Neck & Back: Neck Muscles

Question 1

anterior scalene

Answer 1

origin: transverse processes of C3-C6
insertion: 1st rib

Question 2

middle scalene

Answer 2

origin: transverse processes of C2-C7
insertion: 1st rib
action:
bilaterally: flex cervical vertebrae, elevate 1st rib
unilaterally: laterally flex & rotate cervical vertebrae

Question 3

posterior scalene

Answer 3

origin: transverse processes of C4-C6
insertion: 2nd rib
action:
bilaterally: flex cervical vertebrae, elevate 2nd rib
unilaterally: laterally flex & rotate cervical vertebrae

Question 4

rectus capitis posterior major

Answer 4

origin: spinous process of axis
insertion: lateral portion of occipital bone below inferior nuchal line
action: extension of head; rotation of face to same side as muscle

Question 5

rectus capitis posterior minor

Answer 5

origin: posterior tubercle of atlas
insertion: medial portion of occipital bone below inferior nuchal line
action: extension of head

Question 6

obliquus capitis superior

Answer 6

origin: transverse process of atlas
insertion: occipital bone between superior & inferior nuchal lines
action: extension of head & bends it to the same side

Question 7

obliquus capitis inferior

Answer 7

origin: spinous process of axis
insertion: transverse process of atlas
action: rotation of face to same side

Question 8

posterior triangle borders

Answer 8

anteriorly: posterior border of SCM (sternocleidomastoid)
posteriorly: anterior border of trapezius
inferiorly: clavicle
apex: occipital bone

Question 9

posterior triangle contents

Answer 9

muscles
vessels: external jugular vein, subclavian artery
nerves: brachial plexus, accessory nerve
cervical lymph nodes

Question 10

arterial supply in cervical region

Answer 10

branches of subclavian & internal carotid arteries

Question 11

arterial supply in thoracic & lumbar regions

Answer 11

posterior intercostal arteries (which branch off the aorta)

Question 12

venous drainage of neck & back muscles

Answer 12

deoxygenated blood from muscles move anteriorly in veins
joins veins from vertebrae & spinal cord
→ intervertebral veins → segmental veins → azygous system → superior/inferior vena cava

Question 13

innervation of neck & back muscles

Answer 13

mainly via dorsal rami of spinal nerves
exceptions:
- trapezius: accessory nerve
- latissimus dorsi: thoracodorsal nerve
- rhomboid major & minor: dorsal scapular nerve
- levator scapulae: dorsal scapula nerve
exits vertebral canal between vertebrae: intervertebral foramen
pierce into deep muscles - pass through muscles to innervate overlying skin