Lecture 7-Spinal Cord 1 Flashcards
Where does the spinal cord end?
appx L1
How many cervical spinal segments are there?
8
How many thoracic nerves are there? lumbar? Sacral? Coccygeal?
12 thoracic
5 lumber
5 Sacral
1 Coccygeal
What is the termination of the dura mater that attaches to the coccyx called?
coccygeal ligament
What is the end of the spinal cord called?
Conus Medullaris
What are the three arteries that supply the spinal cord?
1 anterior spinal artery (supplies 2/3)
2 posterior spinal arteries (suppies 1/3)
Where do the anterior and posterior spinal arteries arise from?
vertebral and radiculospinal arterties
Describe the venous drainage of the spinal cord.
radicular veins drain into the epidural venous peluxus
List the three laters of meninges covering the spinal cord from superficial to deep.
Dura mater
Arachnoid mater
Pia mater
What is the extension of the pia mater past the end of the spinal cord called?
filium terminale
What is the function of the denticulate ligaments?
anchor the spinal cord to the dural sheath
Where are spinal taps usually done?
between L3 and L4
What is the term for the collection of spinal rootlets that travel below L1?
cauda equina
Where is the lateral horn present in the spinal cord?
T1-L2
What are the fibers crossing the spinal cord from side to side known as?
anterior white commissure
How many total spinal segments are there?
31
Where do spinal nerves arise for segments C1-C7?
above the vertebral body holding the same name
Where do spinal nerves arise for segments C8-S5?
below the vertebral body holding the same name
Where is the dorsal root ganglion found?
intervertebral foramina
What would a spinal transection at C4 result in?
tetrapeligia- no sensation or motor control below neck
What would a spinal transection at C6 result in?
tetrapeligia- no sensation or motor control below shoulders
What would a spinal transection at T6 result in?
parapeliga- use of arms but no motor or sensation in torso and lower limbs
What would a spinal transection at L1 result in?
parapeligia- use of arms and torso no sensation or motor activity in legs
What nuclei is found in lamina I?
Nucleus Posteriomarginalis
What nuclei is found in lamina II?
Substantia Gelatinosa
What lamina contains the nuclues proprius?
Lamina III-VI
What spinal segments contain the Nucleus Dorsalis of Clarke?
C8-L3
What type of information does the Nucleus Dorsalis of Clarke receive?
Muscle sense/proprioceptive information that it projects to the cerebellum
What is unique about the gray matter of thoracic levels?
contains a lateral horn
What type of cells are contained in the lateral horn?
Intermediolateral cell column- preganglionic sympathetic autonomic cell bodies that project to the sympathetic chain or prevertebral ganglion via the ventral root
What lamina contains the lateral horn at thoracic levels?
Lamina VII
Where are cells of the Intermediolateral cell column found?
Thoracic level-Lateral Horn-Lamina VII
What levels contain preganglionic parasympathetic cell bodies?
S2-S4
What type of sensation is Lissauer’s tract associated with?
pain and temperature
What tract do cells from Nucleus of Dorsalis of Clarke project to?
Dorsal Spinocerebellar Tract
What lamina surrounds the central canal and is referred to as the “central gray matter”?
Lamina X
List the 3 lamina found in the ventral horn
Lamina VIII, IX and X
What type of neurons are found in lamina VIII?
interneurons- involved in reflex activity and motor coordination
What type of neurons are found in lamina IX?
alpha motor neurons- lg. innervate voluntary muscles
gamma motor neurons- small, innervate muscle spindles
Where in the ventral horn are cells found that innervate extensors?
Most ventrally
Where in the ventral horn are cells found that innervate flexors?
Most dorsally
Where in the ventral horn are cells found that innervate the upper limb?
most laterally
Where in the ventral horn are cells found that innervate the lower limb muscles?
most medially
What are the two main groups of intraspinal reflex circuits?
paucisynaptic
multisynaptic
What types of receptors trigger the stretch reflex (ex. patellar tendon)?
muscle spindles with cell bodies in DRG then activate alpha motor neurons (lamina IX) that contract muscle
What is reciprocal activation in a reflex pathway?
an inhibitory interneuron also is activated to inhibit antagonist muscle
What is the clasp knife reflex?
When considerable tension activates a tendon and Golgi tendon organ that inhibits the muscle and cause it to relax to prevent damage
What is the purpose of the flexion crossed extension reflex?
allows for maintenance of balance but withdrawing the limb that is in contact with the painful stimulus and extending the opposite limb
