14: Cranial Cavity, Meninges, Brain Flashcards
calvarium
the top part of the skull we cut off, composed of frontal, temporal, parietal, and occipital bones (possibly)
dura mater of the brain
outermost, toughest layer
2 layers - 1 - PERIOSTIUM - outer layer continuous with periosteum of the skull
2 - MENINGEAL LAYER - inner layer continuous with the coverings of the spinal cord and cranial nerves
dura reflections
double layered invaginations of the meningeal layer of the dura into the cranial cavity: falx cerebri, tintorium cerebelli, falx cerebelli, diaphragma sellae
falx cerebri
separates two lobes of cerebrum - travels the longitudinal fissure; attaches to crista galli in front and to the upper surface of the tintorium cerebelli in the back; contains superior and inferior sagittal sinuses
tintorium cerebelli
the horizontal plane of dura that separates the cerebrum from the cerebellum; encloses transverse sinuses and superior petrosal sinuses
falx cerebelli
separates two lobes of cerebellum. attaches to tintorium cerebelli and the occipital bone.
diaphragma sellae
protects the pituitary gland; borders are dorsum sellae and tuberculum sellae; two small emanences on either side are middle clinoid processes; innervated by V1
dural venous sinuses
dural spaces filled with venous blood that drain to the internal jugular v.
sinuses that converge at the confluens
superior sagittal sinus straight sinus transverse sinus occipital sinus (TOSS)
blood supply to the dura
anterioraly: anterior meningeal a. (branch of anterior ethmoidal a.)
middle: middle meningeal and accessory meningeal aa. (branches of the maxillary a)
posteriorly: posterior meningeal aa. (various branches of the ascending pharyngeal, occipital, and vertebral aa.)
meningeal
emissary veins: pass directly through the skull
innervation of the dura
anteriorly: meningeal branches of the anterior and posterior ethmoidal nn. (branches of V1)
middle: meningeal branches of V2 and V3 to the middle cranial fossa
posteriorly: posterior cranial fossa by branches from C1-2
arachnoid
thin, filamentous layer over the fluid filled subarachnoid space. Subarachnoid space is filled with CSF.
arachnoid granulations
projections of the arachnoid that resorb circulated CSF; found in extensions of the dural sinuses
makes CSF
choroid plexi
pia mater
delicate, most intimate covering of the brain that follows its gyri and sulci
anterior cranial fossa
frontal bone (orbital plate) ethmoid bone (cribiform plate and crista galli) sphenoid bone (lesser wing)
cribiform plate of ethmoid bone transmits
CN 1
anterior meningeal a.
meningeal branches of the anterior and posterior ethmoidal nn. (V1)
middle cranial fossa
sphenoid bone (greater wing and body) temporal bone (squamous and petrous portions) optic canal superior orbital fissure foramen rotundum foramen ovale foramen spinosum foramen lacerum carotid canal facial hiatus
optic canal transmits
CN II and opthalmic a.
located in sphenoid bone
superior orbital fissure transmits
(between greater and lesser wings of sphenoid bone)
transmits CNS III, IV, V1 (opthalmic division of trigeminal), VI, and opthalmic vv.
foramen rotundum transmits
(in greater wing of sphenoid)
transmits CN V2 (maxillary division of trigeminal)
foramen ovale transmits
(in greater wing of sphenoid)
transmits CN V3 (mandibular division of trigeminal), accessory meningeal a., lesser petrosal n. (branch of CN IX glossopharyngeal n.)
foramen spinosum transmits
(in greater wing of sphenoid)
transmits middle meningeal a.
foramen lacerum transmits
(between sphenoid, petrous temporal, and occipital bones)
is CROSSED by the greater petrosal n. - closed in life by cartilage - doesn’t transmit anything!
carotid canal
(in petrous portion of temporal bone)
transmits internal carotid a., carotid postganglionic sympathetic nerve plexus
facial hiatus
(on petrous portion of temporal bone)
transmits greater petrosal n. (branch of CN VII facial)
lesser petrosal n. courses through
an unnamed foramen!!
(a branch of CN IX glossopharyngeal)
courses lateral to the facial hiatus/greater petrosal n.
posterior cranial fossa
temporal bone (posterior portion of petrous temporal bone) occipital bone internal acoustic meatus foramen magnum jugular foramen hypoglossal foramen
internal acoustic meatus transmits
CNs VII (facial) and VIII (vestibulocochlear) (in petrous portion of temporal bone)
foramen magnum transmits
(in occipital bone)
spinal cord
spinal contribution to CN XI spinal accessory n.
vertebral a.
jugular foramen transmits
(where the petrous portion of the temporal and the occipital bones meet) CNs IX (glossopharyngeal), X (vagus), and XI (spinal accessory) drains blood from sigmoid and inferior petrosal dural sinuses into the jugular v.
hypoglossal foramen transmits
(in occipital bone)
transmits CN XII (hypoglossal n.)
vascular supply to the brain
two systems -
anterior - internal carotid a.
posterior - vertebral a.
**these networks anastomose to form the Circle of Willis
internal carotid a. supplies
anterior and middle portions of the cerebrum
orbit
vertebral a. path
arise from subclavian a. in root of neck
go through transverse foramen of cervical vertebrae 1-6 then continuing through the foramen magnum
supply blood to posterior cerebrum, cerebellum, and brainstem
SCALP
skin connective tissue aponeurosis loose connective tissue periosteum
middle meningeal artery
branch of maxillary artery
passes through foramen spinosum
supplies blood to the dura mater
blood supply to the dura
anterior meningeal a. (fr. anterior ethmoidal a.)
middle meningeal a. (fr. maxillary a.) - the big one, on our practice practical!
posterior meningeal a. (various)
accessory meningeal a. (fr. maxillary a.)
sensory innervation to dura
meningeal branches of trigeminal n.
cervical nerves C1 & C2
dural venous sinuses
between the two layers of dura mater; receive venous blood from internal and external veins of the brain and CSF from the subarachnoid space and drain into the internal jugular vein
superficial cerebral veins drain into the
superior sagittal sinus
deep cerebral veins drain into the
great cerebral vein of Galen —> then into the straight sinus
pathway to internal jugular vein
confluens to transverse sinus to sigmoid sinus to internal jugular v.
lots of structures through the cavernous sinus!
internal carotid artery CN III CN IV CN V 1 CN V 2 CN VI
CSF produced in
choroid plexus
CSF path
through ventricles to subarachnoid space to arachnoid granulations/villi (resorbed here!)
venous lacunae
lateral extensions of the superior sagittal sinus that receive numerous arachnoid granulations
