Cranial vault Flashcards
Skull ossification
Vicerocranium (facial skeleton)
- Intramembranous: facial bones
- Endochondral: ossicles, styloid process of temporal bone, hyoid
Neurocranium (cranial vault)
- intramembranous: calvaria (skull cap)
- endochondral: base of cranial vault
- all cranial nerves leave cranial vault thru endochondral portion
Neurocranium venous system
- Diploic v. drain Diploe (spongy bone)
- Drains into Emissary v
- Valveless
Craniosyntosis
- premature closure of cranial sutures
Trigonocephaly
- premature closure of metopic suture
- linked to brain development
- halt in brain development leads to early closure of cranial sutures
Scaphocephaly
- early closure of saggital suture
- results in a long, wedge-shaped skull
Brachycephaly
- early closure of coronal suture
- results in decreased A-P and increased bilateral dimensions
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Plagiocephaly
- early closure of suture on one side results in asymmetrical skull shape
- may be postural in origin; i.e. lying on one side
Microcephaly
- born with normal size skull
- early closure of sutures & fontanelles results from failure of brain to grow
- result is small skull
- brain development matched with bone development
Arterial supply to brain & brain stem
Internal carotid & Vertebral (C1-6 Transverse Foraminae) arteries supply blood to brain & brain stem:
- Anterior: Frontal, ethmoid, sphenoid
- Middle: Temporal & sphenoid
- Posterior: Sphenoid, Temporal, Parietal, Occipital
Cerebral arterial circle of (Willis)
Internal carotid a. br.
- Anterior communicating a.
- Anterior cerebral a.
Vertebral a. br
- Basilar a.
- Posterior cerebral a.
- Posterior communicating a.
- Ant. Inf. Cerebellar A. (AICA)
- PICA
Cranial dura layers
- Cranial dura has:
- Periosteal layer
- Meningeal layer
- Dural venous sinuses formed where 2 layeers separate; receive blood from cerebral v. & CSF from arachnoid villi
- S. Saggital sinus
- I. Saggital sinus -> Great Cerebral v. (of Galen)
- Transverse sinus
- Sigmoid sinus
- Drain into Interal jugular v.
Emmisary veins
- scalp infection may enter cranial vault via emissary veins
- Epidural bleeds: blow developing due to fusion of layers
Contents of Cavernous sinus
- Infection may result in thrombosis of sinus and/or meningitis:
- CN III, IV, VI, V1 & V2
- Cerebral v. (intracranial)
- Ophthalmic v.
- Pterygoid venous plexus (extracranial)
- Internal carotid a.
- lie on lateral aspect of body of sphenoid
Superior orbital fissureSuperior orbital fissure: strucutres passing through
- CN III
- CN IV
- V1
- CN VI
- Foramen on Sphenoid
F. Rotundum: strucutres passing through
- V2
- sphenoid
F. Ovale: strucutres passing through
- V3
- sphenoid
F. Spinosum: strucutres passing through
- Middle Meningeal a.
- b/w Sphenoid & Temporal
F. Lacerum: strucutres passing through
- nothing passes through it
- passing on top are: recurrent meningeal nerve (from CN V3, into the endocranium) and the middle meningeal artery
Internal acoustic meatus: strucutres passing through
- CN VII
- CN VIII
- Temporal
Jugular foramen: strucutres passing through
- CN IX
- CN X
- CN XI
- in b/w Temporal & Occipital
Hypoglossal foramen: strucutres passing through
- CN XII
- Occipital
