Brainstem Anatomy

Question 1

Brainstem components

Answer 1

-midbrain
-pons
-medulla

Question 2

Dorsal view of brain

Answer 2

-left and right cerebral hemispheres
-cerebellum
-medulla (has lots of cranial nerves)

Question 3

Ventral view of brain

Answer 3

-olfactory bulb
-optic chiasm
-midbrain
-pons
-medulla

Question 4

Sagittal view of brain

Answer 4

-cerebrum
-cerebellum
-olfactory bulb (very large)
-pituitary gland
-midbrain
-pons
-medulla

Question 5

Whats within the brainstem?

Answer 5

-LMN associated with cranial nerves
-UMN (cell bodies and axons)
-Ascending axons carrying proprioceptive information from the limbs
-Pontine Micturition center
-Neural circuitry associated with consciousness
-neural circuitry associated with cardiac and respiratory function

Question 6

Cranial Nerves

Answer 6

-arise from brain or brainstem
-paired
-can have motor, sensory, or both

Question 7

Trigeminal Nerve

Answer 7

-coming off pons
-Motor: muscles of mastication
-Sensory: skin of the head/face

Question 8

Facial Nerve

Answer 8

-coming off rostral part of medulla
-Motor: muscles of facial expression
-Sensory: rostral tongue, ear

Question 9

Innervation of the extra-ocular muscles

Answer 9

-Oculomotor nerve
-trochlear nerve
-abducens nerve

Question 10

Oculomotor Nerve

Answer 10

-innervates medial, dorsal, ventral rectus muscle, and ventral oblique muscle

Question 11

Trochlear nerve

Answer 11

-innervates dorsal oblique muscle

Question 12

Abducens nerve

Answer 12

-innervates lateral rectus muscle

Question 13

Special senses

Answer 13

-Olfactory nerve
-optic nerve
-vestibulocochlear nerve

Question 14

Olfactory nerve

Answer 14

-enters through cribiform plate
-extension of axons from olfactory bulb

Question 15

Optic nerve

Answer 15

-enters at cranial aspect of brain

Question 16

Vestibulocochlear nerve

Answer 16

-enters at junction of pons and medulla
-hearing and balance

Question 17

CNs innervating pharynx, larynx, tongue

Answer 17

-CN IX, X, XI, XII

Question 18

Cranial nerve damage

Answer 18

-CN emerge ventrolaterally and innervate structures on the ipsilateral (same) side of the body
**so will see same damage on same side when CN damaged

Question 19

Damage to brainstem

Answer 19

-results in sensory deficits and LMN signs (decreased tone, diminished/absent reflexes)

Question 20

Deficits to CN V/VII

Answer 20

-LMN damage
>flaccid muscles and no reflexes
»difficulty chewing/prehension of food
»dropped jaw/drooping ears, lips
»inability to blink (palpebral or corneal reflex)
>rapid atrophy of temporalis changes head shape

Question 21

Deficits to CN III, IV, VI

Answer 21

-damage to LMN: strabismus (abnormal eye position at rest)
**will pull eye CN VI-medially, CN III- lateral strabismus, CN IV- ventral

Question 22

Deficits to CN I, II, VIII

Answer 22

-Sensory deficits only because they are only sensory nerves
No LMN damage

Question 23

Deficits to CN IX, X, XII

Answer 23

-all cell bodies located in medulla
>IX, X, XI- mid medulla, XII-caudal medulla
-LMN damage
>difficulty swallowing
>gagging
>deviated tongue to opposite side
>stertor (loud breathing)- aritnoids not moving/expanding on respiration (airway flaccid)