Anatomy Flashcards
What structures arise from the diencephalon?
Thalamus, Hypothalamus, & subthalamus ( & posterior pituitary, & pineal gland)
What does the forebrain develop from?
Prosencephalon
What connects the forebrain with all caudal structures?
Cerebral peduncles
What part of the brain stem is connected to the cerebellum and what structure directly connects these structures?
Pons connects to cerebellum via the cerebellar peduncles.
What is the most caudal portion of the brainstem called?
Medulla
What separates the frontal lobe from the parietal lobe?
Central sulcus
What separates the temporal lobe from the parietal and the frontal lobes?
Lateral sulcus
What separates the occipital lobe from the parietal lobe?
The parieto-occipital sulcus
What brain lobe is located above and around the corpus callosum?
Limbic lobe
What structure is on either side of the third ventricle?
Thalamus
What connects the third ventricle to the fourth ventricle?
Cerebral aqueduct
At what level is the fourth ventricle?
Level of the pons and medulla
What is the function of the precentral gyrus?
Primary motor area
What are the three meningeal layers surrounding the brain, in order from outermost to innermost?
- Dura
- Arachnoid
- Pia
What are the two portions of the dura mater?
- Periosteal portion
- Meningeal portion
Where is the longitudinal fissure?
- what is the name of the flat sheet of dura that is found in this fissure?
The longitudinal fissure separates the two hemispheres of the brain.
The portion of dura in this fissure is called the falx cerebri.
What is the name for the tent-like sheet of dura covering the upper surface of the cerebellum?
Tentorium cerebelli
Which meningeal layer ensheaths blood vessels?
Pia mater
Use the following three options. In the brain, which are potential spaces and which are real spaces? (and what fills the real spaces?)
- Epidural space
- Subdural space
- Arachnoid space
- epidural & subdural spaces are potential spaces
- subarachnoid space is real and is filled with CSF
Where are the meningeal arteries found?
In the epidural space
A fracture of the temporal bone can cause what problem in the brain?
Rupture of the middle meningeal artery leading to an epidural hematoma
What causes a subdural hemorrhage?
Rupture of the bridging veins draining the cerebral hemispheres/subarachnoid space into the dural venous sinus
What is the radiological appearance of a subdural hemorrhage?
Crescent-shaped hematoma
What causes a subarachnoid hemorrhage?
Rupture of arterial aneurysm in the subarachnoid space
What is the radiological appearance of a subarachnoid hemorrhage?
Blood following the contour of the brain - blood may be seen dipping into the sulci
At what level does the spinal cord end?
- what structure is here and what continues below this level?
Spinal cord ends at L1-L2.
- location of conus medullaris
- continues as cauda equina
Use the following three options. In the spinal cord, which are potential spaces and which are real spaces? (and what fills the real spaces?)
- Epidural space
- Subdural space
- Arachnoid space
Real spaces are:
- Epidural space (filled with fat & venous plexus)
- Subarachnoid space (filled with CSF)
…
What separates the anterior and posterior roots of the spinal cord?
Dentate ligament
What is the dentate ligament made up of?
- what is its function?
Thickening of the pia mater & glial elements.
- Acts to anchor the spinal cord
From what brain/spinal levels do sympathetic neurons arise?
T1-L2
From what brain/spinal levels do parasympathetic neurons arise?
CN III, VII, IX, X
S2,3,4
What nerve roots make up the brachial plexus?
C5-T1
What nerve roots make up the lumbar plexus?
L2-S3
What nerve roots form the pre-vertebral plexus?
T5-L2
What attaches the caudal end of the spinal cord to the coccyx bone?
The filum terminale
What is the name of the point where sensory nerves enter the spinal cord?
- and for motor nerves?
- sensory (dorsal nerves) enter at the Posterolateral sulcus
- motor (ventral nerves) enter at the Anterolateral sulcus
What are the two main blood supplies for the spinal cord?
Vertebral-basilar & segmental arteries
Where do the segmental spinal arteries arise from?
intercostal arteries (posterior branches)
What do the segmental spinal arteries branch into?
- what do they supply?
- Radicular arteries –> supply anterior & posterior roots at each level
- and Segmental medullary arteries (only at some levels) –> supply either anterior or posterior spinal arteries
What does the anterior spinal artery supply?
- what does the posterior spinal artery supply?
Anterior - supplies anterior 2/3rds of spinal cord.
Posterior - supplies posterior 1/3rd of spinal cord.
Which spinal levels have lateral horns in the spinal cord cross section?
- what is found in the lateral horns?
T1-L2 (sympathetic portion of spine) & S2-S4 (parasympathetic branches)
- Lateral horns are the location for visceral motor (efferent) cell bodies.
What is the embryological origin of the forebrain?
- what two parts does it split into?
Prosencephalon
- splits into telencephalon & diencephalon
What is the embryonic origin of the midbrain?
Mesencephalon
What is the embryologic origin of the hindbrain?
- what two parts does it split into?
Rhombencephalon
- splits into metencephalon & myelencephalon
What is a large sulcus called?
fissure
What are the two parts of the limbic lobe?
- Cingulate gyrus
- Parahippocampal gyrus
What produces CSF?
Ependymal cells of the choroid plexus (lining of ventricles)
Where (and what, briefly) are the olivary bodies?
- oval-shaped glands in the anterior medulla, lateral to the pyramids
- location of olivary nuclei
Where does cranial nerve IV exit the brain?
Exits from the posterior midbrain and wraps around to join with CN III.
What is found in the medullary pyramids?
Descending motor tracts
Where are the superior and inferior colliculi?
-what is their function?
Located on the posterior/dorsal side of the midbrain.
- superior –> vision
- inferior –> auditory
What are the three types of fibre tracts in the CNS (in the brain)?
- Association - goes btwn parts of brain, but stays in same hemisphere
- Commisural - goes btwn hemispheres
- Projection - projects between brain & body
What nucleus is located directly beside the lateral ventricles?
Caudate nucleus
What nuclei are located lateral to the thymus?
Together, what are these nuclei called?
Globus pallidus
- more laterally –> Putamen.
Together called lentiform nucleus.
What is the internal capsule?
A major bundle of projection fibres located between the thalamus/caudate nucleus and the globus pallidus/putamen
Which structures are part of the basal ganglia?
- caudate nucleus
- globus pallidus*
- putamen*
(*GP + P = Lentiform nucleus) - substantia nigra
- subthalamic nucleus
What are arachnoid granulations?
Conduits from subarachnoid space to between the two dural meninge layers (superior sagittal sinus).
Name the structures where the CSF drains from the 4th ventricle.
Foramen of Magendii (medial).
Foramen of Lushke (lateral)
What are the special senses?
Smell, vision, taste, hearing, balance
Which cranial nerves are purely motor?
CN III, IV, VI, XI, & XII
Which cranial nerves are mixed motor and sensory?
V, VII, IX, X
What closes off the 4th ventricle dorsally?
Superior & inferior velum
What cranial nerves arise in the midbrain?
III (anteriorly) & IV (posteriorly)
Which cranial nerves have a nucleus in the midbrain?
III, IV, & V
Which cranial nerves are associated with the pons?
V, VI, VII, VIII
Which cranial nerve arises in the basal pons?
V
Which cranial nerves arise in the ponto-medullary junction?
Where are their nuclei?
VI, VII, VIII
Nuclei also in ponto medullary junction. W
Which cranial nerves arise in the medulla?
Where are the nuclei?
IX, X, XII
Nuclei also in medulla
Where does cranial nerve XI arise?
Upper levels of spinal cord
What connects the third ventricle to the lateral ventricles?
Interventricular foramen
Which spinal levels have the Joints of Luschka?
- what is another name for these joints?
- what makes up the joint?
C3-C7 have joints of Luschka.
- aka. uncovertebral joints –> forms from uncinate processes below (on lateral aspect of vertebral body) with uncus above.
What modalities are carried by the Glossopharyngeal nerve and what are they each responsible for?
Sensory:
- GSA –> sensation from pharynx, ear,
- GVA –> carotid body input
- SVA –> taste of posterior 1/3 of tongue
Motor:
- SVE –> controls stylopharyngeus muscle
- GVE –> controls parotid body secretion
Where are the nuclei for the visceral afferent (GVA & SVA) fibers of CN IX (glossopharyngeal)?
Nucleus solitarus - rostral medulla
Where are the nuclei for the visceral efferent (GVE & SVE) fibers of CN IX (glossopharyngeal)?
Just dorsal to the olives in the rostral medulla.
- GVE –> salivatory nucleus
- SVE –> nucleus ambiguus
Where is the nucleus for the general somatic afferent (GSA) fibers of CN IX (glossopharyngeal)?
Trigeminal nucleus
What travels through the jugular foramen?
- Jugular vein
- CN IX (glossopharyngeal)
- CN X (vagus)
- CN XI (accessory)
How does CN XII (hypoglossal) exit the skull?
Exits via the hypoglossal canal (adjacent to foramen magnum)
What travels through the superior orbital fissure?
- CN III (oculomotor)
- CN IV (trochlear)
CN VI (abducens) - CN V branch V1 (opthalmic nerve)
- superior opthalmic vein
Where does CN VIII (vestibulocochlear) enter the skull?
- what else travels through this area?
Internal auditory meatus.
- CN VII (facial) also travels through here.
What are the branches of the trigeminal nerve (CN V) and where do they travel through the skull?
V1 (opthalmic) travels through superior orbital fissure.
V2 (maxillary) travels through foramen rotundum.
V3 (mandibular) travels through foramen ovale.
What is the Foramen Lacerum?
an artifact.
- in life it is filled with cartilage.
- nothing travels through this ‘foramen’
What are the branches that form V1 (opthalmic nerve)?
- Frontal nerve –> branches to supratrochlear & supraorbital nerves
- Nasociliary nerve
- Lacrimal nerve
What types of fibers are found in each main branch of CN V (trigeminal)?
V1 - General Somatic Afferent
V2 - General Somatic Afferent
V3 - General Somatic Afferent & this travels with some Special Visceral Efferent fibres (for muscles of mastication)
What and where are the nuclei of CN V?
- what information does each process?
- Mesencephalic Nucleus (traverses midbrain to pons): processes proprioception from muscles of mastication
- Motor Nucleus (pons): controls muscles of mastication
- Chief Sensory Nucleus (pons): discriminative touch and vibration
- Spinal Trigeminal Nucleus (caudal pons to start of spinal cord): pain & temp sensation from face
Which spinal tracts need to be intact for genital orgasm to occur?
Spinothalamic & corticospinal
What separates the thalamus from the globus pallidus/putamen?
The internal capsule (fiber tract)
What are the two main gyri in the limbic lobe?
- cingulate gyrus
- parahippocampal gyrus
What is the main responsibility of the hippocampus?
memory
What is the main responsibility of the amygdala?
emotional processing
What connects the hippocampus to the mamillary bodies of the hypothalamus?
the fornix
Which nerves have SSA (Special Somatic Afferent) fibers?
- what information is carried?
Only CN VIII - balance, hearing
Which nerves have SVA (Special Visceral Afferent) fibers?
- what information do these carry?
CN IX & X - taste
What types of inputs go to the solitary nucleus?
Taste & other visceral sensory inputs
solitary nucleus looks like a doughnut - involved in taste
What is the clinical sign associated with increased pressure on the cerebral peduncles (due to transtentorial herniation)?
Paralysis/weakness on the contralateral side
What is the clinical sign associated with increased pressure on CN III?
Parasympathetic fibers are affected first causing loss of pupil constriction.
What is the parasympathetic efferent nerve for the thoracic and abdominal viscera?
CN X (Vagus)
Where are the nuclei for the visceral afferent fibers of CN X (Vagus)?
- what are these fibers responsible for?
Nucleus Solitarus
- sensory info from thoracic & abdominal viscera, aortic arch stretch receptors, carotid body chemoreceptors, and larynx
What modalities of CN X innervate the thoracic and abdominal viscera?
- General Visceral Afferent (GVA)
- General Visceral Efferent (GVE)
What is the nucleus for CN X fibers that are Special Visceral Efferent (SVE)?
- what is the function of these fibers?
Nucleus Ambiguus
(just posterior to the olives in the rostral medulla)
- motor to muscles of larynx & pharynx
What is the nucleus for General Somatic Afferent (GSA) fibers in CN X?
- what is the function of these fibers?
Spinotrigeminal nucleus in the rostral medulla
- sensory from external ear, pharynx, larynx, & posterior meninges
What is the nucleus for General Visceral Efferent (GVE) fibers in CN X?
- what is the function of these fibers?
Inferior Salivatory Nucleus
(just lateral to the hypoglossal nuclei in the rostral medulla)
- motor to thoracic & abdominal viscera.
- motor to smooth muscle and glands in larynx & parynx.
What is the function of CN XI (Accessory)?
- what is the UMN input to this nerve?
Motor to sternocleidomastoid & trapezius.
- gets input from Corticobulbar tract.
What is the function of CN XII?
- what type of fibers does it carry?
General Somatic Efferent (GSE) fibers.
- motor input to genioglossus & intrinsic muscles of tongue
Is the genioglossus controlled insilaterally, contralaterally, or bilaterally by the UMNs?
Contralaterally
Are the intrinsic muscles of the tongue controlled insilaterally, contralaterally, or bilaterally by the UMNs?
Bilaterally
What is the function of the genioglossus muscle?
Protrudes tongue.
Are the trapezius muscles controlled insilaterally, contralaterally, or bilaterally by the UMNs?
Contralaterally
Are the sternocleidomastoid muscles controlled insilaterally, contralaterally, or bilaterally by the UMNs?
Ispilaterally
What is the clinical sign with increased pressure on the medulla? (ie. in Tonsillar Herniation)
Breathing center is compromised and patient is in respiratory distress
What are the components of the Pharyngeal (branchial) apparatus?
- Pharyngeal arches (consist of muscle component, cartilage, cranial nerve, aortic arch).
- Pharyngeal pouches
- Pharyngeal grooves
- Pharyngeal membranes
What is the main anatomical difference between a pharyngeal pouch & a pharyngeal groove?
Both separate the pharyngeal arches.
- Pharyngeal pouch is a balloon-like pocket found internally;
- Pharyngeal groove is a cleft found externally
Which nerves are associated with each pharyngeal arch?
1st arch - CN V (V2 & V3)
2nd arch - CN VII
3rd arch - CN IX
4th arch - CN X (Superior Laryngeal branch)
6th arch - CN X (Recurrent Laryngeal branch)
What modalities of nerve fibers supply the derivatives of the pharyngeal arches?
- General Visceral Afferent (sensory)
- Special Visceral Efferent (motor)
What does the cartilage in the pharyngeal arches develop into?
1st arch (Meckel Cartilage) - middle ear ossicles & part of mandible
2nd arch (Reichert Cartilage) - one middle ear ossicle, styloid process, & part of hyoid bone
3rd arch cartilage - rest of the hyoid bone
4th/6th arche cartilages - laryngeal cartilage
What muscles are derived from each of the pharyngeal arches?
1st - Muscles of mastication, mylohyoid 2nd - Muscles of facial expression, stylohyoid 3rd - stylopharyngeus & glossopharyngeal 4th - Cricothyroid 6th - other layngeal muscles
Which pharyngeal groove contributes to adult structures? and what are these structures?
1st pharyngeal groove develops into external acoustic meatus.
Which pharyngeal membrane contributes to adult structures? and what are these structures?
1st pharyngeal membrane develops into the tympanic membrane
What connects the middle ear to the nasopharynx?
Eustachian tube.
What are the branches of CN V, V1 division?
- Frontal nerve –> splits into supratrochlear & supraorbital branches
- Nasociliary nerve –> splits into infratrochlear branch & ethmoid branch (adheres to the medial wall of the orbit)
- Lacrimal nerve
What are long & short ciliary nerves?
Long ciliary nerves: all sensory, feed into nasociliary nerve
Short ciliary - same as long ciliary but have parasympathetic fibers from CN III as well –> synapses in ciliary ganglion (has a sensory root & a motor root)
What is another name for the vergence center?
- where is it?
Supraoculomotor nucleus (SOA) - located in rostral midbrain
What modality of fibers go through the Spinal Trigeminal Nucleus & tract?
- from which cranial nerves?
GSA - from CN V, VII, IX, & X
Neurons of the mesencephalic reticular formation normally project to where?
To the intralaminar nucleus.
Stimulation of the mesencephalic reticular formation results in what?
A disruption of slow wave activity indicative of arousal.
What is the lateral geniculate nucleus?
Specific projection nucleus for vision.
What type of nucleus is the VPL? (specific or non-specific)
Specific projection nucleus
Name a non-specific nucleus in the thalamus.
Centromedian nucleus
What nucleus of the thalamus receives projections from CN V?
- specifically, which CN V nuclei are sending the information and what type of information is it?
VPM
- receives info from spinal trigeminal nucleus of V (GSA: pain&temp)
- receives info from chief sensory nucleus of V (GSA: touch&pressure)
Where do fibers from the mesencephalic nucleus project to?
- what information is carried in these tracts?
Cerebellum
- GSA: proprioceoption from muscles of mastication
- important for jaw reflex
The start of CN III (oculomotor) is found between which two arteries?
PCA (Posterior Cerebral a.)
&
SCA (Superior Cerebellar a.)
Which brainstem nucleus is associated with stimulation of parotid gland?
Inferior Salivatory Nucleus
What glands are stimulated by the facial nerve?
Submandibular (V3), sublingual (V3), & lacrimal (V1)
