O & I: Forearm Extensors Flashcards
Origin: Brachioradialis
Proximal two thirds of supra-epicondylar ridge of humerus
Insertion: Brachioradialis
lateral surface of distal end of radius proximal to styloid process
Innervation: Brachioradialis
Radial Nerve (C5, C6, C7)
Action: Brachioradialis
Relatively weak flexion of forearm; maximal when forearm is in neutral position
Origin: Extensor Carpi Radialis Longus (ECRL)
Lateral supra-epicondylar ridge of humerus
Insertion: Extensor Carpi Radialis Longus (ECRL)
Dorsal aspect of base of 2nd metacarpal
Innervation: Extensor Carpi Radialis Longus (ECRL)
Radial Nerve (C6, C7)
Action: Extensor Carpi Radialis Longus (ECRL)
Extend and abduct hand at the wrist joint; active during fist clenching
Origin: Extensor Carpi Radialis Brevis (ECRB)
Lateral epicondyle of humerus
Insertion: Extensor Carpi Radialis Brevis (ECRB)
Dorsal aspect of base of 3rd metacarpal
Innervation: Extensor Carpi Radialis Brevis (ECRB)
Deep Branch of radial nerve (C7, C8)
Action: Extensor Carpi Radialis Brevis (ECRB)
Extend and abduct hand at the wrist joint
Origin: Extensor Digitorum
Lateral epicondyle of humerus
Insertion: Extensor Digitorum
Extensor expansions of medial 4 digits
Innervation: Extensor Digitorum
Deep Branch of radial nerve (C7, C8)
Action: Extensor Digitorum
Extends medial four digits primarily at metacarpophalangeal joints, secondarily at interphalangeal joints
Origin: Extensor Digiti Minimi (EDM)
Lateral epicondyle of humerus
Insertion: Extensor Digiti Minimi (EDM)
Extensor expansion of 5th digit
Innervation: Extensor Digiti Minimi (EDM)
Deep Branch of radial nerve (C7, C8)
Action: Extensor Digiti Minimi (EDM)
Extends 5th digit primarily at metacarpophalangeal joint, secondarily at interphalangeal joint
Origin: Extensor Carpi Ulnaris (ECU)
Lateral epicondyle of humerus; posterior border of ulna via a shared aponeurosis
Insertion: Extensor Carpi Ulnaris (ECU)
Dorsal aspect of base of 5th metacarpal
Innervation: Extensor Carpi Ulnaris (ECU)
Deep Branch of radial nerve (C7, C8)
Action: Extensor Carpi Ulnaris (ECU)
extends and adducts hand at wrist joint (also active during fist clenching)
Origin: Supinator
lateral epicondyle of humerus; radial collateral and anular ligaments; supinator fossa; crest of ulna
Insertion: Supinator
lateral, posterior, and anterior surfaces of proximal third of radius
Innervation: Supinator
Deep Branch of radial nerve (C7, C8)
Action: Supinator
supinates forearm; rotates radius to turn palm anteriorly or superiorly (if elbow is flexed)
Origin: Extensor Indicis
Posterior surface of distal third of ulna and interosseous membrane
Insertion: Extensor Indicis
Extensor expansion of 2nd digit
Innervation: Extensor Indicis
Posterior interosseous nerve (C7, C8), continuation of deep branch of radial nerve
Action: Extensor Indicis
extends 2nd digit (enabling its independent extension); helps extend hand at wrist
Origin: Abductor Pollicis Longus (APL)
posterior surface of proximal halves of ulna, radius, and interosseous membrane
Insertion: Abductor Pollicis Longus (APL)
base of 1st metacarpal
Innervation: Abductor Pollicis Longus (APL)
posterior interosseous nerve (C7, C8), continuation of deep branch of radial nerve
Action: Abductor Pollicis Longus (APL)
abducts thumb and extends it at carpometacarpal joint
Origin: Extensor Pollicis Longus (EPL)
posterior surfae of middle third of ulna and interosseous membrane
Insertion: Extensor Pollicis Longus (EPL)
dorsal aspect of base of distal phalanx of thumb
Innervation: Extensor Pollicis Longus (EPL)
posterior interosseous nerve (C7, C8), continuation of deep branch of radial nerve
Action: Extensor Pollicis Longus (EPL)
extends distal phalanx of thumb at interphalangeal joint; extends metacarpophalangeal and carpometacarpal joints
Origin: Extensor Pollicis Brevis (EPB)
posterior surface of distal third of radius and interosseous membrane
Insertion: Extensor Pollicis Brevis (EPB)
dorsal aspect of base of proximal phalanx of thumb
Innervation: Extensor Pollicis Brevis (EPB)
posterior interosseous nerve (C7, C8), continuation of deep branch of radial nerve
Action: Extensor Pollicis Brevis (EPB)
extends proximal phalanx of thumb at metacarpophalangeal joint; extends carpometacarpal joint
Origin: Triceps Brachii
Long Head: infraglenoid tubercle of scapula
Lateral Head: posterior surface of humerus, superior to radial groove
Medial Head: posterior surface of humerus, inferior to radial groove
Insertion: Triceps Brachii
Proximal end of olecranon of ulna and fascia of forearm
Innervation: Triceps Brachii
radial nerve (C6, C7, C8)
Action: Triceps Brachii
Chief extensor of forearm; long head resists dislocation of humerus; especially important during adduction
Origin: Anconeus
lateral epicondyle of humerus
Insertion: Anconeus
lateral surface of olecranon and superior part of posterior surface of ulna
Innervation: Anconeus
Radial nerve (C7, C8, T1)
Action: Anconeus
assists triceps in extending forearm; stabilizes elbow joint; may abduct ulna during pronation