Lecture 3

Question 1

Spinal cord is a continuation of _______

Answer 1

The brainstem

Question 2

Where does the solid spinal cord end and at what vertebral level, in adults?

Answer 2

Ends at the Conus Medullaris around L1-L2

Question 3

What is the Conus Medullaris tethered to? And by what?

Answer 3

• Tethered to the coccyx

- By the Filum Terminale

Question 4

What are the 3 meningeal layers?

Answer 4

1. Dura mater
2. Arachnoid mater
3. Pia mater

Question 5

What 3 general components of the nervous system do the meningeal layers cover? And where do they continue to?

Answer 5

1. Brain
2. Spinal cord
3. Nerve roots
4. Continue into sacrum

Question 6

What 3 things make up the Cauda Equina?

Answer 6

Spinal nerve pairs from:

1. L2
2. Sacral nerves
3. Coccygeal nerve

Question 7

Where does the anterior spinal artery(s) arise from and extend to?

Is it single or paired?

Answer 7

• Arises from the vertebral artery
• Extends to the conus Medullaris
• Single artery

Question 8

Where does the posterior spinal artery(s) arise from, and extend to?

Single or paired?

Answer 8

• Arises from the vertebral artery
• Extends to the conus Medullaris
• Paired

Question 9

Where do the radicular arteries arise from? (2)

Answer 9

1. Intercostal arteries

2. Lumbar arteries

Question 10

What 3 sets of arteries supply the spinal cord?

Answer 10

1. Anterior spinal artery
2. Posterior spinal arteries
3. Radicular arteries

Question 11

What are dorsal roots?

Where do they arise from?

Answer 11

• SENSORY fibers

- Rising from the cell bodies in the Dorsal Root Ganglia

Question 12

What are Ventral roots?

Where do they arise from?

Answer 12

• Motor fibers

- Arise from the ventral horn of the spinal cord

Question 13

What 2 things combine to form spinal nerves?

Answer 13

1. Dorsal (sensory) roots

2. Ventral (motor) roots

Question 14

Where are interneuron cell bodies located?

What do they connect?

What are they responsible for?

Answer 14

• Located in the dorsal horn of the spine
• Connect the sensory & motor neurons
• Responsible for reflex responses to stimuli

Question 15

What do mechanoreceptors detect and what is an example?

Answer 15

• Detect mechanical deformation of the receptor or of cells adjacent to the receptor
• ex: Baroreceptors

Question 16

What do chemoreceptors detect? (4)

Answer 16

Taste, smell, oxygen levels, pH

Question 17

What do thermoreceptors detect?

Answer 17

Temperature

Question 18

What do nocioreceptors detect? (2)

Answer 18

1. Pain

2. Damage to tissue (physical / chemical)

Question 19

What do electromagnetic receptors detect?

Answer 19

Light on the retina

Question 20

What do proprioreceptors detect?

Answer 20

Degree of stretch in skeletal muscles, joints, tendons, & ligaments

Question 21

Cervical spinal nerves exist from ________ the respective vertebral body

Answer 21

Above

Question 22

Spinal nerves, with the exception of cervical spinal nerves, emerge from the spinal cord ________ the same- numbered vertebral body

Answer 22

Below

Question 23

Where does spinal nerve root 1 exit from?

Answer 23

Above C1 vertebral body

Question 24

Where does spinal nerve root 2 exit from?

Answer 24

Between C1 & C2 vertebral bodies

Question 25

Where does spinal nerve root 8 exit from?

Answer 25

Below C7 vertebral body

Question 26

What is dermatome T4 associated with?

Answer 26

Nipple level

Question 27

What is dermatome T6 associated with?

Answer 27

Level of the tip of the xiphoid process

Question 28

What is dermatome level T10 associated with?

Answer 28

Level of the umbilicus

Question 29

What nerve is the sole motor supply of the diaphragm and where does it emerge from?

Answer 29

- Phrenic nerve | - Emerges from C3-C5

Question 30

What does the brachial plexus innervate? Where ones it arise from? How is it primarily injured during sx?

Answer 30

- Innervates the upper limbs & shoulder - Arises from C5-T1 nerve roots - Improper positioning - primarily stretch injuries

Question 31

- What does the ulnar nerve innervate? | - How should pts be positioned to avoid ulnar nerve injury?

Answer 31

- Innervates the muscles of the hand that ADDuct the thumb and pinky finger - Damaged with improper positioning of arms - Abducted arms MUST have supinated hands

Question 32

What does the lumbar plexus arise from? What does it innervate?

Answer 32

- Arises from spinal nerves L1 - L4 | - Innervates anterior & medial muscles of thigh

Question 33

What does the femoral nerve provide sensory innervation from? Motor innervation to?

Answer 33

- Sensory innervation to the anterior thigh | - Motor innervation to the quadriceps muscles

Question 34

Where does the Sacral plexus arise from?

Answer 34

L4 - S4

Question 35

Where does the sacral plexus provide sensory information from? Motor innervation to?

Answer 35

Sensory information from posterior pelvis, posterior thigh; anterior, posterior & lateral leg Motor innervation to muscles of pelvis & lower extremity (gluteal, posterior femoral, lower leg & foot)

Question 36

Where does the sciatic nerve arise from? What 2 nerves does it form?

Answer 36

- Arises from L4 - S3 | - Tibial Nerve & common peroneal (fibular) nerve

Question 37

Give 2 examples of how the common peroneal nerve can be damaged during sx & what does it cause?

Answer 37

- Damaged while in stirrups or in lateral position | - Damage can cause foot drop (inability to dorsiflex)

Question 38

What are the 2 ascending tracts? What kind of information do they provide?

Answer 38

1. Anterolateral (spinothalamic) pathway 2. Posterior column - medial lemniscus pathway - Carry sensory impulses toward the brain

Question 39

How many orders of neurons are associated with the ascending tracts?

Answer 39

3

Question 40

Where do the first order neurons originate & terminate?

Answer 40

Originate in periphery Terminate in spinal cord

Question 41

Where do the second order neurons ascend? Where do they terminate?

Answer 41

- Ascend in the spinal cord | - Terminate in the thalamus

Question 42

Where do the third order neurons project to?

Answer 42

Specific cortex in the brain

Question 43

What are the Descending Tract(s) & what is carried?

Answer 43

Corticospinal tract - carries ??sensory/motor?? impulses away from the brain

Question 44

How many orders of neurons are associated with the Descending Tract(s)?

Answer 44

2 - upper & lower motor neurons

Question 45

Where do the upper motor neurons originate & terminate?

Answer 45

(First order descending neurons) Originate in the brain Terminate in the spinal cord

Question 46

Where do the lower motor neurons originate & terminate?

Answer 46

(Second order descending neurons) Originate in the spinal cord Terminate at the neuro-motor junction