Upper Extremity: Muscles Flashcards
This flashcard deck was created using Flashcardlet's card creator
Flexor Carpi Ulnaris Muscle
O: (humeral head) common flexor origin on the anterior aspect of the medial epicondyle; (ulnar head) medial aspect of the olecranon process & proximal 2/3 of the posterior border of the ulna
I: anterior aspect of the pisiform, hook of hamate (via the pisohamate ligament), 5th metacarpal (via the pisometacarpal ligament)
A: flexion of the humeral-ulnar nerve, flexion of the radio-carpal joint, flexion of the CMC joint, ulnar deviation
N: ulnar nerve (C7-T1)
Notes:
- most medial of the muscles in this compartment
- ulnar nerve enters anterior compartment by passing thru the 2 heads (humeral & ulnar)
- most powerful wrist flexor and ulnar deviator of the wrist
- converge then becomes tendinous in distal 1/2
Brachialis Muscle
O: distal 1/2 of the anterior aspect of the humerus
I: coronoid process & tuberosity of the ulna
A: flexion of humeral-ulnar joint
N: musculocutaneous nerve (C5-7)
Notes:
- strong elbow flexor
- fibers are immediately deep to biceps brachii
- works with brachioradialis and biceps to flex the elbow
- fibers run inferior
Palmaris Longus Muscle
O: common flexor origin on the anterior aspect of medial epicondyle
I: flexor retinaculum & palmar aponeurosis
A: flexion of humeral-ulnar joint, flexion of radio-carpal joint, flexion of the CMC joint
N: median nerve (C5-T1)
Notes:
- contraction of this muscle resists shearing forces when gripping
- short belly (proximal 1/4) and a long cord-like tendon
- absent in ~15% of the population
- lies lateral to flexor carpi ullnaris
- good landmark for median nerve
Flexor Carpi Radialis Muscle
O: common flexor origin on the anterior aspect of the medial epicondyle
I: anterior aspect of the base of the 2nd & 3rd metacarpals
A: flexion of humeral-ulnar joint, flexion of the radio-carpal joint, flexion of the CMC joint, radial deviation, pronation
N: median nerve (C5-T1)
Notes:
- lateral to palmaris longus muscle
- important landmark for radial artery
- powerfulflexor of the wrist
- fibers run slightly oblique (towards lateral side)
- tendinous in distal 1/4
Pronator Teres Muscle
O: (humeral head) common flexor origin on the anterior aspect of the medial epicondyle & distal aspect of the medial supracondylar ridge; (ulnar head) medial surface of the coronoid process
I: middle 1/3 of the lateral aspect of the radius
A: flexion of the humeral-ulnar joint, pronation
N: median nerve (C5-T1)
Notes:
- lateral to the palmaris longus (most lateral)
- important landmark for the radial artery
- forms part of the cubital fossa
- powerful flexor of the wrist
- fibers run oblique and lateral
- humeral head blends in with ulnar head (as it descends)
Pronator Quadratus Muscle
O: distal 1/4 of the anterior and medial aspect of the ulna
I: distal 1/4 of the anterior and lateral aspect of the radius
A: pronation
N: median nerve (C5-T1)
Notes:
- flat shaped
- deep to flexor digitorum profundus and flexor pollicis longus
- cannot be palpated
- prime mover of pronation
- assists the interosseous membrane b/c it runs from the ulna to the radius
Flexor Digitorum Superficialis Muscle
O: (humeral-ulnar head) common flexor origin on the anterior aspect of the medial epicondyle, medial aspect of the coronoid process & ulnar collateral ligament; (radial head) oblique line - just inferior to radial tuberosity
I: anterior and lateral aspects of the middle phalanx (digits 2-5)
A: flexion of the humeral-ulnar joint, flexion of the radio-carpal joint, flexion of the metacarpal-phalangeal joint, flexion of the PIP
N: median nerve (C5-T1)
Notes:
- median nerve and ulnar artery pass between the 2 heads
- passes deep to carpal tunnel, underneaeth flexor retinaculum
- sits anterior to flexor digitorum profundus
- bipennate muscle
- humeral ulnar head fibers descend inferior; radial head fibers run medial and oblique
Flexor Digitorum Profundus Muscle
O: proximal 2/3 of the anterior and medial aspect of the ulna & anterior and middle 1/2 of the interosseous membrane
I: anterior aspect of the distal phalanx (digits 2-5)
A: flexion of the radio-carpal joint, flexion of the metacarpal-phalangeal joint (MP), flexion of the PIP, flexion of the DIP
N: medial aspect = ulnar nerve (C7-T1); lateral aspect = radial nerve (C5-T1)
Notes:
- only muscle that can flex the DIP joint
- runs under the carpal tunnel
- lumbricals originate on flexor digitorum profundus muscle
- lies immediately deep to flexor digitorum superificialis
- common tendon splits into 4 and runs underneath flexor retinaculum then goes thru the middle of the tendon for flexor digitorum superficialis
Flexor Pollicis Longus Muscle
O: anterior surface of the radius (immediately inferior to radial tuberosity) & lateral 1/2 of the interosseous membrane
I: base of the anterior surface of the distal phalanx of the 1st
A: flexion in the radio-carpal joint, flexion of the metacarpal-phalangeal (MP) joint, flexion of the IP joint
N: median nerve (C5-T1)
Notes:
- only muscle that flexes the IP joint of the thumb
- deep to flexor retinaculum (in carpal tunnel)
- tendon lies lateral to tendons of the flexor digitorum superficialis & flexor digitorum profundus
- tendon lies between flexor opponens and adductor hallucis
- fibers run down and oblique (medial)
- converge onto tendon (deep to flexor retinaculum)
Brachioradialis Muscle
O: distal 1/2 of the lateral supracondyle ridge of the humerus
I: lateral surface of the distal radius just proximal to radial styloid
A: flexion the the humeral-ulnar joint (forearm in mid-pronation), pronation & supination (when resisted in mid-range)
N: radial nerve (C5-T1)
Notes:
- forms the lateral boundary of cubital fossa
- action is most efficient when forearm is in mid-pronation
- anterior fibers descend vertically then come over top proximal radius (medial and descending); other fibers descend inferiorly
Extensor Carpi Radialis Longus Muscle
O: distal 1/3 of lateral supracondylar ridge
I: dorsal surface of the base of the 2nd metacarpal
A: extension of humeral-ulnar joint, flexion of humeral-ulnar, extension of radiocarpal joint, radial deviation
N: radial nerve (C5-T1)
Notes:
- immediately deep to brachioradialis
- tendon is crossed by abductor pollicis brevis and extensor pollicis brevis
- fibers descend vertically, underneath extensor retinaculum
Extensor Carpi Radialis Brevis Muscle
O: common extensor origin on posterior aspect of lateral epicondyle
I: dorsal surface of the base of 2nd & 3rd metacarpals
A: flexion of humeral-ulnar joint, extension of humeral-ulnar joint, extension of radiocarpal joint, radial deviation
N: radial nerve (C5-T1)
Notes:
- lies deep to extensor carpi radialis longus
- passes underneath extensor retinaculum
- fibers descend vertically
- acting with flexor carpi radialis to do radial deviation
- acting with extensor carpi ulnaris to do extension of radioulnar joint
Extensor Digitorum Muscle
O: common extensor origin on posterior aspect of lateral epicondyle
I: at base of proximal phalanx, tendon will divide into 3 “intertendinous” connections:
- 2 lateral ones join together and insert on distal phalanx
- middle inserts on base of middle phalanx
A: extension of humeral-ulnar joint, extension of radio-carpal joint, extension of MP, PIP & DIP, abduction of the fingers
N: radial nerve (C5-T1)
Notes:
- no finger can be fully flexed while others remain extended (dorsal digital expansion)
- occupies much of the posterior surface of the forearm
- principal extensor of the 4 fingers
- joins with extensor indicis as it descends
Extensor Carpi Ulnaris Muscle
O: common extensor origin on posterior surface of lateral epicondyle & common aponeurosis shared by FCU & FDP
I: medial side of base of 5th metacarpal
A: extension of the radiocarpal joint, ulnar deviation
N: radial nerve (C5-T1)
Notes:
- long fusiform muscle
- separate compartment - synovial tube runs around it
- acts with ECRL & ECRB to do extensio of radio-carpal joint
- acts with FCU to do ulnar deviation
- descends into extensor retinaculum
Supinator Muscle
O: (superficial head) lateral epicondyle of the humerus, radial collateral ligament & annular ligament; (deep head) supinator crest on ulna (inferior to radial notch)
I: proximal to oblique line on radius & upper 1/3 of radius on lateral surface
A: supination
N: radian nerve (C5-T1)
Notes:
- deep to cubital fossa with brachialis
- envelops the neck and proximal shaft of the radius
- deep branch off radial nerve
- prime mover for slow supination
- fibers go from posterior to anterior (spiral)
Anconeus Muscle
O: common extensor origin (on posterior aspect of lateral epicondyle)
I: lateral surface of olecranon process & posterior surface of proximal 1/3 of ulna
A: extension of humeral-ulnar joint, assists in stabilizing the radius (during pronation/supination)
N: radial nerve (C5-T1)
Notes:
- most medial of the group
- fibers run medial
- triangular
Extensor Pollicis Longus Muscle
O: posterior surface of the distal 1/3 of the ulna, medial aspect of the interosseous membrane
I: posterior aspect of the base of the distal phalanx of the thumb
A: extension of the CMC, MP & IP joints of the 1st; radial deviation of the 1st
N: radial nerve (C5-T1)
Notes:
- own tunnel, own synovial sheath
- medial to the dorsal tubercle of the radius lister’s tubercle)
- forms anatomical snuff box
Extensor Pollicis Brevis Muscle
O: posterior surface of the distal 1/3 of the radius
I: posterior aspect of the base of the proximal phalanx of the thumb
A: extension of CMC & MP joint of the 1st; radial deviation of the radiocarpal joint; abduction at CMC & MP joints of the 1st
N: radial nerve (C5-T1)
Notes:
- distal to Abductor Pollicis Longus
- part of the anatomical snuff box
Abductor Pollicis Longus Muscle
O: posterior aspect of the middle 1/3 of the ulna, medial aspect of the interosseous membrane, posterior surface of the middle 1/3 of the radius
I: lateral surface of the trapezium, lateral surface of the base of the 1st metacarpal
A: supination, flexion of the radio-carpal joint, extension of the CMC joint of the 1st, abduction of the CMC joint of the 1st
N: radial nerve (C5-T1)
Notes:
- passes deep to the extensor retinaculum with EPB
- fibers run lateral
- tendon splits into 2 to insert
Extensor Digit Minimi Muscle
O: common extensor origin (on the posterior surface of the lateral epicondyle)
I: dorsal hood of the 5th metacarpal (at the head of the metacarpal)
A: extension of the MP of the 5th
N: radial nerve (C5-T1)
Notes:
- part of extensor digitorum, splits proximally
- similar to fibularis tertius
- separate compartment
- fibers run down, pass under extensor retinaculum
- tendon is medial to extensor digitorum