metacarpal bone
Action of ECRL and ECRB
Extend and abduct at the wrist
Origin and Insertion of Extensor digitorum
O: CEO
I: Extensor hood of the four fingers
Action of Extensor Digitorum
Extension of the four fingers at the metacarpophalangeal and interphalangeal joints
What links the four tendons of extensor digitorum and what is the function of it ?
Juncturae tendinum
Function: prevents full extension of the middle and ring finger if the other fingers are flexed
Describe the course of the superficial branch of the radial nerve
It passes superficial to the supinator, deep to the brachioradials muscle
Describe the course of the posterior interosseous branch (deep branch) of the radial nerve
Exits the cubital fossa by passing between the two heads of the spinator and enters the posterior compartment of the forearm
Origin and Insertion of Extensor digiti minimi
O: CEO
I: Extensor hood of the little finger
Actions of Extensor digiti minimi
Extension of the little finger
Assists extension at the wrist
Which muscles from the posterior forearm is supplied by the posterior interosseous nerve
Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris
Abductor pollicis longus
Extensor pollicis longus
Extensor pollicis brevis
Extensor indicis
Origin and Insertion of Extensor carpi ulnaris
Origin
Humeral head: CEO
Ulnar head: Olecranon
I: Base of the 5’th metacarpal
Action of Extensor carpi ulnaris
ADduction at the wrist
Extension at the wrist
Origin and Insertion of Anconeus
O: CEO
I: Radial side of olecranon
Posterior surface of the proximal ulna
Action of Anconeus
Weak extensor of the elbow (Only assists triceps in the movement)
Stabilises elbow joint
During pronation, it ABducts the ulna and prevents the joint capsule from impingement within the olecranon fossa
Origin and Insertion of Supinator
Origins
Humeral head: CEO
Ulnar head: Supinator crest
I: Proximal radial border of the radius
Actions of Supinator
Supinated the forearm in the absence of resistance
Origin and Insertion of ABductor pollicis longus
O: Interosseous membrane of the adjacent posterior surfaces of the radius and ulnar
I: Radial side of the base of the first metacarpal of the thumb
Actions of ABductor pollicis longus
ABducts the thumb
Extension of the carpometacarpal joint
Origin and Insertion of Extensor pollicis longus
O: Middle third of the posterior surface of the ulnar
Interosseous membrane
I: Distal phalanx of the thumb
Actions of Extensor pollicis longus
Extends all joints of the thumb
(carpometacarpal, metacarpophalangeal joint, interphalangeal joint)
Origin and Insertion of Extensor pollicis brevis
O: Posterior surface of the radius
Interosseous membrane
I: Base of the proximal phalanx of the thumb
Origin and Insertion of Extensor pollicis brevis
O: Posterior surface of the radius
Interosseous membrane
I: Base of the proximal phalanx of thumb
Action of Extensor pollicis brevis
Extends metacarpophalangeal and interphalangeal joints of the thumb
Origin and Insertion of Extensor indicis
O: Posterior surface of ulna
Interosseous membrane
I: Extensor hood of the index finger
Action of Extensor indicis
Extension of the index finger
Origin of superficial muscles of the anterior forearm
CFO: Medial epicondyle
Origin and Insertion of Flexor carpi ulnaris
O: Humeral head- CEO
Ulnar head- Medial margin of the
olecranon of the ulna
I: Pisiform, hook of hamate, 5’th metacarpal
Course of the ulnar nerve
Passes between the two heads of Flexor carpi ulnaris to enter the anterior compartment of the forearm
Action and Innervation of Flexor carpi ulnaris
A: Flexion and ADduction at the wrist
Inv: Ulnar nerve
Origin and Insertion of Palmaris Longus
O: CFO
I: Flexor retinaculum
Palmar aponeurosis
Action and Innervation Palmaris Longus
A: Weak flexor of the wrist
I: Median nerve
Origin and Insertion of Flexor carpi radialis
O: CFO
I: Base of the 2’nd and 3’rd metacarpals
Action and Innervation of Flexor carpi radialis
A: Flexion and ABduction of the wrist
Inv: Median nerve
Origin and Insertion of Pronator Teres
O: Humeral head- CFO
Ulnar head- Coronoid process of the ulna
Action and Innervation of Pronator Teres
A: Pronation of the arm
Inv: Median nerve
Course of the median nerve
Passes between the two heads of Pronator Teres and Flexor digitorum superficialis to exit the cubital fossa
Origin and Insertion of Flexor digitorum superficialis
O: Humeral head- CEO
Radial head- Anterior surface of the radius
I: Middle phalanges of the four fingers
Action and Innervation of Flexor digitorum superficialis
A: Flexes the metacarpophalangeal joints and proximal interphalangeal joints of the four fingers
Inv: Median nerve
Origin and Insertion of Flexor digitorum profundus
O: 2/3 of the shaft of the luna
Interosseous membrane
I: Base of the distal phalanges of the four fingers
Action and Innervation of Flexor digitorum profundus
A: Flexion of interphalangeal joints (only muscle)
Flexion of metacarpophalangeal joints
Assist flexion at wrist
Inv: Ulnar nerve (little, ring finger)
Anterior interosseous branch of the median nerve (lateral half)
Origin and Insertion of Flexor pollicis longus
O: Middle of the anterior surface of the radial shaft
Interosseous membrane
I: Base of the distal phalanx of the thumb
Action and Innervation of Flexor pollicis longus
A: Flexion of interphalangeal joint of thumb
Flexion of metacarpophalangeal joint of thumb
Inv: Anterior interosseous branch of median nerve
Origin and Insertion of Pronator Quadratus
O: Anterior surface of the distal ulna
I: Anterior surface of the distal radius
Action and Innervation of Pronator Quadratus
A: Pronates the forearm at the radio-ulnar joints
Inv: Anterior interosseous branch of median nerve