Neuro Anatomy Flashcards
1
Q
Parts of forebrain
A
Cerebral hemispheres: telencephalon
-lateral ventricle
Diencephalon: thalmus and hypothalamus
-third ventricle
2
Q
Parts of midbrain
A
Mesencephalon
-cerebral aqueduct
3
Q
Parts of hindbrain
A
Pons
Medulla
Cerebellum
4th ventricle
4
Q
Primary brain vesicles
A
Prosencephalon –> forebrain
=telencephalon and diencephalon
Mesencephalon –> midbrain
=mesencephalon
Rhombencephalon –> hindbrain
=metencephalon and mylencephalon
5
Q
Prosencephalon
A
=Forebrain
–> Telencephalon –> cerebrum
+ lateral ventricles
–> Diencephalon –> thalamus and hypothalamus
+third ventricle
6
Q
Mesencephalon
A
= Midbrain
–> mesencephalon + cerebral aqueduct
7
Q
Rhombencephalon
A
=Forebrain
–> Metencephalon –> Pons + cerebellum
–> Mylencephalon –> Medulla oblongata
AND fourth ventricle
8
Q
Lateral sulcus of brain
A
Separates:
parietal and frontal lobes
temporal lobe from
9
Q
Central sulcus of brain
A
Separates:
pre-central gyrus = MOTOR - frontal lobe
post-central gyrus = SENSORY - parietal lobe
10
Q
Parieto-ooccipital sulcus of brain
A
Separates:
occipital lobe
parietal lobe
11
Q
Calcarine and postcalcarine sulci
A
Medial aspect of occipital lobe
= visual centre
12
Q
Broca’s area
A
Posterior part of the inferior frontral gyrus
(of dominant hemisphere)
Controls the motor elements of speech
13
Q
Auditory cortex
A
Temporal lobe
Lying on the superior temporal gyrus, which receives afferents from the medial geniculate body and is concerned with auditory stimuli
Temporal association cortex, which surrounds the auditory cortex and is responsible for the perception of auditory stimuli and their integration with other sensory modalities
14
Q
Temporal uncus function
A
Major role in olfactory stimuli
15
Q
Cranial nerves in the midbrain
A
Cranial nerves III and IV
Portion of sensory nucleus of cranial nerve V
16
Q
Cranial nerves of the medulla
A
Contains cranial nerve nuclei IX, X, XI and XI
Contains nucleus ambiguus (motor to cranial nerves
IX and X
Contains nucleus of tractus solitarius (sensory for
cranial nerves VIII, IX and X)
17
Q
Cranial nerves of the medulla
A
Contains cranial nerve nuclei IX, X, XI and XI
Contains nucleus ambiguus (motor to cranial nerves
IX and X)
Contains nucleus of tractus solitarius (sensory for
cranial nerves VIII, IX and X)
18
Q
Cranial nerves origin
A
2 : brain itself
2: midbrain
4: pons
4: medulla
19
Q
Blood supply to cerebellum
A
Three arteries
PICA - vetebral arteries
AICA - basilar arteries
SICA - basilar arteries
20
Q
Cerebellar peduncles
A
Three pairs
Midbrain: superior peduncles
Pons: middle peduncles
Medulla: inferior peduncles
21
Q
Cerebellar lesions
A
Give signs on same side of body
22
Q
End of subarachnoid space
A
Dura mater fuses with filum terminale at S2
= end-point of subarachnoid space
23
Q
31 pair of nerves originate from the cord:
A
- eight cervical
- twelve thoracic
- five lumbar
- five sacral
- one coccygeal
24
Q
Dorsal horns
A
Grey matter sensory cell bodies
25
Ventral horns
Grey matter motor cell bodies
26
Lateral horns
Found in the thoracic and upper lumbar cord
Cells of origin of preganglionic sympathetic system.
27
Arrangemen of motor fibres indescending tract
somatotopically arranged in the tract
Upper half medially
Lower part of the cord laterally
28
Descending tracts
Lateral corticospinal tracts = limbs
- Commences motor cortex
- Decussates in medulla
- Descends in pyramidal tract on contralateral side
- Enters anterior horn at each spinal segment to synapse with morot nuclei
Anterior corticospinal tracts =axial muscles (of the trunk)
- Fibres do no decussate in medulla
- Fibres eventually cross midline at segmental levels and terminate close to those in lateral corticospinal tract
29
Lateral corticospinal tract
= limbs
- Commences motor cortex
- Decussates in medulla
- Descends in pyramidal tract on contralateral side
- Enters anterior horn at each spinal segment to synapse with morot nuclei
30
Anterior corticospinal tract
=axial muscles (of the trunk)
- Fibres do no decussate in medulla
- Fibres eventually cross midline at segmental levels and terminate close to those in lateral corticospinal tract
31
Ascending tracts
Lateral and anterior spinothalamic tracts
=pain and temperature
Anterior and posteiror spinocerebellar tracts
=equilibrium
Posterior dorsal columns
=sensation: vibration, touch and proprioception
-medial fasciculus gracilis (of Goll) and the lateral fasciculus cuneatus (of Burdach)
32
Lateral and anterior spinothalamic tracts
Fibres enter posterior roots
Ascend a few spinal segments and relay in substanti gelatinosa
Cross to opposite side in ventral grey commissure close to central canal
Ascend in spinothalamic tracts to the thalamus, whence they are relayed to the sensory cortex
33
Arrangement of spinothalamic tracts
somatotopically arranged in the lateral spinothalamic tract
lower limb = superficial
upper limb = deep
34
Anterior and posteiror spinocerebellar tracts
Ascend on same side of cord
Anterior --> superior cerebellar peduncle
Posterior --> inferior cerebellar peduncle
Concerned with the maintenance of equilibrium
- This is why cerebellar lesions affect unilateral side
35
Dorsal columns
Composed of:
- Medial: fasciculus gracilis (of Goll)
- Lateral: fasciculus cuneatus (of Burdach)
Contain fibres subserving fine and discriminative
tactile sensation, proprioception and vibration
As cord is ascended, fibres are added to lateral part of posterior columns
— fasciculus gracilis deals mostly with the lower
limb and the fasciculus cuneatus with the upper limb
Fibres in dorsal columns are uncrossed
- -> synapse in gracile and cuneate nuclei in medulla
- -> second–order fibres cross in the sensory decussation whence they synapse in the thalamus
- -> third–order fibres pass to the sensory cortex
Some fibres pass from medulla to cerebellum
along the inferior cerebellar peduncle.
36
Lateral: fasciculus cuneatus (of Burdach)
Lower limb sensation and propioception
37
Medial: fasciculus gracilis (of Goll)
Upper limb sensation and propioception
38
Blood supply to spinal cord
Vertebral arteries -->
- anterior spinal artery
- posterior spinal artery
Anterior spinal artery
-whole of cord in front of posterior grey columns
Posterior spinal artery
-posterior grey columns and dorsal columns
Spinal artery reinforced at segmental level by radicular arteries, i.e. branches of the ascending cervical, cervical part of the vertebral, posterior intercostal and lumbar arteries
39
Blood supply to dorsal columns
Posterior spinal artery, branch of vertebral arteries
Supplies posterior grey columns and dorsal columbs
(anterior spinal arterior supples rest of cord)
40
Anterior cord syndrome
Associated with flexion / rotation injuries --> anterior dislocation or compression fracture
--> Loss of power below lesion
--> Loss of pain and temperature below lesion
(the anterior spinal artery may be compressed)
Posterior columns remain intact so sensation and proprioception normal
Also can occur if anterior spinal artery interupted for any reason
41
Central cord syndrome
Occurs in syringomyelia and centrally placed tumours
Initially involves decussating spinothalamic tracts
--> pain and temperature sensation is lost below lesion
Later, the lateral corticospinal tracts are involed
--> intially involing the more centrally placed cervical tract supplying the arm
--> flaccid weakness of the arms
--> distal leg and sensory fibres are spared, perianal sensation and some leg movement and sensation may
be preserved
Proprioception and fine touch are preserved in
the dorsal columns until late
42
Posterior cord syndrome
Hyper-extension injuries with fractures of the posterior vertebral elements
Loss of proprioception with profound ataxia with unsteady and faltering gait
Good power and pain and temperature sensation below the lesion
43
Brown Sequard syndrome
Hemisection of the cord - stab injury or damage to lateral mass of vertebrae
--> Paralysis on affected side below lesion (pyramidal
tract)
--> Loss of proprioception and fine discrimination
(dorsal columns) on affected side below lesion
AND
--> Loss of pain and temperature on opposite side
below lesion (normal on affected side because of decussation below level of hemisection)
Therefore the uninjured side has good power, but absent sensation to pinprick and temperature
44
Cauda equina syndrome
Compression of lumbosacral nerve roots below conus medullaris
Caused by bony compression OR disc protrusion in lumbosacral region
--> Lower motor lesion
- -> Faecal incontinence
- -> Over-flow incontinence from urinary retention
- -> Leg numbness and weakness
45
Layers of dura mater
Two layers
- Endosteal layer (outermost)
- Meningeal layer (innermost)
Continuos together except when meningeal layer folds to make walls of venous sinuses
Inner meningeal layer is continuous with dura mater of spinal cord
46
Folds in dura mater
Falx cerebri
= between the two cerebral hemispheres
Tentorium cerebelli
=posterior clinoid process of sphenoid bone --> runs posteromedially along the superior border of the petrous temporal bone where superior petrosal sinuses enclosed
Falx cereblli
=lies between the two lateral lobes of the cerebellum
47
Tentorium cerebelli
Attaches anteriorly to clinoid process of sphenoid
Runs posteromedially along superior border of petrous temporal bone where superior petrosal sinus enclosed
Runs posterior and medially, curving round the
midbrain, forming tentorial notch.
Just behind the apex of the petrous temporal bone,
the inferior layer prolongs into the middle cranial fossa as the trigeminal cave
48
Straight sinus
Inferior sagittal sinus lies in free inferior border of falx cerebri
Straight sinus = where the falx meets the tentorium cerebelli
49
Subarachnoid cisterns
Cerebellomedullary cistern (cisterna magna): posterior to medulla below cerebellum
Pontine cistern: anterior to pons
Interpeduncular cistern: between cerebral peduncles and optic chiasma—contains circle of Willis and cranial nerves III and IV
50
Openings of fourth ventricle
Three openings in roof of fourth venttricle
Foramen of Magendie in midline
Paired: foramina of Luschka laterally
51
Branches of basilar artery
Anterior inferior cerebellar
Labyrinthine artery
Pontine arteries
Superior cerebellar arteries
Posterior cerebral artery (terminal branches of basilar artery)
52
Branches of internal carotid artery
Posterior communicating artery
Anterior cerebral artery
Middle cerebral artery
Anterior choroidal artery
53
Superior cerebral veins
Drain into superior sagittal sinus
- runs from crista galli --> internal occipital protuberence
- -> becomes right transverse sinus
54
Inferior dural sinus
Lies along inferior border of falx cerebri.
- Receives cerebral veins from medial surface of hemispheres
- Joins great cerebral vein to form straight sinus
Straight sinus
- Formed by union of inferior sagittal sinus and great cerebral vein
- Lies in attachment of falx cerebri to tentorium cerebelli
- Becomes continuous with left transverse sinus near internal occipital protuberance
55
Confluence of sinuses
Formed by the two transverse sinuses near the internal occipital protuberance
Superior sagittal --> RIGHT
Inferior sagittal --> straight sinous --> LEFT
56
Sigmoid sinus
Passes through jugular foramen
Becomes continuous with internal jugular vein
57
Occipital sinus
Small sinus extending from foramen magnum
--> drains into confluence of sinuses
Lies along falx cerebelli and connects vertebral venous plexuses to transverse sinus
58
Cavernous sinus
Situated on body of sphenoid
From suprior orbital fissure --> apex of petrous temporal bone
Medial: pituitary gland and sphenoid sinus
Lateral: temporal lobe
59
Structures running THROUGH cavernous sinus
Internal carotid artery
Abducens nerve CN VI
60
Structures running in lateral wall of cavernous sinus
| OTOM
From superior --> inferior:
- oculomotor nerve CN III
- trochlear nerve CN IV
- opthalmic division of trigeminal CN V1
- maxillary division of trigeminal CN V2
OTOM
61
Drainage of the cavernous sinus
Opthalmic veins drain into anterior part
Emissary veins passing through the foramina of the middle cranial fossa connect the cavernous sinus to the pterygoid plexus and facial veins
Two sinuses are connected by anterior and posterior cavernous sinuses lying in front of and behind the pituitary gland
Cavernous sinus drains posteriorly
- superiorly: transverse sinus via superior petrosal sinus
- inferiorly: sigmoid sinus via inferior petrosal sinus
62
Cavernous sinus thrombosis
Oedema of conjuctivae and eyelids
Exopthalmos with transmitted pulsations from internal carotid artery
Opthalmoplegia due to CN palsies
Opthalmoscopy: papilloedema and retinal haemorrhages
63
Uncinate fit
Tumours of temporal uncinate may present as an unincate fit
Uncinate = olfactory centre
Unincate fit = olfactory hallucinations with impairment of consciousness and involuntary chewing movements
64
Lamina cribrosa
Axons of ganglion cells of the retina pierce sclera to form optic nerve
65
Geniculate body
Geniculate body is in thalamus
=end of optic tract
66
Superior colliculus or prerectal nucleus
Small proportion of optic tract end at superior colliculus or prerectal nucleus
--> pupillary, ocular and head and neck reflexes =afferent limb of light reflexes
67
Complete division of CN III causes..
Ptosis, due to paralysis of levator palpebrae superioris
Divergent squint, caused by unopposed action of lateral rectus and superior oblique
Dilatation of the pupil, caused by unopposed action of dilator pupillae
-supplied by sympathetic fibres in the long ciliary branches in the nasociliary nerve
Loss of accommodation and light reflexes, due to paralysis of ciliary muscles and constrictor pupillae
Diplopia
68
Path of CN III
Oculomotor nere emerges between cerebral peduncles
Passes forwards between SICA and PCA
Pierces dura to lie on lateral wall of cavernous sinus
Divides into superior and inferior branches before entering superior orbital fissure
- superior: levator palpebrae superiosis and superior rectus
- inferior: medial rectus, inferior rectus, inferior oblique
Parasympathetic leaves inferior branch heaidng for inferior oblique to synapse in ciliary ganglion
Post-ganglionic fibres via short ciliary nerve to constrictor pupillae and ciliary muscles
69
Only CN to airse from dorsum of brianstem
Trochlear nerve
Arises from dorsal surface of pons
70
Path of CN IV
Nucleus lies at level of inferior colliculus
Fibres pass dorsally around cerebral aqueduct and decussate in superior medullary vellum
Emerges from dorsum of pons (only cranial nerve
to arise from dorsum of brainstem)
Winds round cerebral peduncle
Passes forwards between superior cerebellar and
posterior cerebral arteries to pierce dura
Runs forward on lateral wall of cavernous sinus
between oculomotor and ophthalmic nerves
Enters orbit through superior orbital fissure lateral
to tendinous ring from which recti take origin
Passes medially over optic nerve to enter superior
oblique muscle
71
Difficulty walking downstairs
Trochlear nerve palsy
Resulting in diplopia when patient looks downwards and laterally
72
Nuclei of the trigeminal nerve
Motor: upper pons near floor of fourth ventricle
Sensor:
- mesencephalic nucleus in midbrian
- chief sensory nucleus, lies in the pons
73
Nervus spinosus
Branch of mandibular division og trigeminal
Nervus spinosus to supply dura mater and nerve to medial pterygoid,
--> from which otic ganglion is suspended
74
Sympathetic output from otic ganglion
--> middle meningeal artery causing vasoconstriction
75
Only cranual ganglion with motor fibres
Otic ganglion
Nerve to medial pterygoid passes through it supplying tensor tympani and tensor palati
76
Path of CN VI
Nucleus in floor of fourth ventricle in upper part of pons
Fibres of facial nerve wind round nucleus to form facial colliculus.
Emerges between medulla and pons.
Passes forwards through pontine cistern.
Pierces dura mater to enter cavernous sinus lying
on lateral aspect of internal carotid artery.
Enters orbit through tendinous ring at superior orbital
fissure.
77
CN VII Nuclei
Motor nucleus in lower pons
--> fibres loop around abducens nerve nucleus (facial colliculus) and emerge at cerebellopontine angle with nervus intermedius
Nervuus intermedius contains sensory and parasympathetic fibres
-autonomic fibres originate in the superior salivary
nucleus in the pons
-sensory fibres synapse in tractus solitarius in the pons
78
Nervus intermedius
Lies lateral to motor fibres of facial nerve
79
Branches of facial nerve in petrous temporal bone
- Greater petrosal nerve
- Nerve to stapedius
- Chorda tympani
80
Supranuclear facial palsy
Contralateral side affected with sparing of frontalis and orbicularis oculi
81
Infranuclear facial palsy
Unilateral side affected, complete side of face
82
Nuclei of glossopharyngeal nerve
Nuclei in medulla
Nucleus ambiguus: fibres to stylopharyngeus; also
innervates the muscles of the pharynx, larynx and
soft palate via the vagus nerve
Inferior salivatory nucleus, supplying the parotid gland
Nucleus of tractus solitarius, which receives taste
fibres via the glossopharyngeal nerve
Dorsal motor nucleus of vagus (shared with vagus)
for general sensation from the posterior third of the tongue and oropharynx
83
Branches of vagus nerve
At jugular forman forms superior ganglion, upon leaving foramen forms infeiror ganglion
Branches:
-meningeal: supplies dura of posterior cranial fossa
-auricular: supplies medual aspect of auricle and external auditory meatus and outer surface of tympanic membrane
- pharyngeal: supplies muscle of soft palate and phaynx
- superior laryngeal: divides into internal and external branches
- ->external = cricothyroid
- ->internal = sensation to laryngeal pharynx and laryngeal mucosa above level of cords
-recurrent laryngeal nerve
- cardiac branches
- pulmonary branches
- branches to abdominal viscera
84
Nucleus of accessory nerve
Nucleus ambiguus: emerges with fibres from vagus nerve
- -joins spinal root for short distance
- ->cranial section branches off to rejoin vagus to be distributed to muscles of soft palate, pharynx and larynx
Spinal segment: C1 -C5
- -> enters skull through foramen magnum
- joins cranial root
- leaves through jugular foramen
- immediately below jugular foramen --> spinal root passes backwards to supply sternocleidomastoid and trapezius
85
Innervation of palatoglossus
Only extrinsic tongue muscle NOT to be innervated by hypoglossal nerve
Innervated by cranial root of accessory nerve CN XI, carried by vagus nerve
86
Supranuclear hypoglossal palsy
Infranuclear division of hypoglossal nerve cause satrophy of extrinsic muscle on same sid
--> deviation to affected side on protrusion due to atrophy
Supranuclear damage causes weakness to CONTRALTERAL side but not atrophy,
hence still points to affected side?
87
Dorsal rami of C1 L4 and L5
Have no cutaneous branches
88
Ventral rami plexi
Cervical plexus: C1 - C4
Brachial plexus: C5 - T1
Lumbar plexus: L1 - L4
-contribution from T12
Sacral plexus: S1 - S5
-contribution from L4 L5
89
Cervical plexus
C1 - C4
Motor:
- prevertebral muscles
- levator scapulae
- scalene muscles
- sternocleidomastoid and trapezius via accessory nerve XI
- diaphragm (+C5)
Sensory:
- skin of anterior and lateral neck
- shoulder
- lower jaw
- external ear.
90
Sympathetic outflow
Lateral horn of grey matter T1 - L2
| --> white rami communicantes
91
Lumbar sympathectomy
L3 and L4 GANGLION removal
| sympathetic ouput from T12 -L2 roots
92
Thoracic sympathectomy
T2 and T3 GANGLION removal
T1 not removed as this would cause Horner’s syndrome
Sympathetic outlfow form T2–T7 roots
93
Location of hypogastric plexus
Lies in front of L5 vetrebrae as continuation of aortic plexus
Hypogastric and aortic plexuses may be damaged
in aortic aneurysm surgery and extensive pelvic surgery,
e.g. anterior resection of the rectum: ejaculation may be compromised.
94
Four head and neck parasympathetic ganglion
Ciliary ganglion in orbit
- site of pre-ganglionic fibres with oculomotor nerve
- postganglionic fibres supply ciliary muscles and constrictor pupillae
Sphenopalatine ganglion in pterygopalatine fossa
- site of pre-ganglionic synapse of facial nerve
- post-ganglionic fibres supply lacrimal gland and glands in nasal cavity and palate
Submandibular ganglion attached to lingual nerve
-site where preganglionic fibres accompanying
facial nerve and chorda tympani synapse
- postganglionic fibres supply submandibular and
sublingual glands, and glands in tongue and
floor of mouth
Otic ganglion attached to trunk of mandibular nerve in infratemporal fossa
- pre-ganglionic nerves from glossopharyngeal
- post-ganglionic fibres innervate parotid
95
Ciliary ganglion
Ciliary ganglion in orbit
- site of pre-ganglionic fibres with oculomotor nerve
- postganglionic fibres supply ciliary muscles and constrictor pupillae
96
Sphenopalatine ganglion
Sphenopalatine ganglion in pterygopalatine fossa
- site of pre-ganglionic synapse of facial nerve
- post-ganglionic fibres supply lacrimal gland and glands in nasal cavity and palate
97
Submandibular ganglion
Submandibular ganglion attached to lingual nerve
-site where preganglionic fibres accompanying
facial nerve and chorda tympani synapse
- postganglionic fibres supply submandibular and
sublingual glands, and glands in tongue and
floor of mouth
98
Otic ganglion
Otic ganglion attached to trunk of mandibular nerve in infratemporal fossa
- pre-ganglionic nerves from glossopharyngeal
- post-ganglionic fibres innervate parotid
