L5 - Anatomy of forearm COPY Flashcards
SKELETON OF FOREARM
i) which bone sits laterally and which bone sits medially
ii) which part of the radius artciulates with the ulna?
iii) where does the biceps attach?
iv) which muscle attaches to the styloid process of the radius?
v) what holds the two bones together
vi) label diagram
i) radius is lateral and ulna is medial
ii) radial notch articulates with the ulna
iii) biceps attaches onto the radial tuberosity
iv) brachioradialis attaches to styloid process (drinking action)
v) interosseus membrane holds the two bones together
vi) A - olecranon, B - trochlear notch of ulna, C - radial notch
D - ulna tuberosity, E - IO mem, styloid of ulna F - styloid proc of radius, G - radial tuberosity
JOINTS OF FOREARM
i) what is the main types of joint found in the forearm?
ii) which joint allows flexion and extension? where is it found?
iii) which joint allows supination and pronation? where is it found?
iv) which joint is circled in the diagram?
i) synovial joint
ii) synovial hinge joint allows flexion and extension - elbow
iii) synovial pivot joint - radioulnar joint (proximal)
iv) synovial pivot joint between the radius and ulna
LIGAMENTS OF FOREARM
i) what two roles to ligaments play?
ii) which ligament is labelled A? which two places does it have slips to?
iii) which ligament is labelled B? what does it wrap around? which two areas does it attach onto?
iv) which ligament is labelled C? what shape does it form and what does this aid? where does it attach to? (2)
i) ligaments = stabilise and strengthen the joint
ii) A = radial collateral ligament > slips to radius and ulna
iii) B = annular ligament
- wraps around head of radius
- attaches at the radial notch and ulna
iv) C = ulna collateral ligamnt
- forms a triangle shape for strength
- attaches at coronoid process of ulna and the olecranon
SUPERFICIAL MUSCLE LAYER OF ANTERIOR COMPARTMENT
i) what type of muscles are found in this compartment? where do all muscles in this layer originate from?
ii) label A-D - give the insertion and action of each muscle
iii) which clinical condition implicates these muscles? what happens and what causes it?
i) flexors > orginate from common flexor origin = medial epicondyle of the humerus
ii) A - pronator teres - inserts onto radius = pronates
B - flexor carpi radialis - inserts into base of metacarpal 2&3
- flexes the wrist
C - palmaris longus - inserts into palmar apneurosis
- weak flexor
D - flexor carpi ulnaris - inserts into 5th metacarpal
- flexes wrist
iii) golfers elbow/medial epicondylitis > inflammation of tendons from CFO due to overuse/gripping action
INTERMEDIATE MUSCLE LAYER OF ANT COMPARTMENT
i) which muscle sits in this compartment?
ii) how many muscles bellies make up the muscle?
iii) which structure do the tendons cross and where do they insert?
iv) what are the three actions of this muscle?
i) flexor digitorium superficialis
ii) four bellies
iii) tendos cross the carpal tunnel and insert into the middle phalanx of digits 2,3,4,5
iv) actions = flex wrist, flex metacarophalangeal joints, flex proximal interphalangeal joints
DEEP MUSCLE LAYER OF ANTERIOR COMPARTMENT
i) name the two muscles in this compartment
ii) label A, B and C and give origin/insertion/action of each
iii) do these muscles come from the common flexor origin
i) flexor pollicus longus, flexor digitorium profundus
ii) A - flexor pollicus longus - orig from radius & IO membrane
- inserts into the distal phalanx of the thumb
- action - flexes the thumb
B - flexor digitorum profundus - orig from ulna and IO mem
- has four tendons that insert into distal phalanx of digit 2,3,4,5
- flexes wrist, metacarpophalan joint, proximal and distal interphalangeal joints
iii) these flexors do not come from the common flexor origin (med epicondyle of humerus)
SUPERFICIAL MUSCLE LAYER OF POSTERIOR COMPART
i) where do all of the muscles originate? which two principal actions do these muscles have?
ii) label A - E and insertions/actions of each
iii) which muscle is D an accessory to?
iv) which clinical condition implicates the tendons of these muscles? what causes it?
i) all originate from common extensor origin (lateral epicondyle of the humerus)
ii) A - extensor carpi radialis longus - inserts to base of 2nd metacarpal > extends the wrist
B - extensor carpi radialis brevis - inserts into base of 3rd metacarpal > extends wrist
C - extensor digitorum - four tendons insert into mid and distal phalanx of digits 2,3,4,5
- extends wrist, MCP joint in digit 2-5 and prox/distal
IP joints 2-5
D - extensor digiti minimi - tendons join with ED into digit 5
E - extensor carpi ulnaris - inserts into base of 5th metacarpal
- weak extensor of the wrist
iii) D = extensor digiti minimi is an accessory muscle to extensor digitorium and joins tendon to insert into digit 5
iv) tennis elblow/lateral epicondilytis - inflammation of CEO tendons due to overuse/foreful extension
SUPERFICIAL EXTENSOR MUSCLES CONTINUED
i) name two other muscles also found in the extensor compartment
ii) label diagram - where does each originate, insert and what is the action?
iii) which muscle allows drinking action
i) brachioradialis and anconeus
ii) A - brachioradialis - orig at supra condylar ridge
- inserts into the styloid process of the radius
- acts to flex when half pronated (drinking)
B - anconeus - originates from lateral epicondyle
- inserts into olecranon
- action to stabilise elbow when pronating/supinating
DEEP MUSCLE LAYER OF EXETENSOR COMPARTMENT
i) label A-E - where does each insert/action
ii) which three places do these muscles originate from?
iii) which three muscles in this layer make up the anatomical snuff box?
iv) how many phalanx does the thumb have? name them. how many do the fingers have? name them
i) A - supinator
B - abductor pollicus longus - long tendon ins into thumb
C - extensor pollicus brevis - ins proximal phalanx of thumb
D - extensor pollicus longus - ins distal phalanx of thumb
E - extensor indicis - tendons join extensor digitorum
ii) orignate from radius/ulna/IO membrane
iii) abductor pollicus longus, extensor pollicus longus and brevis
iv) thumb - 2x phalanx = proximal and distal
fingers = 3x phalanx = proximal, middle, distal
WRIST ABDUCTION AND ADDUCTION
i) which muscles perform this action?
ii) what is abduction also known as? which three muscles do this?
iii) what is adduction also known as? which two muscles do this?
iv) what do these muscles do together? what does this allow? give two examples
i) carpi muscles
ii) abduction = radial deviation
- flexor carpi radialis, extensor carpi radialis longus & brevis
iii) adduction = ulna deviation
- flexor and extensor carpi ulnaris
iv) together the muscles splint the wrist
- allows fine movement of the hand eg typing and precision gripping eg holding pen
PRONATION AND SUPINATION
i) which two muscles are involved in supination? which two muscles are involved in pronation? where does each origin and insert?
ii) how are the radius and ulna position in supination? how are they positioned in pronation?
iii) which two joints allow pro and supination?
iv) label diagram
i) supination - biceps brachii and supinator (sup head from lat epicondyle and deep head from ulna) > ins prox shaft of radius
pronation - pronator teres ( hum head from CFO and ulna head from ulna > radius)
and pronator quadratus (orig ulna inserts to radius)
ii) supination - radius and ulna are parallel
pronation - ulna is stationary and radius rotates/crosses top of ulna
iii) proximal and distal radioulnar joints
iv) A - biceps brachii, B - supinator, C - pronator teres, D - pronator quadratus
CARPAL TUNNEL AND FLEXOR RETINACULUM
i) what forms the roof of the carpal tunnel? what does this prevent from happening?
ii) what are the contents of the tunnel? (3 muscles and 1 nerve)
iii) what surrounds the tendons? what is this for?
iv) where does the ulna nerve pass in relation to the FR
v) label diagram
i) flexor retinaculum forms roof of carpal tunnel and prevents bowing of tendons (stops tendons popping out when flexing wrist)
ii) tunnel contains median nerve, flexor pollicus longus and flexor digitorum superficialis and profundus
iii) tendons are surrounded by synovial sheaths which lubricate the tendons as they move
iv) ulna nerve passes above the tunnel with the ulna artery
v) A - median nerve, B - flexor pol longus, C - flex dig sup,
D - flex dig profundus, E - flexor retinaculum
EXTENSOR RETINACULUM
i) which two bones does it span across? what does roles does it play?
ii) label diagram
i) spans radius and ulna
- prevents bowing of tendons passing to hand
- seperates tendons into compartments (6 comparts)
ii) A - extensor retinaculum, B - extensor digitorium tendons,
C - abductor pollicus longus, D - extensor policus longus
LONG TENDON INSERTIONS
i) which digits to the long tendons go to?
ii) name the three muscles that have long tendons to the digits and where each one inserts
iii) which tendon splits to form a chiasm? which tendon then passes through the chiasm?
iv) label diagram
i) digits 2,3,4,5
ii) extensor digitorum > middle and distal phalanx
flex digitorum superficialis > middle phalanx
flex digitorum profundus > distal phalanx
iii) flex dig superficialis splits and flex dig profundus passes through it to insert onto the distal phalanx
iv) A - extensor dig, B - flex dig superfic, C - flex dig profundus
CUBITAL FOSSA
i) between which two bony prominences does the top of the CF pass between?
ii) what forms the medial and lateral edges? what muscle forms the floor?
iii) which main nerve passes through it?
iv) which main artery passes through? which two branches does it divide into?
v) which nerve passes through and supplies skin of lateral forearm? what nerve is this a branch of?
vi) tendon of which muscle passes through? what apneurosis does it form?
i) medial and lateral epicondyle form top
ii) medial edge - pronator teres, lateral edge - brachioradialis
- floor formed by brachialis
iii) median nerve passes through
iv) brachial artery > split to radial and ulna artery
v) lateral cutaneous nerve passes through
- branch of musculocutaneous nerve
vi) tendons of biceps > bicpital apneurosis
CUBITAL FOSSA CONTINUED
i) which nerve sits under the brachioradialis? what do its branches supply?
ii) label diagram
iii) which vein passes through? which two veins does it traverse between? what is the clinical relevance of this vein?
i) radial nerve sits under brachioradialis
- sup branch supplies skin and dorsolat aspect of. hand
- deep branch supplies extensors
ii) B - pronator teres, C - brachioradialis, D - biceps tendon,
E - median nerve, F - brachial artery, G - brachialis, H - bicipital apneurosis, I - radial nerve, J - lat cutaneous nerve
iii) median cubital vein passes through
- traverses between cephalic (lat) and basilic vein (medial)
MCV is where you take blood from
RADIAL ARTERY
i) which muscle does it sit under? what nerve does it sit with?
ii) which structure does it pass through as it heads down the arm? which muscle does it then pierce?
iii) what does it ultimately form in the hand?
iv) does it pass deep or superficial to the flexor tendons?
v) label diagram
i) sits under brachioradialis and with radial nerve
ii) passes through anatomical snuffbox then pierces 1st interosseus muscle
iii) forms deep palmar arch in hand
iv) passes deep to flexor tendons
v) A - brachioradialis, B - brachial artery, C - superficial branch of radial nerve
ULNAR ARTERY
i) which muscle does it lie underneath? which nerve does it run with?
ii) what is the main branch it gives off in the forearm? which two branches does this give off and what do they supply?
iii) label diagram
i) lies underneath the flexor carpi ulnaris
ii) gives of branch of common interosseus artery
- splits to ant inteross > runs deep in anterior compart
- post inteross > pierces IO membrane and supplies extensors
iii) A - ulnar artery, B - common interosseus artery,
C - flexor carpi ulnaris, D - posterior interossus, E - ant inteross
F - ulnar nerve
NERVE SUPPLY TO FOREARM
i) label diagram
ii) which nerve passes the cubital fossa?
iii) which nerve runs through the cubital tunnel
iv) what does the lateral cutaneous nerve supply? what is it a branch of?
i) A - radial nerve, B - musculocutaneous nerve,
C - median nerve, D - ulnar nerve
ii) median nerve passes cubital fossa
iii) ulnar nerve runs through cubital tunnel
iv) lateral cut nerve supplies skin on lat side of forearm
- branch of musculocutaneous
MEDIAN NERVE
i) which two muscles does it lie between?
ii) what does it supply
iii) what does it branch into? what does this supply?
iv) does it pass through the carpal tunnel?
v) label diagram
vi) how can the median nerve be implicated clinically? give three things that can cause this
i) lies between flexor dig superficialis and flexor dig prodfund
ii) supplies lat hand muscles and anterior compart muscles (flexors) except FCU and medial bellies of FDP
also has sensory to skin of lateral palm + D1,2,3 1/2 D4
iii) branches into the anterior inteross nerve > supplies deep flexors except FCU and FDP medial bellies
iv) yes
v) A = median nerve, B = carpal tunnel, C = ant inteross nerve
vi) carpal tunnel syndrome = median nerve compression
- increased pressure in carpal tunnel due to trauma, obesity, pregnancy
LABEL
US of the wrist
A = flexor retinaculum
B = median nerve
C = synovival fluid
D - flexor tendons
E - ulnar artery
RADIAL NERVE
label diagram
i) what does E eventually become?
A - radial nerve
B - brachioradialis
C - superficial branch of radial nerve
D - posterior interosseus nerve
E - deep branch of radial nerve
i) deep branch of radial becomes posterior interossus nerve
CUTANEOUS INNERVATION
i) label diagram
ii) what what area of a nerve is mostly likely damaged if there is altered sensation to one of these areas?
i) A - lateral cutaneous nerve of forearm
B - median nerve
C - ulnar nerve
D - medial cutaneous nerve of forearm
E - radial nerve
ii) damage to distal nerve segment
