CH. 5 Shoulder Girdle

Dislocation

Displacement of a bone from the joint space

Fracture

Disruption in the continuity of a bone

Osteoarthritis or degenerative joint disease

Form of arthritis marked by progressive cartilage deterioration in synovial joints and vertebrae

Shoulder Girdle

Formed by 2 bones: 1) Clavicle 2) Scapula The function of these bones is to connect the upper limb to the trunk.

Scapulohumeral Articulation

Scapulohumeral Articulation: Located between the glenoid cavity and the head of the humerus. It forms a synovial ball-and-socket joint, allowing movement in all directions. This joint is often referred to as the glenohumeral joint. Radiographically, we are concerned with the insertion points of the short rotator cuff muscles: the subscapular, supraspinatus, infraspinatus, and teres minor.

Metastasis

Transfer of a cancerous lesion from one area to another

SHOULDER JOINT// Superoinferior Axial Projection

*Technique:* *IR:* 10x12" CW. *SID:* 40" *Collimation:* *Marker:* *CR:* Angled 5 to 15 degrees through the shoulder joint and toward the elbow; a greater angle is required when the patient cannot extend the shoulder over the IR. *Patient Position:* Seated with IR in armpit and arm extended over the table. *Part Position:* Place IR at end of table and parallel with its long axis. Have the patient lean laterally over the IR until the shoulder joint is over the midpoint of the IR. Bring elbow to rest on table. Flex the patients elbow 90 degrees and place the hand in the prone position. Have the patient tilt head towards the unaffected shoulder. T obtain direct lateral positioning of the head of the humerus, adjust any anterior or posterior leaning of the body to place the humeral epicondyles in the verticle position. SHIELD. Suspend Respiration. *Structures Shown:* Shows the joint relationship of the proximal end of the humerus and the glenoid cavity. The AC articulation, the outer portion of the coracoid process and point of insertion of the subscapularis muscle and teres minor muscle are shown.

PROXIMAL HUMERUS: INTERTUBECULAR GROOVE// Tangential Projection/ Fisk Modification

*Technique:* 70kvp @ 4mas *IR:* 10x12" *SID:* 40" *Collimation:* 4x4" *Marker:* R or L depending on side of interest. *CR:* Angled 10 to 15 degrees posterior to the long axis of the humerus for the supine position. FISK: Perpendicular to IR. *Patient Position:* Place the patient supine, seated, or standing. Rotate head away from affected side. *Part Position:* When patient is supine: Locate intertubecular groove (in line with armpit). Place IR against superior surface of shoulder and immobilize the IR. Fisk Mod: Will create OID. Patient standing, flex elbow and lean forward to place posterior surface of forearm on table. The patient will hold the IR (put lead shield between arm and IR). Have patient lean forward to place verticle humerus at angle of 10-15 degrees. Suspend Respiration. *Structures Shown:* The tangential image profiles the intertubecular groove free from superimposition of the surrounding shoulder structures. Intertubecular groove should be in profile.

SHOULDER JOINT// Inferosuperior Axial/ Lawrence Method

*Technique:* 75kvp @ 5mAs *IR:* 10x12" *SID:* 40" *Collimation:* 10x12" *Marker:* R or L affected side. *CR:* CR is horizontal through the axilla to the region of the AC articulation. The degree of medial angulation of the central ray depends on the degree of abduction of the arm. Between 15 and 30 degrees. The greater the abduction, the greater the angle. *Patient Position:* Patient supine. Elevate head, shoulders, and elbow about 3 inches. *Part Position:* Abduct the arm of the affected side as much as possible. Keep the humerus in external rotation (palm supinated). Have patient turn head away from the side being examined so that the IR can be placed against the neck. Respiration: Suspend. SHIELD. *Structures Shown:* An inferosuperior axial image shows the proximal humerus, the scapulohumeral joints, the lateral portion of the corocoid process, and the AC articulation.

CLAVICLE// PA Axial Projection

*Technique:* 81 kvp @ 10 mas IR:* 10x12" CW. *SID:* 40" *Collimation:* 8x12" *Marker:* R or L side. *CR:* Directed to enter midshaft of clavicle. Caudal central ray angulation can vary from the long axis of the torso; thinner patients require more angulation to project clavicle off of ribs. 15 degree angulation caudal. For supine 15 to 30 degree angulation is recommended. *Patient Position:* Standing or supine. *Part Position:* Standing: have patient upright against grid. Center clavicle to center of IR. Supine: Center IR to clavicle. SHIELD. Suspend on Full Inspiration. *Structures Shown:* Clavicle projected above the ribs. Most of the clavicle is projected above the ribs and scapula with the medial end overlapping the first or second rib. Clavicle in horizontal placement.

CLAVICLE// AP Projection

*Technique:* 81 kvp @ 10mas *IR:* 10x12" *SID:* 40" *Collimation:* 8x12" *Marker:* R or L side. *CR:* Perpendicular to the midshaft of the clavicle. *Patient Position:* Supine or upright. If clavicle is being examined for fracture or destructive disease, place patient supine to reduce possibility of further injury. *Part Position:* Adjust body to center the clavicle to the midline of grid. Place arms at sides and shoulders in same plane. Center clavicle to IR. SHIELD. Suspend Respiration. *Structures Shown:* Frontal image of clavicle. Entire clavicle centered to grid. Lateral half of the clavicle above the scapula, with medial half superimposing the thorax.

CLAVICLE// AP Axial/ Lordotic Position

*Technique:* 81 kvp @ 10mas *IR:* 10x12" CW. *SID:* 40" *Collimation:* 8x12" *Marker:* R or L side. *CR:* Directed to enter midshaft of clavicle. Cephalic central ray angulation can vary from the long axis of the torso; thinner patients require more angulation to project clavicle off of ribs. 15 degree angulation cephalic. For supine 15 to 30 degree angulation is recommended. *Patient Position:* Standing or supine. Stepping 1 foot out from the board, lean shoulders back and in contact with grid. *Part Position:* Standing lordotic: Have the patient lean backward until in extreme lordosis, the neck and shoulders should rest on the grid. Center clavicle to center of IR. Supine: Center IR to clavicle. SHIELD. Suspend on Full Inspiration. *Structures Shown:* Clavicle projected above the ribs. Most of the clavicle is projected above the ribs and scapula with the medial end overlapping the first or second rib. Clavicle in horizontal placement.

ACROMIOCLAVICAL ARTICULATIONS// AP Projection/ Bilateral Position (Pearson Method)

*Technique:* 81 kvp @ 11mas *IR:* 14x17" CW for bilateral, 10x12" for unilateral. *SID:* 72" for bilateral. 40" for unilateral. *Collimation:* 6x17" for bilateral. 6x8 for unilateral. *Marker:* R or L side. *CR:* Perpendicular to the midline of the body at the level of the AC joints. Directed at specific AC joint if unilateral. *Patient Position:* Upright. *Part Position:* Midpoint of IR aligned with AC joints (at shoulder slope). Shoulders should lie in same plane. First without weights, second exposure with 5-10 pound weights attached to wrists. This shows separation of AC joints. SHIELD. Suspend Respiration. *Structures Shown:* This projection is used to show dislocation, separation, and function of the joints. AC joints should be visualized with some soft tissue. Both AC joints included for bilateral. No rotation. AC joint separation, if present, is clearly seen on images with weights.

CLAVICLE// PA Projection

*Technique:* 81kvp @ 10mas *IR:* 10x12" CW. *SID:* 40" *Collimation:* 8x12" *Marker:* R or L side. *CR:* Perpendicular to the midshaft of the clavicle. *Patient Position:* Upright with back to xray tube or prone. *Part Position:* Center clavicle to midline of grid. Place arms at sides. Center clavicle to IR. SHIELD. Suspend Respiration. *Structures Shown:* Frontal image of the clavicle, however, clavicle is closer to IR to reduce OID. SAME AS AP, JUST TURNED AROUND.

SHOULDER// AP Projection/ External Rotation Humerus

*Technique:* 85 kVp @ 10 mAs *IR:* 10x12" CW *SID:* 40" *Collimation:* 10x12" *Marker:* R or L side *CR:* Perpendicular to a point 1 inch inferior to the coracoid process, which can be palpated inferior to the clavicle and medial to the humeral head. (ARMPIT & INFERIOR ANGLE OF SCAPULA) *Patient Position:* Supinate the hand and adjusting the epicondyles parallel to the plane of the IR. Abduct the arm slightly. *Part Position:* In center of grid. shoulder relaxed, hand supinated, arm abducted. Suspend Respiration. SHIELD. *Structures Shown:* Greater tubercle of the humerus and the site of insertion.

SHOULDER// AP Projection/ Internal Rotation

*Technique:* 85 kVp at 10 mAs *IR:* 10x12" CW *SID:* 40" *Collimation:* 10x12" *Marker:* R or L side *CR:* Perpendicular to a point 1 inch inferior to the coracoid process, which can be palpated inferior to the clavicle and medial to the humeral head. (ARMPIT & INFERIOR ANGLE OF SCAPULA) *Patient Position:* Ask patient to flex elbow, rotate the arm internally and rest the back of the hand on the hip. Adjust arm to place the epicondyles perpendicular to the IR. (HAVE PATIENT BRING ARM OUT AND REST HAND ON STOMACH) *Part Position:* Center of shoulder joint should be in the center of the grid. Suspend Respiration. SHIELD. *Structures Shown:* The proximal humerus is seen in a true lateral position. When the arm can be abducted enough to clear the lesser tubercle of the head of the scapula, a profile image of the site of insertion of the subscapular tendon is seen.

SCAPULA// AP Projection

*Technique:* 85 kvp @ 11 mas *IR:* 10x12" *SID:* 40" *Collimation:*10x12" *Marker:* R or L side. *CR:* Perpendicular to the midscapular area at a point 2 inches inferior to the coracoid process. *Patient Position:* Upright or supine. *Part Position:* Adjust patients body and center affected scapula to midline of grid. Abduct the arm to a right angle with body to draw the scapula laterally. Flex elbow and support the hand in a comfortable position. For this projection, do not rotate the body towards the affected side. Position top of IR 2 inches above the top of the shoulder. SHIELD. Slow and shallow breaths. *Structures Shown:* Lateral portion of the scapula free of superimposition from the ribs. Scapula horizontal and not slanted. Acromion and inferior angle. Scapular detail shown through superimposed lungs and ribs.

SCAPULA// Lateral Projection/ RAO or LAO Position

*Technique:* 85 kvp @ 14 mas *IR:* 10x12" LW *SID:* 40" *Collimation:* 10x12" *Marker:* R or L side. *CR:* Perpendicular to midmedial border of the protruding scapula. *Patient Position:* Upright, standing, or seated. Facing grid. *Part Position:* RAO or LAO for affected side to be against grid. 45 degree angle. To display acromion and coracoid process: have patient flex elbow and place the hand on the posterior thorax and prevent the humerus from overlapping the scapula. To show body of scapula: ask the patient to extend arm upward and rest the forearm on the head across the upper chest by grasping the opposite shoulder. Place body of scapula perpendicular to plane of IR. Do this by grasping the medial and lateral borders of the scapula between your index finger and thumb and rotate patient accordingly. SHIELD. Suspend Respiration. *Structures Shown:* A lateral image of the scapula is shown. Placement of arm determines the portion of the superior scapula that is superimposed on the humerus. Lateral and medial borders of the scapula are superimposed. No superimposition of the scapular body on the ribs. No superimposition of the humerus over the area of interest. Inclusion of the acromion and inferior angle.

SHOULDER JOINT// Scapular Y/ PA OBLIQUE PROJECTION/ RAO or LAO Position

*Technique:* 85 kvp @ 18 mas *IR:* 10x12" *SID:* 40" LW *Collimation:* 10x12" *Marker:* Over side down R or L *CR:* Perpendicular to the scapulohumeral joint. (ARMPIT & INFERIOR ANGLE OF SCAPULA) *Patient Position:* Upright or recumbent. *Part Position:* Position shoulder being examined against board. Oblique patient 45 degrees. Arm position does not matter. SHIELD. Suspend Respiration. *Structures Shown:* Humeral head and glenoid cavity superimposed. Acromion projected laterally and free of superimposition. Scapula in lateral profile.

GLENOID CAVITY// AP Oblique Projection/ RPO or LPO Position (Grashey Method)

*Technique:* 85kvp @ 10 or 18 mas? *IR:* 10x12" *SID:* 40" *Collimation:* 10x12" *Marker:* R or L side (mark for side down) *CR:* Perpendicular to the IR; should be at a point 2 inches medial and 2 inches inferior to the superolateral border of the shoulder. *Patient Position:* Patient upright or supine. *Part Position:* Center the IR to the scapulohumeral joint. The joint is 2 inches medial and 2 inches inferior to the superolateral border of the shoulder. Rotate body approximately 45 degrees towards the affected side. Scapula should be parallel to IR. Abduct arm slightly in internal rotation and place the palm of hand on abdomen. Suspend Respiration. SHIELD. *Structures Shown:* The joint space between the humeral head and the glenoid cavity (scapulohumeral or glenohumeral joint) is shown.

SHOULDER// AP Projection/ Neutral Rotation

*Technique:* 85kvp @ 10mAs *IR:* 10x12" CW *SID:* 40" *Collimation:* 10x12" *Marker:* R or L side. *CR:* Perpendicular to a point 1 inch inferior to the coracoid process, which can be palpated inferior to the clavicle and medial to the humeral head. (ARMPIT & INFERIOR ANGLE OF SCAPULA) *Patient Position:* Ask patient to rest hand against thigh. This position rolls the humerus slightly internal into a neutral position, placing the epicondyles at an angle of about 45 degrees with the plane of the IR. *Part Position:* Shoulder joint should be at center of grid. Suspend Respiration. SHIELD. *Structures Shown:* The posterior part of the supraspinatus tendon are visualized.

Shoulder Girdle Articulations

3 Articulations: 1) Scapulohumeral Articulation 2) Acromioclavicular Articulation 3) Sternoclavicular Articulation

Clavicle

A long bone with a body and two articular extremities. The clavicle lies in a horizontal oblique plane just above the first rib and forms the anterior part of the shoulder girdle. The lateral aspect is termed the acromial extremity. The medial aspect is termed the sternal extremity, and articulates with the manubrium and the first costal cartilage. Serves as a fulcrum for movement. Curvature is more acute in males than females.

Bursae

Bursae are small, synovial fluid-filled sacs that relieve pressure and reduce friction in tissue. They are often found between the bones and the skin, and they allow the skin to move easily when the joint is moved. Bursae are found also between bones and ligaments, muscles, or tendons. One of the largest bursae of the shoulder is the subacromial bursa. It is located underneath the acromion and lies between the deltoid muscle and the shoulder joint capsule. The subacromial bursa does not normally communicate with the joint. Other bursae of the shoulder are found superior to the acromion between the coracoid process and the joint capsule, and between the capsule and the tendon of the subscapular muscle. Bursae become important radiographically when injury or age cause the deposition of calcium.

Rheumatoid Arthritis

Chronic, systemic, inflammatory collagen disease

Scapula

Classified as a flat bone. Forms posterior aspect of shoulder girdle. Triangular in shape. Has 2 surfaces, 3 borders, and 3 angles. Lies between the second and seventh ribs. Medial border runs parallel to the spine. The flat aspect lies about 45 to 60 degrees angled in relation to anatomic position. The teres minor muscle arises from the superior two thirds of the lateral border of the dorsal surface, and the teres major from the distal third and the inferior angle. The dorsal surface of the medial border affords attachment of the levator muscles of the scapulae, greater rhomboid, and lesser rhomboid muscles. The superior border extends from the superior angle to the coracoid process and at its lateral end has a deep depression called the scapular notch. The medial border extends from the superior to the inferior angles. The lateral border extends from the glenoid cavity to the inferior angle. The superior angle is formed by the junction of the superior and medial borders. The inferior angle is formed by the junction of the medial and lateral borders and lies over the seventh rib. The lateral angle, the thickest part of the body of the scapula, ends in a shallow oval depression called the glenoid cavity. The constricted region around the glenoid cavity is called the neck of the scapula. The coracoid process arises from the scapular notch to the superior portion of the neck of the scapula. The coracoid process can be palpated just distal and slightly medial to the acromioclavicular articulation. The acromion, coracoid process, superior angle, and inferior angle are common positioning landmarks for the shoulder.

Hill-Sachs defect

Impacted fracture of posterolateral aspect of the humeral head with dislocation

Osteopetrosis

Increased density of atypically soft bone

Bursitis

Inflammation of the bursa

Tendinitis

Inflammation of the tendon and tendon-muscle attachment

Chondrosarcoma

Malignant tumor arising from cartilage cells

Tumor

New tissue growth where cell proliferation is uncontrolled

Acromioclavicular Articulation

The AC articulation between the acromion of the scapula and the acromial extremity of the clavicle forms a synovial gliding joint. It permits gliding and rotary (elevation, depression, retraction and protraction) movement. Because the end of the clavicle rides higher than the adjacent surface of the acromion, the slope of the surfaces tend to favor displacement of the acromion downward under the clavicle.

Sternoclavicular Articulation

The SC articulation is formed by the sternal extremity of the clavicle with two bones: the manubrium and the first rib cartilage. The union of the clavicle with the manubrium of the sternum is the only bony union between the upper limb and trunk. This articulation is a synovial double gliding joint. The joint is adapted by a fibrocartilaginous disk, however, to provide movements similar to a ball and socket joint: circumduction, elevation, depression, foreward and backward. The clavicle carries the scapula with it through movement.

Anterior Scapula

The costal (anterior) surface of the scapula is slightly concave and contains the subscapular fossa. It is filled almost entirely by the attachment of the subscapularis muscle. The anterior serratus muscle attaches to the medial border of the costal surface from the superior angle to the inferior angle.

Dorsal Scapula

The dorsal (posterior) surface is divided into two portions by a prominent spinous process. The crest of the spine arises at the superior third of the medial border from a smooth, triangular area and runs obliquely superior to end in a flattened ovoid projection called the acromion. The area above the spine of the scapula is called the spinous fossa and gives origin to the supraspinatus muscle. The infraspinatus muscle arises from the portion below the spine, which is called the infraspinatus fossa.

Humerus

The proximal end of the humerus consists of a head, an anatomic neck, two prominent processes called the greater and lesser tubercle, and the surgical neck. The head is large, smooth, and rounded, and it lies in an oblique plane on the superomedial side of the humerus. Just below the head, lying in the same oblique plane, is the narrow, constricted anatomic neck, which is the site of many fractures. The lesser tubercle is situated on the anterior surface of the bone, immediately below the anatomic neck. The tendon of the subscapular muscle inserts at the lesser tubercle. The greater tubercle is located on the lateral surface of the bone, just below the anatomic neck, and is seperated from the lesser tubercle by the intertubecular (bicepital) groove. The superior surface of the greater tubercle slopes posteriorly at an angle of 25 degrees and has three flattened impressions for muscle insertion. The anterior impression is the highest of the three and affords attachment to the tendon of the supraspinatus muscle. The middle impression is the point of insertion of the infraspinatus muscle. The tendon of the upper fibers of the teres minor muscle inserts at the posterior impression (the lower fibers insert into the body of the bone immediately below this point).

SHOULDER// Transthoracic Lateral Projection/ R or L Position (Lawrence Method)

Used for trauma and the arm cannot be rotated or abducted because of injury. *Technique:* 85kvp at 56 mas *IR:* 10x12" *SID:* 40" *Collimation:* 10x12" *Marker:* R or L side *CR:* Perpendicular to IR; entering MCP at level of surgical neck. IF the patient cannot move unaffected arm, angle CR 15 degrees cephalad. *Patient Position:* Upright or supine. *Part Position:* Have patient rest noninjured arm on the head and elevate noninjured shoulder. Elevation of noninjured shoulder drops injured shoulder, to prevent superimposition. Ensure that the midcoronal plane is perpendicular to IR. Center at surgical neck of injured arm. Respiration: Suspend. SHIELD. *Structures Shown:* A lateral image of the shoulder and proximal humerus is projected through the thorax.

Osteoporosis

loss of bone density