Brainstem Flashcards
What sulci do the following nerves exit from?
- 12
- 11
- 10
- 9
- 12: Anterior lateral sulcus
- 11: Posterolateral sulcus
- 10: Posterolateral sulcus
- 9: Posterolateral sulcus
What is the surface marking which represents the surface marking of the spinal nucleus of the trigeminal nerve?
Tuberculum cinereum
BETWEEN THE CUNEATE TUBERCLE AND THE POSTEROLATERAL SULCUS
What are the structures on the floor of the 4th ventricle?
Hypoglossal trigone
Vagal trigone
Facial colliculus
Explain how hemiplegia cruciata works.
This happens with injuries to the lower medulla. One side with crossed upper extremity fibers is injured along with uncrossed lower extremity fibers!
Also note that the UE and neck fibers cross first AND ARE MORE SUPERFICIALLY LOCATED.
Which fibers project to nucleus cuenatus and which ones go to nucleus gracilis?
C: C1 to T7
G: Below T7
How can one have bilateral upper extremity paresis form a medullary lesion?
A lesion that hits the area where both UE fibers decussate.
The spinal trigeminal nuclei
- Descends up to what spinal level?
- Continuous with what nuclei rostrally and caudally
C3
Rostral main sensory nucleus of the trigeminal nerve in the pons
Substantia gelatinosa of the spinal cord
What are the 3 divisions of the spinal trigeminal nucleus and what are their functions
- Caudal nucleus: Pain and temp on the ipsilateral face
- Nucleus interpolaris: Dental pain
- Nucleus oralis: Tactile sensation from the oral mucosa
T or F: The perioral region projects to a more rostral portion of the spinal trigeminal nuclei while the region anterior to the mandible projects to a more inferior division.
T
What nucleus of the thalamus does the trigeminal thalamic tract carrying CN 5, 7, 9, 10 fibers synapse on?
VPM
Which fibers in the spinothalamic tract subserve temperature? More dorsal or more ventral?
Dorsal fibers
Ventral fibers subserve pain more
What fibers come from the nucleus gracilis and cuneatus to form the medial lemnisci?
Internal arcuate fibers
What are the functions of the accessory cuneate nucleus located dorsolaterally to the cuneate nucleus?
- Unconscious proprioreception: fibers from the dorsal spinocerebellar system
- Autonomic functions: Fibers from the vasopressor and cardioaccelaratory areas of the posterior hypothalamus, CN 9 and CN 10
What is the area posterma formed from?
Astroblast like cells, arterioles, sinusoids and apoloar and unipolar neurons
induces vomiting
What are the areas of the brain without BBB?
- Area posterma
- Subcommisural organ
- Pineal gland
- Subfornical corgan
- Organum vasculosum
- Neurohypophysis
- Median eminence
What are the 3 peduncles that connect the brainstem and the cerebellum?
- brachium conjunctivum to midbrain
- brachium pontis to pons
- restiform body to medulla
What are involved in the Jackson and Tapia syndromes?
Jackson: 9 10 11 12 and hemiparesis
Tapia: 9, 10 12
What is also known as Galen’s nerve?
Recurrent laryngeal nerve
Name the CN 10 nuclei and their functions:
EFFERENT
- Dorsal motor nucleus of Vagus: Preganglionic parasympathetic responsible for
- Nucleus ambiguus: ventral motor nucleus of vagus for the muscles of the pharynx and larynx
AFFERENT
- Nucleus of the spinal tract of CN 5 receiving somatic afferent fibers from the external ear, external auditory canal, external surface of the tympanic membrane
- Nucleus solitarius: Taste from the epiglottis (rostral) and general visceral (caudal) afferent from the pharynx and larynx, trachea and esophagus– also receives taste from 7 and 9
Name the CN 9 nuclei and their functions:
- Nucleus ambiguus: motor to the stylopharyngeus msucle
- Inferior salivatory nucleus for the parotid gland
- Nucleus of the spinal tract of CN 5 for the retroauricular region
- Nucleus solitarius: taste from the posterior 1/3 of the tongue and general visceral afferent from the posterior 1/3 of tongue and tonsils and eustachian tube
How does the CN9 contribute to the regulation of BP and HR?
Receives the carotid sinus nerve which innervates the carotid body (chemoreceptor) and carotid sinus (baroreceptor)– based on these inputs it can send volleys of signals to the dorsal vagal nucleus to effect HR and BP changes.
Nucleus is solitarius
Which vestibular nuclei are in the medulla?
Medical and inferior
Where do taste fibers synapse at the thalamus?
Ventroposteromedial
Lesions where cause Ondine’s curse?
Failure of automatic respiratory function asleep
Nucleus ambiguus and the adjacent reticular formation
Where are the inspiratory and expiratory neurons?
Inspiratory neurons are driven by nucleus solitarius
N ambiguus and n retroambiguus contains both
What is the effector site for neurogenic pulmonary edema?
N. Solitarius
Where are the
dorsal swallowing group and dorsal respiratory group
ventral SG and ventral RG
Located?
Dorsal N ambiguus
Ventral N solitarius
What are the inputs to the vomiting center in the nucleus solitarius?
Area postrema
Tast: CN 7, 9, 10
Autonomics
Vestibular system
What NT is secreted by:
- CN 12 nucleus
- Dorsal motor nucleus of vagus
- Nucleus ambiguus
- Reticular formation
- Raphe nucleus
- CN 12 nucleus Ach
- Dorsal motor nucleus of vagus Ach
- Nucleus ambiguus Ach
- Reticular formation: NE, Enkephalin
- Raphe nucleus Serotonin, Enkephalin
What are the sxs of
- Dejerine anterior bulbar syndrome/ Medial medullary syndrome
- Wallenburg
- Ipsilateral 12, contalateral hemiparesis with sparing of the face, contralateral loss of position sense
- Contralateral loss of pain and temp on the body but ipsilateral on the face
Ipsilateral horner’s syndrome
N ambiguus: dysphagia and dysarthria
Vestibular nuc: Dizziness, vomiting
Inferior cerebellar peduncle: ataxia
Hiccups
Olivoverebellar fibers: Ocular lateropulsion
saccadic eye movements with hypermetria toward the side of the lesion and hypometria away from it
What areas are affected with the babinski nageotte syndrome?
Combined lateral and medial medullary syndrome
What are affected:
- Vernet
- Collet Sicard
- Villaret
- Vernet: 9 10 11
- Collet Sicard: 9 10 11 12
- Villaret: 9 10 11 12 sympathetic
What is the largest group of fibers in the basis pontis?
The corticopontocerebellar fibers responsible for rapid correction of movements
What percentage of the tegementum needs to be lost before loss of consciousness occurs?
25%