022 anatomy of the forearm and wrist Flashcards
hat are the 4 epicondyles on the distal end of the humerus?
- lateral supraepicondylar ridge
- medial supraepicondylar ridge
- lateral epicondyle
- medial epicondyle
where is the oblique line on the radius and what attaches to it?
ridge on anterior surface going downwards and laterally
- origin of flexor digitorum superficialis and flexor pollicis longus muscles
what way round are the ulna and radius?
- radius = thumb = lateral
- ulna = pinky = medial
what connects in between the radius and ulna?
- interosseous membrane
describe the distal anatomical features of the radius
- ulna notch (medial side)
- radial styloid process (bump on lateral side)
- dorsal tubercle on posterior side
- on bottom fact for articulation with scaphoid and lunate bone of hand
what attaches to the dorsal tubercle of the radius?
- extensor pollicis longus tendon origin
describe the distal anatomical features of the ulna
- roughening attachment medially for pronator quadratus
- ulnar styloid process medially with attachment of articular disc
how many bones are in the hand?
27 bones
what are the 3 different types of bones in the hand?
- carpal, metacarpal, phalanges
how many carpal bones are there?
8
how many metacarpal bones are there?
5
how many phalanges are there?
14
what are the names of the 8 carpal bones (starting from the base of the thumb going towards the pinky)
so long the pinky here comes the thumb
- scaphoid
- lunate
- triquetrum
- pisiform
- hamate
- capitate
- trapezoid
- trapezium
what 2 carpal bones articulate with the radius?
- lunate and scaphoid
what is defining about the hamate?
- hook of hamate
what is the use of the sesamoid bones in the hand?
-Sesamoid bones are located where a tendon passes over a joint, such as the hand, wrist, knee, and foot.
-The main function of the sesamoid is to decrease friction and to protect the tendon.
what is between the ulna and the carpal bones?
- articular disc
what is around the wrist joint?
- synovial capsule
what are all the different movements of the wrist?
- pronation, supination
- abduction, adduction
- extension, flexion
- circumduction
what is abduction/adduction of the wrist?
- abduction = away from midline, towards thumb
- adduction = towards midline, towards pinky
what is flexion/extension of the wrist?
- flexion = downwards = towards palm
- extension = upwards
what is abduction/adduction of digits 2-5?
- abduction = away from, midline, 3rd finger (spread fingers)
- adduction = towards midline, 3rd finger (fingers together)
what is extension/flexion of digits 2-5?
- extension = fingers straight, in line with palm
- flexion = fingers bent, 90 degrees to palm
what is the extension/flexion of digit 1 (thumb)?
- extension =away from midline = away from 1st finger/palm
- flexion = towards midline = towards 1st finger/palm
what is adduction/abduction of digit 1 (thumb)?
- adduction = hand sideways, thumb in line with rest of fingers
- abduction = hand sideways, thumb in front of palm (straight out)
what are the 6 different joints in the wrist/hand?
- wrist joint
- midcarpal joint
- carpometacarpal joints
- metacarpophalangeal joints
- proximal interphalangeal joints
- distal interphalangeal joints
describe features of the wrist joint and the movement it allows
- synovial joint between radius and articular disc overlaying ulna and the proximal carpal bones
- abduction/adduction
- flexion/extension
describe the features of the midcarpal joint and the movement it allows
- between proximal and dital row of carpal bones
- limited flexion/extension
describe the features of the carpometacarpal joints and the movement they allow
- between the carpal and metacarpal bones
- digits 2-5 = very limited range of motion
- digit 1 = saddle joint = flexion/extension, abduction/adduction and opposition (rotation)
describe the features of the metacarpophalangeal joints and the movement they allow
- between the metacarpals and the phalangeals
- digits 2-5 = flexion/extension, abduction/adduction, circumduction
- digit 1 = hinge digit = flexion/extension
describe the interphalangeal joints and the movement they allow
- between the phalangeal joints of the fingers
- thumb = only distal, all other have proximal and distal joints
- hinge joints = flexion/extension
why are the anterior/posterior compartments of the lower arm twisted?
- we evolved as humans to have our hands pronated, which twists our radius and ulna
- so the muscles, arteries and nerves are also slightly twisted
- e.g. anterior = more medial and posteror = more lateral
what compartment are the ulnar carpal flexor and extensor muscles in and what movement of the wrist do they allow?
- anterior = adduction
what compartment are the radial carpal flexor and extensor muscles in and what movement of the wrist do they allow?
- posterior = abduction
what are the 4 anterior superficial muscles of the forearm?
- flexor carpi ulnaris
- palmaris longus
- flexor carpi radialis
- pronator teres
what is the origin of the flexor carpi ulnaris?
medial epicondyle of the humerus and ulnar head (olecranon and posterior border of ulna)
what is the insertion of the flexor carpi ulnaris?
- pisiform, then to hamate and base of 5th metacarpal by ligaments
what is the innervation of the flexor carpi ulnaris?
- ulnar nerve (C7, C8, T1)
what is the action of the flexor carpi ulnaris?
- flexion and adduction
what is the origin of the palmaris longus?
- medial epicondyle of humerus
what is the insertion of the palmaris longus?
- becomes the palmar aponeurosis = onto each finger but not thumb
what is the innervation of the palmaris longus?
- median nerve (C7,8)
what is the action of the palmaris longus?
- tightening palm skin and some wrist flexion
what is the origin of the flexor carpi radialis?
- medial epicondyle
what is the insertion of the flexor carpi radialis?
- base of metacarpals 2,3
what is the innervation of the flexor carpi radialis?
- median nerve (C6,7)
what is the action of the flexor carpi radialis?
- flexion and abduction of the wrist
what is the origin of the pronator teres?
- medial epicondyle of humeral head and ulna head (coronoid process of ulna)
what is the insertion of the pronator teres?
- lateral midshaft of radius
what is the innervation of the pronator teres?
- median nerve (C6,7)
what is the action of the pronator teres?
pronation of forearm (palm facing down)
what is the intermediate layer muscle in the anterior forearm?
- flexor digitorum superfialis
what is the origin of the flexor digitorum superficialis?
- medial epicondyle of humerus and coronoid process of ulna and oblique line of radial head
what is the insertion of the flexor digitorum superficialis?
margins of middle phalanges digits 2-5 (goes through carpal tunnel) (splits into tendons after carpal tunnel)
what is the innervation of the flexor digitorum superficialis?
median nerve (C8,T1)
what is the action of the flexor digitorum superficialis?
- flexes the wrist, metacarpophalangeal joints and interphalangeal joints (2-5)
what are the 3 deep muscles of the anterior forearm?
- flexor digitorum profundus
- flexor pollicis longus
- pronator quadratus
what is the origin of the flexor digitorum profundus?
- anterior surfaces of ulna and the interosseus membrane
what is the insertion of the flexor digitorum profundus?
- bases of distal phalanges of digits 2-5
what is the innervation of the flexor digitorum profundus?
- median nerve (C7,8) for lateral half and medial half innervated by ulnar nerve (C8,T1)
what is the action of the flexor digitorum profundus?
flexes wrist, metacarpophalangeal joints and proximal and distal interphalangeal joints
what is the origin of the flexor pollicis longus?
- anterior surfaces of radius and the interosseous membrane
what is the insertion of the flexor pollicis longus?
- base of distal phalanx of digit 1 (thumb)
what is the innervation of the flexor pollicis longus?
median nerve (C7,8)
what is the action of the flexor pollicis longus?
- flexes metacarpophalangeal and interphalangeal joint of digit 1 (thumb)
what is the origin of the pronator quadratus?
- anterior surface of distal part of ulna
what is the insertion of the pronator quadratus?
- anterolateral surface of the distal radius
what is the innervation of the pronator quadratus?
- median nerve (C7,8)
what is the action of the pronator quadratus?
pronation of forearm
what are the superficial posterior muscles of the forearm(7)?
- brachioradialis
- extensor carpi radialis longus
- extensor carpi radialis brevis
- extensor digitorum
- extensor digiti minimi
- extensor carpi ulnaris
- anconeus
(all innervated by radial nerve)
what is the origin of the brachioradialis?
- lateral supraepicondylar ridge on humerus
what is the insertion of the brachioradialis?
- lateral surface of distal radius
what is the innervation of the brachioradialis?
- radial nerve (C5,6)
What is the action of the brachioradialis?
- flexes elbow when arm is partially pronated
what is the origin of the extensor carpi radialis longus?
- lateral supraepicondylar ridge of humerus and lateral epicondyle
what is the origin of the extensor carpi radialis brevis?
-lateral epicondyle
what is the insertion of the extensor carpi radialis longus?
- base of metacarpal 2
what is the insertion of the extensor carpi radialis brevis?
- base of metacarpals 2 and 3
what is the innervation of the extensor carpi radialis longus and brevis?
- radial nerve (C6,7,8)
what is the action of the extensor carpi radialis longus and brevis?
- extends and abducts wrist
what is the origin of the extensor digitorum?
- lateral epicondyle of humerus
what is the insertion of the extensor digitorum?
extensor hoods of digits 2-5
what is the innervation of the extensor digitorum?
- radial nerve and posterior interosseous (C7,8)
what is the action of the extensor digitorum?
- extends digits 2-5 and the wrist
what is the origin of extensor digiti minimi?
- lateral epicondyle of humerus
what is the insertion of extensor digiti minimi?
- extensor hood of digit 5
what is the innervation of extensor digiti minimi?
- radial nerve, posterior interossous nerve (C7,8)
what is the action of the extensor digiti minimi?
- accessory extensor of digit 5
what is the origin of the extensor carpi ulnaris?
- lateral epicondyle of humerus
what is the insertion of the extensor carpi ulnaris?
base of metacarpal 5
what is the innervation of the extensor carpi ulnaris?
- radial nerve, posterior interosseous nerve ( C7,8)
what is the action of the extensor carpi ulnaris?
- extends and adducts the wrist
what is the origin of the anconeus?
- lateral epicondyle of humerus
what is the insertion of the anconeus?
-olecranon and posterior surface of ulna
what is the innervation of the anconeus?
radial nerve (C6,7,8)
what is the action of the anconeus ?
- abducts ulna during pronation to maintain position of the hand
what are the deep posterior muscles of the forearm (5)?
- supinator
- abductor pollicis longus
- extensor pollicis longus
- extensor pollicis brevis
- extensor indicus
what is the origin of the supinator?
- lateral epicondyle of humerus and ulna
what is the insertion of the supinator?
oblique line of radius
what is the innervation of the supinator?
- radial nerve and posterior interosseous nerve (C6,7)
what is the action of the supinator?
- supinates forearm (palm facing up)
what is the origin of the abductor pollicis longus?
- posterior surfaces of radius and ulna and the interosseous membrane
what is the insertion of the abductor pollicis longus?
- lateral side of metacarpal 1
what is the innervation of the abductor pollicis longus?
- radial nerve an posterior interosseous nerve (C7,8)
what is the action of the abductor pollicis longus?
- abducts thumb (away from index finger)
what is the origin of the extensor pollicis brevis?
- posterior radius and interosseous membrane
what is the origin of the extensor pollicis longus?
- posterior ulna and interosseous membrane
what is the insertion of the extensor pollicis brevis?
- proximal phalanx of digit 1
what is the insertion of the extensor pollicis longus?
- distal phalanx of digit 1
what is the innervation of extensor pollicis brevis and longus?
- radial nerve and posterior interosseous nerve (C7,8)
what is the action of the extensor pollicis brevis and longus?
extends the thumb
what is the origin of the extensor indicus?
- posterior ulna and interosseous membrane
what is the insertion of the extensor indicus?
- extensor hood of digit 2
what is the innervation of the extensor indicus?
- radial nerve and posterior interosseous nerve (C7,8)
what is the action of extensor indicus?
extends digit 2
what are the muscles used for abduction/adduction of the wrist?
- abduction = extensor and flexor carpi radialis
- adduction = extensor and flexor carpi ulnaris
how many flexors and extensor carpis are there in the forearm and what are they called?
- 5
- flexor carpi radialis
- flexor carpi ulnaris
- extensor carpi ulnaris
- extensor carpi radialis brevis
- extensor carpi radialis longus
what are the 4 muscles used for extension of the wrist?
- extensor carpi radialis longus and brevis
- extensor digitorum
- extensor carpi ulnaris
what muscles contract to pronate the hand?
- pronator teres and pronator quadratus
what muscles contract to supinate the hand?
- supinator and biceps brachii
what is the function of the anconeus in pronation/supination?
- stabilises the bones in the elbow
what are the 3 main branches off the brachial artery?
- radial artery, ulnar artery, common interosseous artery
describe the location and function of the radial artery
- down lateral aspect of arm under the brachioradialis (starts from cubital fossa)
- supplies posterolateral aspect of hand - forms superficial palmar branch
describe the location and function of the ulnar artery
- medial side of foream with ulnar nerve
- enters hand through carpal tunnel
- supplied forearm and hand
describe the location and function of the common interosseous artey
- middle of forearm
- branch of ulnar artery
- spits into anterior and posterior branches to supply both compartments of arm
what is A?
anterior interosseus artery
what is B?
posterior interosseus artery
what is C?
radial recurrent artery
what is D?
- common interosseus artery
what is E?
anterior and posterior ulnar recurrent arteries
what is F?
- ulnar artery
what are the 2 pulses in the forearm?
- brachial pulse
- radial pulse
where can you feel the brachial pulse?
- cubital fossa
where can you feel the radial pulse?
- at wrist
- lateral to the tendon of flexor carpi radialis (wrist anterior under thumb)
what are the 4 main nerves in the forearm?
- median, ulnar, radial, interosseus
give an overview of the location and function of the median nerve
- from lateral and medial cords in brachial plexus
- central anterior of forearm
-innervates anterior forearm muscles (except FCU and medial 1/2 of FDP) and fingers 1-4 muscles - passes through cubital fossa, down anterior aspect of arm and through carpal tunnel
- 2 branches = anterior interosseous and palmar cutaneous
- sensory of thumb, index middle and half 4th finger
give an overview of the location and function of the ulnar nerve
- from medial cord of brachial plexus
- medial anterior of forearm
- innervates FCU and medial 1/2 of FDP and fingers 4/5 muscles
- sensory = fingers 5 and 1/2 of 4th and palm area
- around back of medial epicondyle of elbow down medial edge of arm and enters hand above carpal tunnel
- branches = deep ulnar nerve, superficial ulnar nerve, dorsal branch, palmar cutaneous branch
give an overview of the location and function of the radial nerve
- from posterior cord of brachial plexus
- innervates posterior muscles of forearm
- sensory = lateral and posterior of arm and dorsal digits 1- 4 (1/2)
- branches = deep and superficial and various cutaneous branches
- around front of lateral epicondyle then divides into superficial and deep branches (lateral posterior)
where is the anterior interosseous nerve and what does it innervate?
- branch off median nerve
- branches to innervate FDP, FPL and pronator quadratus
- terminates before wrist joint
- passes between the 2 heads of pronator teres
where is the posterior interosseus nerve and what does it innervate?
- continuation of the deep radial branch
- innervates all posterior muscles in forearm (all the extensors, APL and supinator)
what is A?
radial nerve (posterior cutaneous nerve of arm)
what is b?
musculocutaneous nerve (lateral cutaneous nerve of forearm)
what is c?
- radial nerve (superficial branch)
what is d?
median nerve
what is e?
T2
what is f?
T1
what is g?
ulnar nerve
what is h?
radial nerve (posterior cutaneous nerve of arm)
what is I?
- musculocutaneous nerve ( lateral cutaneous nerve of forearm)
what is J?
radial nerve (superficial branch)
what is k?
median nerve
what is L?
T2
what is M?
T1
what is N?
ulnar nerve
what is the carpal tunnel formed by?
- carpal bones and the flexor retinaculum
what does the flexor retinaculum of the carpal tunnel attach to?
- pisiform and hook of hamate across to trapezium and scaphoid
what is a?
median nerve
what is b?
flexor retinaculum (transverse carpal ligament)
what is c?
- ulnar artery and nerve
what is d?
- pisiform
what is e?
carpal tunnel
what is f?
hypothenar eminence
what is g?
triquetrum
what is h?
extensor carpi ulnaris tendon
what is i?
extensor digiti minimi tendon
what is j?
hamate
what is k?
extensor digitorum and extensor indicis tendons
what is L?
capitate
what is M?
extensor carpi radialis brevis tendon
what is n?
extensor carpi radialis longus tendon
what is o?
radial nerve superficial branch
what is p?
extensor pollicis longus tendon
what is q?
extensor pollicis brevis tendon
what is r?
abductor pollicis longus tendon
what is s?
thenar eminence
what is t?
trapezium
what is u?
scaphoid
what is in the carpal tunnel?
- median nerve
- flexor pollicis longus tendon (1)
- flexor digitorum profundus tendons (4)
- flexor digitorum superficialis tendons (4)
what is carpal tunnel syndrome and what are its symptoms?
- compression of the median nerve due to swelling of tendons and sheath
- patients report pain and numbness in distribution of median nerve ( thumb to 4th finger)
- weakness and eventually atrophy of thenar muscles
