Brainstem Anatomy Flashcards
Brainstem components
-midbrain
-pons
-medulla
Dorsal view of brain
-left and right cerebral hemispheres
-cerebellum
-medulla (has lots of cranial nerves)
Ventral view of brain
-olfactory bulb
-optic chiasm
-midbrain
-pons
-medulla
Sagittal view of brain
-cerebrum
-cerebellum
-olfactory bulb (very large)
-pituitary gland
-midbrain
-pons
-medulla
Whats within the brainstem?
-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
Cranial Nerves
-arise from brain or brainstem
-paired
-can have motor, sensory, or both
Trigeminal Nerve
-coming off pons
-Motor: muscles of mastication
-Sensory: skin of the head/face
Facial Nerve
-coming off rostral part of medulla
-Motor: muscles of facial expression
-Sensory: rostral tongue, ear
Innervation of the extra-ocular muscles
-Oculomotor nerve
-trochlear nerve
-abducens nerve
Oculomotor Nerve
-innervates medial, dorsal, ventral rectus muscle, and ventral oblique muscle
Trochlear nerve
-innervates dorsal oblique muscle
Abducens nerve
-innervates lateral rectus muscle
Special senses
-Olfactory nerve
-optic nerve
-vestibulocochlear nerve
Olfactory nerve
-enters through cribiform plate
-extension of axons from olfactory bulb
Optic nerve
-enters at cranial aspect of brain
Vestibulocochlear nerve
-enters at junction of pons and medulla
-hearing and balance
CNs innervating pharynx, larynx, tongue
-CN IX, X, XI, XII
Cranial nerve damage
-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
Damage to brainstem
-results in sensory deficits and LMN signs (decreased tone, diminished/absent reflexes)
Deficits to CN V/VII
-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
Deficits to CN III, IV, VI
-damage to LMN: strabismus (abnormal eye position at rest)
**will pull eye CN VI-medially, CN III- lateral strabismus, CN IV- ventral
Deficits to CN I, II, VIII
-Sensory deficits only because they are only sensory nerves
No LMN damage
Deficits to CN IX, X, XII
-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)
