Events that happens at transition from SC to medulla
-Decussation of pyramids
-Termination of posterior column
-Dorsal/lat tract and posterior horn replaced by spinal tract and nuc of CN V
-Central canal opens to 4V at caudal medulla
The structures where the posterior column terminates
N. gracilis and n. cuneatus
Surface features seen at the SC to medulla transition
-Anterior median fissure
-Ventral root of C1
-Spinall roots of CN XI
Surface features seen at medullary region
-Rootlets of CN X, XII
-Cranial root of XI
Cranial nerves seen at pontomedullary junction
CN VI, VII and VIII
Surface features seen in pontine region
-Midline groove from basilar artery
-Mediolateral striations from fib.s forming middle cerebellar peduncle (MCV
-CN V piercing thru MCV
Surface features seen in midbrain region
-CN III exiting from fossa
-Crus cerebri (central portion of cerebral peduncle)
Medial to lateral dorsal structures in the medullary region
-FG terminates in the n. gracilis
-FC terminates in the n. cuneatus
Other structures seen in the dorsal medullary region
-Obex and median aperture of the 4V
-Inferior medullary velum
-Floor of 4V
Structures seen in the dorsal pontine region
-Floor of 4V
-Inf, mid and sup cerebellar peduncle
-Superior medullary velum
Structures seen in dorsal midbrain region
-Exit point of CN IV
-Brachium of the inferior colliculus
-Brachium of the inferior colliculus
Information conveyed by GSA's
Afferent information from the skin and mm
Information conveyed by GVA's
Afferent info from the viscera
What are GSE's and what do they inn
Motor neurons that inn striated m derived from the somites
N fibers and structures inn.ed by GVE's
-Pregang symp and para neurons
-Inn sm.m, card m and glands
Name of the dorsal region in the SC
Alar plate - sensory
Name of the ventral region of the SC
Basal plate - motor
What do SSA's deal with
Audition, vestibular sensation and vision
What do SVA's deal with
Associated with taste and olfaction
What do SVE's deal with
Inn striated m of branchiomeric orgin
What kind of nerve is CN XII
Special sensory efferent
What does CN XII innervate
-Intrinsic mm of tongue
-Extrinsic mm of tongue except palatoglossus
Where does CN XII come out
Dorsomedial portion of the rostral medulla LMNs go through reticular formation and exit between pyramids and olive
How does CN XI originate and travel
Comes from C1-C5 -> runs up through the foramen magnum -> joins small cranial component from the nucleus ambiguous -> exit brain lateral to olive
What does What does CN XI innervate
-mm of the larynx and pharynx
What kind of fibers run in the vagus
CN X SVE fibers innervate...
Mm of pharynx, palatoglossus, larynx and tensor veli palatini
CN X GVE fibers innervate...
Sm.m and glands of pharynx, larynx and thoracic/abdominal viscera
CN X visceral afferent fibers innervate...
-Larynx, trachea, eso, thoracic and abdominal viscera
-Stretch receptors in aortic arch
-Chemoreceptors in the aortic bodies adjacent to the arch
CN X GSA fibers innervate...
-Skin at back of ear and in external acoustic meatus
-Part of external surface of tympanic mem
Where does CN X leave the medulla
Laterally between the olive and tuberculum cinereum
What are the 5 components of CN IX
CN IX SVE fibers innervate...
CN IX GVE fibers innervate...
Where does the otic ganglion send fibers to
CN IX GVA fibers innervate...
Brings in sensation from the carotid body and carotid sinus
CN IX GSA fibers innervate...
-Sensation from posterior 1/3 of the tongue
-Skin of the external ear
-Internal surface of the tympanic membrane
CN IX SA fibers innervate...
Taste from posterior 1/3 of the tongue
Where does CN IX exit the medulla
Just rostral to CN X and just lateral to the olive
What are the sensory ganglia used by SVA and GVA fibers
Superior and inferior ganglia
Tractus solitarius and associated n. hold cell bodies for...
-CN IX SVA and GVA
Spinal trigeminal n. holds cell bodies for...
-CN IX SA
Inferior salivatory n. holds cell bodies for...
-CN IX GVE
Nucleus ambiguus holds cell bodies for...
-CN IX SVE
-CN X SVE
What fibers are embedded w/in the basilar pontine n.
What do decussating pontocerebellar fibers do
Course laterally to form middle cerebellar peduncle (MCP)
Where is the medial lemniscus
In the ventral portion of the tegmentum of the pons
What does the MCP provide
An efference copy of motor commands being sent to the BS and SC for mov't
How do the arm and leg innervations switch in the pons
Arms go medially and legs go laterally
Where is the STT located in the pons
Lateral portion of the pontine tegmentum
Which fibers go to the ventral posterior lateral nucleus (VPL)
What does the superior olive relay
-Auditory, inputs from both ears first come together
What makes up the trapezoid body
Fibers coursing mediolaterally from the superior olive
-Portion of the auditory pathway
What fibers run in the abducens n
Axons of GSE lower motor neurons
Where does the abducens nerve exit the BS
At the PMJ
What does CN VI inn and where are the cell bodies
Lateral rectus m
-Cell bodies in abducens n. in dorsomedial portion of caudal pons
What n fibers run in CN VII and which n. do they come from or project to
-SVE (Facial motor n.)
-GVE (Sup salivatory n.)
-GSA (Spinal trigeminal n.)
-SA (Solitary n.)
SVE fibers of CN VII inn...
Stapedius, stylohyoid, post belly of digastric, facial expression mm
GVE fibers of CN VII inn...
-Mucous mem of nose and hard/soft palate
GSA fibers of CN VII inn...
-Skin of concha and auricle
-Small area of skin behind ear
SA fibers of CN VII inn...
Taste from anterior 2/3 of the tongue and hard/soft palate
What four n. are associated with CN VII
-Facial motor n.
-Superior salivatory n.
-Spinal trigeminal n.
Where does the facial motor n. get inn from
How do the diff corticobulbar fib.s differ
-Fibs of inn of lower face receive only contralateral inn
-Fibs of inn of upper face receive bilateral inn
What kind of paralysis do you see with lesion of UMN of corticobulbar fib.s
Lower face only on one side
What kind of paralysis do you see with lesion of LMN of corticobulbar fib.s
Upper and lower of only one side
What fiber components are seen in CN V
SVE fibers of CN V inn...
-Mm of mastication
-Ant belly of digastric
GSA fib.s of CN V inn...
-Top of head
-Conjuntiva of eye
-Mucous mem of paranasal sinus
--External aspect of tympan mem
--Meninges of ant and middle cranial fossae
Which four n. do the fib.s of CN V associate with
-Spinal n. of trigem (GSA)
-Main sensory n. of trigem (GSA)
-Mesencephalic n. of trigem (GSA)
-Motor trigeminal n. (SVE)
Where is CN V located
Rostral portion of pons -> pierces thru middle cerebellar peduncle
Where are the GSA cell bodies
Trigeminal ganglion (in SC or mesencephalic n.)
What signals go to the main sensory n.
What fibers go to the Spinal n. of V
C and A∂ fibers
What is the spinal tract and n. of V equivalent to
Lissaurer's tract and dorsal horn of gray matter
What anatomical feature is made by the the spinal tract and n. of V
What is lat and med in the dorsolateral portion of the rostral pontine tegmentum
Lat: Motor trigem n.
Med: Main sensory n.
What is located just dorsal to the motor trigem n. and main sensory n.
Mesencephalic tract and n.
(medial to sup cerebellar peduncle)
Where does the second order projection from the main sensory and spinal n. of the trigem go to
Across midline thru medulla and caudal pons -> forms ventral trigeminothalamic tract -> terminate w/in VPM n. of thalamus -> then project to primary SS cortex in post central gyrus
What other smaller tract ariss from the main sensory n.
Small ipsilateral dorsal trigeminothalamic tract