Humerus and Shoulder Anatomy & Positioning (PDF)

Humerus and Shoulder Humerus Anatomy - humerus is longest bone of upper extremity - Articulates w the scapula - Head most proximal...

Humerus and Shoulder Humerus Anatomy - humerus is longest bone of upper extremity - Articulates w the scapula - Head most proximal - Anatomic neck- slightly constricted area directly below and lateral to the head appears as line between head and greater and lesser tubercle - Lesser tubercle- the process directly below the anatomic neck on the anterior surface - Greater tubercle- larger, lateral, where pectoralis major and supraspinatus muscles attach - Intertubercle groove- the deep groove between tubercles - Surgical neck- the tapered area below head and tubercles - Shaft- below surgical neck A. Head of humerus B. Greater tubercle C. Intertubercular sulcus D. Lesser tubercle E. Anatomic neck F. Surgical neck G. Body/shaft A: external rotation A- greater B- lesser B: internal rotation A- greater B- lesser C: no rotation A- greater B- lesser Arthrology - diarthrodial “hinge” articulation - formed by 2 articulations o humeroradial (capitulum & radial head) o humeroulnar (trochlea & trochlear notch) Clinical indications - pain - history of pathology - trauma/injury pathologies - There is much overlap w shoulder and elbow pathologies - in addition: humeral shaft fracture Humerus Technical Considerations Pt. Prep - Pending patient attire, may not need to change - Check for necklace or other jewelry that may be in the way - If have patient change, gown with opening in the back. NO SNAPS! - May need to assist patient in changing Image Receptor § Image receptor for most adults is 14 x 17 § Most projections utilize the IR in the Portrait, Lengthwise position § Images should be taken with a grid in adults, can be done non-grid in pediatric patients pending size Shielding - ALL patients should be shielded from waist down. - If patient is lying down on table (because unable to be upright) use a larger shield to also cover chest below collimated field of interest Technical factors - SID = 40”  - kVp range = 80-85 with digital systems - Center Cell for AEC, if used - Close collimation - Correct Marker used - Breathing- suspended respiration o “Stop breathing, don’t breathe or move” Additional considerations § Always clear female patients for pregnancy § Note LMP and No Chance of pregnancy § Pending patients reason for needing images, adjust accordingly to not cause additional pain Humerus Positioning ´ AP ´ Lateral ´ Rotational ´ Horizontal Beam ´ Considerations ´ Long bone ´ Must include both joints AP Humerus - Pt. erect or supine - Extend hand and forearm as far as tolerable - Abduct arm slightly so that epicondyles are equal distance from IR - Center mid humerus - Include both joints - Rotate body if needed to get humerus in contact w IR Criteria - Entire humerus - Greater tubercle - Medial and lateral epicondyles  - Optimal exposure factors Lateral Humerus (rotational) - Pt. erect or supine - Lateromedial vs. mediolateral - Epicondyles perpendicular to IR - Center at midpoint to include both joints Lateromedial - Pt. erect w back to IR - Elbow partially flexed w body rotated toward adected side as needed - Internally rotate arm - Epicondyles perpendicular to IR Mediolateral - Face pt. toward IR and oblique as needed 20-30º from PA to bring humerus close to IR - Flex elbow 90º Criteria - Entire humerus - Lesser tubercle - Epicondyles superimposed Figure 2 mediolateral Figure 1 lateromedial Lateral Mid and Distal Humerus Trauma (horizontal beam) - Shield thorax and pelvis - Pat. Recumbent - Utilize horizontal beam - Flex elbow if possible - Do not rotate arm - CR to midpoint Criteria - Mid and distal humerus - Distal 2/3 humerus - 90º perspective from AP - Epicondyles superimposed Horizontal Beam Transthoracic Lateral Humerus Trauma - Entire humerus w/ out rotation - Unadected limb raised over head - CR to mid aspect to involve humerus o Can do spine if necessary o Can be done for entire humerus or proximal portion only Criteria - Lateral view of the entire humerus and shoulder joint - Optimal density - Shaft of humerus clearly visualized anterior to thoracic vertebrae Shoulder Anatomy - Shoulder girdle consists of clavicle and scapula - Function of clavicle and scapula is to connect each upper limb to the axial skeleton - Anteriorly connects at the SC joint to manubrium of sternum posteriorly connects to trunk by muscles only - Girdle and upper limb connect at the shoulder joint - Clavicle- long bone - Acromial extremity - Sternal extremity SC joint helps from jugular notch - Shaft - Female clavicle usually shorter an less curved than males Anterior Flat triangular bone with 3 borders 3 angles and 2 surfaces BORDERS 1. Medial – long edge near vertebrae 2. Superior – upper most margin 3. Lateral – border nearest the axilla ANGLES Lateral Angle – thickest part and ends laterally in the glenoid cavity Superior Angle upper end of medial border Lower Angle – lower end of medial border SURFACES Costal Surface – is anterior surface as name suggests proximity to ribs Mid area of surface has large depression called subscapular fossa Upper margin of scapula is at second posterior rib Lower margin at seventh posterior rib Posterior - Divided into two halves o Infraspinous fossa and Supraspinous fossa which both serve as surfaces for the attachment of muscles o Spine posterior border or ridge, starts at the vertebral border as a smooth triangular area and continues laterally to end at acromion o Crest of spine is the thickened posterior ridge of spine Lateral - Acromion expanded distal end of the spine that extends superiorly and posteriorly to the glenoid cavity - Coracoid is thick beak like process that projects anteriorly beneath the clavicle and in relationship to the glenoid cavity - All three joints are classified as synovial joints which are characterized by fibrous capsule that contains synovial fluid - Mobility type is freely movable or diarthrodial Types of movement of shoulder girdle joints - Scapulohumeral: spheroidal or ball and socket o Greater freedom of movement o Scapulo humeral articulation head of humerus and glenoid o spheroidal – flexion, extension, abduction, adduction, circumduction and medial and lateral rotation - Sternoclavicular: plane or gliding o limited amount of gliding motion in nearly every direction  - Acromioclavicular: plane or gliding o two types of movement gliding between end of clavicle and acromion o secondary rotary movement when scapula moves forward and backward with the clavicle Muscles of Rotator Cud - SITSS o Supraspinatus § Originates above the spine of the scapula and inserts on the greater tuberosity of the humerus § Abducts shoulder joint o Infraspinatus § Originates below spine of scapula, in infraspinatus fossa, inserts on the posterior aspect of greater tuberosity of humerus o Teres minor § Originates on lateral scapula border, inserts on inferior aspect of greater tuberosity of humerus, Externally rotates the shoulder joint o Subscapularis § Originates on the anterior surface of scapula, sit directly over the ribs, inserts on the lesser tuberosity of humerus, works to depress the head of the humerus allowing it to move freely in the glenohumeral joint during elevation of arm - Muscles work together to stabilize head of humerus in glenohumeral joint Positioning AP (external rotation) - Epicondyles of elbow parallel to IR a. Greater tubercle lateral in profile b. Lesser tubercle anterior - This represents a true AP projection in anatomic position - Intercondylar line parallel to image receptor Lateral (internal rotation) - Epicondyles of elbow perpendicular to IR a. Greater tubercle anterior b. Lesser tubercle medial in profile - Epicondyles perpendicular to IR - This is a lateral of the proximal humerus - Lesser tubercle seen in profile - Greater moves to anterior and medial aspect Oblique (neutral) - Epicondyles of elbow 45º to IR a. Greater tubercle not in profile b. Lesser tubercle anteriorly not in profile - Neutral used when rotation is not possible such as trauma - Epicondyles are in 45 degree angle to IR – palm of hand is facing inward. Pathologies/clinical indications š Bursitis vs. Tendonitis Bursitis - inflammation of the bursae or fluid filled sacs enclosing the joints. Generally involves the formation of calcification in associated tendons, causing pain and limitation of joint movement. ( AP and Lat Shoulder ) Most common joint to develop bursitis with repetitive motion being the most common cause Tendonitis - inflammatory condition of the tendon that usually results from a strain š Bankhart’s Lesion š Radiculopathy - - is a condition due to a compressed nerve in the spine that can cause pain, numbness, tingling, or weakness along the course of the nerve. - can occur in any part of the spine, but it is most common in the lower back (lumbar radiculopathy) and in the neck (cervical radiculopathy). š Hill- Sach’s Defect š Adhesive capsulitis š Dislocation š Thoracic Outlet Syndrome (TOS) š Osteoarthritis vs Rheumatoid Arthritis Hill- Sach’s vs. Bankhart’s Lesions Hill-Sach’s - Deformity of superior and posterior border of humeral head - Typically a result of impaction during dislocation - deformity of the superior and posterior border of the humeral head and is typically a result of impaction during dislocation - Seen on internal rotation Bankhart’s - Associated w shoulder dislocations and labrum tear at the inferior glenoid - Seen as a defect on the inferior portion of the glenoid - best demonstrated on the AP with External rotation…the book says diderently - It is associated with shoulder dislocations and labrum tear at the inferior glenoid, visually seen as a defect on the inferior portion of the glenoid - Seen on external *both associated w shoulder dislocations but adect diderent areas in shoulder girdle *both typically associated with Anterior shoulder dislocations Adhesive Capsulitis Aka frozen shoulder - Disability of joint caused by chronic inflammation in and around the joint - Characterized by pain and limited range of motion Dislocations - Traumatic removal of humeral head from the glenoid cavity o Shoulder will look visibly deformed, swollen o Pt. will have pain and inability to move - 95-97% of dislocations are anterior - 2-4% are posterior - 0.5% are inferiorly displaced Thoracic Outlet Syndrome (TOS) Aka supraspinatus outlet syndrome - Occurs when blood vessels or nerves in the space between your clavicle an first rib are compressed - Can cause pain in your shoulders and neck and numbness in your fingers - Common causes include physical trauma, repetitive injuries from sports related activities, anatomical defects - Requires positions / projections with caudal angles, to better visualize the subacromial space. - Can also be performed to demonstrate subacromial bursitis - Attempting to visualize “osteophytes” (spurs) extending from the inferior acromial surface Osteoarthritis vs Rheumatoid Arthritis Osteoarthritis - Aka dengenerative joint disease (DJD) - Non-inflammatory joint disease characterized by gradual deterioration of articular cartilage - Most common type of arthritis - Considered part of aging Rheumatoid - Chromic systemic disease - Characterized by inflammatory changes that occur throughout the connective tissues of body - RA occurs more frequently in women - Radiographically- loss of joint space, destruction of cortical bone and bony deformities *both require decrease in technical factors Technical considerations Pt. Prep š Patient should undress for the waist up š Examples: jewelry, artifacts on clothing (bra, hooks, buttons) š Gown should be worn with opening in the back š Prefer a gown that ties with no snaps on the shoulder sleeve as these create artifacts š You may need to assist patient in changing depending on reason for exam š Patients with Shoulder injuries are generally more comfortable in an upright position IR š Image receptor for most adults is 10 x 12 š Most projections utilize the IR in the horizontal (crosswise projection) š Images should be taken with a grid in adults, can be done non-grid in pediatric patients pending size Sheilding š ALL patients should be shielded from waist down. š If patient is lying down on table (because unable to be upright) use a larger shield to also cover chest below collimated field of interest Technical factors š SID = 40” š kVp range = 70-90 with digital systems š Center Cell for AEC, if used š Grid – preferred in adults and larger pediatric patients š Close collimation š Correct Marker used š Breathing- suspended respiration š “Stop breathing, don’t breathe or move” Additional considerations - Always clear female patients for pregnancy - Note LMP and No Chance of pregnancy - Pending patients reason for needing images, adjust accordingly to not cause additional pain Positioning Routine - AP w/ internal rotation - AP w/ external rotation Additional views - Posterior Oblique – Grashey - Posterior Oblique – Garth - “Y” view o AP, PA, AP w internal rotation š Pt positioned AP š Abduct slightly and Rotate upper extremity internal š Epicondyles are perpendicular š CR directed to 1” inferior to coracoid š 10x12 crosswise š Must include entire shoulder girdle from SC joint to lateral border of humerus š If didicult to feel coracoid, can approximate by moving 2” inferior to the lateral position of the AC joint which is often easier to palpate. š Average technique = 70-80 kVp š Done upright when possible š Can do recumbent Criteria š Lesser tubercle profiled medially š Scapulohumeral joint centered š Proximal humerus, scapula, clavicle and SC joint visualized š Optimal exposure factors AP w external rotation š Pt positioned AP š Rotate upper extremity Externally š Epicondyles are parallel ← Greate š CR directed to 1” inferior to coracoid Tuberc š 10x12 crosswise š Must include entire shoulder girdle Criteria š Greater tubercle profiled laterally š Scapulohumeral joint centered š Proximal humerus, scapula, clavicle and SC joint visualized š Optimal exposure factors Additional projections Posterior Oblique (grashey method) š AKA – AP Oblique, Glenoid Cavity š Patient is rotated 35-45 degrees toward adected side š More rotation may be necessary if patient is recumbent š CR 2” inferior and medial from superlateral border of humerus Criteria š Glenoid cavity profiled š Scapulohumeral joint centered š Optimal exposure factors Apical Oblique Axial (garth method) š Frequently referred to as a 45 / 45 š Position is same as AP Oblique, but CR is directed @ 45° caudal angle š IR is placed vertical/lengthwise š CR Scapulohumeral joint š 2” medial and 2” inferior to supralateral border of humerus Criteria - Humeral head, glenoid cavity, and neck free of superimposition - Scapulohumeral joint centered - Opens the subacromial space; elongates the humeral head & neck AND open glenohumeral joint - Optimal exposure factors Scapular “Y” view š Provides a Lateral of the shoulder to r/o anterior / posterior dislocations š Can be performed PA or AP pending patient scenario š PA with adected side towards IR š Oblique shoulder 30° - 45° towards IR š AP with adected side away from IR š Adected shoulder rotated 60° away from the IR š CR 2” below top of shoulder (approx. at proximal humerus) In the event of trauma, the PA scapular Y can be performed in the supine position. The AP “Y” would visualize all the same anatomy as the PA scapular “Y” but with increased magnification Criteria š Body of scapula superimposed on end š Acromion and coracoid processes in profile š Humeral head and glenoid cavity superimposed š Optimal exposure factors Figure 3 dislocated Apical AP Axial š Patient is positioned AP with arm in neutral position š Epicondyles 45 degrees š Use a 30° caudal angle to open the subacromial space š CR enters ½” above coracoid Criteria Arm in neutral Neither tubercle seen SC joint to proximal humerus and entire scapula seen Subacromial space visible Anterioinferior aspect of acromion is visible Optimal exposure factors Transthoracic Employed to demonstrate anterior/posterior dislocations or other fractures associated with the proximal humerus Employs an orthostatic (breathing) technique (min. 3 seconds) Increased kVp to penetrate thorax 85 +/- 5 kVp Patient supine or erect lateral position Side of interest against IR CR at Surgical neck Drop shoulder and elevate uninjured arm  If patient unable to drop shoulder angle 10-15º cephalic Last resort lateral due to heavy superimposition of thoracic structures. Considered a “last resort” lateral Criteria Lateral view of proximal humerus and scapulohumeral joint visualized through thorax Collimate to area of interest No superimposition of opposite shoulder Inferiosuperior Axial: Lawrence Method š Orthopedic’s choice for lateral š Patient Supine š Use radiolucent sponge to elevate adected shoulder š Arm is abducted 90° & externally rotated š Make sure arm is supported š CR directed 15°– 30 ° medially š If arm is not fully abducted to 90 degrees decrease angle š 8x10 IR placed gently against shoulder and neck Criteria š Lateral view of the proximal humerus in relation to the glenoid cavity š Coracoid process and lesser tubercle seen in profile š Spine of scapula seen on edge š Optimal Exposure š No Motion Inferosuperior Axial: Clements Modification š Modification made to patient’s position š Patient in lateral recumbent position, adected side up š All other criteria the same š If patient cannot abduct 90°, angle the tube 5-15° toward axilla Superioinferior axillary Done with patient seated Creates Object Image Distance (OID) leading to Magnification Utilize a 5-10 degree angle toward the distal humerus Done for ortho choice of lateral, Increased OID Utilize a 8-10 degree angle toward distal humerus Tangential projection = supraspinatus outlet: Neer Method š Patient is erect or recumbent š Patient is positioned same as routine PA Scapular “Y” š Anterior oblique 45-60 degrees š Abduct arm slightly to reduce superimposition of humerus š Use 10° - 15° caudal angle š CR centered posteriorly to pass through superior margin of humeral head (1” superior to medial aspect of scapular spine) š Collimate Criteria š Supraspinatus outlet / Coracoacromial arch (arrow) open and in profile š Humerus superimposed over body of scapula Routine Y view vs Neer method Figure 5 neer method Figure 4 CR Perpendicular Visual Appearance of pathological conditions Bankart’s lesion Best demonstrated on the AP with External rotation Hill-Sachs Defect Bankart’s vs Hill-Sachs Dislocation Thoracic Outlet Syndrome š Requires projections with Caudal angle š Projections for TOS: š Apical AP š Apical Oblique (Garth) š Neer Scapular “Y” š *Routine AP with Internal and External rotation with 10° Caudal angle š Really done to rule out osteophyte formation