1 / 27

Understanding the Shoulder Joint: Bones, Movements, and Muscles

Learn about the anatomy and function of the shoulder joint, including the bones involved, movements possible, and the crucial muscles responsible for stability and motion. Understand the shoulder girdle and the role of connective tissues like the glenoid labrum and ligaments in joint stability.

salena
Download Presentation

Understanding the Shoulder Joint: Bones, Movements, and Muscles

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Shoulder Joint

  2. Bones of the shoulder joint • Scapula • Glenoid Fossa Infraspinatus fossa • Supraspinatus fossa Subscapular fossa • Spine Coracoid process • Acromion process • Clavicle • Humerus • Greater tubercle Lesser tubercle • Intertubercular goove Deltoid tuberosity • Head of Humerus

  3. Shoulder Joint • Bones: • humerus • scapula • clavicle • Articulation • glenohumeral joint • Glenoid fossa of the scapula (less curved) • head of the humerus • enarthrodial (ball and socket) Shoulder Girdle

  4. Shoulder Joint • Connective tissue • glenoid labrum: cartilaginous ring, surrounds glenoid fossa • increases contact area between head of humerus and glenoid fossa. • increases joint stability • Glenohumeral ligaments: reinforce the glenohumeral joint capsule • superior, middle, inferior (anterior side of joint) • coracohumeral ligament (superior) • Muscles play a crucial role in maintaining glenohumeral joint stability.

  5. Movements of the Shoulder Joint • Arm abduction, adduction about the shoulder • Arm flexion, extension • Arm hyperflexion, hyperextension • Arm horizontal adduction (flexion) • Arm horizontal abduction (extension) • Arm external and internal rotation • medial and lateral rotation • Arm circumduction • flexion, abduction, extension, hyperextension, adduction

  6. Shoulder Joint abduction adduction flexion extension internal rotation external rotation horizontal abduction horizontal adduction Shoulder Girdle upward rotation downward rotation elevation/upward rot. Depression/downward rot. Abduction (protraction) adduction (retraction) adduction (retraction) abduction (protraction) Scapulohumeral rhythm

  7. Understanding Scapula Movements • Functions of movements: • Stabilize scapula when shoulder complex is loaded/moving • allows for different axes of rotation and lengths of muscles (which is related to force generating capability) • Positioning scapula to facilitate movement of glenohumeral joint by changing orientation of glenoid fossa.

  8. Muscles of the Shoulder Joint • Organization • anterior, posterior, superior, inferior • rotator cuff muscles • Origins and insertions • Organization • adductors, abductors, flexors, extensors …

  9. Muscles of the Shoulder Joint • Anterior • pectoralis major • coracobrachialis • subscapularis • biceps brachii

  10. Muscles of the Shoulder Joint • Posterior • infraspinatus • teres minor • latissimus dorsi • teres major • triceps brachii, long head • Superior • deltoid • supraspinatus

  11. Rotator Cuff muscles • Rotator Cuff: provides stability • Supraspinatus • infraspinatus • teres minor • subscapularis • Note: there is an inherent lack of inferior stability of the shoulder joint.

  12. Muscles of the Shoulder Joint • Origin • Insertion • Actions • Palpation

  13. Deltoid Musclep119-121 • Origin: • anterior fibers: anterior lateral third of the clavicle • middle fibers: acromion process • posterior fibers: inferior edge of the scapular spine • Insertion: • deltoid tuberosity on the lateral humerus

  14. Deltoid Muscle(deltoid: triangular) • Action • anterior: abduction, flexion, internal rotation, horizontal adduction • middle: abduction • posterior: abduction, outward rotation, extension, horizontal abduction

  15. Coracobrachialis Muscle (p118) • Origin • coracoid process of the scapula • Insertion • Middle 1/3 of the medial surface of the humerus • Action • horizontal adduction, flexion, adduction

  16. Supraspinatus Muscle (p126) • Origin • supraspinatus fossa • Insertion • Superiorly on the greater tubercle of the humerus • Action • abduction

  17. Infraspinatus Muscle (p122) • Origin • infraspinatus fossa of the scapula • Insertion • Superior/lateral surface of the greater tubercle of the humerus • Action • outward rotation, horizontal abduction, adduction, abduction

  18. Teres Minor Muscle (p128)(teres: rounded) • Origin • Upper 2/3 of axillary border of the scapula • Insertion • Posterior surface of greater tubercle of the humerus • Action • Outward rotation, extension, adduction, horizontal abduction

  19. Subscapularis Muscle (p125) • Origin • subscapular fossa • Insertion • lesser tubercle of the humerus • Action • inward rotation, extension

  20. Teres Major Muscle (p127) • Origin • Lower 1/3 of the axillary border of the scapula/inferior angle of scapula • Insertion • crest of lesser tuberosity of humerus • Action • extension, adduction, inward rotation

  21. Latissimus Dorsi Muscle (p123)(latissimus: widest) • Origin • Spines of lower 6 thoracic and lumbar vertebrae • Posterior surface of sacrum • Posterior aspect of crest of illium • Lower 3-4 ribs • Inferior angle of scapula • Insertion • intertubercle groove of humerus • Action • extension, adduction, inward rotation, horizontal adduction

  22. Pectoralis Major Muscle (p124) • Origin • upper fibers (clavicuolar head) • medial half of anterior surface of clavicle • lower fibers (sternal head) • anterior surface of costal cartilage of first six ribs, adjacent portion of sternum • Insertion • Crest of the greater tuberosity of the humerus • tendon “twists” such that lower fibers insert superior to upper fibers

  23. Pectoralis Major Muscle • Action • horizontal adduction • flexion • inward rotation • adduction

  24. Summary of Muscles • Deltoid (anterior, middle, posterior) • Coracobrachialis • Supraspinatus • Infraspinatus • Teres minor • subscapularis • teres major • Latissimus dorsi* • Pectoralis major * (upper and lower) • *do not originate on the scapula

  25. Summary: Shoulder Joint • Bones: Humerus, Scapula (Glenoid Fossa) • glenohumeral joint • Muscles • Rotator Cuff • supraspinatus, infraspinatus, teres minor, subscapularis • deltoid, coracobrachialis, teres major, latissimus dorsi, pectoralis major • Stability is sacrificed for flexibility • ligaments: glenoid labrum, Glenohumeral ligaments, coracohumeral

  26. Summary of actions • Flexors • pectoralis major, anterior deltoid, coracobrachialis • Extensors • Posterior deltoid, latissimus dorsi, teres major, teres minor subscapularis • Abductors • Anterior and middle deltoid, supraspinatus • Adductors • latissimus dorsi, teres major, teres minor

  27. Summary of Actions (cont) • Inward rotators • subscapularis, pectoralis major, latissimus dorsi, anterior deltoid • Outward rotators • Teres minor, infraspinatus, posterior deltoid

More Related