CHP10TheMuscularSystem

Of musclesanterior pectoralis minor serratus anterior

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Unformatted text preview: (verts to ribs) & deep (verts to verts) superficial deep • Superficial group maintains posture, helps to straighten up after bending @ waist after • Deep group extends & rotates vertebral column 10 muscles to know (shoulder & back) ‘Scapula’ Muscles Scapula loosely attached to thoracic cage (= multidirectional) Scapula loosely Clavicle stabilizes shoulder & moderates movements Clavicle stabilizes Shoulder joint= humeroscapular joint Shoulder humeroscapular Muscles originate on axial skeleton & insert on clavicle &/or Muscles scapula scapula • 2 groups of musclesAnterior= pectoralis minor & serratus anterior Anterior pectoralis serratus Posterior= trapezius, levator scapulae, & Posterior trapezius levator rhomboideus major/minor Scapula muscles (cont.) Scapula Pectoralis minor= protracts & depresses scapula when ribs protracts fixed; elevates ribs when scapula fixed fixed; • Origin @ ribs 3-5, inserts on coracoid process Serratus anterior= holds scapula against rib cage; elevates holds ribs; forced depression of scapula; prime mover in throwing/pushing (boxer’s muscle) throwing/pushing • Origin @ ribs 1-9, inserts on medial border of scapula Origin Posterior group~ Posterior Trapezius= actions vary w/ contraction of superior, middle, & actions inferior fibers (triangular muscle) inferior • Stabilizes scapula & shoulder during arm movements; Stabilizes elevate/depresses shoulder apex; rotates & retracts scapula elevate/depresses • Recall head/neck actions as well • Origin @ external protuberance, superior nuchal line, nuchal Origin ligament, & spinous processes C7-T3 or T4 ligament, Scapula muscles (cont.) Scapula Levator scapulae= rotates scapula to tilt glenoid cavity down; rotates flexes neck; elevates scapula when acting w/ trap’s (heavy lifting above shoulders) lifting • Opposes upper trap’s when acting alone • Origin @ transverse processes of C1-4, inserts on superior Origin angle of medial border of scapula angle Rhomboideus major/minor= retract & elevate scapula; fixes retract scapula & rotates to tilt g.cavity down scapula • Origin @ spinous processes of vert’s, inserts on medial border of scapula inserts ‘Shoulder’ Muscles Muscles acting on humerus (Table 10.10) Muscles acting • 9 muscles originate on axial or clavicle/scapula & insert on muscles humerus humerus 2 axial muscles= pectoralis major & latissimus dorsi axial (antagonists) (antagonists) • Pectoralis major= prime mover of shoulder flexion; climbing, prime pushing, throwing pushing, • Origin @ clavicle/sternum/costal cartilages, inserts on Origin intertubercular groove intertubercular • Latissimus dorsi= extends shoulder jnt; strong downward extends stroke in hammering, ‘swimmer’s muscle’ stroke • Origin @ T7-L5, iliac crest, inferior angle of scapula, inserts on Origin intertubercular groove intertubercular 7 scapular muscles= deltoid, t...
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This note was uploaded on 01/12/2014 for the course ZOO 250 taught by Professor Staff during the Fall '08 term at S.E. Louisiana.

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