What two bones make up the shoulder girdle proper?
- (humerus is a part of the shoulder girdle, but not the shoulder girdle proper)
What type of girdle is the shoulder girdle?
incomplete (open in the back)
Give the common name for the clavicle and list its three parts:
- collar bone
- acromial extremity (flattened, lateral end)
- sternal extremity (medial end)
Describe the differences in the female and male clavicle:
- male: stronger, thicker, more prominent double curve
- female: shorter, not as thick, double curve less pronounced
The thickest part of the scapula:
The most anterior part:
- coracoid process (positioning landmark)
How is the costal surface of the scapula shaped:
What part of the scapula lies against the rib cage and gives the scapula it's strength and concave shape?
Name 3 borders and 3 angles of the scapula:
- medial/vertebral border
- lateral/axillary border
- superior border
- superior angle
- lateral angle
- inferior angle
What starts at the posterior surface of the scapula and projects anteriorly to articulate with the clavicle?
acromion process (forming the AC joint)
- A. medial/vertebral border
- B. inferior angle
- C. lateral/axillary border
- D. glenoid cavity
- E. superior border
- F. superior angle
- G. acromion process
- H. coracoid process
The spine of the scapula separates the posterior surface into the _____________ and ____________.
- supraspinous fossa
- infraspinous fossa
What is the function of the the infraspinous and supraspinous fossas?
they both serve as muscle attachments for the infraspinous and supraspinous muscles
What does the head of the humerus articulate with to form the shoulder joint?
glenoid cavity or fossa
What is the most common reason for a Y view?
humeral head displacement
Anatomical names for the shoulder joint:
- scapulohumeral joint
- glenohumeral joint
What is the name of the deep cleft or depression that runs between the greater and lesser tubercles of the humerus?
intertubercular groove/ bicipital groove
Which tubercle of the humerus is located directly below the anatomic neck on the anterior surface?
Which tubercle of the humerus is located laterally?
What is the tapered area inferior to the head and tubercles of the humerus and what is the reason for its name?
- surgical neck
- because it is a site of frequent fractures requiring surgery
- A. greater tubercle
- B. intertubercular (bicipital) groove
- C. head
- D. anatomic neck
- E. lesser tubercle
- F. body (shaft)
The largest bursa where the most bursitis occurs, and where it is positioned:
- subacromial bursa
- under the acromion
Small, synovial-fluid filled sacs between the bones and skin:
What is the condition when the small, synovial-fluid filled sacs between the bones and skin become inflammed from calcium deposits rubbing and grinding?
bursitis (doesn't show up on xray unless very severe)
Name movements of a spheroidal (ball & socket) joint:
- medial (internal) rotation
- lateral (external) rotation
Name three classification descriptions of the shoulder joint:
- synovial (enclosed in an articular capsule with synovial fluid)
- diarthrodial (freely movable)
- spheroidal (ball and socket)
Name two joints of the shoulder girdle besides the shoulder joint:
- AC (acromioclavicular) Joints
- SC (sternoclavicular) Joints
What types of joints are the AC and SC joints?
diarthrodial, plane or gliding joints
What does the SC joint have that allows it to make movements similar to a ball and socket joint?
a fibrocartilaginous disk between the clavicle and the sternum
Name technique considerations for the shoulder joint:
- (if over 10cm) medium kVp, 70-80 with grid
- (if less than 10cm) 65-70 kVp, without grid
- center cell (for AEC)
- 40"SID except for AC joints (72"SID for less divergence)
Name alternate modalities that are used for the shoulder girdle (4)
- CT & MRI
- Nuclear Medicine
For positioning, how do you locate the coracoid process?
it is about 1" inferior to the lateral portion of the clavicle
- AP Shoulder, External Rotation
- (slight overlap of glenoid cavity)
- (greater tubercle visualized on lateral aspect, in profile)
- (lesser tubercle is superimposed over humeral head)
What are the breathing instructions for an AP shoulder projection?
- AP Shoulder, Neutral Rotation
- (both tubercles are mostly superimposed by humeral head)
- (humeral head in partial profile with slight overlap of glenoid cavity)
- (slightly more overlap of joint compared with external rotation)
- AP Shoulder, Internal Rotation
- (lesser tubercle visualized in full profile medially)
- (outline of greater tubercle superimposed over humeral head)
- (greater amount of overlap than in other two AP projections)
What are the breathing instruction for a transthorasic lateral projection of the shoulder?
- short, panting breaths
- long exposure time
- this blurs out the ribs and lung markings
- Transthorasic Lateral Shoulder
- (lateral view of proximal half of humerus and glenohumeral joint visualized)
- (relationship of humeral head and glenoid cavity demonstrated)
How should the CR be angled for the Inferosuperior Axial projection:
25-30 degrees medially
Name the projection and label:
- Inferosuperior Axial Projection
- A. lesser tubercle
- B. head
- C. coracoid process
- D. clavicle
- E. scapulo-humeral joint
- F. acromioclavicular joint
- G. Acromion
Name the two Shoulder projections that are named the Lawrence Method:
- Transthorasic Lateral Projection
- Inferosuperior Axial Projection
What specific pathologies are reasons to perform a West Point Method view of the the shoulder?
- Hill-Sachs defects
- Bankart fractures
What is a condition of the posterior lateral aspect of the humeral head that results in chronic instability of the shoulder?
What is a chip or fracture of the rim of the glenoid cavity?
Name some of the positioning aspects of the West Point Method (5):
- no grid
- 10x12 CW, 40"SID
- patient prone with forearm hanging freely from table
- shoulder elevated 3 " from tabletop, head rotated away
- CR angled 25 degrees anterior & 25 degrees medial
How should the scapula be positioned in reference to the IR for the Scapular Y lateral projection?
scapula should be perpendicular to IR
What type of projection is the Scapular Y lateral view?
PA oblique projection
- PA Oblique shoulder projection (Scapular Y Lateral)
- (lateral position of scapula, humerus, and joint)
- (Body of scapula with no rib superimposition)
- (acromion and coracoid process nearly symmetrical upper limbs of the Y)
Name some pathologies demonstrated by the Grashay Method (AP oblique projection):
- fractures and dislocations of the proximal humerus
- fractures of glenoid brim (Bankart fracture)
Where do you center the CR for the Grashey Method?
mid scapulohumeral joint
How do you center to the scapulohumeral joint for the Grashey Method?
it's 2 inches inferior and 2 inches medial to the border of the shoulder
- Grashey Method (AP Oblique projection)
- (no superimposition of humeral head and glenoid cavity)
- (joint space open)
- (soft tissue detail of joint space and axilla)
What is the tangential projection demonstrating the bicipital groove (intertubercular groove)?
the Fisk Method
What method is the AP projection of the AC joints?
What projections are made for the AC joints?
- 2 AP projections
- one with weights, one without weights
In projections of the AC joint, what usually indicates a joint separation?
A widening of one joint space as compared with the view with weights
Name some positioning aspects of the AC Joints:
- 72" SID for magnification
- CR centered approx. 1" superior to jugular notch
- use both markers
What are the two common projections of the clavicle?
Why do we use an AP projection of the clavicle instead of a PA projection which would give better recorded detail?
Patient comfort (pt condition usually requires AP projection)
How should the CR be angled for the AP axial projection of the clavicle?
15-30 degrees cephalic to mid-clavicle
What body habitus would require more angulation of the CR for the AP axial projection of the clavicle?
What are the breathing techniques for the clavicle projections?
- AP: expose on exhalation
- AP axial: expose on inhalation
What is an alternative to angling the CR for the AP axial projection of the clavicle?
- placing patient in a lordotic position
- (projection will project most of clavivle above scapula and ribs)
Name some aspects of positioning for the AP scapula:
- 10x12 LW, 40" SID
- arm abducted 90 degrees and supinate hand (external rotation)
- center CR to midscapula (2" inferior to coracoid process and 2" medial from lateral border)
- breathing technique if possible
For the Scapula Y view of the scapula, what is better visualized with the arm behind the back? across the anterior surface of the chest?
- behind back: acromion and coracoid process (requires closer to 60 degree oblique)
- across anterior surface of chest: body of the scapula (requires closer to a 45 degree oblique)