1: Topographic Anatomy of the Brain and Spinal Cord Flashcards
Contains surface images for identification of parts and details about all parts covered in topographic anatomy lecture and lab
Spinal cord enlargements: where are they, and why are they present?
Enlargements are at cervical and lumbar segments
Cervical contain nerves supplying the arms, lumbar the legs
Conus medullaris
The lowest tapering portion of the spinal cord
Filum terminale interna
The continuation of the pia mater from the end of the conus medullaris
Cauda equina
The lumbar and sacral nerve roots arising from the conus medullaris
What are the dorsolateral and ventrolateral sulci?
Small grooves on the dorsolateral and ventrolateral portions of the spinal cord
Located at the point of exit of the nerve roots
Briefly describe the anterior median sulcus, dorsal median sulus, and dorsal intermediate sulcus
All help divide the spinal cord into three basic divisions (dorsal, lateral, and ventral funiculi)
AMS: anterior spinal artery runs here
DMS: very small sulcus
DIS: between the DMS and dorsolateral sulcus, a sulcus only present in the upper part of the spinal cord because it separates the fibers from the legs (medial) from those of the arms (lateral)
Dorsal funiculus: where is it and what is it?
Between dorsal median sulcus and dorsolateral sulcus
Almost exclusively contains the dorsal columns: ascending tract that conveys vibratory sense, well-localized touch, and joint position sense
Lateral funiculus: where is it and (brief) what does it do?
Between dorsolateral and ventrolateral sulci
Contains contralateral corticospinal and spinothalamic tracts
Damage -> weakness
Ventral funiculus: where is it?
Between ventrolateral and anterior median sulci
Distinguish the ventral horn from the dorsal horn
Ventral horn protrudes forward, dorsal protrudes back
Ventral is motor, dorsal is sensory
Briefly, what is the substantia gelatinosa?
A term for the most posterior portion of the dorsal horn
What is this structure?
Pons
What is this structure?
What does it do?
What emanates from it?
What is the effect of damage to this structure?
Middle cerebellar peduncle
Large white matter tract connecting the basal pons to cerebellum
The trigeminal nerve emerges from the junction of the basal pons with the middle cerebellar peduncle.
Incoordination (cerebellum functions to coordinate skilled movements)
Where is the medulla?
Portion of the brainstem from the spinal cord to the pons
What is the midbrain?
The portion of the brainstem extending rostally form the pons
What is this structure?
What does it contain?
Inferior olive (inferior olivary nucleus)
Contains a motor nucleus connected to the contralateral cerebellum
What is the post olivary sulcus and what does it contain?
What is the preolivary sulcus and what does it contain?
Post.: groove located dorsal to the protuberance of the inferior olive; CN IX and CN X nerve filaments emerge from here
**Pre.: **groove located ventral to protuberance of the inferior olive; CN XII filaments emerge from here
What is this structure?
What does it contain?
Brief description of purpose
Medullary pyramids
Bundles of fibers from cerebral cortex extending down to spinal cord (corticospinal neurons)
Critically important for voluntary movements (especially skilled)
What is this structure?
What does it contain?
Pyramidal decussation (crossing of fibers)
Comprise the descending motor tract in the lateral funiculus of the cord
What is this structure?
What is its function?
CN VI - Abducens nerve
Lateral eye movement
What is this structure?
What is its function?
CN VII - Facial nerve
Movement of muscles of facial expression
What is this structure?
What is its function?
CN VIII - Vestibulocochlear nerve
Hearing and inner ear balance
What is the acoustic tubercle?
Portions of CN VIII that wrap around the inferior cerebellar peduncle
What is this structure?
What is its function?
CN V - Trigeminal Nerve
Facial sensations and jaw movements
What is this structure?
What is its function?
Cerebral peduncle (crus cerebri): prominent bands of fibers on either side of the interpeduncular fossa (peduncle means “stalk”)
The primary fiber bundles that connect the cerebral cortex to the brainstem.
Allows the cortex to control the contralateral side of the body and head
What is this structure?
What is its function?
From where is it emanating?
CN III - Oculomotor nerve
Opening the eye, controlling many eye muscles, constricting the pupil
Found in the interpeduncular fossa: the depression in between the cerebral peduncle; contains the posterior perforated substance where branches of the basilar artery enter the midbrain
Name this structure.
Optic chiasm: location where the right and left optic nerves meet and form the optic tracts
Name this structure.
Olfactory tract
Name this structure.
Optic tract
Name this structure.
Pituitary stalk (infundibulum): part of the hypothalamus that is funnel-shaped; at the narrow part of the funnel is the stalk of the pituitary gland.
Name this structure.
Mamillary bodies: prominences on the ventral side of the hypothalamus that are part of the limbic system
Demarcate the junction between the midbrain and diencephalon
Name this structure.
Cerebellar flocculus: the small piece of cerebellum that lies in the area between the ventral pons and cerebellum
Flocculus = “a small tuft or mass”
Part of the flocculonodular lobe
Name this structure.
Cerebellar hemisphere: one of the two lateral portions of the cerebellum, separated by the vermis
Name this structure.
Cerebellar tonsil: the most inferior part of the cerebellum that lies just superior to the foramen magnum
Fill in the following structures related to the cerebellum:
The majority of the cerebellum consists of small folds, called ________
A deep division (___________) separates the anterior lobe of the cerebellum from the posterior.
There are two easily identified divisions to the cerebellum. The __________ is in the midline, while the lateral portions are termed the __________.
There are also two small lobes that are situated between the cerebellum and medulla, the ________ laterally and the _________ in the midline.
The majority of the cerebellum consists of small folds, called folia.
A deep division (primary fissure) separates the anterior lobe of the cerebellum from the posterior.
There are two easily identified divisions to the cerebellum. The vermis is in the midline, while the lateral portions are termed the hemispheres.
There are also two small lobes that are situated between the cerebellum and medulla, the flocculus laterally and the nodulus in the midline.
What is this structure?
Inferior cerebellar peduncle (aka restifom body): white matter tract connecting the medulla to the cerebellum
Forms part of the wall of the 4th ventricle
What is this structure?
Superior cerebellar peduncle (aka brachium conjunctivum): white matter tract connecting the midbrain to the cerebellum
What is this structure? What is it separating?
4th ventricle
Separates cerebellum from dorsal brain stem
Fill in the blank:
CSF leaves the fourth ventricle to the subarachnoid space through openings caudal to the cerebellum, the lateral __________________ and the midline ______________________
Lateral foramina of Luschka
Midline foramen of Magendie
What is the obex?
The caudal-most point of the 4th ventricle
What is this structure?
Gracile tubercle: prominence immediately lateral to the midline over the gracile nucleus
Continuous with the fasciculus gracilis inferiorly
What is this structure?
Cuneate tubercle: prominence lateral to the gracile tubercle over the cuneate nucleus
Continuous with the fasciculus cuneatus inferiorly
What is this structure?
Facial colliculus: prominence over the facial nerve as it does its “U-turn” around the abducens nucleus inside the pons
What is this structure?
Vestribular trigone: area lateral to the sulcus limitans that marks the position of the underlying vestibular nuclei
What is this structure?
Sulcus limitans: vertical groove on either side of the median sulcus
Marks the embryologic division between the alar and basal plates, which in the adult, separates motor and sensory nuclei (the motor nuclei are medial to the sulcus, sensory lateral).
Define corpora quadrigemina.
The four bumps on the dorsal surface of the midbrain (two inferior colliculi, two superior colliculi)
What is this structure?
What is its function?
Inferior colliculus: the “midbrain auditory center”; receives just about all the information from the cochlear nuclei (some directly and some indirectly) and integrates it
Neurons from the inferior colliculus project to the medial geniculate body, which is the thalamic relay for auditory information
What is this structure?
What is its function?
Superior colliculus: receives information directly from the retina (first-order neurons in the optic tract project to superior colliculus as well as other locations)
Involved in coordinating movements of the head and eyes
What are the brachium of the inferior colliculi and brachium of the superior colliculi?
Small ridges running laterally from the inferior/superior colliculi, respectively, on the lateral side of the midbrain
Superior: connects the superior colliculus to the lateral geniculate body; it passes superior to the medial geniculate body in its course
**Inferior: **conveys neurons from the inferior colliculus to the medial geniculate body
What is this structure?
Hypoglossal trigone: prominence over the hypoglossal nucleus (near the midline)
What is this structure?
Vagal trigone: prominence over the dorsal motor nucleus of CN X located immediately lateral to the hypoglossal trigone
The dorsal motor nucleus contains cell bodies of preganglionic parasympathetic neurons.
What is this structure?
CN XI - Accessory nerve
What is this structure?
Cerebral peduncle
What is this structure?
Dorsal median sulcus
What is this structure?
CN VII - Facial nerve
What is this structure?
Fasiculus cuneatus
What is this structure?
Fasiculus gracilis
What is this structure?
CN XII - Hypoglossal nerve
What is this structure?
Lateral funiculus
What is this structure?
Middle cerebellar peduncle