Valley: CNS Issues Flashcards
Superficial to deep order of the meninges:
Dura mater
Arachnoid
Pia mater
Spinal cord
Afferent nerves are — and enter the spinal cord on the — (—) side.
Sensory , dorsal (posterior)
Efferent nerves are — and exit the spinal cord from the — (—) side.
Motor , ventral (anterior)
The spinal nerve root is connected to the paravertebral sympathetic ganglia by communicating channels called the — and — rami communicans.
White and gray
White rami carry — sympathetic pre ganglion is neurons.
Myelinated
Gray rami carry — sympathetic postganglionic neurons (type C fibers)
Unmyelinated
Motor nerves to skeletal muscle arise from the —— of the spinal cord.
Anterior horn
Preganglionic sympathetic nerves arise from the —— of the spinal cord.
Intermediolateral horn
What are the 2 divisions of the peripheral nervous system?
Somatic division and autonomic division
Somatic division of peripheral nervous system is made up of what two nerves?
Motor nerves to skeletal muscles
Sensory nerves for pain, touch, pressure, temp
Where is the epidural space located in relation to the ligamentum flavum: anterior, posterior, superior, inferior, or lateral?
The epidural space is anterior to the ligamentum flavum.
CN 1
Olfactory
CN 2
Optic
CN 3
Oculomotor
CN 4
Trochlear
CN 5
Trigeminal
CN 6
Abducens
CN 7
Facial
CN 8
Acoustic
CN 9
Glossopharyngeal
CN 10
Vagus
CN 11
Accessory
CN 12
Hypoglossal
Function of CN 1 (olfactory)
Smells
Function of CN 2 (optic)
Sees
Function of CN 3 (oculomotor)
Moves eyes; adduction of eye (medial rectus); pupil size
Function of CN 4 (trochlear)
Moves eyes
Function of CN 5 (trigeminal)
Chews (muscles of mastication), sensory from face
Function of CN 6 (abducens)
Moves eyes; abduction of eye (lateral rectus)
Function of CN 7 (facial)
Facial muscles, taste (anterior 2/3rds of tongue)
Function of CN 8 (acoustic)
Balance (vestibular); audition (cochlear)
Function of CN 9 (Glossopharyngeal)
Taste (posterior 1/3rd of tongue); carotid body and carotid sinus afferents
Functions of CN 10 (vagus)
Many actions including decreased HR; motor control of larynx and pharynx (NB: vagus has involvement with the airway)
Function of CN 11 (accessory)
Should and head movements
Functions of CN 12 (hypoglossal)
Moves tongue
The oculomotor nerve (CN3) innervates the — rectus muscle and causes the eye to —.
Medial , adduct
The abducens nerve (CN6) innervates the — rectus muscle and causes the eye to —.
Lateral , abduct
The cerebrospinal circulation pathway (10):
- Choroid Plexus
- Lateral Ventricles
- Foramina of Munro
- 3rd Ventricle
- Aqueduct of Sylvius
- 4th Ventricle
- Foramina of Lushka & Foramen of Magendie
- Subarachnoid Space of Spinal Cord
- Brain
- Arachnoid Villi
What are the 3 sites of formation of CSF?
Choroid plexuses of lateral, 3rd, and 4th ventricles
What is the site of reabsorption of CSF?
Arachnoid Villi
The — — — permits collateral blood flow in the event that a major vessel (right or left internal carotid arteries or basilar artery) becomes occluded.
Circle of Willis
What are the 3 major vessels that supply the circle of Willis?
- Right internal carotid
- Left internal carotid
- Basilar artery
What 2 arteries supply the basilar artery?
- Right vertebral artery
- Left vertebral artery
Stump pressure measures the pressure transmitted through the — back to the — for which endarterectomy is proposed.
Circle of Willis , carotid artery
What is a good stump pressure that is as reliable as EEG monitoring (gold standard) in predicting cerebral ischemia during cross-clamp application in CEA?
> 40mmHg
Volatile agents — cerebral blood flow and — cerebral metabolism.
Increase , decrease
Nitrous oxide — cerebral blood flow and — cerebral metabolism.
Increase , increase
Why does nitrous oxide increase cerebral flood flow and cerebral metabolism?
Due to the sympathomimetic actions of nitrous oxide.
Intravenous general anesthetics — cerebral blood flow and — cerebral metabolism.
Decrease , decrease
Ketamine — cerebral blood flow and — cerebral metabolism.
Increase , increase
Why does ketamine increase cerebral blood flow?
Because ketamine stimulates the sympathetic nervous system.
If a pt is hyperventilated prior to or during the administration of isoflurane, the cerebral blood flow —.
Decreases
Arterial blood is delivered to the spinal cord via what 3 ways?
- 1 anterior spinal artery
- 2 posterior spinal arteries
- Small segmental spinal arteries
The major source of blood (75%) to the spinal cord is the — which traverses the length of the spinal cord.
Anterior spinal artery
The posterior spinal arteries supply —% to the posterior cord.
25
Radicular (segmental) arteries, arising form the intercostal and lumbar arteries, augment — and — spinal artery blood flow.
Anterior and posterior
Radicular arteries enter each side of the cord via the intervertebral foramen and give rise to — and — radicular arteries that accompany — and — nerve roots to the spinal cord.
Anterior and posterior , Anterior and posterior
There are usually — radicular branches.
8
How many radicular branches are in the cervical, thoracic and lumbar regions?
Cervical: at least 1
Thoracic: 2
Lumbar: 1 in the upper lumbar region
Which is the largest radicular artery?
Great radicular artery (GRA), or the artery of Adamkiewicz
The artery of adamkiewicz (or GRA) enter the vertebral canal form the — side in the majority of pts (it is not bilateral) in the lower thoracic regions or upper lumbar region.
Left
What is the importance of the artery of adamkiewicz (or GRA)?
Major source of blood to the lower 2/3rds of the spinal cord.
If there is interruption of blood flow in the artery of adamkiewicz (or GRA) what can this lead to?
Paraplegia
The two posterior arteries, which together supply only —% of the blood to the cord, are formed from the
anastomoses of the — branch of the vertebral artery and the — branch of the bifurcation of
the second posterior radicular artery.
25 , posterior , ascending
The anterior spinal artery, which supplies blood to the anterolateral —% of the cord, is formed throughout by a series of ——.
75 , radicular arteries
The mid-thoracic region, supplied by the ———, usually receives only one afferent vessel, which arises from a left or right ——.
anterior spinal artery , intercostal vessel
The blood supply to the thoracolumbar cord (from T8 to the conus terminalis) is derived from the ———.
artery of Adamkiewicz
In 75% of cases the artery of Adamkiewicz joins the anterior spinal artery between — and —, and in 10% of cases it joins between — and —.
T8 and T12 , Ll and L2
With cross-clamp of the descending thoracic aorta, you would be most concerned about interrupting flow
through what vessel supplying the spinal cord? Why?
You should be most concerned about interrupting flow through the artery of Adamkiewicz. Aortic cross-clamping, which either incorporates the artery of Adamkiewicz between clamps or exposes it to hypo-perfusion, may lead to paraplegia.
Condition of non-arousal due to damage of the reticular activating system (RAS).
Coma
Caused by damage to brain above cerebellum and brainstem supratentorial); clinical manifestations include upper extremity flexion and lower extremity extension.
Decorticate Rigidity
Caused by extensive damage to brainstem or cerebral lesions that compress the thalamus and brainstem; clinical manifestations include arms and legs rigidly extended, body arched, and clenched teeth (see figure at left). Mechanical ventilation will be required for this patient because the brainstem, where the vital respiratory centers are located, is damaged.
Decerebrate Rigidity
What is normal intracranial pressure?
<15mmHg
Cushing’s Triad: In response to an increase in intracranial pressure there is?
(1) a reflex increase in mean arterial blood pressure, (2) a reflex decrease in heart rate, and (3) irregular respirations
— and — promote cerebral steal, which is also known as luxury perfusion.
Vasodilators or hypoventilation (increased C02)
When a vasodilator such as nitroprusside is administered, or when the patient is hypoventilated so that CO2 accumulates, vessels in non-ischemic brain dilate, flow to non-ischemic brain increases, and flow to ischemic brain decreases.
Cerebral Steal (Luxury Perfusion)
When the patient with an ischemic region of brain is hyperventilated such that PaC02 falls, blood vessels in non-ischemic brain constrict and blood is diverted to ischemic brain.
Inverse Steal (Robin Hood, Reverse Steal)
— improves blood flow to ischemic brain.
Hyperventilation
Cerebral Steal:
Non-Ischemic Brain: Blood Flow & Vessel Diameter
Ischemic Brain: Blood Flow & Vessel Diameter
Non-Ischemic Brain: Blood Flow increase & Vessel Diameter increase
Ischemic Brain: Blood Flow decrease & Vessel Diameter no change (maximally dilated)
Inverse Steal:
Non-Ischemic Brain: Blood Flow & Vessel Diameter
Ischemic Brain: Blood Flow & Vessel Diameter
Non-Ischemic Brain: Blood Flow decrease & Vessel Diameter decrease
Ischemic Brain: Blood Flow increase & Vessel Diameter no change (maximally dilated)
sella turcica, which houses the ——, is found in the ——.
pituitary gland , sphenoid bone
The —— rest on the anterior cranial fossa.
Frontal lobes
The —— rest on the middle cranial fossa.
Temporal lobes
The — and — are found resting on the posterior cranial fossa.
Brainstem and cerebellum
What is the correct placement of the multi-orifice catheter for withdrawing air entrained into the circulation during craniotomy when the patient is in the sitting position?
Optimal recovery of air following venous air embolism is provided by a multi-orificed catheter positioned high in the right atrium, 2cm below the superior vena cava (SVC)-atrial junction. Proper placement of the right atrial catheter high in the right atrium at its junction with the superior vena cava can increase its effectiveness because this is where air tends to localize. Note: the tip of a single-orifice catheter should be in the right atrium, 3cm above the superior vena cava-atrial junction.
Correct positioning of a single-orifice catheter is where?
3.0cm above the junction of the SVC atrial junction
Where is the correct position of a multi-orifice catheter?
2cm below the SVC arterial junction
Time of birth until fontanelles close: anterior?
18 months
Time of birth until fontanelles close: posterior?
2 months
Time of birth until fontanelles close: anterolateral?
2 months
Time of birth until fontanelles close: posterolateral?
2 years