Epicranial Aponeurosis - Strong membranous tendon connecting the anteriorly placed fontalis and posteriorly placed occipitalis
Loose Connective Tissue - allows the outher three layers to move freely ove the skull
Pericranium - outside tissue of the bone.
What are the walls of the cranial cavity made up of?
Inner and outer tables of compact bone that are seperated by spongy bone called "diploe".
so the spongy bone in the middle is diploe bone.
What is a cranial meninges?
The meninges are the membranes that surround the brain and that are continous with the meninges of the spinal cord.
What are the two parts of the outer most layer?
The Dura mater is the outer most layer. It has two layers:
Periosteal dura: This is the part of the dura mater that is continous with the inner surface of the skull
Meningeal dura: This part is continous with the dura of the spinal cord.
What is the arachnoid mater? arachnoid trabeculae?
Delicate membrane that lines the inner surface of the dura.
Arachnoid trabeculae are fine extensions tha span across the subdural (subarachnoid) space and attach to the pia mater.
What is the pia mater?
The delicate mater that lines the outside of the brain.
What happens when periosteal dura is seperated from meningeal dura?
When this happens, what is the benfit?
What are the four major folds?
Channels in the dura mater are created.
The channels are lined with endothelium and receive veins that drain the brain and the mininges.
So essentially, the channels in the dura matter create venous channels for the drainage of the contents of the cranial cavity.
What folds to dip between the fissures in the brain?
What are the four main folds?
The meningeal dura.
Describe the Falx Cerebri.
Runs vertical between the hemispheres of the brain. (The longitudinal cerebral fissure) It is continues with the tentorium cerebelli posteriorly. It connects posteriorly to the internal occipital protuberence and anteriorly to the crista galli of the ethemoid and frontal crest of the frontal bone..
Describe the Falx Cerebelli.
Small triangular process of dura mater that is received into the posterior cerebellar notch. It is between the lateral lobes of the cerebellum.Attaches at the internal occipital crest, and partially seperates the cerebellar hemispheres.
Describe the Tentorium Cerebelli.
Second largest dural infolding. An extension of the dura mater that seperates the cerebellum from the inferior portion of the occipital lobes of the brain. Attaches rostally to the clinoid process of the sphenoid and rostrolaterally to the petrous portion of the temporal bone, posterolaterally to the internal surface of the occipital bone.
Describe the diaphragma sellae.
Smallest dural infolding. Suspended between the clinoid processes forming a partial roof over the hypophysial fossa in the sphenoid. It covers the pituitary gland and has an opening for passage of the infundibulum and hypophysial veins.
What are the 8 dural sinuses?
Superior Sagittal Sinus
Inferior Sagittal Sinus
Superior Petrosal Sinus
Inferior Petrosal Sinus
Where does the superior sagittal sinus run?
Anterior to posterior. It helps to drain blood. It houses the arachnoid granulations where cerebrospinal fluid drains.
Where does the inferior sagittal sinus run?
Beneath the brain. Allows drainage of blood from center of brain posteriorly into the straight sinus. It runs inferior to the falx cerebri and superior to the corpus callosum. It ends in the straight sinus.
Where does the transverse sinus run?
Runs from the back of the head towards the nose. Drains from the superior sagittal sinus and the straight sinus (confluence of sinuses). The left is usually bigger (used more dominantly)
Where does the occiptal sinus run?
The smallest cranial sinus. It starts at the attached border of the falx cerebelli and ends superiorly at the confluence of sinuses.
Where does the cavernous sinus run?
It is a large venous plexus located on each side of the sellea turcica. The internal carotid runs through it. The cavernous drains into the superior and inferior petrosal sinuses.
Wher eis the superior petrosal sinus located?
Connects the cavernous sinus to the transverse sinus.
The sinus runs in the attached margin of the tentorium cerebelli, in a groove in the petrous part of the temporal bone formed by the sinus itself - the superior petrosal sulcus.
Where is the inferior sinus?
It connects the cavernous sinus to the sigmoid sinus.
Where is the sigmoid sinus?
Runs from straight sinus to the Internal jugular vein.
Where is the anterior cranial fossa? What are some of the major contents?
From the body and lesser wings of the sphenoid, the ethemoid, and the frontal bone. The greater part is formed by the orbital parts of the frontal bone, which supports the frontal lobes of the brain and froms the roofs of the orbits.
Where is the middle cranial fossa?
The posterior part of the lesser wings of the sphenoid, the sellea turcica, the greater wings, upto the petrous portion of the temporal bone.
What is the posterior cranial fossa?
From the dorsum sellea, petrous portion and mastoid to the occiput. Houses the cerebellum, pons, and medulla oblongata.
What are the bones of the neural cranium?
two parietal, two temporal, occipital, sphenoid, frontal, ethemoid