Neuroanatomy

Question 1

Describe the pupillary light reflex pathway.

Answer 1

“1. light stimulates retina.

2. travels down optic nerve.
3. synapses with pretectal nucleus.
4. then synapses with bilateral edinger-Westphal nuclei
5. then travels to ciliary ganglion.
6. then innervates pupil to constrict.”

Question 2

what spinal levels innervate the hypogastric nerve?

Answer 2

“T10-L2.

Ref: Braddom, pg 602.”

Question 3

What spinal levels innervate the pelvic nerve?

Answer 3

“S2-4.

Ref: Braddom pg 602.”

Question 4

“For the following blood vessels, name the originating blood vessel, and what structures it supplies.

a. lenticulostriate
b. anterior choroidal
c. recurrent artery of heubner
d. thalmoperforator”

Answer 4

“a. Lenticulostriate: MCA (1. basal ganglia 2. IC).

b. anterior choroidal: ICA (1. Optic tract 2. lateral geniculate body 3. posterior limb IC).
c. recurrent artery of heubner: ACA (1. head of caudate 2. anterior limb IC).
d. thalamoperforator: PCA. (1.thalamus 2. posterior limb IC).

Ref: Netter’s concise neuroanatomy.”

Question 5

Where is the origin of the corticospinal tract?

Answer 5

“Prefrontal (primary motor) cortex, frontal lobe.
NOTE: lateral CST contralateral; anterior CST ipsilateral.
Ref: Netter’s concise neuroanatomy pg 48.”

Question 6

Give two CNS tracts responsible for a positive Rhomberg’s sign

Answer 6

“1. Vestibulospinal tract

2. Dorsal columns – fasciculus gracilis
3. Spinocerebellar tract (Anterior and posterior).”

Question 7

“Give the spinal tracts for:
a. Tactile and kinesthetic sense from hands
b. Tactile and kinesthetic sense from feet
c. Golgi and spindle afferents from hands (i.e. Proprioception)
d. Golgi and spindle afferents from feet (i.e. Proprioception)
E. Contralateral temperature sense
“

Answer 7

“a. Tactile and kinesthetic sense from hands: fasciculus cuneatus.
b. Tactile and kinesthetic sense from feet: fasciculus gracilis.
c. Golgi and spindle afferents from hands (i.e. Proprioception): cuneocerebellar tract, rostral spinocerebellar tract.
d. Golgi and spindle afferents from feet (i.e. Proprioception): spinocerebellar tract (posterior and anterior).
E. Contralateral temperature sense: spinothalamic tract (lateral > anterior).
Ref: wikipedia.”

Question 8

Name 3 tracts from the midbrain and pons

Answer 8

“1. Tectospinal: Reflex postural movement in response to visual, auditory, or tactile stimuli (superior colliculus).

2. Rubrospinal: Facilitate activity of flexor muscles and inhibits extensors (red nucleus).
3. Vestibulospinal: Facilitates activity of extensor muscles and inhibition of flexor muscles under the influence of the ear and cerebellum in maintenance of balance (lateral vestibular nucleus).
   Ref: Netter’s concise neuroanatomy pg 48.”

Question 9

List 4 areas of the brain responsible for memory.

Answer 9

“1. amygdala: emotional memories.

2. mammillary bodies: ie Korsakoff’s.
3. medial temporal lobes: declarative memory.
4. hippocampus
5. thalamus
6. caudate nucleus
7. cerebral cortex (prefrontal): retrieval.”

Question 10

List 5 functions of cranial nerve 7 (facial nerve).

Answer 10

“EFFERENT:
1. somatic motor (facial muscles, digastric, stylohyoid).
2. Visceral motor (via chorda tympani):
a. Submandibular and sublingual salivary glands.
b. Lacrimation.
3. Nerve to stapedius muscle.
AFFERENT:
1. taste (anterior 2/3 tongue) via chorda tympani.
2. somatic sensory around auricle (outer ear).
Ref: Wikipedia.”

Question 11

List 5 descending tracts in the spinal cord.

Answer 11

“1. corticospinal tract (lateral and anterior).
2. rubrospinal tract.
3. reticulospinal tract (lateral and medial) – inhibitory.
4. vestibulospinal tract.
5. tectospinal tract.
Ref: Netter’s concise neuroanatomy pg 49.”

Question 12

List 4 ascending tracts in the spinal cord.

Answer 12

“1. dorsal columns (fasciculus cuneatus and gracilis).
2. spinocerebellar tracts (posterior and anterior).
3. spinothalamic tract.
4. spinoreticular tract.
Ref: Netter’s concise neuroanatomy pg 49.”

Question 13

Name 3 descending excitatory tracts.

Answer 13

“1. Rubrospinal

2. Vestibulospinal
3. Corticospinal – glutamate – Can we use anterior and lateral as separate pathways”

Question 14

Name 1 descending inhibitory tract.

Answer 14

“Reticulospinal tract:

Inhibits flexor response to non-noxious stimulus; also contains circuitry for many complex actions, such as orienting, stretching, and maintaining a complex posture”

Question 15

Anatomic location of the corticospinal tracts at the cortical, internal capsule, medullary and SC levels (1999)

Answer 15

“Cortical – Precentral gyrus, Giant pyramidal cells of Betz in Layers 3 and 5 in Primary Motor Cortex - Primary motor neuron
Corona radiata
IC – Posterior limb
Cerebral peduncles
Basis pontis
Medullary – Pyramids - deccusation
SC – Lateral (Dorsal lateral) and Anterior (Medial) corticospinal tracts
80-85% - contralateral lateral corticospinal tract
20-25% - ipsilateral anterior corticospinal tract
Anterior Horn Cells”

Question 16

Name tracts from the medulla

Answer 16

“Vestibulospinal (vestibular nucleus in medulla so NOT from midbrain and pons!!!)
Facilitates activity of extensor muscles and inhibition of flexor muscles under the influence of the ear and cerebellum in maintenance of balance
Controls head and neck position
Balance for the entire cord
Medullar reticulospinal tract

Note
Hypothalmo-spinal tract – runs to the Cilliospinal intermediolateral column at T1-T2
Sympathetic chain”

Question 17

List 2 branches that come off of the ICA.

Answer 17

“1. ophthalmic artery.

2. anterior choroidal artery.
   a. Lateral geniculate body.
   b. Globus pallidus.
   c. Internal capsule (posterior limb, inferior portion).”

Question 18

List 2 branches that come off of the ACA.

Answer 18

“1. recurrent artery of Heubner.
2. medial striatal arteries.

a. head of caudate.
b. putamen.
c. globus pallidus
d. internal capsule (anterior limb).”

Question 19

List 4 branches/divisions of the MCA.

Answer 19

“1. lenticulostriate.

a. Caudate.
b. Lentiform nucleus.
c. Internal capsule (superior portion, posterior limb).
2. anterior temporal artery: temporal lobe (anterior portion).
3. orbital frontal artery.
4. M2 division (superior): frontal & parietal lobes.
5. M2 division (inferior): temporal & occipital lobes.”

Question 20

List a branch coming off the PCA.

Answer 20

Thalamoperforator branches.

Question 21

List 2 branches coming off the vertebral artery.

Answer 21

“1. anterior spinal artery: anterio 2/3 spinal cord.

2. PICA:
   a. Dorsal lateral medulla.
   b. nucleus 9, 10, 11 (nucleus ambiguus)
   c. Interior surface of cerebellum.”

Question 22

List 4 branches off the basilar artery.

Answer 22

“1. paramedian arteries: small penetrating arteries to base of pons.

a. Corticospinal tracts.
b. CN 6 exiting fibres.
2. labyrinthe artery: supplies inner ear (15% from basilar, 85% from AICA).
3. AICA:
a. Caudal lateral pons.
b. CN 5 and 7.
c. Inferior surface cerebellum.
4. SCA:
a. Dorsal lateral pons (above CN 5 nuclei).
b. Superior cerebellar surface.
c. Cochlear nuclei.”

Question 23

What are the contents of the cavernous sinus?

Answer 23

“Acronym: OTOM CAT (T is repeated).

1. O: oculomotor (CN 3).
2. T: trochlear (CN 4).
3. O: ophthalmic branch (CN 5, V1).
4. M: maxillary branch (CN 5, V2).
5. C: internal carotid artery.
6. A: Abducens (CN 6).
7. T: Trochlear (CN 4).

NOTE: “OTOM” is vertical, “CAT” is horizontal, with the “T”s overlapping.
Ref: http://radiopaedia.org/articles/o-tom-cat”

Question 24

“Name spinal nerve(s), Trunk(s), division(s), and cord for the following nerves:

1. Axillary nerve
2. Medial antebrachial cutaneous nerve”

Answer 24

“1. axillary nerve: posterior division, upper trunk, C5/6.

2. MAC: anterior division, inferior trunk, C8.”