MSK anatomy Flashcards
categories of muscles in anterior forearm
superficial, intermediate and deep
what do muscles in the anterior compartment perform, in general?
flexion at wrist and fingers
pronation
what are the superficial muscles in the anterior compartment of the forearm? where do they originate from?
flexor carpi ulnaris, palmaris longus, flexor carpi radialis and pronator teres
common tendon which arises from the medial epicondyle of the humerus
what are the attachments of the flexor carpi ulnaris?
originates from the medial epicondyle with other superficial flexors
long origin from the ulna
passes into wrist, attaches to pisiform carpal bone
what are the actions of the flexor carpi ulnaris?
flexion and adduction at the wrist
what is the innervation of the flexor carpi ulnaris?
ulnar nerve
what are the attachments of the palmaris longus?
originates from the medial epicondyle
attaches to the flexor retinaculum of the wrist
what are the actions of the palmaris longus?
flexion at the wrist
what is the innervation of the palmaris longus?
median nerve
what are the attachments of the flexor carpi radialis?
originates from medial epicondyle
attaches to base of metacarpals II and III
what are the attachments of the flexor carpi radialis?
flexion and abduction at the wrist
what is the innervation of the flexor carpi radialis?
median nerve
what does the lateral border of the pronator teres form?
medial border of the cubital fossa (anatomical triangle located over the elbow)
what are the attachments of the pronator teres?
originates from the medial epicondyle and from the coronoid process of the ulna
attaches laterally to the mid-shaft of the radius
what are the actions of the pronator teres?
pronation of the forearm
what is the innervation of the pronator teres?
median nerve
what is the muscle in the intermediate compartment?
flexor digitorum superficialis
why is the flexor digitorum superficialis used as an anatomical landmark?
median nerve and ulnar artery pass between its two heads, then travel posteriorly
what are the attachments of the flexor digitorum superficialis?
2 heads - one originates from the medial epicondyle of the humerus, other from the radius
splits into 4 tendons at wrist, which travel through the carpal tunnel
attaches to middle phalanges of 4 fingers
what are the actions of the flexor digitorum superficialis?
flexes metacarpophalangeal joints and proximal interphalangeal joints at the 4 fingers
flexes at the wrist
what is the innervation of the flexor digitorum superficialis?
median nerve
what are the muscles in the deep anterior forearm?
flexor digitorum profundus, flexor pollicis longus, pronator quadratus
what are the attachments of the flexor digitorum profundus?
originates from ulna and associated interosseous membrane
splits into 4 tendons at wrist, pass through carpal tunnel
attach to distal phalanges of 4 fingers
what are the actions of the flexor digitorum profundus?
flex distal interphalangeal joints of the fingers
flexes at metacarpophalangeal joints and at wrist
what is the innervation of the flexor digitorum profundus?
medial half - ulnar nerve
lateral half - anterior interosseous branch of median nerve
what does the medial half of the flexor digitorum profundus act on?
little and ring fingers
what does the lateral half of the flexor digitorum profundus act on?
middle and index fingers
where does the flexor pollicis longus lie?
laterally to FDP
what are the attachments of the flexor pollicis longus?
originates from anterior surface of radius and surrounding interosseous membrane
attaches to base of distal phalanx of thumb
what is the innervation of the flexor pollicis longus?
median nerve (anterior interosseous branch)
what is the shape of the pronator quadratus? where is it found?
square shaped
deep to tendons of FDP and FPL
what are the attachments of the pronator quadratus?
originates from anterior surface of ulna
attaches to the anterior surface of radius
what are the actions of the pronator quadratus?
pronates forearm
what is the innervation of the pronator quadratus?
median nerve (anterior interosseous branch)
what is the origin and insertion of the brachioradialis?
origin from lateral supracondylar ridge of humerus
inserted to distal end of radius just above its styloid process
what is the action of the brachioradialis?
flexor of the elbow
what is the innervation of the brachioradialis?
radial nerve
what bones in the wrist and hand are commonly injured?
scaphoid and 5th metacarpal
what is the arterial supply to the upper limb provided by?
proximal to distal: subclavian artery, axillary artery, brachial artery, radial artery, ulnar artery
divisions of the subclavian artery
first part: origin of the subclavian artery to the medial border of the anterior scalene
second part: posterior to the anterior scalene
third part: lateral border of anterior scalene to the lateral border of the first rib
where does the axillary artery lie? what is it enclosed in?
deep to the pectoralis minor
enclosed in the axillary sheath
what is the axillary sheath?
a fibrous layer covering the artery and three cords of the brachial plexus
divisions of the axillary artery
first part: proximal to pectoralis minor
second part: posterior to pectoralis minor
third part: distal to pectoralis minor
branches of the axillary artery in its first part
superior thoracic artery
branches of the axillary artery in its second part
thoracoacromial artery
lateral thoracic artery
branches of the axillary artery in its third part
subscapular artery
anterior and posterior circumflex arteries
what do the anterior and posterior circumflex arteries of the axillary artery form?
anastomotic network around surgical neck of the humerus
can be damaged in fractures
when is the axillary artery renamed? into what?
lower border of the teres major muscle
brachial artery
what is the main blood supply of the arm?
brachial artery
what does the brachial artery give off? where?
distal to the teres major
profunda brachii (deep artery)
how does the profundal brachii travel? what does it supply?
with radial nerve in radial groove of the humerus
supplies structures in posterior aspect of the upper arm
what are the structures in the posterior aspect of the upper arm supplied by?
profunda brachii
how does the profunda brachii terminate?
contributing to an anastomotic network around elbow joint
how does the brachial artery terminate?
terminates by bifurcating into radial and ulnar arteries
underneath bicipital aponeurosis
how are the radial and ulnar arteries formed?
by bifurcation of brachial artery within cubital fossa
what does the radial artery supply?
posterolateral aspect of forearm
contributes to anastomotic networks surrounding elbow joint and carpal bones
what does the ulnar artery supply?
anteromedial aspect of the forearm
contributes to an anastomotic network surrounding the elbow joint
what does the ulnar artery give rise to?
anterior and posterior interosseous arteries - supply deeper structures in forearm
anastomosis of radial and ulnar arteries
in hand
form superficial palmar arch and deep palmar arch
how does the ulnar artery enter the hand?
anteriorly to the flexor retinaculum and laterally to ulnar nerve
what does the ulnar artery give rise to in the hand?
deep palmar branch
continues laterally across the palm as the superficial palmar arch
how does the radial artery enter the hand?
dorsally, crossing the floor of the anatomical snuffbox
what does the radial artery give rise to?
supplies branch of the thumb, index finger and superficial palmar arch
continues as deep palmar arch
arterial arches in the hand
superficial palmar arch
deep palmar arch
where is the superficial palmar arch located?
anteriorly to the flexor tendons in the hand
deep to the palmar aponeurosis
what does the superficial palmar arch give rise to?
digital arteries - supply four fingers
where is the deep palmar arch located?
deep to the flexor tendons of the hand
what does the deep palmar arch supply?
blood supply to the digits and to the wrist joint
division of the venous system of the upper limb
superficial and deep
main superficial veins
cephalic and basilic veins
where are the cephalic and basilic veins located?
within subcutaneous tissue of the upper limb
what is the course of the basilic vein?
originates from dorsal venous network of hand
ascends medial aspect of upper limb
when does the basilic vein move deep into the arm?
at border of teres major
how is the axillary vein formed?
basilic vein combines with brachial veins from the deep venous system to form axillary vein
what is the course of the cephalic vein?
arises from dorsal venous network of the hand
ascends anterolateral aspect of upper limb
travels between deltoid and pectoralis major muscles and enters axilla region via clavipectoral triangle
how does the cephalic vein enter the axilla region?
via clavipectoral triangle
what does the cephalic vein drain into?
axillary vein in the axilla
how and where are the cephalic and basilic veins connected?
at elbow by median cubital vein
where is the deep venous system of the upper limb located?
underneath deep fascia
what are the names of the deep veins?
brachial, radial, ulnar - same name as the artery they accompany
what are perforating veins?
run between deep and superficial veins of upper limb, connecting the two system
what is the wrist joint?
scaphoid and lunate articulating with radius
what is the flexor retinaculum?
membranous band
spans between medial and lateral edges of the arch formed by carpal bones in coronal plane
forms carpal tunnel
what are the carpal bones in the proximal row, lateral to medial?
scaphoid, lunate, triquetrum, pisiform
what are the carpal bones in the distal row, lateral to medial?
trapezium, trapezoid, capitate, hamate
what are the 2 groups of the muscles acting on the hand?
extrinsic and intrinsic
what are the extrinsic muscles of the hand?
located in anterior and posterior compartments of the forearm
control crude movements and produce a forceful grip
what are the intrinsic muscles of the hand?
within hand itself
responsible for fine motor functions of the hand
what are the thenar muscles? what is their innervation?
three short muscles at the base of the thumb
muscle bellies produce a bulge - thenar eminence
fine movements of the thumb
median
opponens pollicis, abductor pollicis brevis, flexor pollicis brevis
what are the attachments, actions and innervation of the opponis pollicis?
originates from tubercle of trapezium and flexor retinaculum
inserts into lateral margin of metacarpal of thumb
opposes thumb by medially rotating and flexing metacarpal on trapezium
median nerve
what are the attachments, actions and innervation of the abductor pollicis brevis?
anterior to opponens pollicis and proximal to flexor pollicis brevis
originates from scaphoid and trapezium tubercles and flexor retinaculum
attaches to lateral side of proximal phalanx of thumb
abducts thumb
median nerve
what are the attachments, actions and innervation of the flexor pollicis brevis?
most distal
originates from the trapezium tubercle and flexor retinaculum
attaches to base of proximal phalanx of thumb
flexes metacarpophalangeal joint of thumb
median nerve. deep head by deep branch of ulnar nerve
what are the hypothenar muscles? what is their innervation?
produce hypothenar eminence - muscular protrusion on medial side of the palm, at base of little finger
ulnar
opponens digiti minimi, abductor digiti minimi, flexor digiti minimi brevis
what are the attachments, actions and innervation of the opponens digiti minimi?
lies deep to other hypothenar muscles
originates from hook of hamate and flexor retinaculum
inserts into medial margin of metacarpal V
rotates metacarpal of little finger towards palm, producing opposition
ulnar nerve
what is the attachments, action and innervation of the abductor digiti minimi?
most superficial
originates from pisiform and tendon of flexor carpi ulnaris
attaches to base of proximal phalanx of little finger
abducts little finger
ulnar nerve
what are the attachments, action and innervation of the flexor digiti minimi brevis?
lies laterally to abductor digiti minimi
originates from hook of hamate and adjacent flexor retinaculum
inserts into base of proximal phalanx of little finger
flexes MCP joint of little finger
ulnar nerve
what are lumbricals?
4 in each hand, each associated with a finger
link extensor tendons to flexor tendons
what does denervation of lumbricals lead to?
ulnar claw and hand of benediction
what are the types of lumbrical?
I and II - unipennate
III and IV - bipennate
what are the attachments, actions and innervation of the lumbricals?
originates from a tendon of flexor digitorum profundus
pass dorsally and laterally around each finger
insert into extensor hood
flex at MCP joint, extend at IP joints
lateral lumbricals - median nerve
medial lumbricals - ulnar nerve
what are interossei? what groups can they be divided into?
between metacarpals
dorsal and palmar
what are the actions of interossei?
abduction (dorsal interossei)
adduction (palmar interossei) of fingers
assist lumbricals in flexion at MCP joints and extension at IP joints
what are the attachments, actions and innervation of the dorsal interossei?
most superficial. 4/hand
originates from lateral and medial surfaces of metacarpals
attach into extensor hood and proximal phalanx of each finger
abduct fingers at MCP joint
ulnar nerve
what are the attachments, actions and innervation of the palmar interossei?
anterior on hand. 3/hand
originate from medial or lateral surface of metacarpal
attach into extensor hood and proximal phalanx of same finger
adducts fingers at MCP joint
ulnar nerve
what are the other muscles in the hand?
palmaris brevis and adductor pollicis
what are the attachments, actions and innervation of palmaris brevis?
small thin muscle found in subcutaneous tissue of the hypothenar eminence
originates from palmar aponeurosis and flexor retinaculum
attaches to dermis of skin and medial margin of hand
wrinkles skin of hypothenar eminence and deepens curvature of hand
ulnar nerve
what are the attachments, actions and innervation of the adductor pollicis?
large triangular muscle with 2 heads
one head originates from metacarpal III, the other from the capitate and adjacent areas of metacarpals II and III
both attach into base of proximal phalanx of thumb
adductor of thumb
ulnar nerve
what is the function of muscles in the posterior compartment of the forearm? what is their innervation?
extensor muscles
produce extension at the wrist and fingers
radial nerve
what are the layers of the muscles in the posterior compartment of the forearm? how are they separated?
deep and superficial
layer of fascia
what are the superficial muscles in the posterior compartment of the forearm?
brachioradialis, extensor carpi longus and brevis, extensor digitorium, extensor digiti minimi, extensor carpi ulnaris, aconeus
what is the brachioradialis?
paradoxical - origin and innervation are characteristic of an extensor muscle, but it’s a flexor at elbow
when is the brachioradialis most visible?
when forearm is half pronated and flexing at elbow against resistance
what lies between the brachioradialis and deep flexor muscles?
radial artery and nerve
what are the attachments, actions and innervation of the brachioradialis?
originates from the proximal aspect of the lateral supracondylar ridge of humerus
attaches to distal end of radius, before its styloid process
flexes at elbow
radial nerve
what are the attachments, actions and innervation of the extensor carpi radialis longus and brevis?
ECRL originates from supracondylar ridge
ECRB originates from lateral epicondyle
tendons attach to metacarpal bones I and II
extends and abducts the wrist
radial nerve
what is the extensor digitorum? how is it tested?
main extensor of the fingers
forearm is pronated and fingers extended against resistance
what are the attachments, actions and innervation of the extensor digitorum?
originates from lateral epicondyle
tendon continues into the distal part of forearm, and splits into four, and inserts into the extensor hood of each finger
extends medial 4 fingers at MCP and IP joints
radial nerve (deep branch)
what is the attachment, action and innervation of the extensor digiti minimi?
originates from lateral epicondyle of humerus
attaches with extensor digitorum tendon into the extensor hood of little finger
extends little finger, contributes to wrist extension
radial nerve (deep branch)
what are the attachments, action and innervation of the extensor carpi ulnaris?
originates from lateral epicondyle of humerus
attaches to base of metacarpal V
extension and adduction of wrist
radial nerve (deep branch)
what is the aconeus?
situated medially and superiorly in extensor compartment
blended with fibres of triceps brachii
what are the attachments, actions and innervation of the aconeus?
originates from lateral epicondyle, attaches to posterior and lateral part of olecranon
extends and stabilises the elbow joint
abducts ulna during pronation of forearm
radial nerve
what are the muscles in the deep layer of the posterior forearm?
supinator, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus and extensor indicis
what do the muscles in the deep layer of the posterior forearm act on?
except the supinator, they act on the thumb and index finger
where does the supinator lie?
in floor of cubital fossa
what are the attachments, actions and innervation of the supinator?
one head originates from lateral epicondyle of humerus, other from posterior surface of ulna
insert into posterior surface of radius
supinates forearm
radial nerve (deep branch)
where does the abductor pollicis longus lie?
immediately distal to supinator
what are the attachments, actions and innervation of the abductor pollicis longus?
originates from interosseous membrane and adjacent posterior surfaces of radius and ulna
attaches to lateral side of base of metacarpal I
abducts thumb
radial nerve (posterior interosseous branch)
where does the extensor pollicis brevis lie?
medially and deep to abductor pollicis longus
what are the attachments, actions and innervation of the extensor pollicis brevis?
originates from posterior surface of radius and interosseous membrane
attaches to base of proximal phalanx of thumb
extends at MCP and CM joints of thumb
radial nerve (posterior interosseous branch)
what are the attachments, actions and innervation of the extensor pollicis longus?
originates from posterior surface of the ulna and interosseous membrane
attaches to distal phalanx of thumb
extends all joints of thumb: CM, MCP, IP
radial nerve (posterior interosseous branch)
what are the attachments, actions and innervation of the extensor indicis proprius?
originates from posterior surface of ulna and interosseous membrane, distal to extensor pollicis longus
attaches to extensor hood of index finger
extends index finger
radial nerve (posterior interosseous branch)
