muscle anatomy Flashcards
Levator scapula origin
posterior tubercle of transverse process of C1-4
Levator scapula insertion
vertebral margin of scap. between the superior angle and root of scap spine
Levator scapula action
- elevates and rotates scapula,
- extends neck with trapezius,
- lateral flexion of neck
levator scapula innervation
cervical nerve (C3-C4) and dorsal scapular nerve (C5)
Trapezius origin
medial third of superior nuchal line, EOP, nuchal ligament, spices process of C7-T12
Trapezius insertion
lateral third of clavicle, acromion, and scap spine
Trapezius action
- elevates, retracts, and rotates scapula
- superior fibers elevate, middle retract, inferior depress scapula
- superior and inferior act together for superior rotation of scapula
Trapezius innervation
accessory nerve CN XI(motor), cervical nerves C3 and C4 (pain and proprioception
sternocleidomastoid origin
manubrium, medial clavicle
sternocleidomastoid insertion
mastoid process, superior nuchal line
sternocleidomastoid action
- lateral flexion off neck to same side,
- rotates head to opposite side
- bilaterally flexes neck , draws head ventrally and elevates chin”
sternocleidomastoid innervation
accessory nerume CN XI
pectoralis major origin
clavicular head - anterior surface of medial half of clavicle
sternocostal head- anterior surge of serum, superior six costal cartilages, aponeurosis of external oblique muscle
pectoralis major insertion
lateral lip of intertubercular groove of humerus
pectoralis major action
- adducts and medially rotates humerus,
- draws scapula anteriorly and inferiorly
- alone clavicular head flexes humerus and sternocostal head extends it
