Week 5 - finished

Question 1

James, a 67 year-old retired butcher describes intermittent back pain of several years duration. His work involved standing for many hours. Pain in the low back and buttock arise after standing for short periods and are relieved by resting forward on a chair. Recently, James has had to discontinue his habit of walking for exercise due to pain in the low back, buttock, thighs and calf during prolonged ambulation.

Answer 1

xx

Question 2

1. What, and where, is the lumbosacral enlargement of the spinal cord?

Answer 2

Lumbosacral enlargement extends from T11 to S1. This is a section of the spinal cord which is larger because of the anterior rami that arise from these regions with motor and sensory innervation to the lower limb.

Question 3

2. At what level does the spinal cord end in a newborn infant, and in an adult?

Answer 3

In an infant, the spinal cord spans most of the vertebral canal. However as a persons bones grow, the vertebral canal lengthens when the spinal cord does not, so the spinal cord in an adult only reaches 2/3rds the way down the vertebral canal.

Question 4

3. What is the conus medullaris?

Answer 4

The inferior tapering of the spinal cord as the spinal nerves for the lumbar and sacral segments branch off from the spinal cord. Conus medullaris = medullary cone

Question 5

4. Describe the basic organisation of the grey and white matter in the spinal cord.

Answer 5

In the spinal cord the grey matter is in a butterfly shaped section in the deep aspect, with the white matter on the outside. The grey matter is in a butterfly/H shape, with each side consisting of an anterior/ventral (motor) horn and a posterior/dorsal (sensory) horn, connected by an intermediate zone. Between the levels of T1-L2-3 there are lateral horns which contain the sympathetic nervous system cell bodies. The white matter is arranged into columns. Between the 2 dorsal horns (with the dorsal median fissure in between) are the dorsal columns, and between the 2 anterior horns (with the ventral median sulcus in between) are the ventral columns. Between the anterior and posterior horns on each side are the lateral columns, which contain the tracts for the ALS, spinocerebellar tracts, as well the corticospinal tracts.

Question 6

5. What are the rootlets and roots of the spinal nerve?

Answer 6

Rootlets are the tracts that either enter or exit directly from the ventral/dorsal horns. They extend outwards from the spinal cord, and join together to form ventral or dorsal roots. The dorsal and ventral root join to form the spinal nerve. This spinal nerve then divides again into ventral and dorsal rami, which exit the IVF and either travel dorsally or ventrally (depending on their name) to innervate certain structures.

Question 7

6. What type of fibres does the anterior root contain?

Answer 7

Motor fibres

Question 8

7. What are the major branches of the spinal nerve?

Answer 8

Ventral primary ramus - supplies muscles and skin over the anterolateral body wall, upper and lower limbs Dorsal primary ramus - supplies deep (intrinsic) muscles & skin of the back, synovial joints of the vertebral column Meningeal branch - supplies vertebrae and spinal meninges

Question 9

8. What is the cauda equina?

Answer 9

The loose bundle of spinal nerve roots arising from the lumbosacral enlargement (L1 and below) and the medullary cone which course within the lumbar cistern of CSF, distal to the termination of the spinal cord. Nerves exit at their appropriate level. The “horses tail”. The inferior end of the spinal cord divides into its respective spinal nerves between the vertebral levels of T12 and L2. These spinal nerves however, do not exit the vertebral canal until they have reached their respective vertebral level.

Question 10

9. What spinal segmental levels are contained within the cauda equina?

Answer 10

All segments distal to L2

Question 11

10. What are the dural sac and the lumbar cistern?

Answer 11

Dural sac: Formed by the spinal dura, which extends between its attachments to the foramen magnum superiorly, and its terminal end at the level of S2. At the level of S2 it finishes, but it is anchored to the coccyx via the filum terminale; the vestigial remnant of the spinal cord and is made of pia mater. This pia mater pierces the dural sac and with a added layer of dura continues inferiorly to anchor onto the coccyx. Lumbar Cistern: Enlargement of the subarachnoid space between the conus medullaris of spinal cord (about vertebral level L2) and inferior end of subarachnoid space and dura mater (about vertebral level S2). Occupied by the posterior and anterior roots constituting the cauda equina, the terminal filum, and cerebrospinal fluid.

Question 12

11. What are the attachments of the spinal dura?

Answer 12

The spinal dura adheres to: - The margin of the foramen magnum - Vertebral bodies of C2, C3 and S2. - Rectus capitus posterior minor - Anchored to the coccyx by the filum terminale - Each pair of spinal nerves evaginates the dura so that the dural root sleeves extend laterally to adhere to the periosteum surrounding each IVF. ** remember the spinal dura is continuous with the inner meningeal layer of the dura of the skull.

Question 13

12. What is the filum terminale?

Answer 13

The vestigial remnant of the caudal spinal cord of the embryo. Its proximal part is formed by the vestiges of neural tissue and connective tissue covered by pia mater. The filum terminale pierces the end of the dural sac at around the level of S2 where the dural sac ends, and continues with a layer of dura mater to attach to the coccyx, anchoring the spinal cord and the dural sac inferiorly.

Question 14

13. List the three major arteries supplying the spinal cord.

Answer 14

The spinal cord is supplied by 3 longitudinal arteries: - they arise from the vertebral artery - 2 posterior spinal arteries - 1 anterior spinal artery They run within the vertebral canal. The supply from these arteries alone is not enough to supply the whole cord so circulation is reinforced by arteries that enter the vertebral canal via the IVF (Radicular arteries?)

Question 15

14. Review venous drainage of the spinal cord. Do these veins contain valves?

Answer 15

• Three anterior and three posterior spinal veins arranged longitudinally drain into anterior and posterior medullary and radicular veins. - Do not contain valves.

Question 16

15. Outline the level of disability caused by spinal cord transaction at different spinal levels.

Answer 16

C1 - C3 – No function below head level, ventilator to maintain respiration – otherwise death - C3,4,5 deeps the diaphragm alive! C4 - C5 – Respiration occurs, Quadriplegic – no function of upper or lower limbs C6 - C8 – Loss of hand and variable amount of upper limb function – self feed and propel wheelchair T1 - T9 – Between Cx and Lx enlargements – Paraplegic – paralysis of both lower limbs, amount of trunk control depends on height of lesion T10 – L1 – Some thigh muscle function – may allow walking with long leg braces L2 – L3 – Individual retains most leg function – short leg braces may be required for walking

Question 17

Upon further questioning, James told you that over the last 5 years, he has had increasing difficulty with micturition with decreasing levels of continence.

Answer 17

xx

Question 18

16. What are thecal signs?

Answer 18

Thecal signs – Valsalva manoeuvre/ SLR etc , tense of dura that’s already irritated o Meningeal irritation. o Where is the pain being reproduced.

Question 19

17. What size changes do the spinal and root canals undergo with normal movement?

Answer 19

• Flexion: o “opens” facets and creates a larger IVF o Affect on spinal canal= Gain 5-10 cm’s in height. o In degen: : Stretch on slacken structures, will increased the space. - Extension: o “closes” the facets and creates a smaller IVF - Side bending: o decreases the IVF on the ipsilateral side

Question 20

18. What is central canal stenosis and what is the clinical presentation?

Answer 20

Encroachment/narrowing of the central canal containing the spinal cord and spinal nerves. This can happen by: - disc herniation - vertebral fracture - spondylolisthesis - bony degeneration and growths - tumour Presentation – Flexed position, aggravated at night, chronic pain, possibly older person. Possibly UMN or LMN SSX depending on site. Sensory disturbances - A secondary ssx could be neural claudication

Question 21

19. What are redundant nerve roots and how do they diminish central canal space?

Answer 21

During normal aging, vertebral discs and bodies narrow which causes some of the nerves of the cauda equina to loop and buckle. They begin to fill the subarachnoid space.

Question 22

20. Which nerve roots are vulnerable to compression by a disc bulge at the L4 level?

Answer 22

Spinal nerves L5 and down (but realistically anything from L4 down)

Question 23

21. What is neurogenic claudication?

Answer 23

Compromising of vascular system of the neural tissue. o Venous back pressure, compressing a nerve that is already going through a narrowed space. Causes: o Anything that can cause spinal stenosis, narrow of the nerve passageways and restriction of nerve blood supply. o Hx of cancer, red flag for mets. Symptom: - leg pain (and occasionally numbness or weakness) on walking or standing, relieved by sitting or spinal flexion, related to neural compression, usually spinal stenosis.

Question 24

22. Compare neurogenic and vascular intermittent claudication. - Site - Age - Rest - Change in position - Arterial signs - Neuro screen - Walking uphill - Cause - Management

Answer 24

Vascular claudication: - Site: Distal > Proximal - Age: >40 yoa - Rest: Pain disappears almost instantly - Change in position: No effect - Arterial signs: Decreased skin nutrition, hair loss, decreased pulse. - Neuro screen: N/a - Presentation: Bilateral pain on walking - Walking up hill: Very aggravating - Cause: PVD - Management: Aspirin, balloon angioplasty, control risk factors, exercise. Neurogenic claudication: - Site: Proximal > distal - Age: 65+ - Rest: Back pressure through venous system so pain takes a while go to away. - Change in position: aggravated by extension, standing or being supine. Relieved by flexion, bending knees while supine (tensions loose structures which compromise blood vessels) - Arterial signs: N/a - Neuro screen: LMN ssx, paraesthesia - Walking uphill: Relieving (body is more flexed) - Cause: Spinal changes, age related changes (disc height decreases, redundant nerve roots, venous plexus dilates more, PLL and ligamentum flavum stretch). - Management: anaesthetic block, epidural corticosteroids, surgical decompression, flexion based Lx stabilisation.

Question 25

23. What are the signs and symptoms of upper motor neuron lesion and lower motor neuron lesion?

Answer 25

UMN: Are Excitatory Hyperreflexia Hypertonia (spastic paralysis) Clonus +ve superficial reflexes Muscle weakness - no wasting LMN: Are Inhibitory Hyporeflexia Hypotonia (flaccid paralysis) Shooting pains into arms and legs (electric shocks) Muscle weakness - wasting Muscle fasciculations

Question 26

24. What is cauda equina syndrome?

Answer 26

Compression of the nerve roots distal to L1. Causes: - bone tumour - bony spurs - spondylolisthesis - disc herniation - vertebral fracture - bony fragments Signs and symptoms: - LMN ssx (uni or bilateral) - bowel and bladder control problems - Impotence/ sexual dysfunction - Back pain - Numbness and tingling in the saddle area.

Question 27

25. What nerves to the lower limb may be affected if the cauda equina is compressed?

Answer 27

Any nerves with origins from nerve roots L1-L2 down. Most of lumbar plexus and sacral plexus - Femoral Nerve - Nerve to Piriformis - Nerve to quadratus femoris - Posterior femoral cutanenous nerve - Lateral femoral cutaneous nerve - Sciatic nerve - Obturator nerve - Sup and inf gluteal nerves

Question 28

26. What muscles may become weak, affecting gait, if the cauda equina is compressed?

Answer 28

Psoas (Ventral Rami of spinal nerves L1-3) Hip: - Flexors (L2-4, Femoral) - Extensors (L5-S2, Inferior and Superior Gluteal) - Adductors (L2-4, Obturator) - Abductors (L2-5, Superior Gluteal and Femoral) - External Rotators (L5-S1, Nerve to Obturator Internus and Nerve to Quadratus Femoris) - Internal Rotators Knee: - Flexors (tibial and common peroneal, L5-S2) - Extensors (L2-4, femoral) Ankle: - Dorsi flexors (deep peroneal, L4-S1) - Plantar flexors (tibial, L4-S3)

Question 29

28. What is the nerve supply to the bowel, bladder and penis?

Answer 29

S2 – S4 Pudendal - Parasympathetic - Pelvic splanchnic nerves - Sympathetic: T12-L2

Question 30

27. Which myotomes need to be assessed in the neurological exam for cauda equina, and what is the resisted movement for each level?

Answer 30

L2 - Hip flexion L3 - Knee extension L4 - Dorsiflexion L5 - Great toe extension S1 - Plantar flexion S2 - Toe flexion

Question 31

29. Which dermatomes correspond to the peri-anal region?

Answer 31

S2-S4

Question 32

30. Draw and label a schematic diagram of the reflex arc. Which segmental levels are assessed via a knee jerk reflex, and an ankle jerk reflex?

Answer 32

􀁸 Knee Reflex L4 (+L3) and the Ankle Reflex S1 (+L5)

• Striking the patellar tendon with a tendon hammer just below the patella stretches the sensory nerve fiber of the femoral nerve which synapses (without interneurons) at the level of L4 in the spinal cord, completely independent of higher centres. From there, an alpha-motor neuron conducts an efferent impulse back to the quadriceps femoris muscle, triggering contraction. This contraction, coordinated with the relaxation of the antagonistic flexor hamstring muscle causes the leg to kick.

Question 33

31. Cauda equina syndrome is regarded as a surgical emergency. Why is this so?

Answer 33

Can result in faecal and urinary incontinence as well as sexual dysfunction in men. Max time since onset can be 48hrs

Question 34

32. What structures may cause cauda equina compression?

Answer 34

Bones - trauma/fractures, body outgrowths, spondylolisthesis

Tumours

Disc herniations