Download Petrous part of the temporal bone

View of a Skull, 1489 by Leonardo Da Vinci
Kaan Yücel M.D., Ph.D.
26.11.2013 Tuesday
1.SKULL
skeleton of the head
cranium
22 bones
excluding ossicles of the ear
1.SKULL
Mandible
Lower jaw bone
1.SKULL
skeleton of the head
Neurocranium
Viscerocranium facial skeleton
22 bones in the cranium
8 @ neurocranium
Frontal bone- single
Occipital bone- single
Parietal bones- paired
Temporal bones- paired
Sphenoid bone- single
Ethmoid bone- single
neurocranium
1 roof (calvaria)
1 floor base (base of the skull) basicranium
CALVARIA
TEMPORAL BONES
PARIETAL BONES
parts of the single
frontal, sphenoid,
& occipital bones
CRANIAL BASE
mainly parts of the
Sphenoid bone
Temporal bones
Occipital bone
BONES OF THE NEUROCRANIUM
FRONTAL BONE
OS FRONTALE
FRONTAL BONE
1. Squama vertical portion
region of the forehead
2. Orbital portion frontal orbit/orbita frontalis horizontal portion
formation of roofs of the orbital & nasal cavities
Squama
ANTERIOR VIEW
supra-orbital margin of the frontal bone
angular boundary between squamous & orbital parts
superciliary arches
superior to
supra-orbital margin & rim of the
orbit
prominence of these ridges
greater in males
glabella
small depression between superciliary
arches
ANTERIOR VIEW
frontal eminences
in some
calvaria looks like a square
ANTERIOR VIEW
Medially
frontal bone projects inferiorly
forms
part of the medial rim of the orbit.
Laterally
zygomatic process of the frontal bone
projects inferiorly
forms
upper lateral rim of the orbit.
articulates with frontal process of the
zygomatic bone.
ANTERIOR VIEW
a persistent frontal suture or remnant of it
In some adults
Visible in the midline of the glabella
Smooth, slightly depressed area between superciliary arches
INTERNAL VIEW
Sagittal sulcus
vertical groove @ upper part of the midline squama frontalis
Frontal crest
formed by the union of the edges of the sagittal sulcus
median bony extension of the frontal bone
Foramen cecum (blind hole)
@ the base of the frontal crest
Nasal process
downward projection of the nasal part
of the frontal bone terminates as
nasal spine
PARIETAL BONES
OS PARIETALE
Two parietal bones unite and form the sides & roof of the cranium.
Each bone is irregularly quadrilateral in form.
PARIETAL BONES
OS PARIETALE
Parietal eminence (tuber parietale)
an elevation near the centre of the convex and smooth external surface
Superior and inferior temporal lines
two curved lines crossing the middle of the bone in an arched direction
PARIETAL BONES
OS PARIETALE
Parietal foramen
small, inconstant aperture posteriorly in the parietal bone near sagittal suture
TEMPORAL BONES
OS TEMPORALE
Situated at the sides and base of the skull.
Contributes most of the lower portion of lateral wall of the cranium.
TEMPORAL BONES
3 parts
1. Squamous part
2. Tympanic part
3. Petromastoid part
Squamous part of the temporal bone
large flat plate, forms the anterior & superior parts of the temporal bone
contributes to lateral wall of the cranium
articulates
anteriorly with greater wing of the sphenoid bone
superiorly with parietal bone
Squamous part of the temporal bone
Zygomatic process
anterior bony projection from the lower surface of the squamous part of the temporal bone
Zygomatic arch
zygomatic process of the temporal bone+temporal process of the zygomatic bone
Temporomandindibular joint
mandibular fossa
concave depression located inferiorly @ squamous portion
Head of the mandible enters here!
articular tubercle
downward projection of the anterior border of the mandibular fossa
Tympanic part of the temporal bone
just below the origin of the zygomatic process
External acoustic opening (pore)
entrance to the external acoustic meatus (canal)
leads to the tympanic membrane (eardrum).
Mastoid part of the temporal bone
most posterior part of the temporal bone
continuous with squamous part anteriorly
articulates with
parietal bone superiorly
occipital bone posteriorly.
Mastoid part of the temporal bone
mastoid process
on the lateral aspect, cone-shaped projection from the inferior surface
mastoid notch
medial aspect of the mastoid process
Petrous part of the temporal bone
lateral to the basilar part of the occipital bone
between
greater wing of the sphenoid anteriorly
basilar part of the occipital bone posteriorly.
Petrous part of the temporal bone
foramen lacerum
apex of the petrous part forms one of the boundaries of this foramen.
opening for the carotid canal
large circular opening posterolateral to the foramen lacerum
Petrous part of the temporal bone
Anterior surface
1. Arcuate eminence (Eminentia arcuata)
@ centre of the anterior surface.
2. Tegmen tympani tegmen (covering; covering, cover, protection)
anterolateral to arcuate eminence,thin bony roof of the middle ear
cavity.
Petrous part of the temporal bone
Anterior surface
3. Groove for greater petrosal nerve (Sulcus nervi petrosi majoris)
anterior to tegmen tympani.
4. Groove for lesser petrosal nerve (Sulcus nervi petrosi minoris)
parallel and laterally to the groove for greater petrosal nerve.
Petrous part of the temporal bone
Anterior surface
6. Trigeminal impression (Impressio trigeminalis)
slight depression located medially
marks the location of the sensory ganglion for the trigeminal nerve [V].
Petrous part of the temporal bone
Anterior surface
6. Trigeminal impression (Impressio trigeminalis)
CAROTID CANAL
5. Carotid canal (Canalis caroticus)
large circular opening
posterolateral from the foramen lacerum
along the petrous part of the temporal
bone.
INTERNAL CAROTID ARTERY
1.
2.
3.
4.
5.
6.
Internal carotid artery
Vertebral artery
Cavernous sinus
Carotid canal
Anterior cerebral artery
Posterior cerebral artery
Petrous part of the temporal bone
Jugular foramen
large opening between the occipital bone & petrous
vein draining the brain
3 of the 12 cranial nerves pass through here (CNs 9-10-11)
Styloid process
needle-shaped bone marking
projects from the lower border of the temporal bone.
anteromedial to the mastoid process
point of attachment for numerous muscles and ligaments
stylomastoid foramen
Transmits the nerve for the muscles of the
face
Posterior to the base of the styloid process
Between
styloid process & mastoid process
CN VII
FACIAL NERVE
SPHENOIDAL BONE
OS SPHENOIDALE
at the base of the skull in front of the temporal bones 6 basilar part of occipital bone
median portion body
two great and two small wings extending outward from the sides of the body
two pterygoid processes project from it below.
SPHENOIDAL BONE
OS SPHENOıDALE
sphenoidal crests
. formed by the sharp posterior borders of the lesser wings
saddle-like bony formation on the upper surface of the body of the sphenoid
Anterior & posterior
clinoid processes
Clinoid means «bedpost»
4 processes (2 anterior 2 posterior) surround hypophysial fossa
“bed” of the pituitary gland like the posts of a four-poster bed.
composed of three parts
1. tuberculum sellae (horn of saddle)
2. hypophysial fossa (pituitary fossa)
3. dorsum sellae (back of saddle)
on each side of the body,4 foramina perforate the greater wings of the sphenoid
Superior orbital fissure
between the greater and the lesser wings
Foramen rotundum
posterior to medial end of the superior orbital fissure
Foramen ovale
posterolateral to the foramen rotundum
Foramen spinosum
posterolateral to the foramen ovale
Pterygoid
processes
lateral medial
pterygoid plates
Pterygoid fossa
Optical canal
Chiasmatic sulcus
OCCIPITAL BONE
OS OCCIPITALE
at the back and lower part of the cranium
foramen magnum
cranial cavity communicates with the vertebral canal
Major structures passing through
spinal cord
meninges & spinal cord
vertebral arteries
anterior & posterior spinal arteries
spinal accessory nerve (CN XI)
4 parts of the occipital bone
arranged around the foramen magnum
Squama
Basilar part
Lateral (condylar) portions
external occipital protuberance
external occipital crest
descends from the protuberance toward the foramen magnum.
superior nuchal line
marks the superior limit of the neck.
extends laterally from each side of the protuberance.
occipital condyles
Two large protuberances @ lateral parts of the occipital bone
Vertebral column-cranium articulation here
clivus (Lat., slope)
shallow depression, incline behind the dorsum sellæ
cruciate eminence
divides the interior surface into four fossae
cerebral fossae
cerebellar fossae
internal occipital
crest
Lower divison of the
cross!
internal occipital
protuberance
Centre of the cross!
hypoglossal canal
for the hypoglossal nerve (CN XII)
superior to the anterolateral margin of the foramen magnum
superior nuchal line
marks the superior limit of
the neck. extends laterally
from each side of the
protuberance.
inferior nuchal line
less distinct.
ETHMOID BONE
Gk, ethmos, sieve sifter, eidos, form
Light, spongy, & cubical
@ anterior part of the base of the cranium
Between two orbits, at the roof of the nose
Contributes to each of these cavities.
4 parts
1) A horizontal cribriform plate
2) Perpendicular plate
3) Two ethmoidal labyrinths
Crista galli
midline ridge
Number 3
4 parts
1) A horizontal cribriform plate
2) Perpendicular plate
3) Two ethmoidal labyrinths
body and lesser wings of
the sphenoid bone
Frontal
bone
E
greater wings of the
sphenoid
shallowest
X
squamous part of the temporal bone
petrous part of the
temporal bone
X: dorsum sellae
Occipital
bone
largest and deepest
SUTURAE
form of articulation
margins of bones united by a thin layer of fibrous tissue
CORONAL
SUTURE
Frontal bones
Parietal bones
LAMBDOID
SUTURE
Parietal bones
Occipital bones
SAGITTAL
SUTURE
Parietal bones
coronal & sagittal sutures intersect
frontal, sphenoid, parietal &
temporal bones
sagittal & lambdoidal sutures
FONTANELLES
parietal bones
occipital bones
anteriorly
posteriorly
@ the junction of lambdoid & sagittal sutures
Lambda
1 y old. Closed.
halves of frontal bone anteriorly
parietal bones
posteriorly
@ the junction of sagittal, corona & frontal sutures
Bregma
1.5 y old. Closed.
Sphenoidal & mastoid fontanelles fuse during infancy.
less important clinically than midline fontanelles
Bone marking
@ which bone
Important structures passing through
A lesion here might result in…
-particularly cranial nervesCarotid canal
Temporal
Foramen magnum
Occipital
Foramen ovale
Sphenoid
Foramen rotundum
Sphenoid
Foramen spinosum
Hypoglossal canal
Internal acoustic meatus
Sphenoid
Occipital
Temporal
Jugular foramen
Temporal
Optic canal
Stylomastoid foramen
Sphenoid
Temporal
Superior orbital fissure
Sphenoid
Internal carotid artery and nerve plexus
Problem in the anterior arterial supply of
the brain; as a result; weakness
(hemiplegia) and numbness in the face,
and extremities on the opposite side of
the body, difficulty in speech, visual loss,
etc.
Continuation of brain and spinal cord; vertebral
arteries and nerve plexuses; roots of accessory
nerve [XI]; meninges
Third branch of the CN V (Trigeminal nerve):
Sensorial loss in the mandibular region of
Mandibular nerve [V3]
the face
Second branch of the CN V (Trigeminal nerve): Sensorial loss in the maxillary region of
Maxillary nerve [V2]
the face
Hypoglossal nerve [XII] and vessels
Loss of movement of the tongue.
Facial nerve [VII]; vestibulocochlear nerve [VIII] Problems in hearing, balance, or
movements of the facial (expression)
muscles
Internal jugular vein; glossopharyngeal nerve
[IX]; vagus nerve [X]; accessory nerve [XI]
Optic nerve (II)
Problems in vision.
Facial nerve [VII]
Loss of movement of the muscles of the
face
Oculomotor nerve (III)
Problems in vision.
Trochlear nerve (IV)
Branches of ophthalmic nerve (II)
Abducens nerve (VI)