Lecture 2 -Deep Back & Sub-Occipital Region

Question 1

Extrinsic Back Muscles

Answer 1

Function: Control limbs/ respiratory movements
Innervation: Ventral (anterior) rami of spinal nerves
Subdivided into: - superficial -intermediate
-migrate to back in embryologic development

Question 2

Intrinsic Back Muscles

Answer 2

Function: move/stabilize vertebral column, posture
Innervation: Dorsal (posterior) rami of spinal nerves
Subdivided: -superficial -intermediate -deep
-Develop in back during embryological development
-Intrinsic(deep) muscles sit deep to thoracolumbar fascia

Question 3

Semispinalis

Answer 3

-Deep layer of Deep Back Muscles
Divided into: Capitis, cervicis, thoracis
Origin: Cv4-Cv7 and Tv1-Tv6 and transverse processes of Tv7-Tv12
Insertion: occipital bone, spinous processes of C2-C5 and T1-T4
Nerve supply: dorsal rami of cervical, thoracic and lumbar spinal nerves
Action: extends head to vertebral column

Question 4

Splenius Capitis

Answer 4

-Superficial Deep
Origin: Spinous process of C7-T4
Insertion: Superior nuchal line and mastoid process of temporal bone
Nerve: Dorsal rami (C4-C8) spinal nerves
Action: Extends and hyper-extends head -Laterally bends and rotates head to ipsilateral side when acting unilaterally
-Mostly for stability/posture

Question 5

Splenius Cervicis

Answer 5

-Superficial Deep
Origin: spinous process of T3-T6
Insertion: Transverse process of C1-C3
Nerves: Dorsal rami (C4-C8) spinal nerves
Action: Extends and hyper-extends head -Laterally bends and rotates head to ipsilateral side when acting unilaterally
-Mostly for stability/posture

Question 6

Erector Spinae (Sacrospinae)

Answer 6

-Intermediate Deep
3 columns of muscles:
Iliocostalis: -laterally -from ileum to ribs -Divided into : cervicis, thoracis, lumborum
Longissimus: -intermediate -from skull to sacrum -Divided into: capitis, cervicis, thoracis
Spinalis: -medially -spans from spinous process to spinous process of adjacent vertebrae (posture control) -Divided into: capitis, cervicis, thoracis
Innervation: Posterior Dorsal rami of spinal nerves
Action: -Unilaterally, bends vertebral column to ipsilateral side -Bilaterally, extends vertebral column and head

Question 7

Transversospinalis Muscles

Answer 7

-Deep Deep
-runs from transverse to spinous processes
-Made of 3 layers: Semispinalis, Multifidus, Rotatores
Action: -Unilaterally, rotate vertebral column/head to contralateral side -Bilaterally, extend vertebral column/head

Question 8

Semispinalis

Answer 8

• Deep Deep

- In upper half of vertebral column, span 4-6 segments

Question 9

Multifidus

Answer 9

-Deep Deep
-Span 2-4 segments
Origin: Transverse process (C4-C7, thoracid and lumbar vertebrae, posterior superior iliac spine, sacrum)
Inserts: spinous process of superior vertebrae
Innervated by: Posterior Dorsal rami of spinal nerves
Action: extends/rotates vertebral column

Question 10

Rotatores

Answer 10

-Deep Deep
-Only in thoracic region
-span 1-2 segments
-Divided into longus and brevis
Origin: Transverse process of vertebrae
Inserts: spinous process of superior vertebrae
Innervated by: Posterior Dorsal rami of spinal nerves
Action: extends/rotates vertebral column

Question 11

Interspinalis

Answer 11

-Deep Deep
-Segmental muscles (span one vertebrae to next)
Origin: Spinous processes (C3-C7, T2-T12, L2-L5)
Inserts: spinous process of superior vertebrae
Innervated by: Posterior Dorsal rami of spinal nerves
Action: extends vertebral column

Question 12

Intertransversarii

Answer 12

-Deep Deep
-Segmental muscles (span one vertebrae to next)
Origin: Transverse process of lumbar vertabrae to axis (C2)
Inserts: transverse process of superior vertebrae
Innervated by: Posterior Dorsal (minor ventral contribution) rami of spinal nerves
Action: Laterally flexes vertebral column

Question 13

Levatores Costarum

Answer 13

-Deep Deep
-Segmental muscles (span one vertebrae to next)
Origin: Tips of transverse processes (C7-T11)
Inserts: Pass inferolaterally, insert to rib (between tubercle and angle)
Innervated by: Posterior Dorsal rami of spinal nerves
Action: elevate ribs, assist w respiration

Question 14

Suboccipital Region

Answer 14

Muscles: -suboccipital triangle
Nerves: -Suboccipital -Greater occipital -3rd (least) occipital)
Vessels: -Occipital artery -Vertebral artery

Question 15

Sub-Occipital Triangle

Answer 15

-In neck, deep to semispinalis capitis
Action: extend/rotate head
Innervated by: Suboccipital nerve (dorsal ramus C1)
Rectus Capitis Posterior Major: -in triangle -Origin: Spinous process of axis (C2) Insertion: -Inferior nuchal line
Obliquus Capitis Superior: - in triangle -Origin: Transverse process of Atlas (C1) -Insertion: between superior/inferior nuchal lines
Obliquus Capitis Inferior: -in triangle -Origin: Spinous process of axis (C2) Insertion: Transverse process of Atlas (C1)
Rectus Capitus Posterior Minor: -NOT in triangle -Origin: Posterior tubercle of Atlas (C1)
Insertion: Inferior nuchal line

Question 16

Suboccipital Nerve

Answer 16

• Formed by dorsal ramus of C1 spinal
• Emerges superior to posterior arch of atlas and inferior to vertebral artery where it enters suboccipital triangle
• Supplies suboccipital triangle

Question 17

Greater Occipital Nerve

Answer 17

• Formed by dorsal ramus of C2 spinal nerve
• Emerges between posterior arch of atlas and lamina of axis caudal to obliquus capitis inferior (just below triangle)
• Courses superiorly becoming subQ and found in scalp w occipital artery
• Supplies skin over neck and occipital bone

Question 18

3rd (least) Occipital Nerve

Answer 18

• Cutaneous part of 3rd cervical nerve
• Ascends along side of head behind ear, found on trap.
• Supplies skin of posteriolateral nack and scalp behind ear

Question 19

Occipital Artery

Answer 19

• Branch of external carotid artery
• Ascends medially toward greater occipital nerve
• Accompanies greater occipital nerve in scalp

Question 20

Vertebral Artery

Answer 20

• Branches from first part of subclavian artery and ascends through transverse foramina of vertebrae C6-1
• Bends 90 degrees medially to occupy groove on superior surface of posterior arch of atlas
• Turns superiorly and pierces posterior atlantooccipital membrane to enter cranial cavity to farm basilar artery