Neuroanatomy Flashcards
Name the three meningeal layers
Dura matter
Arachnoid matter
Pia matter
Name the 3 meningeal spaces
Epidural(extradural) space- space between skull and dura
Subdural space- space between dura and arachnoid
Subarachnoid- space between arachnoid and pia
Contents and clinical importances of meningeal spaces
- Extradural- contains meningeal vessels especially meningeal arteries
- extradural haemorrhage due to rupture of middle meningeal artery ( fast) - Subdural space- contains superficial cerebral veins (on their way to dural sinuses). - shaken baby syndrome
- rupture will lead to subdural haemorrhage( slow) - Subarachnoid- Contains cerebral spinal fluid and cerebral arteries
-subarachnoid haemorrhage due to rupture of cerebral aneurysm
Name the dural folds and state their locations
- Falx cerebri - between the two cerebral hemispheres
- Falx cerebelli- between the two cerebella hemispheres
- Tentorium cerebelli- between cerebrum and cerebellum
- Diaphragma sellae- forms roof of hypophyseal fossa
Functions of dural folds
- Protect the brain
- Prevent displacement of the brain
- Minimize the effect of vibrations
Discuss falx cerebri
Shape- sickle shaped
Related sinuses:
1. Superior sagittal sinus- upper border
2. Inferior sagittal sinus - lower border
3. Straight sinus- base
Discuss tentorium cerebelli
Site- located between cerebrum above and cerebellum below
Shape- tent like
Borders- free anterior border surrounding the brainstem, posterior attached border( attached to the skull; groove for transverse sinus, groove for superior petrosal sinus and posterior clinoid process
Sinuses:
1. Superior petrosal sinus
2. Transverse sinus
3. Straight sinus
Discuss falx cerebelli
Site- between two cerebella hemispheres
Shape- triangular
Related sinus: occipital sinus
Arterial supply of the dura
- Anterior meningeal arteries( anterior cranial fossa)
-from the anterior and posterior ethmoidal artery branches of the opthalmic artery - Middle meningeal artery ( middle cranial fossa)
- from the first part of the maxillary artery - Accesory meningeal artery (middle cranial fossa)
- from first part of maxillary artery - Posterior meningeal artery (posterior cranial fossa) from:
- vertebral artery
- occipital artery
- ascending pharyngeal artery
Nerve supply of dura
- Anterior cranial fossa
- from the anterior and posterior ethmoidal branches of the opthalmic nerve - Middle cranial fossa
- from the maxillary and mandibular nerves
- Posterior cranial fossa
- from the cervical nerves through the glossopharyngeal, vagus and hypoglossal cranial nerves
What and how do dural sinuses drain?
- Brain- through cerebral veins
- Meninges - meningeal veins
- Skull bones- diploic veins
- CSF- arachnoid vellae and granulations
Name the single sinuses(middle sinuses)
- Superior sagittal sinus
- Inferior sagittal sinus
- Straight sinus
- Occipital sinus
- Intercavernous sinuses
- Basilar plexus
Name the paired sinuses
- Sphenoparietal sinus
- Cavernous sinus- drains by superior and inferior petrosal
- Superior petrosal sinus
- Inferior petrosal sinus
- Transverse sinus
- Sigmoid sinus- continuation of transverse sinus
Origin and termination of each sinus
Superior sagittal sinus begins at foramen cecum, runs along the upper border of falx cerebri and deviates to the right to form the right transverse sinus. Therefore, The right transverse sinus is a continuation of the superior sagittal sinus. The inferior sagittal sinus is present along the lower free border of falx cerebri. It unites with the great cerebral vein to form the straight sinus. The straight sinus is formed by the union of the inferior sagittal sinus and the great cerebral vein. It deviates to the left to form the left transverse sinus. The transverse sinus terminates by forming the sigmoid sinus. The sigmoid sinus is the continuation of the transverse sinus. It passes through the jugular foramen to To continue as the internal jugular vein.
Superior petrosal sinus connects the cavernous sinus with the transverse sinus. Inferior petrosal sinus connects the cavernous sinus With the internal jugular. Basila plexus of sinuses connected to inferior petrosal sinuses.
Discuss the cavernous sinus, mentioning the site, extents, tributaries, drainage and relations.
Site: located on the each side of the body of sphenoid
Extents- from the medial end of the superior orbital fissure to the apex of the petrous temporal bone
Tributaries:
1. Anterior- ophthalmic veins, central vein of retina and sphenoparietal sinus
2. Medially- 3 intercavernous sinuses
3. Superiorly- middle & inferior cerebral veins
4. Inferiorly- emissary veins connecting it with pterygoid plexus ( foramen ovale and Lacerum) and pharyngeal plexus ( carotid canal)
Drainage: posteriorly to
1. Superior petrosal sinus- to transverse sinus
2. Inferior petrosal sinus- to internal jugular vein
Relations:
Anterior- superior orbital fissure
Medially- pituitary gland and sphenoidal air sinus
Laterally - temporal lobe of brain
Superiorly- internal carotid artery and optic chiasma
Inferiorly- sphenoidal air sinus
Posterior- petrous temporal bone
