Exam #3: Deep Back

Question 1

Which germ layer are the deep back muscles derived from?

Answer 1

Mesoderm

Question 2

Which germ layer do somites differentiate from?

Answer 2

Mesoderm

Question 3

What do somites differentiate into?

Answer 3

• Sclerotomes
• Myotomes
• Dermatomes

Question 4

What does the myotome give rise to?

Answer 4

Myoblast cells

Question 5

What are myoblast cells?

Answer 5

Embryonic muscle cells

Question 6

What two layers do myotomes divide into?

Answer 6

Epaxial & Hypaxial

Question 7

Epaxial

Answer 7

Dorsal division of the myotome

Question 8

Hypaxial

Answer 8

Ventral division of the myotome

Question 9

Nerve supply to the epaxial division

Answer 9

Dorsal Primary Ramus

Question 10

Nerve supply to the hypaxial division

Answer 10

Ventral Primary Ramus

Question 11

What muscles are derived from the epaxial division?

Answer 11

Deep Extensor Muscles of the Back

Question 12

What muscles are derived from the hypaxial division?

Answer 12

1) Infrahyoid
2) Flexor muscles of the vertebral column
3) Quadratus Lumborum

Question 13

What is the functional outcome of the origins and insertions of the deep back muscles over-lapping?

Answer 13

Smooth movement during flexion, extension, and rotation

Question 14

What is the main function of the muscles of the deep back?

Answer 14

• Support body weight by extending the vertebral column
• Maintaining posture & balance
• Movement of the back

Question 15

What are the only muscles of the body innervated by the Dorsal Primary Ramus?

Answer 15

Intrinsic muscles of the deep back

Question 16

Anatomically, what is a back strain?

Answer 16

Microscopic tearing of intrinsic muscle cells or ligaments

Question 17

How are the muscles of the deep back innervated?

Answer 17

Segmentally by the dorsal primary ramus

Question 18

What are the five major groups of intrinsic back muscles?

Answer 18

1) Splenius Group
2) Erector Spinae Group
3) Trasversopinalis Group
4) Suboccipital Muscles
5) Segmental Group

Question 19

Splenius Group

Answer 19

• Arise from the posterior midline and travel laterally & superiorly
• Mainly assist withe head movements

Question 20

Erector Spinae Group

Answer 20

Arise from midline or slightly laterally and run longitudinally (straight up & down)

Question 21

Transversospinalis Group

Answer 21

Arise laterally from the transverse procesess and travel to the midline/spinous process to their insertion

Question 22

What are the three layers of muscles in the deep back?

Answer 22

1) Superficial Layer
2) Intermediate Layer
3) Deep Layer

Question 23

Superficial Layer

Answer 23

• Erector Spinae

- Splenius

Question 24

Intermediate Layer

Answer 24

Transversospinalis

Question 25

Deep Layer

Answer 25

- Segmental Muscles | - Suboccipital Muscles

Question 26

What are the two muscles of the Splenius Group?

Answer 26

- Splenius Capitus (superior) | - Splenius Cervicis (inferior)

Question 27

What is the difference between the splenius capitus and splenius cervicis?

Answer 27

Splenius Capitus inserts into the skull & the Splenius Cervicis does NOT (inserts into the neck)

Question 28

What are the three columns of Erector Spinae muscles?

Answer 28

1) Iliocostalis= lateral (ribs) 2) Longissimus= Intermediate (vertebral transverse processes) 3) Spinalis= Medial (just lateral to spinous processes) "I Love Spaghetti" (from lateral to medial)

Question 29

Origin of the Erector Spinae Muscles

Answer 29

Common tendon of Origin

Question 30

How is each column of Erector Spinae muscles divided?

Answer 30

Each column is divided into three parts according to its superior attachment

Question 31

Iliocostalis

Answer 31

Most lateral division Erector Spinae

Question 32

Longissimus

Answer 32

Middle division of Erector Spinae

Question 33

Spinalis

Answer 33

Most medial division of Erector Spinae

Question 34

What are the three parts of the Iliocostalis muscle?

Answer 34

- Iliocostalis lumborum - Iliocostalis thoracis - Iliocostalis Cervicis All are associated with the ribs

Question 35

Splenius Capitus Origin

Answer 35

- Ligamentum nuchae | - Spines of the upper throacic vertebrae

Question 36

Splenius Capitus Insertion

Answer 36

- Occipital Bone | - Mastoid Process

Question 37

Splenius Cervicis Origin

Answer 37

T3-6, upper thoracic vertebrae

Question 38

Splenius Cervicis Insertion

Answer 38

C2-4, upper cervical vertebrae NOT skull

Question 39

Erector Spinae Origin

Answer 39

Common Tendon of Origin

Question 40

What is the common tendon of origin attached to?

Answer 40

1) Sacrum 2) Iliac Crest 3) Spinous processes of T11-L5

Question 41

Erector Spinae Function

Answer 41

Chief Extensor of the vertebral column

Question 42

What structures pass through the semispinalis capitis?

Answer 42

Greater occipital nerve & artery

Question 43

Interspinales

Answer 43

Muscle

Question 44

Intertransversarii

Answer 44

asdf

Question 45

Rotators (Short & Long)

Answer 45

asdf

Question 46

What are the three muscles of the transversospinalis muscle group?

Answer 46

1) Semispinalis 2) Multifidus 3) Segmental Muscles

Question 47

Which two muscle groups of the deep back mainly assist with head movements?

Answer 47

- Splenius Group | - Suboccipital Muscles