Neuroanatomy Flashcards
From inferior to superior (i.e. ascending), what is the 4th branch of the external carotid artery in the neck?
a. Maxillary artery
b. Occipital artery
c. Facial artery
d. Lingual artery
e. Posterior auricular artery
a. Maxillary artery
b. Occipital artery
c. Facial artery
d. Lingual artery
e. Posterior auricular artery
The external carotid artery has several branches in the neck (SALFOPSI in ascending order): superior thyroid, ascending pharyngeal, lingual, facial (aka
external maxillary), occipital, posterior auricular,
superficial temporal, maxillary (aka internal maxillary). It can be distinguished on angiogram (figure) from the ICA, which has no branches in the neck.
During EC/IC bypass procedures for Moya Moya
disease, anastomosis of the superficial temporal
artery to the middle cerebral artery (or less commonly occipital artery to the posterior cerebralartery/posterior inferior cerebellar artery) may be performed
The pathway best describing how sympa- thetic fibers of the autonomic nervous system exit the spinal cord is
a. Via the dorsal roots and white rami
communicans
b. Via the ventral roots and white rami communicans
c. Via the dorsal roots and gray rami
communicans
d. Via the ventral roots and gray rami
communicans
e. Via the ventral roots and spinal nerves
a. Via the dorsal roots and white rami
communicans
b. Via the ventral roots and white rami communicans
c. Via the dorsal roots and gray rami
communicans
d. Via the ventral roots and gray rami
communicans
e. Via the ventral roots and spinal nerves
The left vertebral artery usually arises from the:
a. Arch of the aorta
b. Brachiocephalic trunk
c. Left common carotid
d. Left subclavian artery
e. Costocervical trunk
a. Arch of the aorta
b. Brachiocephalic trunk
c. Left common carotid
d. Left subclavian artery
e. Costocervical trunk
Each vertebral artery arises from its ipsilateral
subclavian artery. The aortic arch gives off three
branches in order: brachiocephalic trunk (or
innominate artery), left common carotid and left
subclavian arteries (A). The second commonest
branching pattern (termed a “bovine arch”) is
where the left common carotid arises from the
brachiocephalic trunk (B).
Hemiballismus results from lesioning which basal ganglia target?
a. Globus pallidus interna
b. Subthalamic nucleus
c. Substantia nigra pars reticularis
d. Striatum
e. Pedunculopontine nucleus
a. Globus pallidus interna
b. Subthalamic nucleus
c. Substantia nigra pars reticularis
d. Striatum
e. Pedunculopontine nucleus
Hemiballismus is a condition characterized by
unilateral, involuntary, violent flinging of the
limbs. Lesion is based in the contralateral subthalamic nucleus or its connections and due to vascular cause (PCA territory) but can occur in MS. Often settles spontaneously and drug treatment is ineffective
Lesion of which structure increases extensor tone?
a. Dentate nucleus
b. Pedunculopontine nucleus
c. Red nucleus
d. Ventral tegmentum
e. Superior olive
a. Dentate nucleus
b. Pedunculopontine nucleus
c. Red nucleus
d. Ventral tegmentum
e. Superior olive
Factors normally inhibiting extensor action in the
arms and legs are:
(A) Cortical inhibition of lateral vestibular
nucleus (vestibulospinal tract) and pontine
reticular formation
(B) Red nucleus projections to spinal cord
(rubrospinal tract; possibly arms only)
(C) Medullary reticular formation
Disconnection lesion involving red nucleus
results in loss of normal inhibition of extension
(rubrospinal and medullary reticular formation)
and loss of cortical inhibition of extensor action
of LVN and pontine RF, producing hyperreflexia
and increased extensor tone (decerebrate rigidity). Disconnection lesions above the red nucleus
result in extension in legs, but flexion in arms
(decorticate rigidity). This is explained as in
humans the rubrospinal tract terminates in the
cervical spine, meaning intact rubrospinal
input could counteract vestibulospinal (extensor)
input in the arms but it remains unopposed in
the legs.
Which one of the following drain into the cavernous sinus?
a. Superior ophthalmic vein
b. Superior petrosal sinus
c. Inferior petrosal sinus
d. Basal vein of Rosenthal
e. Vein of Labbe
a. Superior ophthalmic vein
b. Superior petrosal sinus
c. Inferior petrosal sinus
d. Basal vein of Rosenthal
e. Vein of Labbe
The cavernous sinus receives the superior and
inferior ophthalmic veins, sphenoparietal sinus
and the superficial middle cerebral vein (coursing
from superiorly to inferiorly in the Sylvian fissure). It drains via superior petrosal sinus (to
the junction of the transverse and sigmoid
sinuses), inferior petrosal sinus (to the internal
jugular vein). Right and left cavernous sinuses
are also connected across the midline anterior
and posteriorly to the pituitary gland via the anterior and posterior intercavernous sinuses, resulting in the circular sinus. Each cavernous sinus is also connected to the pterygoid venous plexus via small branches in the foramen Vesalii, foramen ovale and foramen lacerum
Persistent trigeminal artery is commonly:
a. Found in 3-5% of people
b. Found to connect to the proximal basilar artery
c. Found to branch off from the ICA just proximal to the meningohypophyseal trunk
d. Found to have a vascular abnormality in approximately 50% of cases
e. Found in conjunction with internal carotid artery aplasia
a. Found in 3-5% of people
b. Found to connect to the proximal basilar artery
c. Found to branch off from the ICA just
proximal to the meningohypophyseal
trunk
d. Found to have a vascular abnormality in approximately 50% of cases
e. Found in conjunction with internal
carotid artery aplasia
After the Pcomm, persistent primitive trigeminal
artery is the next commonest remnant of the fetal
circulation. It is seen in 0.1-0.6% of cerebral angiograms. It connects the cavernous ICA (just proximal to meningohypophyseal trunk) to the basilar artery between superior cerebellar and anterior inferior cerebellar arteries. Its persistence is usually associated with a hypoplastic basilar and vertebral arteries proximal to the anastomosis, as well as a hypoplastic PcommA. Its frequency is explained as the order of regression during embryogenesis is otic/acoustic artery first, then hypoglossal followed by trigeminal. Vascular abnormalities (AVM, aneurysm) is seen in 25%. Characterized by the tau sign (flow void) on sagittal MRI
The afferent loop of the Hering-Breuer inflation and deflation reflexes is mediated by:
a. CN XIII
b. CN IX
c. CN X
d. CN XI
e. C2
a. CN XIII
b. CN IX
c. CN X
d. CN XI
e. C2
The Hering-Breuer inflation and deflation reflexes
are thought to play a role in controlling the depth
of breathing, although may be less important in
humans at rest. Their overall effect is to prevent
overinflation and extreme deflation of the lungs.
The inflation reflex is mediated by pulmonary
stretch receptor afferents signaling via CNX during lung inflation to inhibit medullary inspiratory
center and the pontine apneustic center, as well
as inhibiting cardiac vagal motor neurons resulting
in sinus tachycardia. The deflation reflex also acts
via CNX and directly activates medullary inspiratory centers, stopping expiration and initiating
inspiration.
Which one of the following nerves is outside the annulus of Zinn?
a. Abducens
b. Nasociliary
c. Trochlear
d. Oculomotor (superior division)
e. Oculomotor (inferior division)
a. Abducens
b. Nasociliary
c. Trochlear
d. Oculomotor (superior division)
e. Oculomotor (inferior division)
The Annulus of Zinn (or annular tendon) is a
fibrous ring which surrounds the optic nerve,
and which is continuous with the dura of the middle cranial fossa. It is divided into upper (superior tendon of Lockwood) and lower (inferior tendon of Zinn) parts which together give rise to the four recti muscles (superior, inferior, medial,
lateral) and superior oblique. The remaining two
extraocular muscles, inferior oblique and levator
palpabrae superioris arise from the maxillary and
sphenoid bones respectively. The Annulus of
Zinn contains the optic nerve, ophthalmic artery,
superior division of CNIII, nasociliary division
of CNV1, CNVI, and the inferior division of
CNIII.
The C2 vertebra has how many secondary ossification centers?
a. 2
b. 3
c. 4
d. 5
e. 6
a. 2
b. 3
c. 4
d. 5
e. 6
Development of the vertebral column occurs in
three stages:
Mesenchymal stage—where somites gives rise to
sclerotomes (condensation of mesenchymal
cells around notochord and neural tube,
divided into a loosely packed upper half
and a densely pack lower half) and myotomes. The centrum (primordial vertebral
body) forms from the lower half of a cranial
sclerotome and the upper half of the immediately caudal sclerotome, such that the
intervertebral disc forms at the level opposite the myotome and the vertebral body is
at the level between two myotomes.
Cartilaginous stage—chondrification centers
appear in the centrum and vertebral arches,
causing cartilaginous fusion, and spinous
and transverse processes develop from
extensions of the chondrification centers in
the vertebral arches. Chondrification
spreads until a cartilaginous vertebral column is formed.
Bony stage—By the end of the embryonic period
each vertebrae usually has three primary ossification centers (centrum and each half vertebral arch), and the cartilaginous connection
between the arch and centrum allows growth
as the spinal cord enlarges after birth. After
puberty, five secondary ossification centers
appear—tip of spinous process, tip of both
transverse processes and annular epiphyses
of the vertebral body
A line drawn between the highest point of the iliac crests across the back usually denotes
a. L1/2 interspace
b. L2/3 interspace
c. L3/4 interspace
d. L4/5 interspace
e. L5/S1 interspace
a. L1/2 interspace
b. L2/3 interspace
c. L3/4 interspace
d. L4/5 interspace
e. L5/S1 interspace
Intercristal line (Tuffier’s line)—space between
L4 and L5 spinous process, or through L4 spinous process. In infants this is at the L5/S1 level
Which one of the following is labeled X in the image below?
a. Ophthalmic division of the trigeminal nerve
b. Meckel’s cave
c. Oculomotor nerve
d. Maxillary division of trigeminal nerve
e. Abducens nerve
a. Ophthalmic division of the trigeminal nerve
b. Meckel’s cave
c. Oculomotor nerve
d. Maxillary division of trigeminal nerve
e. Abducens nerve
Meckel’s cave (containing Gasserian ganglion). Axial view in T2 MRI is s
Which one of the following statements about the sympathetic nervous system is FALSE?
a. Innervation of thoracic viscera arises from T1-T4 spinal segments
b. Splanchnic nerves are unmyelinated
c. Preganglionic fibers enter the sympa-
thetic chain via white rami communicans
d. Sensory afferent fibers are important for visceral pain sensation
e. Preganglionic fibers synapse in either the sympathetic chain or prevertebral ganglia
a. Innervation of thoracic viscera arises from T1-T4 spinal segments
b. Splanchnic nerves are unmyelinated
c. Preganglionic fibers enter the sympa-
thetic chain via white rami communicans
d. Sensory afferent fibers are important for visceral pain sensation
e. Preganglionic fibers synapse in either the sympathetic chain or prevertebral ganglia
Pre-ganglionic sympathetic fibers (myelinated)
arise in the lateral horn of gray matter T1-L2
and exit the cord via the anterior (ventral) root
then as white rami communicans to reach the
sympathetic ganglion. Here they may synapse
onto unmyelinated post-ganglionic fibers or pass
through unchanged as splanchnic nerves (which
later synapse in prevertebral ganglia and innervate the viscera). Post-ganglionic fibers exit the
sympathetic chain at the same or different level
(after ascending or descending), via a gray ramus
communicans which relays fibers to an existing
spinal nerve. Sympathetic chain runs from the
skull base to coccyx on both sides of the vertebral
column.
Spinal segments responsible for sympathetic
innervation (e.g. vasoconstrictor to skin, pilomotor to hair, sudomotor to sweat glands)
T1-T2: head and neck via ICA/vertebral
arteries
T2-T5: upper limb
T1-T4: thoracic viscera via cardiac/pulmonary/esophageal plexus
T4-L2: abdominal viscera via splanchnic
nerves to coeliac/hypogastric plexuses (except adrenal medulla which receives a preganglionic fiber which has also traversed
the coeliac plexus)
T10-L2: pelvic viscera via splanchnic nerves to
pelvic plexus
T11-L2: lower limb
Sympathetic sensory afferents terminate in the
intermediate zone of gray matter in the cord and
are important in the appreciation of visceral pain.
Nervi erigentes are responsible for:
a. Inhibition of the external anal sphincter
b. Inhibition of the internal vesicle sphincter
c. Inhibition of the internal anal sphincter
d. Inhibition of the external vesicle sphincter
e. Inhibition of the rectal muscles
a. Inhibition of the external anal sphincter
b. Inhibition of the internal vesicle sphincter
c. Inhibition of the internal anal sphincter
d. Inhibition of the external vesicle sphincter
e. Inhibition of the rectal muscles
Sacral parasympathetic outflow:
Anterior (ventral) primary rami of S2, S3 and
(occasionally) S4 give off fibers termed pelvic
splanchnic nerves or nervi erigentes which join
the pelvic sympathetic plexus for distribution to
pelvic viscera:
- Visceromotor to rectal muscles, inhibitor to
internal anal sphincter
- Motor to bladder wall, inhibitor to internal
vesicle sphincter
- Vasodilator fibers to cavernous sinuses of
penis/clitoris
Parasympathetic sensory afferents terminate
in which one of the following?
a. Nucleus ambiguus
b. Solitary nucleus
c. Edinger-Westphal nucleus
d. Red nucleus
e. Superior colliculus
a. Nucleus ambiguus
b. Solitary nucleus
c. Edinger-Westphal nucleus
d. Red nucleus
e. Superior colliculus
Parasympathetic sensory afferents:
Afferent fibers from GI, respiratory, cardiac
and mouth/pharynx travelling in CN VII/
XI/X terminate in the solitary nucleus of
the medulla
Sacral afferents terminate in the S2-S4
gray matter
Important in maintaining visceral reflexes
Which one of the labels in the diagram below
of the internal auditory canal identifies the
facial nerve?
A. A
B. B
C. C
D. D
E. E
F. F
B. B
The internal auditory canal runs lateral and posteriorly from the porus on the medial surface of the
temporal bone to fundus (entry to middle ear).
The lateral portion of the internal canal is divided
into superior and inferior compartments by the falciform or transverse crest. The superior compartment is further divided into anterior and
posterior portions by the vertical crest (Bill’s bar).
Thus the IAC contains four main neural components in quadrants: the facial nerve (superior and
anterior), the superior vestibular nerve (superior
and posterior), the cochlear nerve (anterior and
inferior), and the inferior vestibular nerve (posterior and inferior). The inferior compartment does
not have a bony division for the cochlear and inferior vestibular nerves, but the cochlear nerve leaves
the IAC through a multiperforate osseous plate to
enter the cochlear modiolus.
Blood supply to the posterior pituitary gland
arises from branches of which internal
carotid artery segment?
a. C1 (Cervical)
b. C2 (Petrous)
c. C3 (Lacerum)
d. C4 (Cavernous)
e. C5 (Clinoid)
f. C6 (ophthalmic/supraclinoid)
g. C7 (communicating)
a. C1 (Cervical)
b. C2 (Petrous)
c. C3 (Lacerum)
d. C4 (Cavernous)
e. C5 (Clinoid)
f. C6 (ophthalmic/supraclinoid)
g. C7 (communicating)
Cavernous sinus imaging:
For each of the following descriptions, select the
most appropriate answers from the image above.
Each answer may be used once, more than once
or not at all.
1. Right optic nerve
2. Oculomotor nerve
3. Abducens nerve
1—g, 2—a, 3—c
Internal auditory canal:
For each of the following descriptions, select the
most appropriate answers from the image above.
Each answer may be used once, more than once
or not at all.
1. AICA
2. Basal turn of cochlea
3. Cochlear nerve
1—e, 2—c, 3—f
Cavernous sinus anatomy:
For each of the following descriptions, select the
most appropriate answers from the diagram
above. Each answer may be used once, more than
once or not at all.
1. ACA
2. Maxillary division of CN V (V2)
3. Oculomotor nerve (III)
1—b, 2—m, 3—g
Internal auditory canal:
For each of the following descriptions, select the
most appropriate answers from the image above.
Each answer may be used once, more than once
or not at all.
1. Facial nerve
2. Superior vestibular nerve
3. Greater superficial petrosal nerve
4. Posterior semicircular canal
1—q, 2—o, 3—b, 4—l