Chapter 1: Back and Autonomic Nervous System Flashcards
During week 4, sclerotome cells of the somites (mesoderm) migrate medially to surround what stuctures?
spinal cord and notochord
How many cervical, thoracic, lumbar, sacral, and coccygeal vertebrae are there?
7 cervical, 12 thoracic, 5 lumbar, and fused 5 sacral, and 3-4 coccygeal.
Zygapophyseal joints are classified as what type of joints?
synovial joints
What structure of the vertebra allows for exit of the spinal nerves?
intervertebral foramina
How is each intervertebral disk numbered?
by the vertebral body above the disk
What is each intervertebral disk composed of?
anulus fibrosus
nucleus pulposus
Anulus fibrosus? Also what is it composed of?
consists of the outer concentric rings of fibrocartilage and fibrous connective tissue
Nucleus pulposus?
an inner soft, elastic, compressible material that functions as a shock absorber for external forces placed on the vertebral column
Where is herniation of the nucleus pulposus common?
posterolateral direction
Anterior longitudinal ligament of the vertebral column?
forms a broad band of fibers that connects the anterior surfaces of the bodies of the vertebrae between the cervical and sacral regions.
prevents hyperextension of the vertebrae and is involved in “whiplash” accidents
Posterior longitudinal ligament of the spinal column?
connects the posterior surfaces of vertebral bodies and is located in the vertebral canal
limit flexion of the vertebral column
What does the vertebral (foramen) canal house?
spinal cord
The nucleus pulposus may herniate through what structure and lead to what?
herniate through the anulus fibrosus
herniated nucleus pulposus may. compress the spinal nerve roots, resulting in pain along the involved spinal nerve (sciatica)
What area of the spinal cord does herniation of the nucleus pulposus typically occur? (What levels)
lower cervical (C5/C6 or C6/C7) or lower lumbar (L4/L5 or L5/S1) parts of the vertebral column
Herniated disk will usually compress what spinal nerve roots? (herniated nucleus pulposus)
the nerve roots one number below involved disk (e.g herniation of L4 disk will compress the L5 roots)
This is the same for cervical nerve roots except thoracic in which the thoracic herniation will corresponnd with upper vertebral level above it
What are the boundaries of the intervertebral foramina?
anterior: bodies of the vertebrae and intervertebral disks
posterior: zygapophyseal joint and articular processes
superior and inferior: pedicles of the vertbrae
Dura mater?
cylindrical covering of connective tissue forming a dural sac
Where do the dura mater and dural sac terminate in the spinal cord?
inferiorly at the second sacral vertebra level
Describe the arachnoid.
delicate membrane which completely lines the inner surface of the dura mater and dural sac
Where does arachnoid terminate in the spinal cord?
terminates at the second sacral vertebra
What is pia mater?
tightly attached to surface of the spinal cord and provides a delicate covering of the cord
Where does the spinal cord with the covering of the pia mater terminate?
at the L1 or L2 vertebral levels in the adult
What are the 2 specializations of the pia mater?
denticulate ligaments and filum terminale
What are the denticulate ligaments?
bilateral thickenings of pia mater that run continuously on the lateral sides of the midpoint of the cord
separate the ventral and dorsal roots of the spinal nerves and anchor to the dura mater
What is the filum terminale?
a continuation of the pia mater distal to the lower end of the spinal cord and is part of the cauda equina which is composed of ventral and dorsal roots of lumbar and sacral nerves that extend below the inferior limit of the spinal cord
The internal vertebral venous plexus is valveless and connects what structures?
veins of the pelvis, abdomen, and thorax
What is a clinical correlation to remember related to the fact that the internal vertebral venous plexus is valveless?
provides a route of metastasis
Where is the epidural space located?
between the inner walls of the vertebral canal and dura mater
What does the epidural space contain?
fat and the internal vertebral venous plexus
The internal vertebral venous plexus continues superiorly through the foramen magnum to connect with what veins cranial cavity?
dural venous sinuses
Where is the location of the subarachnoid space?
pressurized space located between the arachnoid and pia mater layers
What does subarachnoid space contain?
cerebrospinal fluid (CSF)
Where does the subarachnoid space terminate?
at the second sacral vertebral level
What is the inferior limit of the spinal cord?
L1 or L2 vertebrae in adults (conus medullaris)
What is the inferior limit of the dural sac and the subarachnoid space?
S2 (CSF)
Dorsal ramus supplies what area of the body?
skin of back and dorsal neck
deep intrinsic back muscles (Erector spinae)
Ventral ramus supplies what area of the body?
skin of anterolateral trunk and limbs
sk. muscles of anterolateral trunk and limbs
Each spinal n. is formed by the union of what 2 nerve roots?
dorsal root
ventral root
What does the dorsal root carry?
sensory fibers from the periphery into the dorsal aspect of the spinal cord
Dorsal root ganglion?
on each dorsal root there is a DRG (sensory) containing the pseudounipolar cell bodies of nerve fibers that are found in the dorsal root
Ventral root?
arises from the ventral axon of spinal cord and carries axons of motor neurons
Spinal n.
formed by union of ventral and dorsal roots; and exit the vertebral column by passing through the intervertebral foramen
Dorsal rami innervate what areas of the body?
innervate the skin of the dorsal surface of back, neck (including zygapophyseal joints, and intrinsic sk. muscle of the deep back)
Ventral rami? (What does it innervate is the question)
innervate skin of the anterolateral trunk and limbs and the sk. muscles of the anterolateral trunk and limbs (ventral rami form the brachial and lumbosacral plexuses
All nerves beginning with T1 and below will exit the intervertebral foramina (inferior or superior) to the pedicle of the same-numbered vertebrae?
inferior
The cervical nerves C1 - C7 exit the intervertebral foramina (superior or inferior) to the pedicles of the same-numbered vertebrae?
superior to
C8 n exits intervertebral foramen inferior to the C7 pedicle
Answer may be inferior for all check
What is lumbar puncture?
used to inject anesthetic material in the epidural space or to withdraw CSF from the subarachnoid space
Where is a spinal tap typically performed? (levels)
L4-L5 interspace
How do you find the L4 vertebra?
a horizontal line drawn at the top of the iliac crest marks the level of L4
When a lumbar puncture is performed in the midline, the needle passes through what part of the vertebral column?
interlaminar space found between the lamina of the lumbar vertebrae
What are the interlaminar spaces covered by?
highly elastic ligamenta flava
What section of the spinal cord are the preganglionic cell bodies of the sympathetic nervous system found? Be specific.
lateral horn gray matter of the spinal cord segments T1 - L2 (thoracolumbar)
Where are the postganglionic cell bodies of the sympathetic nervous system found?
chain or paravertebral
collateral or prevertebral or preaortic (found when traveling to abdomen or pelvis)
Lesions at the superior cervical ganglion, middle cervical ganglion and cervicothoracic ganglion can lead to what syndrome?
Horner’s syndrome
What are the CN that the parasympathetic nervous system innervates?
CN III, VII, IX and X
CN III gives synapses at what ganglion? (for parasympathetic innervation)
ciliary ganglion
What does the ciliary ganglion innervate?
pupillary sphincter
ciliary m.
What parasympathetic innervated ganglion does CN VII connect to?
submandibular ganglion and pterygopalatine ganglion
Parasympathetic innervation through the submandibular ganglion gives innervation to what structures?
submandibular gland and sublingual gland
Parasympathetic innervation through the pterygopalatine ganglion innervates what structures?
lacrimal gland, nasal and oral mucosal glands
Parasympathetic innervation through CN IX synapses with what ganglion?
otic ganglion
Otic ganglion parasympathetic innervation goes to what structures?
parotid gland
CN X innervates what structures? (parasympathetics)
synapses on or near terminal ganglia to viscera of neck, thorax, foregut, and midgut
Pelvic splanchnic nerves S2, S3, S4 innervate what structures? (parasympathetic)
hindgut and pelvic viscera (including the bladder, rectum, and erectile tissue
During a lumbar puncture, a needle is passed through the interlaminar space while the vertebral column is flexed or extended?
flexed
The needles pass through what structures during a lumbar puncture if trying to collect CSF?
- skin
- superficial fascia
- deep fascia
- supraspinous ligament
- interspinous ligament
- interlaminar space
- epidural space
- dura
- arachnoid
- subarachnoid space
