Anterior forearm and wrist Flashcards
what is the anterior compartment of the forearm responsible for
flexion of the wrist and digits and pronation
where is the common flexor origin
medial epicondyle of the humerus
what nerve supplies all but 2 muscles in the anterior compartment of the forearm
the median nerve
what 2 muscles does the median nerve not supply
flexor carpi ulnaris
ring/little finger side of flexor digitorum profundus
what nerve supplies flexor carpi ulnaris and ring/little finger side of flexor digitorum profundus
ulnar nerve
flexor carpi ulnaris lies ___ the ulnar nerve
above
ring and little finger side of flexor digitorum profundus lies ____ the ulnar nerve
directly below
what is the most superficial muscle in the forearm
palmaris longus
where does palmaris longus originate and insert
originates on medial epicondyle
inserts into and helps to tighten the palmar aponeurosis
how does the palmar aponeurosis aid grip
adheres to the skin of the palm above it and the muscles of the hand below it and so stops the skin sliding over the muscles
is palmaris longus necessary
no it is not an essential muscle and some individuals don’t have it or have unilateral presence of it
what nerve innervates palmaris longus
median nerve (C7,8)
function of palmaris longus
tighten aponeurosis
aids with wrist flexion
pronator teres has how many heads
2
what nerve passes between the 2 heads of pronator teres
median nerve
what does pronator teres do
pronation of forearm and assists in elbow flexion
if a muscle acts to move the radius during pronation where must it attach
radius
why would weak flexion of the elbow still be possible if the musculocutaneous nerve was damaged
the musculocutaneous nerve innervates brachialis - the main flexor of the elbowbut pronator teres also crosses the anterior aspect of the elbow and therefore assists in flexion - it is innervated by the median nerve therefore if damage occurs to one nerve the other will still work
what nerve innervates pronator teres
median nerve (C6,7)
what is the origin and insertion of pronator teres
medial epicondyle of humerus and coronoid process of ulna to the lateral surface of the radius
what is another word for wrist
carpus
what do flexor carpi ulnaris and radialis do
flex the wrist
flexor carpi ulnaris is on the ____ side of the forearm
medial (ulnar)
flexor carpi radialis is on the ____ side of the forearm
lateral (radial)
how is the wrist adducted (medial deviation)
if flexor carpi ulnaris and its counterpart in the extensor compartment of the forearm (extensor carpi ulnaris) both act on the wrist it will be adducted
how is the wrist abducted
if the flexor and extensors on the radial side both act on the wrist it will be abducted (lateral deviation)
what nerve innervates flexor carpi ulnaris
ulnar nerve (C7,8)
what nerve innervates flexor carpi radialis
median nerve (C6,7)
what is the function of flexor carpi ulnaris
flexion of wrist and adduction of wrist
what is the function of flexor carpi radialis
flexion of wrist and abduction of wrist
what is the origin and insertion of flexor carpi ulnaris
originates from medial epicondyle and inserts onto base pisiform, hamate and 5th metacarpal
what is the origin and insertion of flexor carpi radialis
originates from medial epicondyle and inserts onto base of 2nd metacarpal
what is the origin and insertion of flexor digitorum superficialis
originates on medial epicondyle of humerus and coronoid process of ulna and inserts on each side of middle phalange of digits 2-5 (not thumb)
what is the function of FDS
flexion of MCP and PIP joint and wrist
what is MCP
metacarpophalangeal
what is PIP
proximal interphalangeal
what nerve innervates FDS
median nerve (C7, C8, T1)
why can FDS not flex the DIP joint
it doesn’t cross the joint between the middle and distal phalanges
what is the origin and insertion of flexor digitorum profundus
ulna and interosseous membrane to distal phalanges digits 2-5 (palmar)
what is the function of FDP
flexion of MCP PIP and DIP of digits 2-5 and wrist
what is the innervation of FDP
ring and little fingers is ulnar nerve (C8, T1)
index and middle fingers = median nerve (C8, T1 - anterior interosseous branch)
FDP is superficial/deep
deep
the tendons of FDP/FDS split to attach onto either side of phalange
FDS
tendons of FDP do not split - attach on palmar surface
FDP is innervated by ____ on the medial side
ulnar nerve
FDP is innervated by ____ on the lateral side
median nerve
what branch of the median nerve supplies FDP
anterior interosseous branch
what is the origin and insertion of flexor pollicis longus
radius and interosseous membrane to base of digital phalanx of thumb (palmar)
what is the function of FPL
flexion of MCP and IP of thumb and flexion of wrist
what nerve innervates FPL
median nerve (C8, T1 - anterior interosseous branch)
how many phalanges does the thumb have
2
what is the origin and insertion of pronator quadratus
distal anterior ulna to distal anterior radius
what is the function of pronator quadratus
pronation and help to stabilise distal radioulnar joint
what is the innervation of pronator quadratus
median nerve (C8, T1 anterior interosseous branch)
what are the fibres of the median nerve
C6 - T1
what cords supply the median nerve
medial and lateral cords
the median nerve is the major nerve of what
anterior compartment of the forearm and thumb side of hand
describe the course of the median nerve in the arm and forearm
forms from components of medial and lateral cords and descends through the arm to pass through the cubital fossa then passes between the heads of pronator teres in the anterior compartment of forearm where it forms the anterior interosseous branch before passing through the carpal tunnel and into the palmar surface of hand
what nerve passes through the carpal tunnel
median nerve
what anatomical spaces does the median nerve pass through
cubital fossa
carpal tunnel
median nerve passes through the 2 heads of
pronator teres
does the median nerve give sensory innervation
yes, gives off sensory branches to supply sensory innervation to parts of the palm
what muscles does the median nerve supply in the hand
muscles in the thenar eminence of the hand and to the lateral 2 lumbricals
describe the course of the anterior interosseous branch
runs along interosseous membrane to supply deeper muscles of the anterior forearm
what fibres form the ulnar nerve
(C7)-T1 fibres
what cords give rise to the ulnar nerve
medial cord
the ulnar nerve runs along the ___ side of the arm
medial
describe the course of the ulnar nerve from the arm to the forearm
passes along a groove in the medial epicondyle of the humerus to reach the anterior compartment of the forearm
the ulnar nerve runs along the ___ side of the _____ compartment forearm
medial side of the anterior compartment of the forearm
what 2 muscles does the ulnar nerve run between the anterior compartment of the forearm
flexor carpi ulnaris and the medial side of flexor digitorum profundus
what muscles in the anterior compartment of the forearm does the ulnar nerve supply
flexor carpi ulnaris and medial side flexor digitorum profundus
the ulnar nerve passes close to what bone to reach the palmar surface of the hand
pisiform
does the ulnar nerve pass through the carpal tunnel
no
what does the ulnar nerve supply in the hand
many of the intrinsic muscles of the hand and also sensory innervation to the ring and little fingers
where is the ulnar artery formed
at or near the cubital fossa as a terminal branch of the branchial artery
the ulnar artery runs down the ____ compartment of the forearm
anterior
the ulnar artery runs into the hand with
the ulnar nerve
the ulnar artery is the major contributor to what
superficial palmar arch of the hand
describe the course of the ulnar nerve
(C7) - T1 fibres
medial cord
medial side of arm
groove in medial epicondyle
medial side anterior compartment forearm between FCU and medial side of FDP
supplies these muscles then passes close to pisiform to reach palmar surface of hand
the ulnar artery forms what artery in the anterior forearm
common interosseous artery
the common interosseous artery divides to form what
anterior and posterior interosseous arteries that lie either side of the interosseous membrane in the forearm
where do the anterior and posterior interosseous arteries supply
supply muscles of both the anterior and posterior compartments of the forearm
describe the veins of the anterior compartment of the forearm
veins run with the arteries (radial, ulnar, interosseous) and eventually drain into the brachial veins in the arm
describe the wrist joint
articulation between the radius ulna and carpal bones
what kind of joint is the wrist
synovial condyloid joint
what movements can be done at the wrist
flexion
extension
abduction
adduction
circumduction
can you rotate the wrist
no
how is the wrist “rotated”
pronation and supination of the forearm
the carpal bones are named in
rows - proximal and distal row
what are the bones of the proximal row
scaphoid
lunate
triquetral (pisiform)
what are the bones of the distal row
trapezium
trapezoid
capitate
hamate
what is seen on hamate
hook-shaped protuberance that acts as an attachment point for flexor retinaculum
what attaches onto hamate
flexor retinaculum
what is the function of capitate
‘keystone’ that forces generated by movement pass through
what shape is lunate
half moon when seen from lateral side
what kind of joints are between the carpal bones of the wrist
synovial plane joints
what kind of movement occurs between the bones of the wrist
carpals move slightly to accommodate movements of the hand but stay together to prevent damage to structures that pass through the carpal tunnel
what is the rhyme to remember bones of the wrist
lateral to medial
proximal row (some lovers try positions)
distal row (that they cannot handle)
what holds the wrist together
many small ligaments between the carpal bones and by medial (ulnar) and lateral (radial) collateral ligaments
what forms the roof of the carpal tunnel
strengthened area of flexor retinaculum
the majority of the articulation at the wrist is between what
base of radius and proximal row of carpal bones
the distal end of the ulna is much ____ than the distal end of the radius
smaller
the distal end of the ulna is associated with what
an articular disc to increase the congruency of the joint on the medial side
what is retinaculum
connective tissue that forms bands on the anterior and posterior surfaces of the wrist
the carpal tunnel allows the passage of structures across the ___ surface of the wrist joint
anterior
what is the medial attachment of the flexor retinaculum
pisiform, hook of hamate
what is the lateral attachment of flexor retinaculum
tubercle of scaphoid and ridge on trapezium
the strong roof formed by flexor retinaculum helps to do what
keep the long flexor tendons close to the carpal bones
what forms the floor of the carpal tunnel
carpal bones
where does the tendon of flexor carpi radialis pass through
small space created by flexor retinaculum passing towards trapezium bone
the flexor retinaculum also acts as an attachment site for
small intrinsic muscles of the hand found in the thenar and hypothenar eminences
what sides are the thenar and hypothenar eminences
thenar - thumb
hypothenar - little finger side
what structures pass through the carpal tunnel
- tendons of flexor digitorum superficialis
- tendons of flexor digitorum profundus
- tendon of flexor pollicis longus
- tendon of flexor carpi radialis
- median nerve
will carpal tunnel syndrome affect the blood supply to the hand
no but will affect nerve supply
what structures pass through the carpal tunnel
median nerve and
tendons of FDS, FDP, FCR, FPL
do the radial artery and nerve and ulnar artery and nerve pass through carpal tunnel
no
how do the ulnar nerve and artery reach the hand
pass over the carpal tunnel to reach palmar surface of hand
how does the radial nerve reach the hand
supplies the posterior compartment of the forearm and ends as a superficial sensory branch that passes over the roof of the anatomical snuffbox and into the hand
how does the radial artery reach the hand
passes along the lateral side of the anterior compartment of the forearm and through the floor of the anatomical snuffbox before entering hand