Spinal Anatomy Flashcards
Mesoderm Subgroups (4)
Paraxial (somatic and splanchnic)
Intermediate
Head
Lateral Plate
Endoderm derivatives
Organs, gut, respiratory tract
“tubular structures”
Mesoderm: Paraxial
(two parts…)
Somatic:
musculoskeletal- muscles, ligaments, tendons…
Splanchnic
smooth muscle of organs
Mesoderm: Intermediate
Urogenital system and kidneys
Mesoderm: Head
skull muscles, dentine of teeth
Mesoderm: Lateral Plate
Adrenal cortex, connective tissue, cardiovascular and lymph
Ectoderm Subgroups
“Ectoderm: nerves and skin”
Surface ectoderm
Neuroectoderm (2)
Ectoderm: Surface Ectoderm
Epidermis, anterior pituitary, lens of eye, skin, enamel, hair, nails
Ectoderm: Neuroectoderm
(Subgroups and derivatives)
Neural Tube
posterior pituitary, retina of eye, CNS, oligodendrocyte
CNS: brain and sc
- *Neural Crest**
- *Outside CNS:** sympathetic chain gangion, DRG, ANS, PNS, Schwann cells, Parafollicular cells of thyroid, adrenal medulla
Neuroectoderm:
Embryological order
notochord
↓
neural plate
↓
neural groove
↓
neural tube
↓
neural crest cell
CNS Pathologies derived from neural tube defects:
Spina Bifida Occulta
lamina failed to fuse
tuft of hair growth = “fawn’s beard”
Caused by folic acid deficiency
(“Folic acid” / “Vit B9” / “methylfolate” / “tetrahydrofolate”)
CNS Pathologies derived from neural tube defects:
Spina Bifida Vera / “Spina Bifida Manifesta”
Meningocele, myelocele, meningiomyelocele…
Meningocele: meninges protrude
Myelocele: sc protrudes because of underdeveloped meninges
Meningiomyelocele: sc and meninges protruding
CNS Pathologies derived from neural tube:
Arnold Chiari Syndrome
(two types)
Type I:
cerebellar peduncles come below foramen magnum
Type II:
Type I + meningiomyelocele
CNS Pathologies derived from neural tube:
Cleft Palate
failure of maxillary and palatine bones to fuse
neural tube defect, B9 deficiency
(Embryological stages of development)
Mesodermal Development
Sclerotome = membranous vertebral column
Myotome = muscle
- Somatic: skeletal muscle
- Splanchnic: “visceral” smooth muscle
- Epimere: dorsal, posterior mm, extensors
- Hypomere: ventral, anterior mm, flexors
Dermatome = nerves
(Embryological stages of development)
Ossification
intramembranous/intramedullary ossification
- mesenchymal tissue → bone
- clavicle / parietal bone*
*or any skull bone, all are partially intramembranous
Enchondral ossification = preformed in cartilage
- ossification for all other bones (98%)
Dorsal Primary Rami
to back mm
Ventral Primary Rami
to front mms
Exception: any back mm that is innervated by a nerve coming off brachial plexus is primary..
rhomboids → dorsal scapular n
latissimus dorsi → thoracodorsal n
(GI Embryology)
Mouth
Foregut
Midgut
Hindgut
Mouth: stomodeum
Foregut: back of throat to first 1/3 duodenum
Midgut: last <span>2</span>/3 duodenum to first <span>2</span>/3 transverse colon
Hindgut: last <span>1</span>/3 transverse colon to anus
The Gubernaculum
Males
becomes scrotal ligament aka “gubenacular testes”
Females
suspensory ligament of ovary, ovarian lig, and round lig.
Primary and Secondary Vesicles
“Tell Di Mes Met Mye”
Prosencephalon
- Telencephalon
- Diencephalon
Mesencephalon
- Mesencephalon
Rhombencephalon
- Metencephalon
- Myelencephalon
Telencephalon
Derived from Prosencephalon
Cortices, basal ganglion, cingular gyrus
CN I (Olfactory n)
Lateral Ventricle
Diencephalon
Derived from Prosencephalon
thalamus (hypo-, epi-, sub-)
*epithalamus = pineal gland
CN II (Optic n)
3rd ventricle
Mesencephalon
remains mesencephalon
midbrain
CN III (oculomotor) CN IV (trochlear) *\*only CN off posterior portion of brainstem, and contralateral*
Aqueduct of Sylvius AKA Cerebral Aqueduct
Metencephalon
From Rhombencephalon
Pons and cerebellum
CNs 5-8
(V: trigeminal, VI: abducens, VII: facial, VIII: vestibulocochlear)
roof of 4th ventricle
Myelencephalon
From Rhombencephalon
medulla oblongata
CNs 9-12
(IX: glossopharyngeal, X: vagus, XI: accessory, XII: hypoglossal)
floor of 4th ventricle
*fold of tissue at floor of 4th vent: “obex”
just below 4th ventricle: cisterna magna/”cerebellomedullary cisterm”
(Neurology)
Dendrites vs Axons
Dendrites: impulse towards cell body
Axon: impulse away from body
*impulse originates at axon hillock
Overview
receptor (dendrite) → peripheral nerve → spinal cord → brainstem → cerebellum
(or) ↓
thalamus → parietal lobe → Wernicke’s area (POT) → limbic system → motor response
*Only senseation that bypasses thalamus is smell. Cerebellum receives information after impulses pass thru brainstem and also from cortex
(Action Potential)
Resting Membrane Potential
muscle vs neuron
Resting Membrane Potential: (-) inside, (+) outside
large molecules create (-) inside, sodium creates (+) outside
Muscle = (-85-90mv)
Neuron = (-65-70mv)
(Action Potential)
Receptors
Allow Na+ leak into cell, twoards depolarization of nerve for AP
Depolarization = Na+ rushing in
Dorsal Column Receptors
Pacinian
insignificant vibration
A-beta fibers
Dorsal Column Receptors
Ruffini
joint position sense
A-beta fibers
Dorsal Column Receptors
Meissner’s/Merkel’s
accurate touch
A-Beta fibers
Spinothalamic Tracts
Free Naked endings
pain, temperature, crude touch
unmyelinated C fibers
AP Threshold
controlled by
Ca++
Subnormal Period
“Hyperpolarized”
“relative refractory period”
more negative, harder to fire
Na/K Pump
kicks in after subnormal/hyperpolarized period
helps reach equilibrium/resting
pumps 3 Na+ OUT
2 K+ IN
Medulla and Pons
Respiratory and cardiac center
autonomics
CN 5-12
Midbrain
reflexes to light and sound
proximal flexor relay
CN 3&4
Thalamus
relay station
sensory fibers
Pulvinar region = integration of sensory information
VPM of Thalamus
sensory from face
VPL of Thalamus
sensory from arms and legs
Lateral geniculate of Thalamus
sensory from eyes
Medial Geniculate of Thalamus
sensory from ears
Cerebrum
Intellect and association
Parietal Lobe
localization
“somesthetic cortex”
Post-central gyrus
Brodman 1,2,3
problem solving
Occipital Lobe
Vision
Brodman’s 17
Superior Temporal Lobe
Hearing
Inferior Temporal Lobe
Long term memory
(hippocampal cells)
damage to hippocampus = anterograde amnesia
smell
(parahippocampal cells)
Uncal area
“Uncus is the skunkest”
Wernicke’s Area
junction of P/O/T lobes
sensory matching, interpretation
(does this make sense? if not, fire sympathetics)
Destroyed by B1/Thiamine
d/t alcoholism = Wernicke Korsakoff Syndrome
d/t diet = Beri Beri
sensory aphasia: can’t understand language
word blindness in angular gyrus
Frontal Lobe
Voluntary Motor
precentral gyrus
brodman 4, 4s, 6
corticospinal tracts
corticobulbar/pyramidal tracts = personality
motor aphasia = broca’s speech, left inferior frontal lobe
blood supply from middle cerebral artery
Limbic System
associated w amygdala
pleasure or pain?
do I need to remember this?
Basal Ganglia
inhibits thalamus
Disfunction: trivial information elicits motor response
= Parkinson’s
(stops motor response)
Basal Ganglia
Caudate Nucleus
secretes GABA
defective caudate
= Huntington’s Chorea
Basal Ganglia
Striatum
putamen + caudate
separated by internal capsule
Basal Ganglia
Lentiform Nucleus
globus pallidus + putamen
Hypothalamus
hunger
thirst
temperature regulation
sex
rage
fear
Cerebellum
balance
equilibrium
involuntary coordination
unconscious proprioception
Blood-Brain Barrier
astrocytes + tight capillary beds
stores glucose/glycogen
Microglia
macrophages
Ependymal Cells
line ventricles, produce CSF
CSF made in choroid plexus in lateral ventricles
resorbed in arachnoid granulations of superior sagittal sinus
Oligodendrocytes
myelin in CNS
demyelination = MS
derived from neural tube because within CNS
Schwann Cells
myelinate PNS
demyelinization = post-infectious polyradiculopathy
“Guillan-Barre”
ascending paralysis, post vaccine, post infection
Meissner’s & Auerbach’s Plexuses
allows peristalsis
from neural crest cells
absense = no peristalsis
congenital megacolon/Hirschprung’s Disease
Renshaw Cells
inhibit alpha motor neuron
(-) feedback
Alpha waves
quiet, meditative
disappear in sleep
Beta waves
intense mental activity
REM sleep
Delta waves
deep sleep or coma
ARAS = Ascending REticular Activating System
= wakes up the cortex
flying delta puts you to sleep/coma
Theta waves
normal in children, abnormal in adults
2nd/3rd stage of sleep, non-REM
Association fibers of cerebrum
connect same hemisphere
from frontal to temporal, etc.
Commissural fibers of cerebrum
connect L to R
corpus callosum
Projection fibers of cerebrum
connect up and down both directions
brainstem/sc
pass through internal capsule
Central chemoreceptors
found in brainstem (medullary neurons)
most sensitive to HIGH CO2
dilate cerebral blood vessels
Peripheral chemoreceptors
found in carotid and aortic bodies
most sensitive to LOW OXYGEN
dilate cerebral blood vessels
Vertebral arteries enter spine at
C6 transverse foramen
feed into Circle of Willis
enter skull at foramen magnum
PICA
Posterior Inferior Cerebellar Artery
off Vertebral Arteries
Damage to PICA = Wallenberg Syndrome
ipsilateral loss of pain and temperature to face
contralateral loss of pain and temperature to body
Anterior Spinal Artery
from both vertebral arteries
blood to anterior 2/3 of spinal cord
Posterior Spinal Arteries
off radicular arteries
blood to posterior 1/3 of spinal cord
Carotids
Right Carotid off R brachiocephalic
Left Carotid off Aorta
both bifurcate at C3/4 into
Internal Carotid and External Carotid
manterior and middle cerebral aa // maxillary to middle meningeal a
Straight Sinus
Great Cerebral Vein of Galen drains into Straight Sinus
“Great is Straight”
Straight Sinus found in tentorium cerebelli
Superior Sagittal Sinus
Superior Cerebral Vein drains into Superior Sagittal Sinus
“Superior is Superior”
Superior Sagittal Sinus found in falx cerebri
contains arachnoid granulations for resorbing CSF
Falx Cerebri attachments
Anterior attachment: crista galli of ethmoid
Posterior attachment: tentorium cerebelli
Confluence of Sinuses
torculus herophilus
on inner portion of occipital bone
Damage to sinuses
subdural hematoma
Emissary veins
drain scalp into superior sagittal sinus
Damage to middle meningeal a
epidural hemorrhage
epidural hematoma
Damage to venous system
subdural hemorrage
7-14 days to show
slow bleed
Beri aneurysm
(Circle of Willis)
subarachnoid hemorrhage
worst headache of life
full intensity, immediately
Flocculonodular lobe of cerebellum
midline
balance of spine
Cerebellar Nuclei
Fastigial
spine
Cerebellar Nuclei
Globus
proximal joints
glenohumeral
Cerebellar Nuclei
Emboliform
middle joints
elbow
globus + emboliform = interpose nuclei
Cerebellar Nuclei
Dentate
distal joints
digits
motor output
Interpose Nuclei
globus + emboliform
MSC
type 1a fibers
stretch
GTO
type 1b fibers
tension
Tectum of Midbrain
superior and inferior colliculi
- *superior** = light
- *inferior** = sound
reflex to light and sound = tectospinal tract
Corpora quadrigemina = the 4 colliculi
Tegmentum of Midbrain
CN 3 and 4*
CN4 comes off posterior portion
center of mesencephalon
Cerebral peduncles
“Basis Pedunculi”
contains corticospinal tracts
red nucleus = origin of rubrospinal tract
substantia nigra = dopamine for thalamus
Parkinsons if damaged
CN I: Olfactory
Origin
Foramina/bone
Action
frontal lobe
cribiform plate of ethmoid
smell
CN II: Optic
Origin
Foramina/bone
Action
thalamus
optic foramen of sphenoid
S: vision
R: afferent pupillary light reflex
CN III: Oculomotor
Origin
Foramina/bone
Action
midbrain
superior orbital fissure of sphenoid
M: “All else 3” (SO4, LR6, all else 3)
R: pupillary constriction
P: efferent pupillary light reflex
CN IV: Trochlear
Origin
Foramen/bone
Action
midbrain
superior orbital fissure/sphenoid
M: superior oblique
CN V1: Opthalmic/Trigeminal
Origin
Foramen/bone
Action
pons
superior orbital fissure of sphenoid
S: corner of canthus to bald spot
R: afferent corneal, afferent oculocardiac
“Oval Man, Rotate Max, Spin the Middle”
CN V2: Maxillary
pons
foramen rotundum of sphenoid
S:corner of canthus to corner of mouth
“Oval Man, Rotate Max, Spin the Middle”
CN V3: Mandibular/Trigeminal
pons
foramen ovale of sphenoid
S: corner of mouth to chin, general sensation to tongue
M: mm of mastication and tensor tympani
R: jaw jerk (afferrent and efferent)
CN VI: Abducens
pons
superior orbital fissure of sphenoid
M: lateral rectus
CN VII: Facial
pons
internal auditory meatus to stylomastoid foramen
of temporal bone
pierces parotid
S: “chordae tympani” from middle ear to anterior 2/3 of tongue for taste
M: facial mm and stapedius
R: efferent corneal
P: lacrimation, salivation
CN VIII: Vestibulocochlear
pons
internal auditory meatus, temporal bone
S: Balance (vestibulo)
Hearing (cochlear)
CN IX: Glossopharyngeal
medulla
jugular foramen, temporal/occipital
S: posterior 1/3 tongue - taste. middle ear
M: stylopharyngeus
R: carotid afferent, gag afferent
P: salivation (parotid glands)
CN X: Vagus
medulla
jugular foramen, temporal/occipital
S: tympanic membrane
M: palate, pharynx, larynx
R:carotid, gag, and oculocardiac efferent
P: palate to 1st 2/3 transverse colon
CN XII: Spinal Accessory
medulla
jugular foramen, temporal/occipital
M: SCM (w/CN2,3) - cont’l rotation, ipsi’l lat. flexion
traps (w/CN3,4) - forms slope of neck
O: acromion + clavicle I= sup nuchal line
CN XII: Hypoglossal
medulla
hypoglossal foramen, occiput
M: intrinsic mm of tongue
Temporalis
O: Temporal fossa
I: coronoid of mandible
closes jaw
Masseter
O: Zygomatic
I: external angle of jaw
closes jaw
Internal/medial pterygoid
O: medial pterygoid process
I: internal angle of jaw
closes jaw
External/lateral pterygoid
O: lateral pterygoid process
I: disc of TMJ and condyle of mandible
opens/depresses jaw
protrudes jaw
Greatest input into parasympathetics
nucleus solitarius (CN 7,9,10) for taste
Fovea centralis
most acute vision
has cones: bright light and colors