Ch. 4 - Deep Back and Suboccipital Triangle 9/18

Question 1

Superficial Back Muscles

Answer 1

• attach scapula to torso
  Layer 1: trapezius and latissimus dorsi
  Layer 2: Rhomboideus major, minor and levator scapulae
• innervated by ventral primary rami of cervical spinal nerves via the brachial plexus and the spinal accesory nerve (trapezius only)

Question 2

Intermediate Back muscle

Answer 2

• respiration
  Layer 3: Serratus Posterior Superior and Inferior
• innervated by ventral primary rami of thoracic spinal nerves (intercostal nerves)

Question 3

Deep Back Muscles

Answer 3

• spinal extension, sidebending and rotation
  Layer 4: Erector spinae (no rotation) and splenius capitis et cervicis
  Layer 5: transversospinalis (semispinalis, multifidus, rotatores)
• innervated by dorsal rami of spinal nerves

Question 4

Serratus Posterior Superior

Answer 4

O: Nuchal ligament and spinous processes of CV5-TV3
I: posterior surface of ribs 2-5 lateral to ngle
A: Elevates ribs during inspiration
N: INtercostal nerves T1-T4

Question 5

Serratus posterior inferior

Answer 5

O: spinous processes of TV11-LV2 via thoracolumbar fascia
I: Posterior surface of ribs 9-12 lateral angle
A: Depresses lower four ribs allowing diaphragm to act during inspiration
I: intercostal nerves T9-T11

Question 6

nuchal fascia

Answer 6

fascia over the cervical region

Question 7

Thoracolumbar fascia

Answer 7

covering deep muscles of the thorax and lumbar regions

Question 8

Superficial (posterior) lamina:

Answer 8

attached medially to the nuchal ligament, supraspinal ligament, tips of all spinous processes, median crest of the sacrum

Question 9

Deep (anterior) lamina:

Answer 9

attached medially to the base of the skulll below the superior nuchal line, to the tips of cervical and lumbar transverse processes and in the thoracic region to the angeles of the ribs

Question 10

Splenius capitis et cervicis

Answer 10

= bandage. holds over deeper muscle, holding in place
O: spinous processes of CV7 -TV6
I: Capitis portion: lateral portion of the superior nuchal line and mastoid process
Cervicis portion: posterior tubercles of transverse processes of Cv1 to Cv3
A: Capitis: extends head; rotates and side bends the head and neck to the same side
Cervicis: extends and rotates neck to same side; also binds deeper musculature
N: Dorsal rami of C2-C5

Question 11

Erector spinae

Answer 11

= big back muscle- old name is “sacrum spinalis”
- the erector spinae muscle group is a large corded rope-like muscle which occupies the vertebral costal groove deep to the superficial and intermediate muscles of the back and extends the full length of the vertebral column. inferiorly it attaches via a strong aponeurotic tendon to the iliac crest, sacrum, lumbar spinous processes and supraspinal ligament

As ascend, it separates into three muscles- I Love Spaghetti

• primarily an extensor and side bender of the spine

Question 12

Iliocostalis

Answer 12

• lateral column of erector spinae- divided into iliocostalis lumborum, thoracis and cervicis
  O: crest of ilium and sacrum, posterior surface of ribs at angle
  I: angle of ribs, transverse processes of lower cervical vertebrae
  A: extends vertebral column - laterally flexes (sidebends) to one side
  N: dorsal rami of spinal nerves from vertebral segments covered by muscle

Question 13

Longissimus

Answer 13

• middle column of erector spinae - divided into longissimus thoracis, cervicis, and capitis
  O: transverse processes below
  I: transverse processes above; capitis portion inserts on mastoid process deep to splenius and sternocleidomastoid muscles
  A: extends vertebral column, lateral flexion to same side; capitis portion extends skull and rotates it to the sam side
  N: Dorsal rami of spinal nerves from vertebral segments covered by muscle

Question 14

Spinalis

Answer 14

• medial column of erector spinae; divided into spinalis thoracis, cervicis and capitis; the capitis portion is usually blended with a deeper muscle, the semispinalis capitis
  O: spinous processes below
  I: spinous processes above
  A: extends vertebral column, lateral flexion to sam side; capitis portion extends the skull
  N: dorsal rami of spinal nerves from vertebral segments covered by muscle

Question 15

Transversospinal group

Answer 15

• rotation!
• located deep to erector spinae group
  O: - originate on transverse processes below
  I: spinous processes one to six segments above
  A: one side acting: rotate vertebrae above to opposite side and side bend the vertebral column to the same side. both sides acting simultaneously: extends the vertebral column
  N: dorsal rami of spinal nerves of vertebral segments covered by muscle

Question 16

Semispinalis

Answer 16

-extends one-half of the vertebral column from lower thoracic to upper cervical levels, each subdivision spanning four to six vertebrae
- semispinalis thoracis - continuous with semispinalis cervicis
- semispinalis cervicis - ends at the spinous process of CV2
- semispinalis capitis: largest muscle of the posterior neck, extends from mid-thoracic and lower cervical vertebrae to the skulll, covers semispinalis cervicis
NOTE: spinalis capitis portion of the erector spinae group fuses medially with the semispinalis capitis

Question 17

Multifidus

Answer 17

= means “many segments”
- extends the length of the vertebral column from sacrum to CV2, each subdivision spanning two to four vertebrae
NOTE: most well developed in lumbar area where they act as extensors
- important in extension; minimal rotatory component

Question 18

Rotatores

Answer 18

same general attachments, actions and innervations as multifidus, however each subdivision spans one to two vertebrae
NOTE: because multifidus and rotatores span fewer vertebral segments compared to semispinalis, they function more as stabilizers between individual vertebral segments than as prime movers

Question 19

Intersegmental deep back muscles

Answer 19

• tiny and go between segments - local adjustors
• located deep to transversospinal muscles
• consist of short muscles which span one vertebral segment
• function as stabilizers between individual vertebrae rather than as prime movers
• high concentration of stretch receptors allow them to feedback on large postural spinal muscles
• innervated by dorsal rami of regional spinal nerves
• composed of interspinales and intertransversarii

Question 20

Interspinalis

Answer 20

paired muscles (left and right) that span adjacent spinous processes of cervical and lumbar vertebrae

Question 21

Intertransversarii

Answer 21

• paired muscles (anterior and posterior) that span adjacent transverse processes of cervical and lumbar vertebrae
• anterior is innervated by ventral rami
• posterior divided into lateral and medial portions; medial innervated by dorsal rami, lateral innervated by ventral rami
• in the thoracic region, the lateral posterior intertrasversarii are represented by the levator costarum muscle

Question 22

Levator Costarum

Answer 22

• thoracic region of intertransversarii
• extend from transverse processes above to ribs (medial to angle) one and two segments below
• function to elevate ribs during inspiration
• innervated by corresponding ventral rami of spinal nerves

Question 23

Suboccipital triangle and associated structures

Answer 23

• located deep to the semispinalis capitis
• function to extend the skull and rotate the skull and atlas to the same side
• ALL suboccipital muscles are innervated by the dorsal ramus of cervical spinal nerve C1 (suboccipital n.)

Question 24

Rectus capitis posterior major

Answer 24

O: spinous process of Cv2 (axis)
I: inferior nuchal line and occipital bone below
A: extension and lateral flexion of the skull; minimal rotation to same side
N: suboccipital n (C1- dorsal ramus)

Question 25

Rectus capitis posterior minor

Answer 25

O: posterior tubercle of atlas (Cv1)
I: medial portion of inferior nuchal line and occipital bone between inferior nuchal line and foamen magnum; may attach to dura between Cv1 and occiput
A: extension and some lateral flexion of skull
N: suboccipital N (C1 dorsal ramus)
NOTE: due to the attachment of the rectus capitis posterior minor to the cranial dura, this attachment has been implicated as a “probable component of dural headace

Question 26

Obliquus capitis inferior

Answer 26

O: spinous process of Cv1 (axis)
I: transverse process of atlas
A: rotates skull and atlas on odontoid process to same side
N: suoccipital n (c1 dorsal ramus)

Question 27

Obliquus capitis superior

Answer 27

O: transverse process of atlas
I: occipital bone between superior and inferior nuchal lines
A; exends and side bends the skull to the same side
N: suboccipital n (c1 dorsal ramus)

Question 28

boundaries of suboccipital triangle

Answer 28

lateral superior: obliquus capitis superior
lateral inferior: obliquus capitis inferior
medial- rectus capitis posterior major
roof- semispinalis capitis
floor- posterior atlantoocipital membrane and the posterior arch of the atlas

Question 29

vertebral artery

Answer 29

(located in the groove of atlas)
- after traversing the transverse cervical foramen of the atlas, it turns midialward along the groove in the posterior arch of the atlas and pierces the posterior atlantoocipital membrane to gain the foramen magnum

Question 30

suboccipital nerve

Answer 30

(C1- dorsal ramus) - pierces the posterior atlantooccipital membrane between the posterior arch of the atlas and the vertebral artery, where it passes through the triangle and deistributes to ALL the suboccipital muscles

Question 31

Greater occipital nerve

Answer 31

(C2 dorsal ramus) - emerges from beneath the obliquus capitis inferior, turns upward to cross that mmuscle and the suboccipital traingle and pierces the semispinalis capitis and trapezius muscles to innervate the posterior scalp as far forward as the vertex of the skull
NOTE: constant exension of neck results in continued traction on the nerve and results in tension headaches with reference to its receptive field