Back Muscles Flashcards
Extrinsic Muscles of the Back
1. Superficial Group -move the upper limbs
-innervated by various superficial nerves
2. Intermediate Group -move the ribs.
-Innervated by the anterior rami of the spinal nerves
Epaxial Muscles of the Back
Psoas Major and Quadratus Lumborum)
-are innervated by the anterior rami
Hypaxial Muscles
Superficial Group
Trapezius
Latissimus Dorsi
Levator Scapuli
Rhomboid major
Rhomboid minor
Trapezius Origin
Superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous processes of CVII to TXII
Trapezius Insertion
Lateral one-third of clavicle, acromion, spine of scapula
Trapezius Innervation
Motor—accessory nerve [XI]; proprioception—C3 and C4
Trapezius Function
Assists in rotating the scapula during abduction of humerus above horizontal; upper fibers elevate, middle fibers adduct, and lower fibers depress scapula
Latissimus dorsi
Origin
Spinous processes of TVII to LV and sacrum, iliac crest, ribs X to XII
Latissimus dorsi Insertion
Floor of intertubercular sulcus of humerus
Latissimus dorsi Innervation
Thoracodorsal nerve (C6 to C8)
Latissimus dorsi Function
Extends, adducts, and medially rotates humerus
Levator scapulae Origin
Transverse processes of CI to CIV
Levator scapulae Insertion
Upper portion medial border of scapula
Levator scapulae Innervation
C3 to C4 and dorsal scapular nerve (C4, C5)
Levator scapulae Function
Elevates scapula