Superficial and Intrinsic Muscles of Back

Question 1

Trapezius (extrin)
Blood supply:
Innervation:
Action:

Answer 1

Blood Supply: Transverse Cervical Artery
Innervation: Spinal Accessory Nerve (CN 11), cervical plexus (C3-C4)
Action: Superior –> Raise scapula upward, rotate glenoid cavity suporiority. Middle –> Draw scapula medially. Inferior –> draw scapula medially downward

Question 2

Latissimus Dorsi (extrin)
Blood supply:
Innervation:
Action:

Answer 2

Blood Supply: Thoracodorsal Artery
Innervation: Thoracodorsal nerve
Action: Internal rotation, adduction, extension, and respiration (cough muscle) of arm

Question 3

Levator Scapula (extrin)
Blood supply:
Innervation:
Action:

Answer 3

Blood Supply: Dorsal Scapular Artery
Innervation: Dorsal Scapular nerve
Action: Draw scapula medially forward

Question 4

Rhomboid minor (extrin)
Blood supply:
Innervation:
Action:

Answer 4

Blood Supply: Dorsal Scapular Artery
Innervation: Dorsal Scapular Nerve
Action: Draws scapula medially upward

Question 5

Rhomboid major (extrin)
Blood supply:
Innervation:
Action:

Answer 5

Blood Supply: Dorsal Scapular Artery
Innervation: Dorsal Scapular nerve
Action: Steadies scapula, Draws scapula medially upward

Question 6

Splenius Capitus/Cervicis (in/tru)
Blood supply:
Innervation:
Action:

Answer 6

Blood Supply: Deep Cervical artery, Posterior Intercostal arteries
Innervation: Dorsal Rami
Action: Bilateral –> Extend head and cervical spine. Unilaterally –> Flex and rotate head and cervical spine to same side

Question 7

Semispinalis capitis (in/tru)
Blood supply:
Innervation:
Action:

Answer 7

Blood Supply: Deep cervical artery, posterior intercostal arteries, lumbar arteries
Innervation: Dorsal Rami
Action: Bilateral –> Extend head and cervical spine. Unilaterally –> laterally flex head and cervical spine to same side and rotate to opposite

Question 8

Erector Spinae (Spinalis, longissimus, Iliocostalis)

Answer 8

Blood supply: Deep cerival artery, posterior intercostal artyery, subcostal artery, lumbar artery for spinalis only
Innervation: Dorsal rami
Action: Bilaterally –> Extend vertibral column. Unilaterally –> Laterally flex vertebral column to same side