Extrinsic Back Muscles

Question 1

List the superficial muscles of the back

Answer 1

Trapezius
Latissimus Dorsi
Levator Scapulae
Rhomboideus Major
Rhomboideus Minor

Question 2

Trapezius is superficial to:

Answer 2

• splenius muscles of neck
• lower fibers Levator scapulae
• rhomboids

Question 3

Origins of trapezius

Answer 3

External occipital protuberance
Medial 1/3 of superior nuchal line
Ligamentum nuchae
Spinous processes of C7- T12

Question 4

Trapezius superior fibers insertion

Answer 4

Lateral 1/3 of clavicle

Question 5

Trapezius middle fibers insertion

Answer 5

Spine and acromion of scapula

Question 6

Trapezius inferior fibers insertion

Answer 6

Base of spine of scapula

Question 7

Innervation of trapezius

Answer 7

CN XI accessory: motor
Ventral rami of C3 and C4 nerves: proprioception

Question 8

Trapezius blood supply

Answer 8

superficial branch of transverse cervical artery

Question 9

Trapezius actions on scapula

Answer 9

Raises, retracts, rotates scapula

Question 10

Trapezius actions on head

Answer 10

Bilateral contraction of superior fibers extends head
Unilateral contraction of upper fibers laterally flexes head and cervical vertebrae

Question 11

Trapezius superior fibers action on scapula

Answer 11

Elevate scapula, form force couple to rotate the scapula (upwards)

Question 12

Trapezius middle fibers action

Answer 12

Retract the scapula

Question 13

Trapezius inferior fibers action

Answer 13

Depress scapula

Question 14

Latissimus dorsi origins

Answer 14

Spinous processes of T7-T12
All lumbar and sacral vertebrae (spinous processes)
Posterior part of iliac crest
From lower 3-4 ribs via muscular slips that interdigitate with external oblique muscle

Question 15

Latissimus dorsi insertion

Answer 15

Crest of lesser tubercle, floor of bicipital groove of humerus

Question 16

Latissimus dorsi innervation

Answer 16

Thoracodorsal nerve (posterior cord of brachial plexus, C6-C8 fibers)

Question 17

Latissimus dorsi blood supply

Answer 17

Thoracodorsal artery (branch of subscapular artery)

Question 18

Latissimus dorsi actions

Answer 18

Extension, medial rotation, adduction of arm

Question 19

Levator scapulae origin

Answer 19

Posterior tubercles of transverse processes of C1- C3/4

Question 20

Levator scapulae insertion

Answer 20

Medial border of scapula from superior angle to base of spine

Question 21

Levator scapulae innervation

Answer 21

Ventral rami C3, C4 from deep branches of cervical plexus
Twig from dorsal scapular nerve (C5)

Question 22

Levator scapulae blood supply

Answer 22

Deep branch of transverse cervical artery

Question 23

Levator scapulae actions

Answer 23

Elevates and retracts scapula with trapezius
Laterally flexes cervical vertebral column when scapula is fixed

Question 24

Both r. major and r. minor lie deep to:

Answer 24

Trapezius

Question 25

Which Rhomboideus is more superior

Answer 25

Rhomboid minor

Question 26

Rhomboideus minor origins

Answer 26

Lower part of ligamentum nuchae Spinous processes of C7 and T1

Question 27

Rhomboideus minor insertion

Answer 27

Medial border of scapula at base of spine

Question 28

Rhomboideus minor innervation

Answer 28

Dorsal scapular nerve (C4, C5)

Question 29

Rhomboideus minor blood supply

Answer 29

Deep branch of transverse cervical artery

Question 30

Rhomboideus minor actions

Answer 30

Elevates medial border of scapula Retracts scapula Rotation of scapula (downwards)

Question 31

Rhomboideus major origin

Answer 31

Spinous processes of T2- T5

Question 32

Rhomboideus major insertion

Answer 32

Medial border of scapula between base of spine and inferior angle

Question 33

Rhomboideus major innervation

Answer 33

Dorsal scapular nerve (C4, C5)

Question 34

Rhomboideus major blood supply

Answer 34

Deep branch of transverse cervical artery

Question 35

Rhomboideus major actions

Answer 35

Elevates medial border of scapula Retracts scapula Rotation of scapula (downwards)

Question 36

Serratus posterior superior origin

Answer 36

Lower end of ligamentum nuchae SpInous processes of C7- T2/T3

Question 37

Serratus posterior superior insertion

Answer 37

Ribs 2-5 lateral to angle

Question 38

Serratus posterior superior innervation

Answer 38

First four intercostal nerves (ventral rami of first four thoracic nerves)

Question 39

Serratus posterior superior blood supply

Answer 39

Highest intercostal artery, posterior intercostal arteries

Question 40

Serratus posterior superior action

Answer 40

Elevates upper ribs during inspiration

Question 41

Serratus posterior inferior origin

Answer 41

Spinous processes of T10 – L2

Question 42

Serratus posterior inferior insertion

Answer 42

Lower 3-4 ribs lateral to angles

Question 43

Serratus posterior inferior innervation

Answer 43

Lowest 4 intercostal nerves (ventral rami of lower thoracic)

Question 44

Serratus posterior inferior blood supply

Answer 44

Posterior intercostal arteries

Question 45

Serratus posterior inferior action

Answer 45

Depresses lower ribs down and back during inspiration