Neuroanatomy Flashcards
Skull Vault
1-9
1. Anterior Fossa 2. Middle Fossa 3. Posterior Fossa
4. Frontal Crest. 5. FOramen Caecum
6. Crista Galli 7. Cribiform plate
8. Optic Canal 9. Anterior Clinoid Process
Skull vault
10 -24
10. Sup. Orb. Fissure 11. Foramen Rot.
12. Foramen Oval. 13. Foramen Spin.
14. Foramen Lac. 15. Int. Acc. Meat.
16. Jug. Foramen 17. For. Magnum
18. Hypoglossal Canal 19. tegmen Typamni
20. Pit. Fossa 21. Dorsal Sellae
22. Clivus 23. Sphenoid lesser wing
24. Sphenoid greater wing
Skull Vault
Grooves 25-29
*Groove for*
25. middle meningeal artery
26. Sigmoid Sinus
27. Superior petrosal sinus
28. Transverse sinus
29. Sup. Saggital Sinus
Layers of the SCALP
Skin
Connective Tissue
Aponeurosis
Loose Areolar tissue
Periosteum
Bones of the cranial cavity
1) Name them
2) What is the pterion
1) Frontal, Temporal, Parietal, Occipital, Sphenoid, Ethmoid
2) Pterion is a thin portion of skull at the junction of frontal, temporal, parietal + greater wing of sphenoid.
Anterior branch of middle meningeal artery runs beneat it
Structures running through:
i) Optic Canal
ii) Superior Orbital Fissure
iii) Spinosum
iv) Internal Accoustic Meatus
v) Jugular Foramen
i) Optic Nerves + Ophthalmic Artery
ii) CN III, IV, Va, VI. Ophthalmic Vein
iii) Middle meningeal artery, meningeal branch of mandibular nerve
iv) Facial nerve. travels through facial canal (forms geniculate ganglion) and then exits through stylomastoid foramen
v) IJV, CN IX, X, XI, Inferior petrosal sinus
Boundaries of bony orbit:
Roof:
Frontal Bone (ant.) Great wing sphenoid (post.)
Floor:
Zygoma (lat.) Maxilla (medial.)
Medial Wall:
Maxilla (frontal process), Frontal, Lacrimal,
Ethmoid (orbital plate), Sphenoid
Lateral Wall:
Zygoma (frontal process), Frontal (zygoma process)
The Orbit
Label 1-10
1. Squam. temp. bone. 2. Zygomatic Bone
3. Sphenoid Greater wing
4. Sphenoid lesser wing 5. Nasal Bone
6. Maxilla (Frontal process)
7. Frontal Bone (orbital part)
8. Inferior orbital Fissure
9. Superior Orbital Fissure 10. Optic Canal
The orbit
Label 11-20
11. Infra-orbital groove
12. Infra-orbital foramen
13. Posterior ethmoid foramen
14. Supra orbital foramen 15. Glabella 16. Naison
17. nasal septum 18. Conchae
19. Frontozygomatic suture 20. pterion
The Orbit 2
1-8
1. Parietal Bone 2. Frontal Bone
3. Sphenoid Greater Wing
4. Squamous temporal bone. 5. ethmoid bone
6. Lacrimal bone 7. maxilla 8. Zygomatic Bone
The Orbit 2
9-15
9. ant. ethmoid foramen
10. ant. + post. ethmoid crests 11. Lacrimal fossa
12. Nasolacrimal canal
13. Zygomaticofacial foramen
14. Frontozygomatic suture
15. Pterion
Ocular Muscles
i) Nerves + which muscles they innervate + action
Occulomotor Nerve (III) - Nucleus in Pons-Midbrain junction
- Superior Rectus (Upward Gaze)
- Middle Rectus (Medial Gaze)
- Inferior Rectus (Downward Gaze)
- Inferior Oblique (Upward Gaze)
- Levator palpebrae superioris (raises eye lid)
- Ciliary Muscles (lens adjustments)
- Constrictor Pupillae (Parasympathetic fibers)
Trochlear Nerve (IV) - Nucleus in pons
Superior Oblique (downward gaze)
Abducens Nerve (VI) - nucleus in medulla oblongata
Lateral Rectus (lateral gaze)
Nasociliary N (V1) - Sympathetic fibers
Dilator Pupillae
3rd Nerve Palsy
Down and out pupil - Lateral rectus (lateral) + Superior Oblique dominant (inferior)
Ptosis - Levator palpebra superioris
Pupil Dilation - Unopposed dilator pupillae (under sympathetic control
Loss of reflexes - Ciliary Muscles + Constrictor muscle loss
Where is:
i) Brocha’s Area (+ what does it do)
ii) Sensory Cortex
iii) Motor Cortex (describe the motorcortical representation briefly)
iv) Subarachnoid space (what’s in it)
v) Superior Saggital Sinus
vi) Inferior Saggital Sinus
i) Frontal Lobe (inferior frontal gyrus) and controls motor areas of speech
ii) Sensory Cortex is in the parietal lobe (post-central gyrus)
iii) Motor Cortex is in the frontal lobe (pre-central
gyrus) . Motor humonculous - Medially leg –> hand –> face Laterally on opposite side of body.
iv) Subarachnoid Space - between arachnoid meningeal layer and pia mater. contains CSF and Major Blood Vessels
v) Sup. Sagg. Sinus sits in superior border of Falx Cerebri
vi) Inf. Sagg. Sinus sits in inferior border of Falx Cerebri
Meninges
i) Brief Description
ii) Name the dural folds
i) Layers covering the central nervous system:
Dura - tough fibrous. Inner - meningeal layer and outer - endosteal ayer
Arachnoid - subdural space is inbetween dura and arachnoid layer. subarachnoid space is between the arachnoid and pia mater.
Pia - Thin layer that closely related to the surface of the brain.
ii) Falx Cerebri - Inter- cerebral hemispheric. Attached anteriorly to crista galli and posteriorly to tentorium cerebelli
Falx Cerebelli - Inter- cerebeller hemispheric
Tentorium Cerebelli - attached anteriorly to (both) posterior clinoid (sphenoid) processes spreading transversely across skull + both anterior clinoid processes.
Diaphragma Sellae - Dural fold forming the pituitary fossa. Stalk of pituitary passes through arpeture in centre.
Venous Sinuses
i) Between what are they situated?
ii) How do they connect + respectively where are they located ?
iii) What drains into the IJV
i) Between the inner meningeal dura layer and the outer endosteal dura layer
ii) Sup. Saggital Sinus (Sup. Falx Cerbri) - Drains the sup. cerebral veins
Inf. Sag. Sinus (Inf. Falx Cerebri) - Drains the med. cerebral veins
Straight Sinus (Inf. Post. Falx Cerebri) - Receives Inf. Sag. Sinus + Great Cerebr. Vein
Transverse Sinus (Post. Tent. Cerebell) - Receives Straight Sinus + Sup. Sag. Sinus.
Cavernous Sinus - Lies on sphenoid bone (anteriorly - superior orbital fissure posteriorly - petrous temporal bone.
Sup. Petrosal Sinus - Drain the cavernous sinus into the sigmoid sinus.
Inf. Petrosal Sinus - Drain the cavernous sinus into the IJV
Sigmoid Sinus - Continuation of transverse sinus passing through the jugular foramen then enters IJV
iii) IJV - Inf. Petrosal Sinus
Veins - pharyngeal, facial, lingual, sup. thyr., med. thyr.
Cavernous Sinus
i) Location
ii) Contents
i) Located overlying the sphenoid bone extending from sup. orbital fissure -> Petrous temporal bone
Sphenoid bone (endosteal dura mater) - medial
Temporal Bones + (Meningeal Dura mater) - lateral
Meningeal Dura Mater - Roof
Remember the sinuses are contained beneat the endosteal and meningeal dura mater
ii) Contains ICA (+ Carotid Plexus) and CN VI
BUT on the lateral wall lying close to the sinus:
CN III, CN IV, CN Va, CN Vb
Mnemonic- O TOM CAT (CAT - Carotid + Abducens)
Cavernous Sinus Thrombosis:
I) Features
ii) Causes (briefly)
i) Features
Oedema - conjuctiva and eyelids
Raised intraocular pressure - papilloedena + retinal haemorrhage
Exophthalmus
Ophthalmoplegia
ii) Infectious Causes - Infeciton transmitted through:
a) Face via anterior facial vein + Ophthlamic Veins
b) Deeper via pterygoid venous plexus
Usual thrombotic risks
Base of Skull
1-11
1. Foramen Magnum 2. Incisive Fossa
3. Greater palatine foramen
4. Lesser palatine foramen
5. inferior orbital fissure
6. Foramen ovale 7. Pterygoid Hamulus
8. Carotid Canal 9. Foramen Lacerum
10. palatinovaginal canal 11. Foramen Spinosum
Base of Skull 2
12 - 25
12. Stylomastoid Foramen 13. Jugular foramen
14. Mastoid Foramen 15. Mandibular Fossa
16. Vomer and Chonoae 17. Palatine fossa
18. infratemporal crest of great sphenoid wing
19. Mastoid process
20. External occipital protuberance
21. Sup. Nuchal Line 22. Inf. Nuchal Line
23. Petrous Temporal Apex
24. Occipital Condyle 25. External occipital Crest
Cortex Anatomy
1 - 12
1. Longitudinal Fissure 2. Sylvian Fissure
3. Lateral Ventricles 4. Third Ventricle
5. interpeduncular cistern 6. Pons
7. medulla oblongata
8. middle cerebellar peduncle
9. corpus collosum 10. Corona Radiata
11. Septum Pallucidum 12. Caudate nucleus
Cortex Anatomy
13-25
13. internal capsule 14. External Capsule
15. Claustrum 16. External caps./insula
17. Insula 18. amygdala 19. Cerebral Peduncle
20. Mamillary Body 21. Thalamus
22. Body of fornix 23. Choroid Plexus
24. Putamen 25. Globus Pallidus
Branches of:
i) vertebral arteries
ii) basilar artery
iii) internal carotid arteries
i) Vertebral Branches
- Ant. and Post. Spinal Arteries
- PICA
ii) Basilar Branches
- AICA
- Labryinthine ARtery
- Superior Cerebellar Artery
- PCA
iii) ICA Branches (MAIN)
C6 (ophthalmic portion) - Ophthalmic
C7 (Communicating portion) - PCOM, Anterior choroidal before terminating into ACA + MCA
MCA occlusion - signs
i) Banford Criteria for stroke but broadly -
Contralateral - arm+face weakness / altered sensation
Speech (if dominant) - Brocha’s (expressive aphasia) Wernicke’s (receptive aphasia)
Neglect (if non-dominant) - of the contralteral side of the body
i) Functions of CN VII
ii) why is there a difference between UMN and LMN VII palsy
i) Motor - Muscles of face + Stapedius
Sensory - Taste to anterior 2/3 of tongue
PNS - Submandibular, Sublingual, Lacrimal and Nasal glands
ii) UMN there is scalp + orbicularis oculi sparing as these muscles have a bicortical representation
UMN vs LMN Lesion
UMN:
Spastic paresis, minimal wasting, hyperreflexia
LMN:
Flacid paresis, marked wasting, hyporeflexia, fasciculations
Label
Neuronal Pathways:
i) Spinothalamic
ii) Dorsal Columns Pathway
i) Noiceptors triggered–> C fibers mainly carry signal to dorsal spinal root —> Synapse with substantai gelatinosa –> Decussate at or just above level of entry —-> ascend in contralateral spinothalamic tract and then synapse in the thalamus before somatic organisation in the cortex.
Crude touch, pain + temperature
ii) Sensory nerve cells triggered (meissner’s corpuscles, merkel cells, pacinian corpuscle) –> travel up ipsilateral spinal cord in gracilis (LL) tract or cuneate (UL) tract to medulla oblongata where they synpase —> then decussate forming medial leminiscus before travelling into thalamus and then sorted somatically to the cortex.
i) Anterior Cord Syndrome
ii) Posterior Cord Syndrome
iii) Central Cord Syndrome
iv) Brown - Sequard Syndrome
i) Ant. Spinal Artery disruption.
This causes interruption of corticospinal pathway and spinothalamic pathway
Loss of pain, temperature sensation + power
ii) Post. Spinal arteries (there are two) Disruption.
This causes interruption of the dorsal columns pathway.
Ataxia (due to loss of proprioception) + loss of soft touch
iii) Central Tumours + Syringomyelia
Loss of pain/temperature sensation at level (decussating spinothalamic fibers)
Arm>Leg weakness (expanding lesions cause involvement of lateral corticospinal tracts)
iv) Brown Sequard Syndrome
Ipsilateral loss of power (corticospinal) + finetouch/proprioception/vibration (dorsal columns)
Contralateral loss of pain/temp/crude (spinothalamic)
i) What are lissauer’s tracts?
ii) Which thalamic nucleus do the dorsal column - medial leminiscus + spinothalamic pathways synapse in?
iii) How do the neuron’s post - VPL nucleus innervate the cortices?
iv) Describe the corticospinal tract
i) Lissauers tracts are ascending tracts of the spinothalamic pathway immediately as the peripheral nerve enters the spinal cord (ipsilateral)
The lissauer’s tract THEN synapses in substania gelatinosa
ii) Ventral Postero-Lateral Nucleus
iii) They travel through the posterior limb of the internal capsule
iv) Orinate in PMC (precentral gyrus orinating from broddman’s areas 1-6) –> Descend through posterior limb internal capsule + crus cerebri –> medullary pyramids most tracts decussate —> descend contralterally and synapse on ventral horn before of spinal level the secondary neuron leaves at
Describe spinocerebellar tracts
Carry Proprioceptive Information
i) Anterior spinocerebellar tract (Below L2)
- Primary cell bodies in DRG (1st synapse) –> decussate in spinal cord and then travel contralaterally to superior cerebellar peduncle where they decussate again –> deep cerebblar nuclei
ii) Dorsal Spinal Cerebellar Tract (L2-T1)
- Enters spinal cord and ascends ipsilaterally until synapsing in clarke’s nucleus at about T1 –> Continue to ascend ipsilaterally and enter cerebellum through inferior cerebellar peduncle
iii) Cuneocerebellar Tract (above T1)
- Enters spinal cord and then ascends ipsilaterally until synapsing in accessory cuneate nucleus in medulla –> continue ipsilaterally and enter cerebellum through inferior cerebellar peduncle
Vertebra
1-16
1. vertebral body 2. Transverse process
3. Superior articular facet 4. Cut edge pedicle
5. Vertebral body - anterior
6. Vertebral body - posterior
7. pedicle 8. spinous process
9. Cut edge of lamina
10. Anterior longitudinal lig.
11. Annulos Fibrosis 12. Post. Long. Lig
13. Supraspin. Lig. 14. Interspin. Lig.
15. lig. flavum 16. Basivertebral Foramen
16. Nucleus pulposus
Commonest level for:
i) Spondylolisthesis
ii) Disc Herniation
iii) What type of joint is a IV Disc
i) L5- Spondylolisthesis
ii) L5/S1 - Disc herniation (disc herniation usually occurs in a posterolateral direction) (L4/L5, C5/C6, C6/C7)
- Herniating discs effect the spinal nerve BELOW So L4/L5 –> effects L5 spinal nerve
iii) Secondary cartilaginous joint
Vertebrae numbers + Characteristics :
i) Cervical
ii) Thoracic
iii) Lumbar
iv) Sacral
v) Coccyx
i) 7 Cervical (C1- Atlas C2 - Axis)
a) Small body b)Large Vertebral Canal - thin lamina forming triangular canal c) transverse foramen for vertebral art, vein and plexus d) bifid spinous process
ii) 12 Thoracic
a) Sup/Inf. Demi facets + costal facets for ribs (not 11th and 12th ribs) b) Quite prominent dorsal spinous process c) intermediate body size that increases inferiorly
iii) 5 Lumbar
a) large body b) Spinous process points posteriorly
c) chunky lamina
iv) 5 Sacral (usually fused)
v) 3 coccygeal
Atlantoaxial joint
1, Odontoid Process 2. Body of C2
3. Anterior Tubercle 4. Arch of C1
5. Transverse foramen 6. Upper articulation of skull
7. Transverse process of C2
8. Lamina 9. Spinous Process 10. Vertebral Canal
LL Dermatomes - where to check
L1 - Inguinal
L2 - Upper thigh
L3 - med/lat knee
L4 - Med leg
L5 - Dorsum of foot (not lateral)
S1 - Lateral foot
S2 - Medial posterior thigh
S3-S5 - anal dermatomes
Upper and Lower Limb Myotomes
Causes of Cauda Equina Syndrome
Compression - Disc herniation, Tumour (intrinsic/extrinsic), fracture, degenerative disease, penetrating trauma
Stretch - Spondylolisthesis
Inflamation - Arachnoiditis, demyelination
Toxins - rarely seen with anaesthetic use
i) L3/L4 Disc Herniation Presentation
ii) L4/L5
iii) L5/S1
i) Pain
Signs: - L4 Nerve root
Sensory Loss - Posterolateral thigh, ant/ knee, medial leg
Weakness - quadriceps, dorsiflexion of foot, hip abductors
Reflex deficit - Knee
ii) Pain
Signs: - L5 Nerve root
Sensory Loss - Lateraal leg, Dorsum of foot (Not lateral)
Weakness - Dorsiflexion of foot, Extension of 1st MCP
iii) Pain
Signs - S1 Nerve root
Sensory loss - lateral foot, heel and sole, posterior leg and thigh.
Weakness - Plantarflexion + Foot eversion
Reflex - deficit in ankle reflex
Briefly Describe vertebrae structure
Consist of a:
Body - Has a superior and inferior end plate which articulate with intervertebral discs (Annulus fibrosis peripherally and nucleus pulpsosus centrally). Body has cancellous bone covered by cortical bone
Vertebral Arch -
Formed from the pedicles arising laterally from the body (thin and long cervically, short and fat lumbar). Laterally from the pedicles arise transverse processes. At this point dorso-medially the bone is known as the lamina which meet in the midline again. Where they meet the dorsal spinous process originates pointing dorsally.
Articulation -
Facet joint - superior articular facet of inferior vertebra and inferior articular facet of superior vertebra. The facets are processes on the pedicle also.
IV Joints - Between endplates and IV Discs
Ribs - Here the costal tubercle sits in between the superior demi-facet on the inferior vertebra and the inferior demi-facet on the superior vertebra. The shaft of the rib articulates with the costal facet on the transverse process.
Optic Canal:
What Runs Through?
Optic nerve (3 Layers of meninges)
Ophthalmic Artery
Foramen Magnum:
What runs through?
Nervous- Spinal accessory nerve, Medulla Oblongata
Arteries - Vertebral, Posterior spinal, Anterior spinal
Connective tissue - Apical ligament of dens, tectorial membrane
What is this?
What runs through?
Jugular Foramen:
Vascular: Inf Petrosal Sinus/Sigmoid Sinus –> IJV
Meningeal branch of the ascending pharyngeal art.
Nerves: IX,X,XI
Carotid Canal:
i) Structures running through
ii) Branches of structure running through
Foramen Lacerum:
iii) Structures running through
i) Internal Carotid Artery-
Courses through the carotid canal (temporal bone)
Enters middle cranial fossa ( superior to the foramen lacerum - not actually in the foramen lacerum)
ii) ICA Branches -
Choroidal Art., Opthalmic Art, MCA, ACA, PCOMM
iii)
Artery - of pterygoid canal, meningeal branch of ascending pharyngeal
Vein - Emissary veins (route for infection to cause cavernous sinus thrombosi)
Nerves - Nerve of pterygoid canal (Greater petrosal nerve joins deep petrosal nerve)
Tongue:
Nerve Supply
Nerve Supply -
CNXII
Except
Palatoglossus - CNIX + CNX
i) What is this?
ii) What goes through it ? - describe route and branches of this structure
i ) Stylomastoid Foramen
ii) Facial Nerve - Facial nerve orginates at the pontinemedullar junction and has a motor nucleus / Special sensory component. These fibers then coalesce —>
Exit the cranial cavity through IAM and travels in the facial canal within petrous temporal bone. —>
Now some branches are given whilst in the canal
1) Greater petrosal nerve
2) Nerve to stapedius
3) Chorda tympani (which joins the lingual nerve of CNV3)
4) Auricular Branch
—> then exits the canal through stylomastoid foramen and gives off five major branches beneath the cover of parotid gland
1) Temporal 2) Zygomatic 3) Buccal 4) Marginal Mandibular Nerve 5) Cervical
What are the divisions of the trigeminal nerve
CNVI - Ophthlamic Nerve
Lacrimal, Frontal, Nasociliary
CNV2 - Maxillary Nerve
Pterygopalatine ganglion, then becomes infraorbital nerve (Gives superior alveolar nerve)
CNV3 - Mandibular Nerve
Otic Ganglion, Auriculotemporal nerve, Inferior Alveolar Nerve, Lingual Nerve (submaxillary ganglion), Buccinator, Mylohyoid Nerve (Anterior Digastric + Mylohyoid)
Structures passing through superior orbital fissure
Nerves- CN III, IV, V1 (Some branches), VI
Arteries - Branches of middle meningeal/lacrimal arteries
Veins - Opthalmic Vein
What is this?
What runs through it?
Foramen Ovale
CNV3
Accessory Meningeal Artery
Lesser Petrosal Nerve
What is this?
What runs through?
Foramen Spinosum (lateral and posterior to foramen ovale)
Middle Meningeal Artery
Arteries:
i) ICA enters through the … which is lateral to the …
ii) … lies posterior to the clivus and is formed at the ..
i) ICA enters through the foramen lacereum (alongside artery of pterygoid canal and nerve of pterygoid canal) which is lateral to the clivus)
ii) Basilar artery lies posterior to the clivus and is formed at the junction between pons and medulla
Orbit:
i) Name the bones making up the orbit?
ii) Structures passing through SOF
iii) Structures passing through IOF
iv) N Supply to lacrimal gland
i) 7 Bones - Frontal, Maxillary, Sphenoid, Palatine, Lacrimal, Zygomatic, Ethmoidal
ii) Ophthalmic Vein, CN III, IV, V1 - Frontal, Lacrimal, nasociliary, VI,
iii) CNV2 - Infraorbital, Zygomatic.
Inf. Ophthalmic Veins, Branches of pterygopalatine ganglion
iv) PNS - Pterygopalatine. SNS - Carotid Plexus. GSS- Lacrimal Branch V1
Cranial Sutures:
i) When do cranial sutures ossify?
ii) Condition where cranial sutures are fused at birth?
iii) What bones form pterion?
iv) MMA enters the skull through which foramen?
v) Foramen Lacerum lies lateral to ..
vi) Name the cranial Sutures.
i) Cranial Sutures Ossify between 18-24 months
ii) Craniosynostosis
iii) 4 - Frontal, Parietal, Temporal, Sphenoid
iv) Spinosum
v) Clivus
vi) Metopic Suture (between frontal bones), Coronal Suture (between frontal/parietal bones), Saggital suture ( between parietal bones), Lamboid Suture (between parietal and occipital bone)
Boundaries of the middle cranial fossa
Anterior:
Lesser wing of sphenoid
Anterior Clinoid process
Anterior Chiasmatic Groove
Posterior:
Greater wing of sphenoid
Petrous Temporal Bone
Squamous Temporal Bone ( laterally)
Dorsum Sellae
Sella Turcica:
i) Where is it
ii) What lies in it
iii) Which sinus is in close proximity? - It’s Contents
iv) Thrombosis of this sinus is Caused By
i) Sphenoid bone behind the chiasmatic groove in the middle cranial fossa.
Inferiorly - known as the hypophyseal fossa housing the pitutiary gland
Posteriorly - is the dorsum sellae and the clivus
ii) Houses the pituitary gland
iii) Cavernous Sinus - Paired structures lie laterally to the sella turcica
Drains - Ophthalmic Veins + Sphenoparietal sinus
Drains into - Inf. + Sup. Petrosal sinuses
Contents (O TOM CAT)- Running through ICA + CN VI
On lateral wall - CN III, IV, VI, VII
iv) Thrombosis - Spreading infection from facial areas drained by Facial + Ophthalmic Veins
Formane Magnum:
i) Structures running through
i) Structures - Medulla Oblongata, apical lig. of dens, tectorial membrane
Vessels - Vertebral Arteries, Ant. Spinal Art. Post. Spinal arteries.
Nerve - Spinal CN XI, sympathetic plexus surrounding the vertebral artery.
Describe configuration of the foramina of the middle cranial fossa
Through/Adjacent to the sphenoid bone:
Optic Canal - Formed between the medial lesser wing and body of sphenoid
Superior Orbital Fissure - Formed between the lesser wing (sup.) and greater wing (inf.)
Now Rotundum, Ovale + Spinosum all through greater wing.
Rotundum - Most anterior and medial
Ovale - Largest, posteriolateral to rotundum
Spinosum - Posteriolateral to ovale
Lacerum - In between the posterior dorsum sellae of the posterior portion of sphenoid/ clinoid process of occipital bone/medial petrous temporal bone
Describe the configuration of foramina of the posterior cranial fossa
Foramen Magnum - Occipital Bone
Hypoglossal Canal - Occipital Bone on rim of the Foramen Magnum hidden by the occipital condyles.
Internal Accoustic Meatus - lateral to the occipital bone (clivus) through the petrous temporal bone
Jugular Foramen - Bounded anterior but the petrous temporal bone and posteriorly by the occipital bone.
Spinal Arteries:
i) Gross Description + what they supply
ii) Segmental arterial supply
iii) Anterior Cord Syndrome
i) Grossly -
Posterior Spinal Arteries - Vascularise Dorsal Third
Anterior Spinal ARtery - Vascularise Anterior 2/3rds
ii) Segmental Arterial supply comes from -
cervical, intercostal and lumbar arteries
iii) Beck’s Syndrome - Interrupted blood supply to anterior spinal artery –> Loss of spinothalamic tract and corticospinal tract
Vertebral Arteries:
i) Which is larger
ii) Describe the parts
i) Left is generally larger
ii) 1st Part (preforaminal) - Anterior to C7 Vertebra and Sympathetic Trunk
2nd Part (foraminal) - C2-C6 Transverse Foraminae
3rd Part (atlantic) - C1 Transverse Foramina
4th Part (Intracranial) - Passes through dura through formaen magnum. Travels anterior to medulla oblongata and they join bilaterally and pontomedullary junction to form basilar artery
i) Branches of Basilar Artery
ii) Where are cerebral artery aneurysms found usually?
iii) Modes of presentation of Basilar Artery Aneurysm
i) Pontine Arteries, Anterior Inferior Cerebellar Artery, Posterior Cerebral Arteries, Superior Cerebellar Artery
ii) 1. AComm/ACA + ICA/PComm (30-35% a piece)
- MCA Bifurcation (20%)
- Basilar Artery Bifurcation + Posterior Circulation (5% each)
iii) Most often - Acute SAH
Less often - Bitemporal Hemianiopia
Which veins do various sinuses drain:
SUperior saggital sinus
Inferior Saggital Sinus
Cavernous Sinus
Sphenopalatine Sinus
Transverse Sinus
Straight Sinus
Superior Saggital Sinus - Superior Cerebral Vein
Inferior Saggital Sinus - Medial cerebral Veins
Cavernous Sinus - Superficial middle cerebral vein, Inferior Cerebral vein
Sphenopalatine Sinus - Superficial middle cerebral vein
Transverse Sinus - Inferior Cerebral vein
Straight Sinus - Great Cerebral Vein
Boundaries of :
i) ANterior Cranial Fossa
ii) Middle cranial fossa
iii) Posterior cranial fossa
i) Anterior Cranial fossa -
Anterior - Frontal,
Posterior Medially - ethmoid
Posteriolaterally - sphenoid bones (greater wings)
ii) Middle Cranial Fossa -
Anteriorly - Lesser wings of sphenoid and limbus of sphenoid (medially)
Posterior - Laterally Petrous Temporal bone + Medially dorsum sellae of sphenoid bone
iii) Posterior Cranial Fossa -
Anteriorly - Laterally petrous temporal bone + Medially dorsum sellae of sphenoid bone
Posteriorly - Occipital Bone
Floor - Occipital bone + some temporal bone
Label
Describe motor + Sensory Humunculous
Joints/ Ligaments of the atlanto-axial joint
Transverse ligament of the atlas:
This runs transversely between two lateral masses close to the anterior arch.
Apical ligament of the atlas:
From the odontoid process of the axis to the foramen magnum
Alar (paired) ligaments of the odontoid process:
from the sides of the dens to the occipital tubercles (medial side of the occipital condyle)
Anterior atlanto-axial ligament
From the Anterior arch of atlas to the body of the axis
Posterior atlanto-axial ligament
From the posterior arch of the atlas to the lamina of the axis
Lateral atlanto - axial joints - Paired joints between inferior articular facet of Atlanto (C1) and superior articular facet of Axis (C2)
Medial Atlanto-axial joint - Between the articular facet of C1 and the dens of C2
Jefferson’s Fracture
Hangman’s Fracture
Jefferson’s Fracture:
Fall on to extended neck
Lateral masses of C1 compress between Occipital condyles and Axis leading to fracture of Anterior/Posterior Arch of the Atlas
Hangman’s Fracture:
Sudden decelleration injury
Fracture of the lateral atlanto-axial joints (Inferior atlas facets + superior axis facets)
