Anatomy Quiz #6:
What is the main action of the extensor indicis?
- Extends 2nd Digit - Helps extend hand at wrist
What is the main action of the abductor pollicis longus?
Abducts thumb and extends it at carpometacarpal joint
What is the innervation of the extensor carpi radialis brevis?
Deep branch of radial nerve (C7, C8)
What is the innervation of the extensor carpi ulnaris?
Deep branch of radial nerve (C7, C8)
What is the innervation of the extensor digiti minimi?
Deep branch of radial nerve (C7, C8)
What is the innervation of the extensor digitorum?
Deep branch of radial nerve (C7, C8)
What is the innervation of the supinator?
Deep branch of radial nerve (C7, C8)
What is the distal attachment of the extensor carpi radialis brevis?
Dorsal aspect of base of 3rd metacarpal
What is the distal attachment of the extensor carpi ulnaris?
Dorsal aspect of base of 5th metacarpal
What is the distal attachment of the extensor pollicis longus?
Dorsal aspect of base of distal phalanx of thumb
What is the distal attachment of the extensor pollicis Brevis?
Dorsal aspect of base of proximal phalanx of thumb
What is the main action of the extensor carpi radialis brevis?
Extend and abduct hand at the wrist joint; ECRL is active during fist clenching
What is the main action of the extensor carpi radialis longus ?
Extend and abduct hand at the wrist joint; ECRL is active during fist clenching
What is the main action of the extensor digiti minimi?
Extends 5th digit primarily at metacarpalphalangeal joint, secondarily at inter-phalangeal joint
What is the main action of the extensor carpi ulnaris?
Extends and adductor hand at wrist joint (also active during fist clenching)
What is the muscle action of the extensor pollicis longus?
Extends distal phalanx of thumb at interphalangeal joint; extends metacarpophalangeal and carpometacarpal joints
What is the main action of the extensor digitorum?
Extends medial four digits primarily at metacarpalphalangeal joints, secondarily at interphalangeal joint
What is the muscle action of the extensor pollicis Brevis?
Extends proximal phalanx of thumb at metacarpophalangeal joint; extends carpometacarpal joint
What is the distal attachment of the extensor indicis?
Extensor expansion of 2nd finger
What is the distal attachment of the extensor digiti minimi?
Extensor expansion of 5th digit
What is the distal attachment of the extensor digitorum?
Extensor expansions of medial 4 digits
What is the proximal attachment of the extensor digitorum?
Lateral epicondyle of humerus (common extensor origin)
What is the proximal attachments of the extensor digiti minimi (EDM)?
Lateral epicondyle of humerus (common extensor origin)
What is the proximal attachment of the extensor carpi radialis brevis (ECRB) ?
Lateral epicondyle of humerus (common extensor origin)
What is the proximal attachment of the supinator?
Lateral epicondyle of humerus, Radial collateral and anular ligament, Supinator fossa, Crest of ulna
What is the proximal attachment of the extensor carpi ulnaris (ECU)?
Lateral epicondyle of humerus; posterior border ulna via a shared aponeurosis
What is the proximal attachment of the extensor carpi radialis longus (ECRL) ?
Lateral supra-epicondylar ridge of humerus
What is the distal attachment of the brachioradialis?
Lateral surface of distal end of radius proximal to styloid process
What is the distal attachment of the supinator?
Lateral, posterior, and anterior surface of proximal third of radius
What is the innervation of the abductor pollicis longus?
Posterior interosseous nerve (C7, C8), continuation of deep branch of radial nerve
What is the innervation of the extensor indicis?
Posterior interosseous nerve (C7, C8), continuation of deep branch of radial nerve
What is the innervation of the extensor pollicis brevis?
Posterior interosseous nerve (C7, C8), continuation of deep branch of radial nerve
What is the innervation of the extensor pollicis longus?
Posterior interosseous nerve (C7, C8), continuation of deep branch of radial nerve
What is the proximal attachment of the extensor pollicis brevis (EPB) ?
Posterior surface of distal third of radius and interosseous membrane
What is the proximal attachment of the extensor indicis ?
Posterior surface of distal third of ulna and interosseous membrane
What is the proximal attachment of the extensor pollicis longus (EPL)?
Posterior surface of middle third of ulna and interosseous membrane
What is the proximal attachment of the abductor pollicis longus (APL)?
Posterior surface of proximal halves of ulna, radius, and interosseous membrane
What is the proximal attachment of the brachioradialis?
Proximal two thirds of Supra-epicondylar ridge of humerus
What is the innervation of the brachioradialis?
Radial nerve (C5, C6, C7)
What is the innervation of the extensor carpi radialis longus ?
Radial nerve (C6, C7)
What is the main action of the brachioradialis?
Relatively weak flexion of forearm; maximal when forearm is in the mid-pronated position
What is the main action of the supinator?
Supinates the forearm; Rotates radius to turn palm anteriorly or superiorly (if elbow is flexed)
What is the distal attachment of the abductor pollicis longus?
base of 1st metacarpal
What is the distal attachment of the extensor carpi radialis longus ?
dorsal aspect of base of 2nd metacarpal
