Cranial Cavity (Gray's) Flashcards
What bones make up the Calvaria and what sutures hold them together?
- Frontal, Parietal, and Occipital Bones
Coronal Suture - Between Frontal and Parietal Bones
Sagittal Suture - Between paired parietal bones
Lambdoid Suture - between Parietal and Occipital Bones
What are the Bregma and Lambda?
Bregma
- Junction of Coronal and Sagittal Sutures
Lambda
- Juction of lambdoid and sagittal sutures
What is the Falx Cerebri?
Specialization of Dura Mater that partially Separates the two cerebral Hemispheres
What are the 5 layers of the scalp?
S - Skin C - Connective Tissue (dense) A - Aponeurotic Layer L - Loose CT P - Pericranium
T or F: the skin, dense connective tissue, and aponeurotic layer of the scalp are tightly bound.
True
What is contained in the dense connective tissue layer of the scalp?
Veins, Arteries, and Nerves that supply the scalp
What layer of the scalp provides a point of attachment for the occipitofrontalis muscle?
Aponeurotic layer
What is the point of the loose connective tissue layer of the scalp?
Separates the Aponeurotic layer from the skull allowing for movement of the scalp
Why do injuries in which the dense CT layer of the skull is injured result in profuse bleeding?
- This tissue is hightly vascularized
2. The Dense CT holds the vessel open
Where do infections in the scalp tend to localize and why?
- Loose CT of the Skull
- This is due to its consistency
What is the pericranium attached to and is it removable?
- Attached Directly to the Cranium
- Removable Except at the Sutures
What are the 3 parts of the Aponeurotic Layer of the scalp?
Anterior: Frontal Belly of Occipitofrontalis
Posterior: Occipital Belly of Occipitofrontalis
Between: Epicranial Aponeurosis (galgea aponeurotica)
What is the innervation of the occipitofrontalis muscles?
Facial Nerve (CN VII)
What is an important distinction between the dura of the spinal cord and that of the brain?
- Dura of the Brain consists of 2 layers
- only 1 layer on the spinal cord comes through the foramen magnum
What are the 2 layers of the dura of the brain and what are they in contact with?
- Periosteal Layer - Firmly attached to the skull
- Meningeal Layer - contacts the arachnoid mater
**Meningeal Layer continuous with spinal Dura Mater at Foramen Magnum
What are the 4 dural partitions?
- Falx Cerebri
- Tentorium Cerebelli
- Falx Cerebelli
- Diaphragma Sellae
What layer of the dura contains the meningeal arteries that supply the meninges?
Periosteal layer
What innervates the meningeal layers?
- Small Meningeal Branches of the Three Divisions of the Trigeminal n. (CN V)
- Cervical nn. 1,2, and sometimes 3
Falx Cerebri
- What is it?
- Location
- Anterior Attachment
- Posterior Attachment
Dural Partition
- Meningeal Layer passes between the two Cerebral Hemispheres
Anterior Attachment:
- Crista Galli (ethmoid) and Frontal Crest (frontal bone)
Posterior Attachment:
- Tentorium Cerebelli (it blends in with it)
Tentorium Cerebelli
- What is it?
- Location
Attachments:
- Anterior
- Medial
- Lateral
- Posterior
Dural Partition
- Horizontally oriented between Cerebellum and Posterior Cerebral Hemispheres
Attachments
Anterior:
Anterior and Posterior Clinoid Processes
Posterior: Occipital bone along grooves of TRANSVERSE sinuses
Laterally: Superior border of petrous part of Temporal Bone
Medially: Just a free edge
Falx Cerebelli
- What is it?
- Location
Attachments:
- Anterior
- Posterior
- Superior
Dural Partition
- Small midline projection of meningeal dura in posterior cranial fossa
Attachments:
Anterior: Free edge
Posterior: Internal Occipital Crest
Superior: Tentorium Cerebelli
Diaphragma Sellae
- What is it?
- Location
- What passes through it
Dural Partition
- Horizontal shelf of meningeal dura that covers hypophyseal fossa in sella turcica
- Infundibulum passes through the center of this
What 2 main arteries provide arterial blood to the brain?
- Vertebral
- Internal Carotid
What do the internal carotid arteries form at the base of the brain within the cranial cavity?
- Cerebral Arterial Circle (of Willis)
How do the vertebral arteries and carotid arteries enter the cranial cavity?
Vertebral
- Via Foramen Magnum
Carotid
- Via L and R carotid Canals
Menigeal Arteries
- What do they supply
- Largest branch
- How do they enter the cranial Cavity
- The meninges, middle menigeal supplies 2/3 of the Dura
- Middle = Largest
- Middle enters crainal cavity via FORAMEN SPINOSUM
Which meningeal artery is at risk in head trauma and why?
- Middle Menigeal
- Its close proximity to the pterion
What does the venous drainage of the brain and cranial cavity?
Dural Venous Sinuses
