E-Book, Englisch, 180 Seiten, ePub
ISBN: 978-3-13-257818-0
Verlag: Thieme
Format: EPUB
Kopierschutz: 6 - ePub Watermark
A concise and clearly organized representation of contents in this text allows quick orientation and assimilation of the most important aspects of shoulder imaging.
Zielgruppe
Ärzte
Autoren/Hrsg.
Fachgebiete
- Medizin | Veterinärmedizin Medizin | Public Health | Pharmazie | Zahnmedizin Chirurgie Orthopädie- und Unfallchirurgie
- Medizin | Veterinärmedizin Medizin | Public Health | Pharmazie | Zahnmedizin Medizinische Fachgebiete Bildgebende Verfahren, Nuklearmedizin, Strahlentherapie Radiologie, Bildgebende Verfahren
Weitere Infos & Material
1 Anatomy and Imaging of the Shoulder Joint
2 Traumatology
3 Degenerative Changes
4 Inflammatory Conditions
5 Tumors and Tumor-Like Lesions
6 Hormonal and Metabolic Bone Diseases
7 Ischemic Changes
8 Hematological Diseases
9 Neurogenic and Metabolic Bone Diseases
10 Pediatric Radiology
J. Rudolph and J. Mäurer 1 Anatomy and Imaging of the Shoulder Joint Macroscopic Functional Anatomy The head and the glenoid fossa articulate in the shoulder joint (glenohumeral joint). Functionally, it is a ball-and-socket joint that enables movement in three degrees of freedom. The shoulder is the most mobile of the major joints. Its high mobility, together with its limited osseous embracement accounts for its high rate of injury. Osseous Structures Humerus Articular surface of the humeral head covered hemispherically with hyaline cartilage Rotation of the humeral head around a central point in the depth of the head Important markers of the proximal humerus: major and minor tuberosities as well as bicipital groove Anatomical neck: Transition of the proximal humerus to the humeral head Surgical neck: Frequent fracture site Scapula Gliding and rotation of the scapula on the thoracic surface with arm movement The glenoid fossa is perpendicular to the body of the scapula The osseous glenoid fossa is markedly smaller than the humeral head (ratio about 1:4) According to Bigliani (1982), three different acromial types can be observed in the coronal plane: – Type I: Flat acromion – Type II: Curved acromion – Type III: Hooked acromion with inferior nose Clavicle Flat, sinuous, bridging the upper ribs Medial articulation with the sternum at the sternoclavicular joint (SC joint) Lateral connection with scapula with the acromioclavicular joint (AC joint) Soft Tissues Glenoid Labrum Since the incongruent osseous articular surfaces alone cannot provide structural and functional integrity of the shoulder joint, it is largely stabilized by the glenoid labrum. Circular enlargement of the articular surface Fibrous cuff of fibrocartilage reinforcing the joint capsule Vascular supply through capsular vessels “Transitional zone” (hyaline cartilage) between labrum and osseous glenoid fossa Four labrum segments: anterosuperior and posterosuperior, as well as anteroinferior and posteroinferior quadrants Surgical localization of the labral lesions following the dial of the clock: right anterior positions 12 to 6 o'clock (left posterior positions 12 to 6 o'clock!) Numerous normal variants of the labrum (see Chapter 2, Traumatology) Fig. 1.1 Types of capsular insertion according to Moseley and Övergaard (1962). Diagram of the different insertions of the anterior capsule as seen on the axial plane (arrowheads). Bi Biceps tendon Hu Humerus Gle Glenoid process Capsuloligamentous System The capsuloligamentous system contributes relatively little to the static stability of the shoulder. The joint is further supported by an intra-articular negative pressure. Capsular insertion with fibrous and synovial component in the region of the osseous glenoid fossa Three glenohumeral ligaments (superior, medium, and inferior glenohumeral ligaments) to enforce the anterior capsule Wide variability of course, insertion, and caliber of the three ligaments The inferior ligament is most important for shoulder stability Variable anterior capsular insertion at the glenoid fossa; according to Moseley and Övergaard (1962), three capsular insertions can be distinguished in the axial plane (Fig. 1.1): – Type I: Insertion at the tip or basis of the anterior labrum – Type II: Insertion of the capsule not more than 1 cm medial to the labrum – Type III: Insertion of the capsule more than 1 cm medial to the labrum Type III should predispose to or be the result of anterior dislocation Musculature of the Rotator Cuff Since osseous and ligamentous support is inadequate, stability is achieved by soft tissues. Dynamic stability is primarily provided by the muscles of the rotator cuff together with the deltoid muscle. Four muscles: Anteriorly the subscapular muscle (origin at the minor tuberosity), posteriorly the supraspinatus muscle (origin at the major tuberosity), the infraspinatus muscle and the teres minor (origin at the major tuberosity) Fibrous “tendon cap” of the rotator cuff around the humeral head “Critical zone” within the tendon of the supraspinatus muscle (1–1.5 cm proximal to its origin) presumably predisposes to degeneration with subsequent rupture Additional stabilization of the joint provided by muscular compression through pull of the rotator cuff Bursae of the Shoulder Joint Several bursae (fluid-containing sacs lined with synovial membrane) serve as gliding layers to facilitate free motion of the shoulder joint and partially communicate with the joint cavity. The subacromial bursa and subdeltoid bursa often communicate with each other, but usually not with the joint capsule (important for rotator-cuff tears!) The subtendinous bursa of the sub-scapular muscle and the subcoracoid bursa communicate with the joint anteriorly Normal bursae are not visualized by conventional radiology, only by ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) Conventional Radiology Standard Projections Like all other joints, the shoulder is first examined by obtaining a baseline study consisting of two views perpendicular to each other. Many special projections are available for different clinical questions (Table 1.1), but their diagnostic contribution has diminished following the introduction of CT and MRI. Table 1.1 Recommended radiographic projections of the shoulder joint (please refer to text for technical factors) Clinical question Projections Baseline AP view Axial view Degeneration AP view Axial view 90° abduction view Special impingement Schweden stage I–III View of the intertubercular groove Supraspinatus outlet view Rockwood view General trauma AP view Axial view Impaired mobility Transthoracic view Y-projection Velpeau view Dislocation AP view Axial view Special Bankart lesion West Point view Glenoid rim view according to Bernageau Apical oblique view Special Hill-Sachs defect AP view in 60° internal rotation Stryker view Hermodsson view AC joint AC joint view AP AC joint view AP with weight bearing Supraspinatus outlet view Rockwood view Anteroposterior View/Tangential View of the Glenoid Fossa Caution: The joint space is superimposed on the straight anteroposterior (AP) view! Indication Initial workup for suspected Fractures (location and extent, determination of fracture type, orientation of fracture lines, articular involvement, position of fracture fragments) Dislocations Inflammatory conditions Degenerative changes Neoplasms Technique Shoulder in contact with the cassett Patient sitting with the arm in neutral...
