Back Neurology

Question 1

What is the start and end point of the Spinal Cord?

Answer 1

• start: Medulla Oblongata
• end: Conus Medullaris

Question 2

What are the 5 categories of structures within the back that can be sources of pain?

Answer 2

• Fibroskeletal structures: periosteum, ligaments, and anuli fibrosi of IV discs
• Meninges: coverings of the spinal cord
• Synovial joints: capsules of the zygapophysial joints
• Muscles: intrinsic muscles of the back
• Nervous tissue: spinal nerves or nerve roots exiting the IV foramina

Question 3

What are the innervations of the structural categories of back pain?

Answer 3

• Fibroskeletal structures: Recurrent Meningeal Ns.
• Meninges: Recurrent Meningeal Ns.
• Synovial joints: Posterior Rami
• Muscles: Posterior Rami
• Nervous tissue: Posterior Rami

Question 4

What are the 3 most common causes of back pain?

Answer 4

• muscular pain: result of spasm in muscular tissue producing ischemia
• joint pain: result of osteoarthritis or disease arthritis (RA)
• fibroskeletal pain: result of fractures and dislocation of ligamentous structures

Question 5

What are the different types of spinal cord injury and associated losses of function?

Answer 5

Complete transection of the Spinal Cord results in a loss of sensation and motor function below the lesion

• C1-3: no function below the Head, respiratory necessary for life
• C4-5: no function of Limbs, respiration capable
• C6-8: loss of hand and variable upper limb function, may be able to propel a wheelchair
• T1-9: paralysis of both lower limbs
• T10-11: some thigh muscle function, may allow walking with leg braces
• L2-3: most lower limb function present, may be able to walk with short leg braces

Question 6

What are the components and order (from outermost to innermost) of the Spinal Meninges?

Answer 6

1. Epidural Space: occupied by the Internal Vertebral Venous Plexus and Epidural fat
2. Dura-Arachnoid Interface: potential space, no natural space exists here
3. Spinal Dural Sac: long tube-shaped sheath surrounding the Spinal Cord lining the Vertebral Column
4. Dural Root Sheath: lateral tapering extension of Spinal Dura Mater that surround Anterior and Posterior Roots
5. Filum Terminale Externum: Dural part of the Terminal Filum; continuation of the Filum Terminale Internum inferior to the Dural Sac with an additional layer of Dura, travels through the Sacral Hiatus and inserts on the Coccyx

Question 7

What is the Spinal Arachnoid Mater and its components?

Answer 7

• thin membranous intermediate layer, lines the Spinal Dural Sac, held firmly to the Dural Sac by the pressure of Cerebrospinal Fluid which circulates in the Subarachnoid Space
  1. Subarachnoid Space: Cerebrospinal Fluid filled space between Arachnoid and Pia Mater
  2. Arachnoid Trabeculae: delicate strands of connective tissue that span the Subarachnoid Space joining the Arachnoid and Pia Mater
  3. Lumbar Cistern: enlargement of the Subarachnoid Space inferior to the Conus Medullaris containing the Cauda Equina

Question 8

What is the Pia Mater and its components?

Answer 8

• thinnest innermost covering of the Spinal Cord, follows the entire surface of the Spinal Cord, lines the Spinal Roots
  1. Denticulate L.: lateral extension of fibrous Pia Mater at regular intervals between the Spinal Roots to attach to the Dural Sac, suspend the Spinal Cord in the Dural Sac
  2. Filum Terminale Internum: inferior continuation of Pia Mater inferior to the Conus Medullaris, eventually picks up a layer of Dura Mater, inferior to the Dural Sac and becomes the Filum Terminale Externum

Question 9

an important diagnostic procedure for evaluating a variety of central nervous system disorders

• a needle is inserted between either L3/4 or L4/5 at the level of the iliac crest; this level is typically chosen to avoid the needle injuring the spinal cord
• as the needle passes through the Ligamentum Flavum, it “pops” and passes into the Lumbar Cistern deep to the Spinal Dura and Arachnoid Mater
• Cerebrospinal Fluid can then be drawn out and evaluated

Answer 9

Lumbar Puncture of Spinal Tap

Question 10

swelling of the Spinal Cord from C4-T1 segments of the Spinal Cord that corresponds with the Brachial Plexus and Upper Extremity

Answer 10

Cervical Enlargement

Question 11

swelling of the Spinal Cor from T11-S1 segments of the Spinal Cord that corresponds with the Lumbar and Sacral Plexuses and Lower Extremity

Answer 11

Lumbosacral Enlargement

Question 12

part of the Spinal Cord that produces Spinal Rootlets that converge to form Spinal Roots that converge to form Spinal Nerve that then branches into Spinal Rami

Answer 12

Spinal Cord Segment

Question 13

central projections from neuronal cell bodies in the Anterior Horn (and sometimes Lateral Horn) of the Spinal Cord, converge with a Posterior Root to form a Spinal Nerve at each Spinal Cord Segment

Answer 13

Anterior Root

Question 14

small fibers originating from the Spinal Cord that converge to form a single Anterior Root at each Spinal Cord Segment

Answer 14

Anterior Rootlets

Question 15

central projections from neuronal cell bodies in the Spinal Ganglion, converge with an Anterior Root to form a single Spinal Nerve at each Spinal Cord Segment

Answer 15

Posterior Root

Question 16

small fibers originating from the Spinal Cord that converge to form a single Posterior Root at each Spinal Cord Segment

Answer 16

Posterior Rootlets

Question 17

collection of Sensory nerve cell bodies associated with the Posterior Root

Answer 17

Spinal Ganglion

Question 18

• Mixed General Sensory and Somatic Motor
• 31 pairs: 8 Cervical, 12 Thoracic, 5 Lumbar, 5 Sacral, and 1 Coccygeal
• very short union of Anterior and Posterior Roots that very quickly branches into Anterior and Posterior Rami

Answer 18

Spinal Nerves

Question 19

Where do the Cervical Spinal Nerves exit?

Answer 19

8 pairs

• C1 Spinal nerve exits the Vertebral Column above C1
• C2 Spinal nerve exits the Vertebral Column between C1 and C2

Question 20

What are the Anterior Rami of the Cervical Spinal Nerves?

Answer 20

• Cervical Plexus (C1-4)
• Brachial Plexus (C5-T1)
• Recurrent Meningeal Branches: sensory and Sympathetic fibers to the Dura Mater

Question 21

What are the Posterior Rami of the Cervical region?

Answer 21

• Suboccipital N.: Posterior Ramus of C1, innervates Suboccipital musculature, travels through Suboccipital Triangle
• Great Occipital N.: Posterior Ramus of C2, cutaneous to the posterior Scalp, appears below the Suboccipital Triangle traveling superiorly
• Least Occipital N.: Posterior Ramus of C3, cutaneous and muscular innervation
• C4-8 (cutaneous and muscular innervation): Medial Branch: Muscular Branches (to Transversospinalis muscles), Articular Branches (to Zygopophyseal Joints), Cutaneous Branches (to Skin of Dermatome); Lateral Branch: Muscular Branches (to Erector Spinae and Splenius muscles), Cutaneous Branches (to Skin of Dermatome)

Question 22

What nerve is this?

Answer 22

Suboccipital N.

Question 23

What nerve is this?

Answer 23

Greater Occipital N.

Question 24

What are the Anterior Rami of the Thoracic Spinal Nerves?

Answer 24

• Atypical Intercostal N. (T1, T2, T7-11): T1,2 send branches to the Brachial Plexus; T7-11 become Thoracoabdominal N. as they travel over the Abdomen
• Typical Intercostal N. (T3-6)
• Subcostal N. (T12)
• Recurrent Meningeal Branches: sensory and Sympathetic fibers to the Dura Mater

Question 25

What are the Posterior Rami of the Thoracic Spinal Nerves?

Answer 25

- **Medial Branch**: Musclar Branch (to Transversospinalis muscles and Longissimus Thoracis muscle), Articular Branch (to the Zygopophyseal Joint), Cutaneous Branch (to the Skin of Dermatome) - **Lateral Branch**: Muscular Branch (to Erector Spinae muscles), Cutaneous Branch (to Skin of Dermatome)

Question 26

What are the Anterior Rami of Lumbar Spinal Nerves?

Answer 26

- **Lumbar Plexus (L1-4)** - **Lumbosacral Trunk** (**some of L4** and **all of L5**, travels inferiorly to join with the Sacral Plexus) - **Recurrent Meningeal Branches**: sensory and Sympathetic fibers to the Dura Mater)

Question 27

What are the Posterior Rami of the Lumbar Spinal Nerves?

Answer 27

- **Medial Branch**: Muscular Branch (to Transversospinalis, Interspinalis, and Intertransversarii muscles), Articular Branch (to Zygopophyseal Joint), Cutaneous Branch (to Skin of Dermatome) - **Lateral Branch**: Muscular Branch (to Erector Spinae muscles), Cutaneous Branch (to Skin of Dermatome), Superior Cluneal N. (Lateral Branch of the Posterior Rami of L1-3)

Question 28

What are the Anterior Rami of Sacral Spinal Nerves?

Answer 28

- **Sacral Plexus (L4-S4)** - **Coccygeal Plexus** (**some of S4** and **all of S5**) - **Recurrent Meningeal Branches**: sensory and Sympathetic fibers to Dura Mater

Question 29

What are the Posterior Rami of Sacral Spinal Nerves?

Answer 29

- Medial Branch - Lateral Branch: Middle Cluneal N. (Lateral Branch of Posterior Rami of S1-3)

Question 30

distal cone shaped terminal end of the Spinal Cord that typically begins tapering off at T12 and ends at L2

Answer 30

Medullary Cone or Conus Medullaris

Question 31

- bundle of Anterior and Posterior Roots from the Lumbosacral Enlargement and Medullary Cone - occupies the Vertebral Canal inside the Lumbar cistern from the level of the Medullary Cone inferiorly

Answer 31

Cauda Equina

Question 32

What nerve is this?

Answer 32

Spinal Accessory N.

Question 33

What nerve is this?

Answer 33

Thoracodorsal N.

Question 34

What nerve is this?

Answer 34

Dorsal Scapular N. | (another view)