Muscles of the Pectoral Girdle Flashcards
Where do the different fibres of Trapezius originate?
Upper: External occipital protuberance, superior nuchal line, ligamentum nuchae, spinal process of C7
Middle: Spinous process of T1 - T5
Lower: Spinous process of T6- T7
Where do the different fibres of Trapezius insert?
Upper: Lateral 1/3 of clavicle and acromion process
Middle: Superior border of the lateral 2/3 of the spine of scapula.
Lower: Medial 1/3 of the spine of scapula.
What is trapezius innervated by?
Accessory Nerve CN XI
What is the function of the 3 fibres of trapezius?
Upper: Elevates scapula
Middle: Retract scapula
Lower: Depress scapula
All together: Retract scapula during abduction of the humerus past horizontal.
Where does latissimus dorsi originate?
Spinous process of T7 - L5, iliac crest of sacrum, throacolumbar fascia, inferior angle of the scapula, lower 3-4 ribs.
Where does latissimus dorsi insert?
Floor of the intertubercular sulcus.
What innervates latissimus dorsi?
Thoracodorsal (Long scapular nerve) C6, C7, C8
What is the action of latissimus dorsi?
Adduction, medial rotation and extension of the humerus
Where does levator scapulae originate?
Transverse process of C1 - C4 vertebrae
Where does levator scapulae insert?
Medial border of scapula above the level of the spine
What innervates levator scapulae?
Dorsal Scapular Nerve (C5)
Branches of the anterior rami of C3 - C4
What is the action of levator scapulae?
Elevates scapula
Where does Rhomboid minor originate?
Spinous process of C7 - T1 vertebrae, lower end of ligamentum nuchae
Where does Rhomboid minor insert?
Medial border of the scapula at the level of the spine
Where does Rhomboid major originate?
Spinous process of T2 - T5
