Back and Neck Musculature

Question 1

What are the functions of the Trapezius? (3)

Answer 1

1. Elevation
2. Upward Rotation
3. Adduction of Scapula

Question 2

Trapezius (Origin, Insertion, Nerve, Artery, Action)

Answer 2

• Extrinsic back muscle
• External occipital protuberance, ligament nuchae, spinous process C7-T12
• Scapular spine, acromial process, lateral/ distal 1/3 of clavicle
• Spinal accessory nerve (CN XI)
• Superficial transverse cervical artery
• Elevation, upward rotation, and adduction of scapula

Question 3

What are the functions of the Latissimus Dorsi? (2)

Answer 3

1. Internal rotation, Extension, and Adduction of the glenohumeral joint
2. Accessory muscle for expiration

Question 4

Latissimus Dorsi: Swimmers Muscle (Origin, Insertion, Nerve, Artery, Action)

Answer 4

• Extrinsic back muscle
• Thoracolumbar fascia, iliac crest, spinous process of T6-T12, ribs, inferior angle of scapula
• Medial lip of intertubercular sulcus
• Thoracodorsal nerve/ middle subscapular nerve (C6-C8)
• Subscapular artery
• Internal rotation, Extension, and Adduction of the glenohumeral joint, accessory muscle for expiration

Question 5

What are the functions of the rhomboid minor? (3)

Answer 5

• Elevation
• Downward rotation
• Retraction/ Adduction of scapula

Question 6

Rhomboid Minor (Origin, Insertion, Nerve, Artery, Action)

Answer 6

• Extrinsic back muscle
• Spinous process C7-T1
• Medial border of scapula between superior angle and root of scapular spine
• Dorsal scapular nerve (C4-C5)
• Dorsal scapular artery
• Elevation, downward rotation and retraction/ adduction of scapula

Question 7

What are the functions of the rhomboid major? (3)

Answer 7

• Elevation
• Downward rotation
• Retraction/ Adduction of scapula

Question 8

Rhomboid Major (Origin, Insertion, Nerve, Artery, Action)

Answer 8

• Extrinsic back muscle
• Spinous process T2-T5
• Medial border of scapula inferior to the scapular spine
• Dorsal scapular nerve (C4-C5)
• Dorsal scapular artery
• Elevation, downward rotation and retraction/ adduction of scapula

Question 9

What is the function of the serratus posterior superior? (respiration)

Answer 9

• Elevate upper ribs: inspiration

Question 10

Serratus Posterior - Superior (Origin, Insertion, Nerve, Artery, Action)

Answer 10

• Extrinsic back muscle
• Supraspinous ligament, ligament nuchae, spinous process (C7-T3)
• Superior border of ribs 2-5
• Intercostal nerve ventral rami (T1-T5)
• Posterior intercostal arteries
• Elevate upper ribs: inspiration

Question 11

What is the function of the serratus posterior inferior? (respiration)

Answer 11

• Depress lower ribs: expiration

Question 12

Serratus Posterior - Inferior (Origin, Insertion, Nerve, Artery, Action)

Answer 12

• Extrinsic back muscle
• Supraspinous ligament, spinous process (T11-L2)
• Inferior border of ribs 9-12
• Intercostal nerve ventral rami (T9-T12)
• Posterior intercostal arteries
• Depress lower ribs: expiration

Question 13

What are the functions of the splenius capitis? (2)

Answer 13

1. Neck/ head extension bilaterally
2. Ipsilateral side bending and rotation of the head

Question 14

Splenius Capitis (Origin, Insertion, Nerve, Artery, Action)

Answer 14

• Superficial intrinsic neck muscle
• Ligament nuchae and spinous process C7-T3
• Lateral superior nuchal line and mastoid process
• Dorsal rami of cervical spinal nerves (C2-C3)
• Occipital artery
• Neck/ head extension bilaterally, ipsilateral side bending and rotation of the head

Question 15

What are the functions of the splenius cervicis? (2)

Answer 15

1. Neck extension bilaterally
2. Ipsilateral side bending and rotation of the neck

Question 16

Splenius Cervicis (Origin, Insertion, Nerve, Artery, Action)

Answer 16

• Superficial intrinsic neck muscle
• Spinous process T3-T6
• Transverse process C3-C6
• Dorsal rami of spinal nerves
• Occipital artery, posterior intercostal artery
• Neck extension bilaterally, ipsilateral side bending and rotation of the neck

Question 17

What are the functions of iliocostalis? (2)

Answer 17

• Bilateral: back extension
• Unilateral: ipsilateral back side bending and rotation
• Lumborum and Thoracis: depression of rib cage, expiration

Question 18

Iliocostalis (Origin, Insertion, Nerve, Artery, Action)

Answer 18

• Superficial intrinsic back muscles: erector spinae
• Lumborum:
  ~ Lateral erector spinae common tendon and iliac crest
  ~ Inferior border of angle of rib 6-7
• Thoracis:
  ~ Superior angle of ribs 7-12 and medial tendon of lumborum
  ~ superior angle of ribs 1-6 and C7 transverse process
• Cervicis:
  ~ Superior angle of ribs 3-6
  ~ Posterior tubercle of transverse process of C4-C6
• Innervation: Dorsal rami of spinal nerves
• Blood Supply: Lumbar arteries, subcostal arteries, posterior intercostal arteries
• Function: Bilateral: back extension; Unilateral: ipsilateral back side bending and rotation; Lumborum and Thoracis: depression of rib cage, expiration

Question 19

What are the functions of the longissimus? (2)

Answer 19

• Bilateral: back extension; cervicis/capitis: neck and head extension
• Unilateral: ipsilateral back side bending and rotation; cervicis/ capitis: ipsilateral rotation of neck and head
• Thoracis: depression of rib cage, expiration

Question 20

Longissimus (Origin, Insertion, Nerve, Artery, Action)

Answer 20

• Superficial intrinsic back muscles: erector spinae
• Only one of the ILS muscles that has a distal attachment to the cranium
• Thoracis:
  ~ Erector spinae common tendon, thoracolumbar fascia, transverse and maxillary process of lumbar vertebrae
  ~ Transverse process of all thoracic vertebrae and the lower 9 or 10 ribs between the tubercles and angles
• Cervicis:
  ~ Transverse process of T1-T5
  ~ Posterior tubercle of transverse process of C2-C6
• Capitis:
  ~ Transverse process of C4-T5
  ~ Mastoid Process
• Innervation: Dorsal rami of spinal nerves
• Blood Supply: lumbar arteries, subcostal arteries, posterior intercostal arteries
• Function: Bilateral: back extension; cervicis/capitis: neck and head extension; Unilateral: ipsilateral back side bending and rotation; cervicis/ capitis: ipsilateral rotation of neck and head; Thoracis: depression of rib cage, expiration

Question 21

What are the functions of the spinalis? (2)

Answer 21

• Bilateral: back extension
• Unilateral: ipsilateral back side bending and rotation

*Erector spinae muscles behave like a group of different muscles, different components have huge variations of functions

Question 22

Spinalis (Origin, Insertion, Nerve, Artery, Action)

Answer 22

• Superficial intrinsic back muscles: erector spinae
• Group of muscles from the sacrum to the base of the skill, lowest part merging into longissimus
• Thoracis: blending with longissimus and deep semispinalis
  ~ Most proximally: L2 spinous process; clinically very important
  ~ Spinous process of thoracic vertebrae, 4-8 higher levels
• Cervicis: various
  ~ Spinous process from T-T2 and ligament nuchae
  ~ Spinous process C4-C1
  -Capitis: usually merge with semispinalis capitis
  ~ Spinous process of T1/C7
  ~ Superior nuchal line with semispinalis
• Innervation: Dorsal rami of spinal nerves
• Blood Supply: lumbar arteries, subcostal arteries, posterior intercostal arteries
• Function: Bilateral: back extension; Unilateral: ipsilateral back side bending and rotation

Question 23

What are the functions of the multifidi? (3)

Answer 23

• Bilateral back extension
• Ipsilateral back side bending
• Contralateral rotation (unilateral contaction)

Question 24

Multifidi (Origin, Insertion, Nerve, Artery, Action)

Answer 24

• Deep intrinsic back muscle: transversospinalis
• Core back muscle
• Sacrum, PSIS, SI ligament, lumbar mammillary process, transverse process of T12-C4
• Lateral aspect and tips of the spinous processes of vertebrae 2-5 levels above until C2
• Dorsal rami of spinal nerves; various arteries at different levels
• Back extension bilaterally,