2. Vertebral Column and Somatic Nervous System PDF

Preview

Summary

N/A...

Description

2. Vertebral Column and Somatic Nervous System Learning Objectives Reading Assignment: Gray’s pp. 51 – 86, 101-122 At the end of this session, the student must be able to: 1. define the regions of the vertebral column, and the direction and development of the normal

primary and secondary curvatures of the vertebral column. a. 7 cervical, 12 thoracic, 5 lumbar (fused), and 4 coccyx (fused) b. Primary curvature is a “C” shape as a fetus (thoracic and sacral), then the secondary curvatures develop as an infant when the head is able to be held up (cervical curve), and then as a toddler when walking begins (lumbar curve).

2. identify common abnormal curvatures of the vertebral column, and causes.

a. Scoliosis; late asymmetry in muscles, vertebrae or stance b. Kyphosis; osteoporosis of the vertebrae contributing to loss in height (elderly) c. Lordosis; late pregnancy or obesity

3. diagram and label the component parts of a typical vertebra, paying special attention to the

position of the nerves and spinal cord.

4. describe the synovial and symphysis joints between the vertebrae; describe the site of facet

syndrome. a. Synovial joints (Zygapophysial join) between the superior and inferior articular processes b. Intervertebral discs (Symphysis joint), ¼ of height of vertebral column. Has a pulpy gelatinous inside, and fibrious exterior

5. describe the structures of an intervertebral disc and the effects of motion and ageing on them,

especially how herniation affects nerves. a. Discs will dehydrate with aging and may collapse, when that occurs the nucleuous pulposis can come out (herniate), herniated discs can press on nerves or into the spinal column itself. Usually in the lumbar or cervical regions.

6. describe the locations of the ligaments that connect the vertebrae and discs; relate those to

the most common location of disc herniation, affecting spinal nerves.

Interspinous ligaments Ligaments flava Posterior longitudinal ligament Supraspinous ligament Anterior longitudinal ligament

7. correlate the ligaments with injuries and clinical procedures that involve them. a. Most likely to have herniation on the dorsal lateral aspect of the spinal cord d/t

no ligament support in that area. b. Anterior longitudinal ligament can be damaged during hyperextensions

(whiplash) c. Interspinous ligament can be strained in hyperflexion (whiplash) d. Ligamentum flavum, rich in elastin must be pierced to gain access to vertebral canal for spinal tap.

8. contrast the exact structures of vertebrae from each region with their functions and

vulnerability to injury. a. Larger range of movement in neck than other parts of the spine, but more instability in this area. Vertebral body is smaller in this area and the vertebral canal is largest through this region. Smaller muscle attachments in the neck. Foramen transerarium – specific to the cervical vertebrae (arteries run thru this) Atlas and axis are special vertebrae in the neck. b. Atlas (C1) – holds up the skull, no vertebral body c. Axis (C2) – holds the vertebral body from the Atlas (Dens) d. Hyperextension may fracture axis (diving,hangman’s fx) e. Thoracic vertebrae (has vertebral body to support heavier weight)

9. contrast the movements of the atlanto-occipital joint with the atlanto-axial joint.

a. Atlanto-occipital joint is responsible for yes (up and down motion) (occurs in the superior facets) b. Atlanto-axial joint is responsible for no (left and right motion)

10. relate the kinked position of the vertebral artery to effects of neck turning. a. 2 kinks of the vertebral artery (vulnerable area), can cause lightheadedness

when turning head, especially in elderly (can totally kink off the blood supply!)

11. describe the effects of osteoporosis, osteophytes and stenosis on vertebrae and the associated

nerves or cord. a. Osteoporosis causes decomposition of the vertebrae and possibly fractures or tumors. b. Osteophytes, cause sharp spicule growth on the bone, it can cause “mischief”

c. Stenosis, accumulation of extra bone on top of the vertebral body or lamina, causing stenosis and a decrease in space of the vertebral canal. (squished spinal cord or nerve)

12. correlate the features of the sacrum with access to spinal nerves for anesthesia.

a. The spinous processes of the lumbar vertebrae they leave an opening between the lamina and lumbar vertebrae which is a great access point for anesthesia. A needle can puncture the ligamentum flavam (L3 or L4) b. Sacrum has a gap in the sacral hiatus, allowing for anesthesia access caudal epidural ansethesia 13. define the central vs the peripheral nervous system.

a. Central nervous system brain and spinal cord, lies within the skull/vertebral column b. Peripheral nervous system include cranial nerves, spinal nerves, visceral nerves, and is outside the skull and vertebral column. 14. contrast the somatic with the visceral nervous system, both motor and sensory. a. Somatic controls body walls and limbs i. Motor to voluntary skeletal muscles ii. Sensory from skin, muscles and joint receptors b. Autonomic (visceral) nervous system: visceral organs, smooth muscle, glands

i. Motor 1. Sympathetic 2. Parasympathetic ii. Sensory (from viscera) iii. Enteric (Local intestinal wall circuits)

15. be able to draw and describe the anatomical and functional components of a somatic spinal

nerve (dorsal root, dorsal root ganglion, ventral root, spinal nerve proper, dorsal ramus, ventral ramus). Pay special attention to the sites of cell bodies and synapses.

16. be able to predict what functions would be lost if any of the anatomical components were damaged.

17. describe the layers of the meninges, especially the exact location of the cerebrospinal fluid. a. pia mater – “soft mother” adheres to the cord (inner layer) microscopic layer b. arachnoid mater – middle layer (spider webbing appearance) this contains cerebrospinal fluid below that layer and above the pia mater (subarachnoid space). c. dura mater – “Tough mother” outer layer, surrounds the arachnoid mater and protects the entire structure.

18. follow the arterial blood supply to the spinal cord from the aorta, including not only the segmental and radicular arteries, but the importance of the artery of Adamkiewicz, and the significance of each of these in ischemic stroke. a. Posterior and anterior spinal arteries (longitudinal arteries, 2 posterior, and 1 anterior), this is the main blood supply. b. Segmental arteries, one artery for each intervertebral foramen there’s a radicular artery that is fed from the aorta and this augments the blood supply. c. Artery of adamkiewics, variable in where it comes off T9-L1, large segmental artery that comes off the aorta. Blockage of the aorta at this level can cause paraplegia. d. Venous distribution, intervertebral vein

19. describe the significance of the vertebral venous plexus in the metastatic spread of cancer to the vertebrae. a. veins that nourish the vertebral body has flow that can travel both directions, and no valvues. So it allows metastic spread via the segmental veins draining other organs to the vertebrae. Nerve root compression may be presenting sign of cancer.

20. describe the position of the spinal cord within the vertebral column, and the effect of this on the course of exit of the spinal nerves of each region. a. The spinal cord ends around L1/L2 b. Where the nerves exit from the spinal cord is named after the vertebrae it is superior to. The first nerve that exits between the skull and C1 is named “C1”, and so on, but the cervical region has 8 nerves that exit and only 7 vertebrae. Cervical nerves are C1-C8

c. The thoracic nerves are named after the vertebrae that they are INFERIOR to. T1 vertebrae is superior to T1 nerve root. T1-T12. Same applies to lumbar and sacral.

21. diagram the contents of the lumbar cistern; describe why this is an optimal place to withdraw CSF. Understand the role of the filum terminale. a. the filum terminale is a long filament of pia mater that extends beyond the end of the spinal cord (L1), and all the way down into the sacrum and attaching to the coccyx.

22. describe the arrangement of ventral rami of the cervical and lumbar enlargements in the brachial and lumbo-sacral plexi.

23. contrast the placements of needles for lumbar puncture vs caudal epidural anesthesia, detailing the

exact anatomy. 24. define dermatomes and myotomes; explain how detailed knowledge of these can help diagnose the location of an injury to a spinal nerve. a.Dermatome: the area of skin innervated by a single spinal nerve overlap b. Myotome: the muscle mass innervated by a single spinal nerve. Individual muscles may be innervated by several spinal nerves.

If you know the distribution of that nerve’s dermatome and myotome, the symptoms will lead you back to which spinal nerve is damaged. 25. explain the distribution of shingles blisters in reference to dermatomes and sensory ganglia.

a. shingles is an infection of a single dorsal root ganglion, this causes blistering of the dermatomes in that region.

26. list several forms of peripheral neuropathy, and the significance of glove/stocking paresthesia. a. Diabetes, nerves damaged by inflammation or damage to blood vessel b. Guillain-Barre syndrome, acute autoimmune inflammation of myelin sheaths. Gloves and stocking appearance means that the issue isn’t from the central nervous system, but rather developed in the periphery.

27. use the knowledge of spinal nerve anatomy to predict the symptoms of disc herniation at particular levels. Be specific.

a. Disc damage in the lumbar spine will affect the lower nerve, as in the example of damage to L4, would affect nerve L5.

28. explain how testing of reflexes allows the localization of spinal nerve or spinal cord damage. Be specific. a. Each reflex will reflect the health of specific spinal nerves and cord segments. If the reflex works then you know the spinal nerves are healthy in that area.

Withdrawl reflex is a slower reflex as it happens in the spinal cord.

29. explain the use of the Babinski reflex to test the integrity of descending spinal cord control. a. Babinski reflex – in a baby the toes will sprawl up and out this is normal. (positive response) b. Babinski reflex in an adult, the toes should curl (negative response), if the toes curl up then there is a disconnection between the brain and peripheral nerves. 30. contrast flaccid vs spastic paralysis, and correlate this with your knowledge of the spinal nerves and reflexes. a. flaccid – nerve is damaged and the muscles are limp and don’t move b. spastic paralysis – damage is to brain or descending tracts, and the muscles give an exaggerated response

31. contrast the regenerative properties of the central vs the peripheral nervous system, and correlate this with the recovery from damage to each. Contrast the effects of muscle mass at different stages. a. peripheral nerves can regenerate, but only if surrounding connective tissue is realigned. Muscle will atrophy w/o functioning innervation, but if nerve regenerates so will muscle. b. Central nervous system can not regenerate

32. explain how neuromas may produce local or phantom pain. a. traumatic neuroma - when organized regeneration of a cut nerve cannot occur, in scars or amputation stumps, the nerve may form a hard nodule of disorganized nerves that may produce pain. b. mortons neuroma – involves a thickening of the tissue around one of the nerves leading to the toes. This can cause a sharp, burning pain in the ball of the foot....