Posterior Shoulder Muscles Flashcards
Trapezius Origin
Medial third of superior nuchal line; external occipital protuberance; nuchal ligament; spinous processes of C7-T12 vertebrae
Trapezius Insertion
Lateral third of clavicle; acromion and spine of scapula
Trapezius Innervation
Spinal accessory nerve (CN XI) (motor fibers) and C3, C4 spinal nerves (pain and proprioceptive fibers)
Trapezius Action
Descending part elevates; ascending part depresses; and middle part(or all parts together) retracts scapula; descending and ascending parts act together to rotate glenoid cavity superiorly
Trapezius Roots
C3,C4
Latissimus Dorsi Origin
Spinous processes of the inferior 6 thoracic vertebrae, thoracolumbar fascia, iliac crest, and inferior 3 or 4 ribs
Latissimus Dorsi Insertion
Floor of intertubercular sulcus of humerus
Latissimus Dorsi Innervation
Thoracodorsal nerve (C6, C7, C8)
Latissimus Dorsi Action
Extends, adducts, and medially rotates humerus; raises body toward arms during climbing
Latissimus Dorsi Roots
C6, C7, C8
Rhomboid Minor & Major Origin
Minor: nuchal ligament; spinous processes of C7 and T1 vertebrae
Rhomboid Minor & Major Insertion
Minor: smooth triangular area at medial and scapular spine
Rhomboid Minor & Major Innervation
Dorsal scapular nerve (C4, C5)
Rhomboid Minor & Major Action
Retract scapula and rotate it to depress glenoid cavity; fix scapula to thoracic wall
Rhomboid Minor & Major Root
C4, C5
Levator Scapulae Origin
Posterior tubercles of transverse processes of C1-C4 vertebrae
Levator Scapulae Insertion
Medial border of scapula superior to root of scapular spine
Levator Scapulae Innervation
Dorsal scapular (C5) and cervical (C3, C4) nerves
Levator Scapulae Action
Elevates scapula and tilts its glenoid inferiorly by rotating scapula
Serratus Anterior Origin
External surfaces of lateral parts of 1st-8th ribs
Serratus Anterior Insertion
Anterior surface of medial border of scapula
Serratus Anterior Innervation
Long thoracic nerve (C5,C6,C7)
Serratus Anterior Action
Protracts scapula and holds it against thoracic wall; rotates scapula
Serratus Anterior Root
C5,C6,C7
Infraspinatus Origin
Infraspinous fossa of scapula
Infraspinatus Insertion
Middle facet of greater tubercle of humerus