radiology: shoulder, arm, elbow, forearm Flashcards
what are the joints of the shoulder?
sternoclavicular, scapulothoracic, acromioclavicular, glenohumeral
name the ligaments of the shoulder joint.
costoclavicular (medial clavicle), anterior sternoclavicular, coracoclavicular (conoid, trapezoid), acromioclavicular, transverse scapular, coracoacromial, coracohumeral, coracoglenoid
why do shoulder dislocations have a high recurrence rate>
damage to glenoid labrum
which type of shoulder dislocation is most common and why?
anterior (90%): very common in sport. usually due to impact on shoulder, less stable anteriorly
posterior dislocation: epileptic fit, electric shock. all muscles contract leading to strong internal roation leading to posterior dislocation
what other injuries are associated with shoulder dislocation?
bankart lesion, bony bankart lesion, hills-sachs defect, greater tuberosity fracture, axillary nerve injury, rotator cuff tears
what are the symptoms of axillary nerve injury?
transient neuropraxia of the axillary nerve, present in up to 5% patients with dislocation, weakness of deltoid and loss sensation in regimental badge area
what is a bankart lesion and how is it repaired?
anterior labrum and anterior band IGHL avulse off the anterior inferior glenoid. the lesion is on the glenoid
in 80-90% with shoulder dislocation
surgical repair-anchoring sutures
what is a hills-sachs lesion and mx?
corresponding lesion on humerus to bankart lesion. chondral impaction injury in the posterosuperior humeral head secondary to contact with the glenoid rim
in 80% traumatic dislocations
not clinically significant unless it engages glenoid
what is a bony bankart lesion and how is it managed?
piece of bone pulled of with labrum, fracture of anterior inferior glenoid
49% patients with recurrent dislocation
requires bony procedure to restore bone
defect >20-25% considered critical bone loss
when does dislocation and greater tuberosity fracture occur?
in older people due to force of dislocation and inflexible muscles
what is the common MOI acromioclavicular joint separation and what imaging is used?
falling onto shoulder
XR: give weight to hold and look for shpulder depression
what is a grade 3 acromioclavicular joint separation?
all 3 ligaments damaged (conoid, trapezoid, acromioclavicular)
what rotator cuff injuries are common in overhead sports?
sub acromial bursitis, rotator cuff tendonitis, rotator cuff tear
what is the mechanism of injury of a superior labrum from anterior to posterior tear and imaging?
aka SLAP tear
may occur as an isolated lesion or associated with rotator cuff tear or instability
repetitive overhead activities, fall on outstretched arm withtensed biceps, traction on arm
MRI
how does a sternoclavicular fracture dislocation occur and who is it common in?
“rugby players fracture”
clavicle fracture at proximal end, moves posteriorly
common if younger as weak place due to growth plate which closes at 21/22, impact on shoulder can cause fractue through weak growth plate
why is a sternoclavicular fracture dislocation life threatening?
can pierce brachiocephalic trunk and indent trachea
what clavicle fractures are common in children?
greenstick
what is the MOI scapula fractures and the imagin used
high energy e.g. motorsport
hard to see on XR, need CT
what is a proximal end of humerus fracture an dits mx
tend to fracture into 4 fragments, head collapses and moves up. can get avascular necrosis
surgery: screws or replace shoulder. poor outcomes.career ending
what is adhesive capsulitis and the imaging used?
aka frozen shoulder capsule becomes thick and inflamed passive an dactive loss of movement often as a complication during rehab UR and MRI: thiickened capsule, absent axillar recess
what are the symptoms of long head of biceps rupture?
“pop-eye” muscle: lump on arm as bunches up
function often still quite good as short head still intact
US or MRI
which nerve us likely to be injured if the humerus fractures at the top vs the middl?
axillary nerve
radial nerve
when does radial nerve palsy occur, its symptoms and recovery time?
8-15% closed fractures, increased incidence distal 1/3 fractures
wrist drop
spontaneous recovery avg 7 weeks, full recpvery 6 months
what are the epicondyles for on the distal humerus and which is bigger and why?
large surface area for muscle attachments
medial as has flexor origins and flexors are stronger than extensors
what is a complication of distal humerus fracture?
bones come forward and injure median nerve and brachial artery
check for radial pulse, colour of arm
what is the common MOI for fracture of radial head and how is it mx?
cyclists falling on outstretched hand
no splinting or cast, move
what causes golfers elbow, its sx and imaging?
over use of flexors
pain in medial epicondyle
MRI: oedema and degerneration
what causes tennis elbow, its sx and imaging?
overuse of extensors, extensor carpi radialis brevis
pain in lateral epicondyle
MRI: oedema and degeneration
how is the anterior interosseus nerve tested?
make OK sign-uses muscles it supplies (flexor digitorum profundus and flexor policis longus)
how is the brachial artery protected in the cubital fossa?
bicipital aponeuorsis
where does the median nerve lie relative to the tendon of the biceps in the cubital fossa?
medial
when is the tendon of the biceps most palpable?
flexion and supination
which nerve in the arm is least likely to be damaged by frature of humerus?
musculocutaneous
where are the volar and dorsal surfaces of the hand?
anterior
posterior
what should you look for in the normal anatomy of the distal radius?
find thumb to know which side is anterior.
radial inclination line
radial shortening: styloidshould be highest
volar tilt: fossa facing towards thumb
which fractures of the distal radius are extra articular and intra articular?
extra: angulation-dorsal=colles, volar=smiths
intra: volar bartons, dorsal bartons, lunate fossa die-punch
what arethe features of a dorsal angulation fracture?
colles fracture fall on outstretched hand normall stable few require surgery may be radial shortening
what are the features of volar angulation fracture?
smiths fall on flxed wrist loss of radial inclination and some shortening unstable, usually requires surgery less common than colles
what are the features of dorsal bartons fracture?
wrist slides posterior, unstable surgery
what are the features of volar bartons fracture?
slides anteriorly
what imaging is used for fractures of distal radius?
XR, CT for detail
what are the features of a lunate fossa die-punch fracture?
motor sports, hands on bars and deceleration, lunate pushed on to radius and crushed distal part
XR@ piece of bone pushed down and out by lunate
when is the scaphoid often fractured?
falling on to outstretched hand
where do the extrinisc ligament sof the carpal bones run?
from the radius and ulnar to the carpal bones
where are the intrinsic carpal ligaments?
between carpal bones
which intrinsic carpal ligament is most commonly injured?
scapholunate
how is the scapholunate ligament injured and what imaging is used?
high forced
XR: 2 bones separated, clench fist view on XR also shows separation. lateral view=dorsal intercalated segment instability (lose normal alignment-lunate points to dorsal surface)
what is seen on XR for lunate-triquetral ligament disruption/
volar intercalated segment instability (lunate points to volar surface)
what is the blood supply of the scaphoid?
retrograde
which pole of the scaphoid is at risk of avascular necrosis after fracture?
proximal pole, will start to crumble away
how are scaphoid feactures diagnosed and treated?
often 18-25 years falling from a height. palpate anatomical snuffbox and scaphoid tubercle for pain
XR and delayed XR (10-14d), CT, MRI (look for oedema)
tx: immobilisation forearm in neutral position for 6-8 weeks
what is the MOI and diagnosis perilunate dislocation?
varies, cycling, snatch and grab in weight lifting
capitate falls off lunate
XR: AP=jumble, lateral=lunate fossa not articualting with capitate
what is kienbocks disease and its cause?
avascular necrosis of lunate, most common men aged 20-40 years
ulnar shorter than radius, increased pressure on lunate
not caused by sport byt often injury unmasks condition
what imaging and tx is used for kienbocks disease?
XR: advanced disease, lunate collapsed
MRI: oedema on lunate, can see ulnar shorter than radius
hard to treat
what passes through carpal tunnel
median nerve, flexor digitorum tendons x4, flexor digitorum superficialis tendon x4
which arteries form the palmar arches?
superficial mainly ulnar
deep mainly radial
how many compartments are the extensors divided into>
6
what goes through compartment 1 extensor retinaculum?
1st: extensor pollicis brevis, abductor pollicis longus
forms snuffbox
what goes through 2nd extensor compartment?
extensor carpi radialis brevis
extensor carpi radialis longus
what goes through 3rd extensor compartment?
extensor pollicis longus
commonly has problems due to angle change-arounf listers tubercle to thumb
what goes through 4th extensor compartment?
extensor digitorum and extensor indices
what is in 5th extensor compartment?
extensor digit minimi
what is in 6th extensor compartment?
extensor carpi ulnaris
what is de quervains tendosynovitis?
1st extensor compartment effected, inflammation and swelling
finkelsteins test: tuck thumb into palm and push wrist to ulnar side, pain in compartment
what is intersection syndrome?
1st and 2nd compartments cross in writs, friction causes pain
what causes extensor pollicis longus rupture and presentation?
common after distal radius fracture, rubs on rough surface=post fracture attrition rupture
cant lift up thumb#US
what are the exclusive sensory areas for the nerves in the hand?
ulnar=little finger
median=tip index or middle
radial=anatomical snuffbox
how does carpal tunnel syndrome present?
median nerve area
power: LOAF (muscles supplied by median nerve): 1st 2 lumbricals, opponens pollicic, abductor pollicis brevis, flexor pollicus brevis
which muscles in the hand does the ulnar nerve supply?
hypothenar, adductor pollicis, interossei, 3rd and 4th lumbricals
what are the actions of the interossei?
PAD: palmar cause adduction
DAB: dorsal cause abduction
how does injury to ulnar collateral ligament to thumb present and tx?
skiing, bent in abnormal direction
surgery
where is bennets fracture?
base of thumb
how can the flexor tendons be examined?
profundus: flex distal IP
superficialis: flex proximal IP while holdin other fingers down
US or MRI
what causes rugger jersey finger, presentation and imaging?
digitorum profundus tendon pull cuases bone avulsion
cant flex finger
XR: fracture of insertion of flexor digitorum profundus tendon
what is mallet finger?
damage to extensor tendons
soft tissue if nothing on XR, tendon pulled off bone, often in older people
bone: fracture, in younger people and psort
whenis MRI imaging is used for the hand and wrist?
ligament injuries, occult fractures, avascular necrosis
