week 10: humerus, shoulder Flashcards
in an AP humerus x-ray, the epicondyles are ________ to the IR
parallel
in a lateromedial humerus x-ray, the epicondyles are _______ to the IR
perpendicular
what is the general kVp range for humerus x-rays?
70-85 kVp
in a lateromedial humerus x-ray, the _______ is placed father away from the IR than the ________ (image analysis)
capitulum, medial trochlea
because of medial trochlea/capitulum placement in reference to the IR, in a lateromedial projection, the _________________ (image analysis)
capitulum will be projected to be distal to the medial trochlea
what is the general kVp range for shoulder x-rays?
70-85 kVp
what is the more descriptive name for the Lawrence method?
inferosuperior axial projection of shoulder
what is the more descriptive name for the Grashey method?
AP Oblique Projection – Glenoid Cavity
what are the two bones that make up the shoulder girdle?
clavicle, scapula
mobility type of SC, AC, and SH joints
diarthrodial
movement type of the scaphohumeral joint
ball and socket (spheroidal) joint
movement type of SC joint
double plane (gliding) joint
movement joint of AC joint
plane (gliding) joint
can you have the patient rotate their arm if a fracture/dislocation is suspected?
No
a true AP humerus will be demonstrated by
-greater tubercle of humerus in profile seen laterally
-lesser tubercle of humerus superimposed (now located anteriorly)
a true lateral humerus will be demonstrated by
-epicondyles directly superimposed
-lesser tubercle shown in profile medially, partially superimposed by lower portion of glenoid cavity
in humerus x-rays can scapula and clavicle be clipped from image?
yes
sufficient external rotation of AP shoulder (external rotation) evidenced by…
-greater tubercle visualized in full profile on the lateral aspect of the proximal humeral
-lesser tubercle superimposed over humeral head
where is the CR centered for an AP shoulder (external rotation)?
1 inch inferior to coracoid process
where is the CR centered for an AP shoulder (internal rotation)?
1 inch inferior to coracoid process
sufficient internal rotation of AP shoulder (internal rotation) evidenced by…
-lesser tubercle visualized in full profile on the medial aspect of humeral head
-outline of greater tubercle should be visualized superimposed over humeral head
how would you position a patient for an AP shoulder (external rotation)?
-position patient to center scapulohumeral joint to center of IR
-abduct extended arm slightly, externally rotate arm (supinate hand) until epicondyles of distal humerus are parallel to the IR
how would you position a patient for an AP shoulder (internal rotation)?
-position patient to center scapulohumeral joint to center of IR
-abduct extended arm slightly; internally rotate arm (pronate hand) until epicondyles of distal humerus are perpendicular to IR
where is the CR directed for a lawrence method x-ray?
Direct 25-30 degrees medially, centered horizontally to axilla and humeral head
how is a patient positioned for a lawrence method x-ray?
Patient supine, shoulder raised approx. 2 inches (place support under shoulder)
what is the orientation of the IR for an inferosuperior axial shoulder x-ray?
landscape
how do you know you have properly positioned a lawrence method shoulder?
lesser tubercle of humerus are seen in profile
corocoid process (not acromion) seen
how is the arm positioned for a lawrence method shoulder x-ray?
arm abducted 90 degrees from body
where is the CR centered for a Grashey method x-ray?
Scapulohumeral joint (approx. 2 inches inferior and 2 inches medial from the superolateral border of shoulder)
where is the scapulohumeral joint?
approx. 2 inches inferior and 2 inches medial from the superolateral border of shoulder
what anatomy is to be demonstrated in a Grashey method x-ray?
glenoid cavity seen in profile without humeral head superimposition
how many degrees should the patient be rotated for a Grashey method x-ray?
35-45 degrees toward affected side
what is the CR angle for AP Axial Clavicle
-asthenic patients require 25-30 degrees
-hypersthenic patients require 15-20 degrees
is the CR angled cephalad or caudal for a AP Axial Clavicle x-ray?
cephalad
what is the orientation of the IR for clavicle x-rays?
landscape
what are the respiration instructions for clavicle x-rays? why?
suspend at end of inhalation; helps to elevate clavicles
what is the anatomy to be demonstrated on a clavicle x-ray (both AP and AP axial)
entire clavicle, AC joint, SC joint, acromion process
which is the best projection for clavicles in terms of a radiation protection standpoint?
PA projection
is the PA projection for clavicles angled caudal or cephalad?
caudal (opposite of AP projection)
how would you position patient for an AP Scapula?
abduct arm 90 degrees and supinate hand (“salute”)
where is the CR centered for AP Scapula?
“mid-scapula”; 2 inches inferior to coracoid process (or to level of axilla) and approximately 2 inches medial from lateral border of patient
what gives the “Y” view of lateral scapula x-ray?
direct superimposition of lateral and vertebral (medial borders) of scapula
where is the CR centered for a lateral Scapula?
midvertebral border of scapula
which of the scapula borders is thicker? thinner?
thicker = lateral
thinner = medial/vertebral
how is the patient positioned in a lateral scapula x-ray? (Per textbook)
patient rotated 45-60 degrees; patient facing IR
AP Scapula breathing instructions
orthostatic breathing; exposure for minimum of 3 seconds
how do you know if a lateral scapula x-ray is overrotated?
thicker nearest thorax = too much rotation
how do you know if a lateral scapula x-ray is underrotated?
thinner nearest thorax = insufficient rotation
in a lateral scapula x-ray, where is the acromion process?
on the “outer”/lateral portion of the x-ray; coracoid is more medial
if a patient is rotated toward the affected shoulder in an AP clavicle x-ray, what will occur?
medial end of clavicle is drawn away from vertebral column
if a patient is rotated toward the unaffected shoulder in an AP clavicle x-ray, what will occur?
medial end of clavicle is drawn towards the vertebral column
where will the superior scapular angle be if a patient is tilted anteriorly for a clavicle x-ray?
superior angle will be above clavicle
where will the superior scapular angle be if a patient is tilted posteriorly for a clavicle x-ray?
superior angle will be below clavicle
an AC joints x-ray (can/cannot) be taken at either 40 inch or 72 inch SID
can
where is the CR directed in a unilateral AC joint study?
1 inch below affected AC joint
where is the CR directed in a bilateral AC joint study?
midpoint between AC joints, 1 inch above jugular notch
