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
