bb ch 44&46 - quiz 2 Flashcards
Where is considered the forearm?
Between the elbow and wrist
What is the name of the fascia that courses within the forearm?
Antebrachial fascia
How many muscles are in the forearm? How many are in each compartment?
20
Anterior: 4 superficial, 1 intermediate, 3 deep
Posterior: 7 superficial, 5 deep
What are the compartments of the forearm, including “depth distinction”
superficial anterior
intermediate anterior
deep anterior
superficial posterior
deep posterior
What are the muscles in the superficial anterior forearm? How many are there? What are their innervation?
4 muscles
- pronator teres - median n.
- flexor carpi radialis - median n.
- palmaris longus - median n.
- flexor carpi ulnaris - ulnar n.
What are the muscles in the intermediate anterior forearm? How many are there? What are their innervation?
1 muscle
- flexor digitorum superficialis - median n.
What are the muscles in the deep anterior forearm? How many are there? What are their innervation?
3
- flexor digitorum profundus - medial: ulnar n., lateral: anterior interosseous n.
- flexor pollicis longus - anterior interosseous n.
- pronator quadratus - anterior interosseous n.
What are the muscles in the superficial posterior forearm? How many are there? What are their innervation?
7
- brachioradialis - radial n.
- extensor carpi radialis longus - radial n.
- extensor carpi radialis brevis - deep branch of radial n.
- extensor digitorum - posterior interosseous n. (PIN)
- extensor digiti minimi - PIN
- extensor capri ulnaris - PIN
- aconeus - radial n.
What are the muscles in the deep posterior forearm? How many are there? What are their innervation?
5
- supinator - PIN
- abductor pollicis longus - PIN
- extensor pollicis brevis - PIN
- extensor pollicis longus - PIN
- extensor pollicis - PIN
What is the origin of brachioradialis?
Upper lateral supracondylar ridge of humerus
What is the insertion of brachioradialis?
Styloid process of radius
What is the action of brachioradialis?
flexion of forearm at elbow joint
What is the innervation of brachioradialis?
Radial n.
What is the origin of extensor carpi radialis longus?
lower lateral supracondylar ridge of humerus
What is the insertion of extensor carpi radialis longus?
Base of 2nd metacarpal, posterior surface
What is the action of extensor carpi radialis longus?
Extend hand at the wrist
Abduct hand at the wrist
What is the innervation of extensor carpi radialis longus?
Radial n.
What is the origin of extensor carpi radialis brevis?
lateral epicondyle of humerus
What is the insertion of extensor carpi radialis brevis?
Base of 3rd metacarpal, posterior surface
What is the action of extensor carpi radialis brevis?
extend hand at wrist
abduct hand at wrist
What is the innervation of extensor carpi radialis brevis?
Deep branch of radial nerve
What is the origin of extensor digitorum?
Lateral epicondyle of humerus
What is the insertion of extensor digitorum?
extensor expansions of digits 2-5
What is the action of extensor digitorum?
Extend hand at wrist
Extend digits 2-5 at metacarophalangeal and IP jts.
What is the innervation of extensor digitorum?
PIN
What is the origin of extensor digiti minimi?
Lateral epicondyle of humerus
What is the insertion of extensor digiti minimi?
Extensor expansion of digit 5
What is the action of extensor digiti minimi?
extend digit 5 at metacarpophalangeal and IP joints
What is the innervation of extensor digiti minimi?
PIN
What is the origin of extensor carpi ulnaris?
Lateral epicondyle of humerus
Posterior shaft of ulna
What is the insertion of extensor carpi ulnaris?
Base of 5th metacarpal, medial side
What is the action of extensor carpi ulnaris?
extend hand at wrist
adduction of wrist
What is the innervation of extensor carpi ulnaris?
PIN
What is the origin of aconeus?
lateral epicondyle of humerus
What is the insertion of aconeus?
olecranon process of ulna, lateral surface
What is the action of aconeus?
extend forearm at elbow joint
What is the innervation of aconeus?
Radial n.
What is the origin of supinator?
Superficial - lateral epicondyle of humerus
Deep - supinator fossa and supinator crest of ulna
What is the insertion of supinator?
Superficial - radius between tuberosity and insertion of pronator teres (middle lateral radius)
Deep - shaft of radius, near radial tuberosity
What is the action of supinator?
Supinate forearm at radioulnar joint
What is the innervation of supinator?
PIN
What is the origin of abductor pollicis longus?
Proximal posterior surface of ulna, radius, and interosseous membrane
What is the insertion of abductor pollicis longus?
Base of first metacarpal
What is the action of abductor pollicis longus?
abduct thumb and extend thumb at metacarpophalangeal joints
What is the innervation of abductor pollicis longus?
PIN
What is the origin extensor pollicis brevis?
distal radius, posterior surface
What is the insertion of extensor pollicis brevis?
Base of proximal phalanx of thumb
What is the action of extensor pollicis brevis?
extend thumb at metacarpophalangeal joint
What is the innervation of extensor pollicis brevis?
PIN
What is the origin of extensor pollicis longus?
middle third of ulna and interosseous membrane, posterior surface
What is the insertion of extensor pollicis longus?
Base of distal phalanx of thumb
What is the action of extensor pollicis longus?
extend distal phalanx of thumb at IP joint
What is the innervation of extensor pollicis longus?
PIN
Where does the tendon of extensor pollicis longus course?
Laterally around dorsal tubercle of lister on distal radius
What is the origin of extensor indicis?
distal ulna and interosseous membrane, posterior surface
What is the insertion of extensor indicis?
extensor expansion of digit 2
What is the action of extensor indicis?
extend the 2nd digit at metacarpophalangeal and IP joints
What is the innervation of extensor indicis?
PIN
What is the anatomical snuffbox?
Triangular shaped depression seen when thumb is in extension
What is the anterior boundary of the anatomical snuffbox?
Abductor pollicis longus and extensor pollicis brevis
What is the posterior boundary of the anatomical snuffbox?
extensor pollicis longus
What is the floor of the anatomical snuffbox?
Scaphoid and trapezium bones
What are the structures that go over and through the anatomical snuffbox?
through: radial artery
over the tendons: superficial branch of radial n.
Describe the path of the radial nerve.
Off the posterior cord of the brachial plexus after axillary nerve is given off
Medial to lateral behind the humerus within the posterior compartment
Courses with the profunda brachii artery into triangular interval of shoulder
Innervates one nerve in the arm: triceps
Pierces lateral intermuscular septum as it passes from posterior to anterior compartment
Courses distal through lateral side of cubital fossa
Innervates 3 muscles in the forearm: brachioradialis, extensor carpi radialis longus, aconeus
Bifurcates between brachialis and brachioradialis into: superficial branch of radial nerve, deep branch of radial nerve
SB of radial n. goes distal with radial artery deep to brachioradialis over tendons of anatomical snuffbox and enters dorsum of hand for cutaneous innervation, no muscular innervation
DB of radial n. innervates one muscle in forearm: extensor carpi radialis brevis, enters superior border of supinator muscle and changes of posterior interosseous nerve (PIN)
PIN innervates 8 muscles in the forearm
How many muscles in the posterior forearm does PIN innervate? Name them, and label as either superficial (s), or deep (d) muscles.
8
- extensor digitorum - s
- extensor digiti minimi - s
- extensor carpi ulnaris - s
- supinator -d
- abductor pollicis longus - d
- extensor pollicis longus - d
- extensor pollicis brevis - d
- extensor indicis - d
Where does PIN enter the hand?
It does not enter the hand.