Objectives • Know the principal muscles of the scapular and scapulo-humeral regions. • Understand the mechanism of scapular rotation in relation with shoulder movements.
Surface Anatomy • Spine Acromion (of scapula Trapezius muscle Infraspinatus muscle Triangle of ascultation Teres minor muscle Teres major muscle
Anterior Scapula. -angles, borders -glenoid cavity, -acromion, -coracoid process, -Subscapular fossa Humerus. -Head, -Surgical neck -Anatomical neck -Greater tubercle -Lesser tubercle -Intertubercular (bicipital) groove acromion anatomical neck coracoid process Lesser tubercule Greater tubercule surgical neck bicipital groove glenoid cavity
Posterior Clavicle. Acromioclavicular joint Scapula. - Spine - Acromion - Supraspinous fossa - Infraspinous fossa Humerus. - Head - Anatomical neck, - Surgical neck, - Deltoid tuberosity - Spiral (radial) groove. Acromioclavicular joint Supraspinous Fossa anatomical neck surgical neck Spine Deltoid Tuberosity Infraspinous Fossa Radial Groove
Superior rotation of • Glenoid fossa: • Powerful muscles • pull on bony struts. Scapula rotates when we move our arms to allow more range of motion at the shoulder joint
Complete abduction at the shoulder joint requires superior rotation of the scapula so that the glenoid fossa faces superiorly. Glenoid fossa
Deltoid • Clavicular origin, acromial, and scapular origins, attach all to deltoid tuberosity • Anterior fibers flexes • Posterior fibers extends and laterally rotates • Middle fibers abducts the arm • Innervation C5,6 Axillary nerve Delta= Triangle Deltoid=triangular in shape Principal abductors= Deltoid, supraspinatus
Subdeltoid / Subacromial bursa. Deltoid Sub Acromial Bursa Subdeltoid Bursa Subscapularis Bursa: a closed sac or envelope, lined with synovium and containing fluid, usually in areas subject to friction.
Rotator cuff muscles stabilize the shoulder joint. Supraspinatus, Infraspinatus, Subscapularis, Teres minor Subscapularis Subscapularis Anterior view Supraspinatus Infraspinatus Superior view Teres Minor Posterior view
Rotator Cuff Muscles Because the scapula is triangular deep bone, padded with thick muscles, injuries leading to scapular fractures Will be so severe , and most commonly we will have lots of multiple, or serious other fractures
Transverse scapular ligament • Runs between Subscapular nerve (C5,6) and artery, which supply Supraspinatus and Infraspinatus muscles • Artery above, nerve below
Serratus Anterior Subscapularis Winged Scapula: (long thoracic nerve) "big swing muscle" or "boxer's muscle” Antagonist of Rhomboids Accessory muscle of respiration
Posterior view: - Trapezius - Latissimus Dorsi - Deltoid Trapezius Rhomboids Deltoid Rhomboids: - minor and major - retract / inferior rotate scapula Teres Major Latissimus Dorsi Teres major: - inserts near latissimus dorsi - adduct / medially rotate arm
Rhomboids retract, so injury to the dorsal scapular nerve will make the scapula further away from the midline on the affected side Posterior scapula