Back Muscles

Question 1

Superficial extrinsic back muscles

Answer 1

Trapezius, latissimus dorsi, rhomboids, levator scapulae

Question 2

Intermediate extrinsic back muscles

Answer 2

Serratus posterior superior

Serratus posterior inferior

Question 3

Superficial intrinsic back muscles

Answer 3

Splenius capitis

Splenius cervicis

Question 4

Intermediate intrinsic back muscles

Answer 4

Errector spinae:
Iliocostalis- lateral column
Longissimus- intermediate column
Spinalis- medial column

Question 5

Deep intrinsic back muscles

Answer 5

Semispinalis capitis
Semispinalis thoracis and cervcis
Multifidus
Rotators

Question 6

Trapezius

Answer 6

Origin: medial third of superior nuchal line, external occipital protuberance, nuchal ligaments, spinous processes of C7-T12
Insertion: lateral third of the clavicle, acromion and spine of scapula
Innervation: CN XI, C3& C4 spinal nerves (pain and proprioceptive fibers)
Action : descending (superior)- elevates
Ascending (inferior) - depresses
Middle/all together - retract scapula
Ascending and descending parts act together to rotate
glenoid cavity superiorly
Blood supply : transverse cervical artery

Question 7

Latissimus dorsi

Answer 7

Origin: spinous processes of inferior six thoracic vertebrae, thoracolumbar fasciae, iliac crest, inferior three or four ribs
Insertion : floor of intertubercular sulcus of humerus
Innervation : thoracodorsal nerve, *C6, *C7, C8
Action : extends, adducts , and medially rotates shoulder joint, raises body towards arm during climbing

Question 8

Rhomboids

Answer 8

Minor
Origin : nuchal ligament, spinous processes C7-T1
Insertion : triangular area at medial end of scapular spine
Major
Origin : spinous processes T2-T5
Insertion : medial border of scapula from level of spine to inferior angle
Innervation : dorsal scapular nerve (C5)
Action : retract scapula and rotate it to depress glenoid cavity; fix scapula to thoracic wall

Question 9

Levator scapulae

Answer 9

Origin : posterior tubercles of transverse processes C1-C4
Insertion : medial border of scapula to root of spine
Innervation : dorsal scapular (C5) and cervical (C3,C4) spinal nerves
Action : elevates scapula and tilts its glenoid caviy inferiorly by rotating scapula