Posterior Muscles of Forearm Flashcards
Insertion of Brachioradialis
Lateral surface of Distal end of Radius proximal to Styloid process
Origin of Brachioradialis
Proximal two thirds of Lateral Supraepicondylar ridge of Humerus
Innervation of Brachioradialis
Radial Nerve c5 C6 c7
Action of Brachioradialis
Relatively weak flexion of elbow joint, maximal when forearm is in Midpronated position
Origin of Extensor Carpi Radialis Longus
Lateral Supra-epicondylar ridge of Humerus
Insertion of Extensor Carpi Radialis Longus
Dorsal aspect of base of 2nd Metacarpal
Innervation of Extensor Carpi Radialis Longus
Radial Nerve C6 C7
Actions of Extensor Carpi Radialis Longus
Extend and Abduct wrist joint
Origin of Extensor Carpi Radialis Brevis
Lateral Epicondyle of Humerus
Insertion of Extensor Carpi Radialis Brevis
Dorsal aspect of base of 3rd Metacarpal
Innervation of Extensor Carpi Radialis Brevis
Deep branch of Radial Nerve C7 c8
Action of Extensor Carpi Radialis Brevis
Extend and abducts wrist joint;
Active during fist clenching
Origin of Extensor Digitorum
Lateral Epicondyle of Humerus
Insertion of Extensor Digitorum
Extensor expansions of medial four fingers
Innervation of Extensor Digitorum
Posterior Interosseous Nerve C7 c8, continuation of deep branch of Radial nerve
Action of Extensor Digitorum
Extend Wrist joint
Extend Medial four fingers primarily at Metacarpophalangeal joints, secondarily at Interphalangeal joints
Origin of Extensor Digiti Minimi
Lateral Epicondyle of Humerus
Insertion of Extensor Digiti Minimi
Extensor expansion of 5th finger
Innervation of Extensor Digiti Minimi
Posterior Interosseous Nerve C7 c8
Action of Extensor Digiti Minimi
Extends wrist joint
Extends 5th finger primarily at Metacarpophalangeal joint, secondarily at Interphalangeal joint
Origin of Extensor Carpi Ulnaris
Lateral Epicondyle of Humerus
Posterior border of Ulna via a shared aponeurosis
Insertion of Extensor Carpi Ulnaris
Dorsal aspect of base of 5th Metacarpal
Innervation of Extensor Carpi Ulnaris
Posterior Interosseous Nerve C7 c8
Action of Extensor Carpis Ulnaris
Extends and Adducts wrist joint (also active during fist clenching)
Origin of Supinator
Lateral Epicondyle of Humerus
Radial Collateral and Anular Ligaments
Supinator Fossa
Crest of Ulna
Insertion of Supinator
Lateral, posterior, and anterior surfaces of proximal third of Radius
Innervation of Supinator
Deep branch of Radial nerve c7 C8
Actions of Supinator
Supinates Forearm; rotates Radius to turn palm anteriorly or superiorly (if elbowed is flexed)
Origin of Abductor Pollicis Longus
Posterior surface of Proximal halves of Ulna, Radius, and Interosseous Membrane
Insertion of Abductor Pollicis Longus
Base of 1st Metacrapal
Innervation of Abductor Pollicis Longus
Posterior Interosseous Nerve c7 C8
Action of Abductor Pollicis Longus
Extends wrist joint
Abducts thumb and extends it at Carpometacarpal joint
Origin of Extensor Pollicis Longus
Posterior surface of Middle third of Ulna and Interosseous Membrane
Insertion of Extensor Pollicis Longus
Dorsal aspect of base of distal phalanx of thumb
Innervation of Extensor Pollicis Longus
Posterior Interosseous Nerve C7 c8
Action of Extensor Pollicis Longus
Extends Wrist Joint
Extends distal phalanx of Thumb at Interphalangeal joint; extends Metacarpophalangeal and Carpometacarpal joints
Origin of Extensor Pollicis Brevis
Posterior surface of Distal third of Radius and Interosseous Membrane
Insertion of Extensor Pollicis Brevis
Dorsal aspect of base of proximal phalanx of thumb
Innervation of Extensor Pollicis Brevis
Posterior Interosseous Nerve C7 c8
Action of Extensor Pollicis Brevis
Extend wrist joint
Extends proximal phalanx of thumb at Metacarpophalangeal joint; extends Carpometacarpal joint
Origin of Extensor Indicis
Posterior surface of distal third of Ulna and Interosseous Membrane
Insertion of Extensor Indicis
Extensor expansion of 2nd finger
Innervation of Extensor Indicis
Posterior Interosseous Nerve C7 c8
Actions of Extensor Indicis
Extends wrist joint
Extends 2nd finger (enabling its independent extension); helps extend hand at wrist