Lecture 12

Question 1

What is the anterior longitudinal ligament?

Answer 1

The large continuous ligament located in the front of the verebrae all the way down to the pelvis

Question 2

What do the iliolumbar ligaments connect?

Answer 2

They connect the top of the sacrum to the L4 and L5 vertebrae.

Question 3

What is the inguinal ligament?

Answer 3

Connects the anterior superior iliac spine to pubic tubercle

The dividing line between the front of the pelvis and the leg.

Question 4

What is the vertebral prominens?

Answer 4

The C7 spinous process contributing to the bump in the lower neck.

Question 5

What are the posterior superior iliac spines (PSIS)?

Answer 5

Two small bumps situated just above the butt crack.

Landmarks for s2 posterior sacral foramen

Question 6

What is the clinical significance of finding the PSIS?

Answer 6

It may be useful for locating the hiatus at the base of the sacrum and posterior foramina S2.

Question 7

What is the structure of intervertebral discs (IVDs)?

Answer 7

They consist of a nucleus pulposus and annulus fibrosis.

Question 8

What is the nucleus pulposus?

Answer 8

The jelly interior or gel layer of the intervertebral disc.

Question 9

What is the annulus fibrosis?

Answer 9

The surrounding structure made of fibrous mesh holding the nucleus pulposus in place.

Question 10

What is the role of hyaline cartilage in intervertebral discs?

Answer 10

It sandwiches both the top and bottom parts of the intervertebral discs.

Question 11

What is a common direction for disc herniation?

Answer 11

Herniated discs usually leak out the back side.

Question 12

What happens to intervertebral discs with age?

Answer 12

They tend to solidify and the gel substance dries out.

Question 13

What is the function of the meninges?

Answer 13

They house and protect the spinal cord and CNS structures.

Question 14

What is the pia mater?

Answer 14

The deepest connective tissue layer glued to the spinal cord and brain.

Question 15

What is the arachnoid mater?

Answer 15

The second connective tissue layer that is translucent.

Question 16

What is the dura mater?

Answer 16

The outermost layer of the meninges, tough and leathery.

Question 17

What is found in the subarachnoid space?

Answer 17

Cerebrospinal fluid (CSF) and blood vessels.

Question 18

What is the epidural space?

Answer 18

The space immediately outside the dura layer, containing fat and veins.

Question 19

Where does the spinal cord proper terminate?

Answer 19

At L1.

Question 20

What is the conus medullaris?

Answer 20

The tip or inferior border of the spinal cord - ends at L1

Question 21

What is the cauda equina?

Answer 21

A large collection of nerve roots that descend from the conus medullaris.

Question 22

What is an epidural procedure?

Answer 22

A needle is inserted outside the dura layer in the epidural space.

Question 23

What is a spinal procedure?

Answer 23

A needle pierces both the dura and arachnoid layers to deliver drugs into the subarachnoid space.

Question 24

What is the typical site for a spinal tap?

Answer 24

Lower lumbar spine, commonly at L3-L4 or L4-L5.

Question 25

What is the filum terminale internum and externum?

Answer 25

Ligaments that help hold the spinal cord in place at its inferior end. Filum terminale internum - inside dura sac from spinal cord to s2 Filum terminale externum - continues outside dura sac to coccyx

Question 26

What are the cervical and lumbar enlargements?

Answer 26

Regions with extra neurons for providing feedback and motor function. Cervical enlargement is c3-c6 Lumbar enlargement is T-11 - L1

Question 27

What is the location of the dural sac?

Answer 27

Surrounds the cauda equina in the lower lumbar and sacral spine. Created mostly due to growth of lumbar region. While spinal cord remains around the same size Space full of csf fluid - from L1- S2

Question 28

What is the blood patch used for?

Answer 28

To resolve a CSF leak by injecting the patient's own blood into the subarachnoid space. Spinal cord does not have blood or platelets to path any leaks

Question 29

What happens if the filum terminale ligament is cut?

Answer 29

The spinal cord may move upward.

Question 30

True or False: The epidural space contains a significant amount of adipose tissue.

Answer 30

True.

Question 31

Fill in the blank: The ________ is the outermost layer of the meninges.

Answer 31

[dura mater]

Question 32

What is the specific gravity of drugs in relation to CSF?

Answer 32

Determines if the anesthetic will float or sink in the CSF.

Question 33

What is a characteristic of the anterior corticospinal tract?

Answer 33

It is the secondary descending tract located in the front medial part of the cord. Lateral corticospinal tract is primary tract - relays 90%- crosses over at medulla (midbrain) at pyramidal decussiation Anterior corticospinal tract relays 8% - crosses over at spinal cord where inervation is needed While 2% go straight down without crossing over

Question 34

What is the primary descending tract responsible for the majority of skeletal muscle signaling?

Answer 34

Lateral corticospinal tract ## Footnote The lateral corticospinal tract originates in the cerebral cortex and is larger due to more information passing through.

Question 35

Where is the anterior corticospinal tract located?

Answer 35

Front medial part of the cord ## Footnote The anterior corticospinal tract is a secondary descending tract and is smaller than the lateral corticospinal tract.

Question 36

What are the four tracts that modulate motor activities but do not directly innervate skeletal muscles?

Answer 36

* Rubrospinal tracts * Reticulospinal tracts * Olivospinal tract * Vestibulospinal tract ## Footnote These are referred to as accessory or extrapyramidal tracts.

Question 37

What does DCML stand for?

Answer 37

Dorsal column medial lemniscus system ## Footnote The DCML pathways are primarily responsible for touch and pressure sensations sent via ascending pathways. Cross over happens at the medulla

Question 38

What is the function of spinocerebellar tracts?

Answer 38

Feedback system for sensory information sent to the cerebellum ## Footnote They primarily receive information from muscle spindles and tendons regarding proprioception, tension, and force 2 parts Anterior and posterior both on lateral side of cords

Question 39

What are the two divisions of the spinocerebellar tracts?

Answer 39

* Posterior spinocerebellar tract * Anterior spinocerebellar tract Responsible for proprioception, muscle spindles, and tendons

Question 40

What is the anterolateral system responsible for?

Answer 40

Pain transmission ## Footnote Also known as the spinal thalamic tract, it sends pain signals up the cord to the thalamus. Anterior spinothamalic tract - slow pain Lateral spinothamalic tract - fast pain

Question 41

What are the two divisions of the anterolateral system?

Answer 41

* Lateral spinothalamic tract (fast, sharp pain) * Anterior spinothalamic tract (slow, dull, achy pain)

Question 42

What is the location of the crossover point for the DCML pathway?

Answer 42

Medulla (lowest part of the brain stem) ## Footnote The medial lemniscus indicates both the location of crossover and the pathway after crossing over.

Question 43

What are the two parts of the DCML pathway?

Answer 43

* Fasciculus Gracilis (sensory signals from the lower body) * Fasciculus Cuneatus (sensory signals from the upper body)

Question 44

How does sensory information from the lower extremities travel in the DCML pathway?

Answer 44

It travels up the dorsal columns via heavily myelinated neurons ## Footnote This information is sent up the back of the cord crossing over at medulla DCML - center lower part legs, higher part and lateral cervix senses

Question 45

Where in the brain is sensory information processed for the face?

Answer 45

Lateral in the parietal lobe ## Footnote The face has the highest receptor density, requiring more brain space for processing. Fasculius Cuneate

Question 46

What is the primary pathway for motor signals in the corticospinal tracts?

Answer 46

Lateral corticospinal tract ## Footnote This pathway sends motor signals from the cortex and crosses over at the pyramidal decussation - 90% 8% will go down and cross at cord at level of innervation 2% will go straight down

Question 47

What percentage of motor output is carried by the lateral corticospinal tract?

Answer 47

90% of motor output ## Footnote The secondary pathway, anterior corticospinal tract, carries 8%, while 2% has no crossover.

Question 48

Where does the anterior corticospinal tract cross over?

Answer 48

In the spinal cord where innervation is needed ## Footnote This allows for localized innervation based on tissue location.

Question 49

What is the role of lamina 1 in the spinal cord?

Answer 49

Receives fast pain information via A delta fibers ## Footnote Aka - Lamina Marginlis It is the most posterior piece of gray matter.

Question 50

Which lamina is associated with slow, dull pain?

Answer 50

Lamina 2, 3 , and secondary synapse sometimes 5 ## Footnote Aka substantia Gelintinosa Slow pain information is sent to the other side of the cord at the same level it entered.

Question 51

What is the primary role of mechanoreceptors in the spinal cord?

Answer 51

Capable of impacting reflexes ## Footnote They receive sensory input and can elicit reflex activity without brain command.

Question 52

What is the homunculus?

Answer 52

Describes the representation of sensory fields in the brain for processing ## Footnote The denser the receptor population, the more brain area is allocated for processing.