Extrinsic And Intrinsic Back Muscles

Question 1

Embryological origin of extrinsic back muscles

Answer 1

Hypomere

Question 2

Function of trapezius

Answer 2

Rotate and adduct scapula

Question 3

Innervation of trapezius

Answer 3

Spinal accessory n (CN XI)

Question 4

Function of latissimus dorsi

Answer 4

Adduct brachium, depress scapula

Question 5

What extrinsic muscle is innervated by thoracodorsal? What spinal nerve levels?

Answer 5

Latissimus dorsi. C6-C8

Question 6

Levator scapulae function

Answer 6

Elevate scapula

Question 7

Levator scapula innervation

Answer 7

Cervical nn (C3-C5), dorsal scapular n (C5)

Question 8

Pair of muscles that work to adduct scapula?

Answer 8

Rhomboids

Question 9

Innervation and function of serrated posterior superior?

Answer 9

2-5 intercostal nn. Proprioception, weakly assists as secondary inspiratory mm

Question 10

Innervation and function of serrated posterior inferior

Answer 10

9-12 intercostal nn. Proprioception, weakly assists as secondary expiratory mm

Question 11

Intrinsic back mm arise from what embryologic structure?

Answer 11

Epimere

Question 12

Splenius group function and Innervation

Answer 12

BL: extends C-spine/head
Uni: flexes/rotates head to same side
Posterior rami C1-C6

Question 13

Function of erector spinae muscles?

Answer 13

B/L: extends spine

Uni: bends spine to same side

Question 14

Innervation of Spinalis, Longissimus, iliocostalis?

Answer 14

S: posterior rami spinal nn
L: posterior rami C1-L5
I: posterior rami C8-L1

Question 15

Which intrinsic muscle group is innervated by anterior and posterior rami? What is their function?

Answer 15

Intertransversarii.

Proprioception. Aids in lateral bending and stabilizing.

Question 16

Deep intrinsic back muscles are primarily innervated by what?

Answer 16

Posterior rami spinal nn.

Question 17

Which group of intrinsic back muscles typically span 4-6 segments? 2-4? 1-2?

Answer 17

Semispinalis.
Multifudus.
Rotatores.

Question 18

Major functions of deep intrinsic back muscles?

Answer 18

Proprioception, stabilization, pain

Question 19

Major function of suboccipital muscles?

Answer 19

Extension of head on C1, and rotation of head on C1 and C2

Question 20

Suboccipital muscles are primarily innervated by posterior ramus of what spinal nerve?

Answer 20

C1

Question 21

innervation of suboccipital n?

Answer 21

Posterior ramus of C1.

Motor to mm of suboccipital triangle.

Question 22

Damaging greater occipital n would lead to sensory loss where?

Answer 22

Skin over neck and occiput

Question 23

Sensory loss to superior posterolateral neck and scalp behind ear could indicate damage of which nerve and spinal level?

Answer 23

Lesser occipital nn, anterior rami C2-C3

Question 24

Contralateral mm and ipsilateral mm allow the head to do what movement?

Answer 24

Rotate to one side

Question 25

Strain vs. sprain

Answer 25

Strain = stretching/tearing mm or tendons (quad, hammy)
Sprain = teaching/tearing ligaments (ankle)