Download Anterior cranial fossa

Skull
Yu-Qiang Ding, M.D., Ph.D.
丁玉强
[email protected]
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Head 头
Conceptual view
The head is composed of a
series of compartments that
are formed by bone and
soft tissues.
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The cranial cavity
Two ears
Two orbits
Two nasal cavities
An oral cavity
 The cranial cavity
contains the brain 脑
and associated
membrane (meninges)
 Two ears 耳：external
ears are visible, but
internal ears are
embedded in a bone.
 Two orbits 眶 contain
the eyes. The apex of
cone-shaped chambers
are directed posteriomedially.
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 Two nasal cavities
鼻腔 are the upper part
of the respiratory tract.
The anterior openings are
nares (nostrils), and
posterior one is choanae
(post. nasal aperture).
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 Two nasal cavities
鼻腔 are the upper
part of the respiratory
tract.
Air-filled extensions
are paranasal sinuses.
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 An oral cavity口腔 is
separated from the
nasal cavity by the
palates.
Unlike nasal cavity, the
openings (oral fissure and
oropharyngeal isthmus) can
be opened and closed.
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The face面 and Scalp头皮
Muscles of the facial expression adjust the contours of the face to relay
non-verbal signals.
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Scalp
Clinical note: abundant blood supply and serious bleeding.
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Skull
Many bones of the head
collectively form the
skull.
Most of them are
interconnected by sutures,
which are immovable
fibrous joints.
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Clinical note about the
sutures (fontanelle 囟)
In the fetus and newborn,
large membranous and unossified gaps (fontanelles)
between the large flat bones
that cover the top of the
cranial cavity, allowing its
passage through the birth
canal and postnatal growth.
Bregma and Lambda in
adulthood.
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Twenty two
bones, excluding
the ossicles of
the ear.
Except for the
mandible, which
forms the lower jaw,
the bones of the
skull attach to each
other.
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 An upper domed
part: calvaria 颅顶
(corresponds to the scalp)
 A lower anterior
part: facial skeleton
(corresponds to the face)
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Anterior view
Frontal bone额骨
 Ceiling of the
orbit
Superciliary arch
Supra-orbital notch
 Inferiolaterally,
one process
connects to
zaygomatic bone
 Inferiomedially,
articulates with the
nasal bone and the
frontal process of
the maxilla.
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Anterior view (I)
Zygomatic
bone 颧骨
(cheek bone)
Lateral and
inferior rims of
the orbit
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Anterior view (II)
Nasal bone
鼻骨
Medial to the
frontal process of
the maxilla.
Contribute to
the piriform
aperture, large
opening of bony
nasal cavity.
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Anterior view (III)
Maxilla上颌骨
 Inf. rim of the
orbit
 Lateral wall of
the nasal cavity
Piriform aperture
Bony nasal septum
A paired inferior nasal
concha.
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Anterior view (IV)
Maxilla上颌骨
Inf. rim of the
orbit
Lateral wall of the
nasal cavity
 Two processes:
Laterally: zygomatic
Superiorly: frontal
processes.
 Body: inferior end
is the alveolar process
containing the teeth.
Infra-orbital foramen
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Anterior view (IV)
Mandible下颌
骨 (lower jaw)
Body, anteriorly,
base + alveolar
part.
Ramus, posteriorly,
Ant. and post.
processes.
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Anterior view (V)
Mandible下颌
骨 (lower jaw)
Body anteriorly,
base + alveolar
part.
Ramus posteriorly,
Ant. and post.
processes.
 Condylar process：joint with temporal bone
 Coronoid process: muscle attachment
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Lateral view
Lat. portion of
calvaria
Upper part:
Frontal, parietal,
occipital bones
Lower part:
 great wing of
sphenoid bone 蝶骨
 squamous part of
temporal bone 颞骨.
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Lateral view (I)
Pterion 翼点:
 Four bones are in
close proximity.
 Bones are thin, and
overlay middle
meningneal artery in
the inner surface.
 Skull fracture here
leads to serious
consequences,
because this artery
may be torn resulting
in an extra-dural
hematoma.
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Lateral view (II)
The middle
mengingeal
artery:
Arises from external
carotid artery, enter
the skull through the
foramen spinosum,
goes vertically in a
upward direction,
crossing the pterion
during its course.
Temporal bone颞骨
 Squamous part:
Lateral wall of cranium.
 Zygomatic process:
project laterally and then
anteriorly, form zygomatic
arch with temporal process
of zygomatic bone.
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Lateral view (III)
Temporal
bone 颞骨
 Tympanic part鼓部:
external acoustic
opening leading to
external ear canal.
 Mastoid part乳突部:
posteriorly,
 Petrous part岩部:
Body-invisible
Inferiorly, a long process
called styloid process
Mandibular fossa:
articulate with condylar
process of mandible.
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Lateral view (IV)
clinical note:
Big laugh may lead to a
big anterior movement
of condylar process out
of the mandibular fossa.
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Lateral view (III)
Temporal fossa
Contains temporalis
muscle (coronoid process
of mandible)
, which raises the
mandible and thus
close the jaw.
Masseter muscle
Lateral view (V)
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Posterior view
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Occipital
bone 枕骨
Like temporal
bone, also
has a big
squamous
part.
Several bony
land markers,
e.g. external
occipital
protuberance.
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Posterior view (I)
Inferior view
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Ant. Part
 Alveolar process
牙槽突
 Hard palate :
two components:
(1) palatine process of Maxilla
(2) horizontal process of
palatine bone
Palatine bone: L-shaped
Vertical part: lateral wall of
bony nasal cavity
Horizontal part: hard palate
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Clinical Note
 Hard palate 硬腭:
two components:
(1) palatine process of
Maxilla
(2) horizontal process of
palatine bone
Cleft palate
Caused by a failure of fusion
of two maxilla processes
during embryonic
development.
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Inferior view (II)
Middle part
1. Vomer 犁骨: in midline, resting on the sphenoid bone, post. part of bony nasal
septum.
2. Sphenoid 蝶骨；centrally located, looks like butterfly.
body, greater and lesser wings, pterygoid process
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Sphenoid 蝶骨
 Body: centrally placed cube of
bone containing two air sinuses
separated by a septum.
 Greater and lesser wings:
Sup. view
project from the body laterally
 Pterygoid process 翼突: project
downward from the body
Post. view
Inf. view
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Post. Part
Occipital bone枕
骨
Basilar part: posterior
to the body of the
sphenoid.
More posteriorly,
foramen magnum.
Laterally is bounded
by the temporal bones.
Occipital condyle:
articulate with the first
cervical vertebrate.
 Hypoglossal canal
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Inferior view (III)
Temporal bone
Inferior view (IV)
Petrous part:
Wedge-shaped, its apex is located between the greater wing and basilar part;
forms one of the boundaries of the foraman lacerum, an irregular opening filled
with cartilage in life.
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Temporal
bone 颞骨
 Tympanic part鼓部:
external acoustic
opening leading to
external ear canal.
 Mastoid part乳突
部: posteriorly,
 Petrous part岩部:
Body-invisible
Inferiorly, a long process
called styloid process
Mandibular fossa:
articulate with condylar
process of mandible.
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Lateral view (IV)
Temporal bone
Inferior view (IV)
Petrous part: Wedge-shaped, its apex is located between the greater wing and
basilar part; forms one of the boundaries of the foraman lacerum, an irregular
opening filled with cartilage in life.
Carotid canal: circular opening for carotid artery entering the skull.
Jugular foramen: jugular (vein) and cranial nerves exit the cavity .
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Cranial cavity
Roof:
dome-shaped. Consists of the fontal bone anteriorly, paired parietal bone in
the middle, and the occipital bone posteriorly.
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Cranial cavity 颅腔
The floor of the cavity is divided into ant. middle and post. fossae.
Anterior cranial fossa:
1. Orbital part of the frontal bone: ceiling of the orbits
2. A small wedge-shaped Ethmoid bone 筛骨:
Ceiling of the nasal cavity
Crista galli (cockscomb) in the middle (attachment for the falx cerebrum)
Cribriform plate, laterally,
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Anterior cranial fossa (I)
Anterior cranial fossa:
3. Lesser wing of sphenoid
Ant. clinoid process: widens and curves posteriorly.
Optic canal: through which optic N pass as it exit the cavity to enter the orbit.
located anterior to the anterior clinoid process.
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Middle cranial fossa (II)
Inner surface of two bones: sphenoid and temporal bones
1. Body of the Sphenoid bone: :
Anterior part: elevated, called chiasmatic sulcus
The reminder: sella turcica
Middle: hypophysial fossa, in which the pituitary gland is located.
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Middle cranial fossa (III)
Fissure and foramina in the greater wing of Sphenoid bone :
 Superior orbital fissure: between great and lesser wings; a major passageway to orbit;
several cranial nerves innervating the eyeballs pass through.
 foramen rotundum: V2
 foramen ovale: V3
 foramen spinosum: a artery pass through
 intracranial opening of carotid canal: dorsal to the foramen lacerum
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Middle cranial fossa (III)
Upper surface of the Temporal bone:
Tegmen tympani and Arcuate eminence (middle ear)
Trigeminal impression (trigeminal ganglion)
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Posterior cranial fossa
1. Posterior surface of the petrous part of the temporal bone
internal acoustic meatus, jugular foramen (anterior to the occipital
bone)
2. Occipital bone:
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Clivus, groove and crest, hypoglossal canal lateral to the condyle in the inf.
Surface.
Vertebra and vertebral
column
Functions
Support the body’s weight,
transmit forces through the pelvis to
the lower limbs,
carry and position the head, and
brace and help maneuver (move)
the upper limbs.
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Curvatures
The two primary curvatures of the
vertebral column:
1. Concave anteriorly.
2. Original shape of embryos
3. Retained in the thoracic and
pelvic regions in adult.
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Curvatures
The two primary curvatures of the
vertebral column:
1. Concave anteriorly.
2. Original shape of embryos
3. Retained in the thoracic and
pelvic regions in adult.
The two secondary curvatures of
the vertebral column:
Concave posteriorly; in the
cervical and lumbar regions
Bring the center of the body into a
vertical line, which allows the
body’s weight to be balanced
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Movement
Although the amount of movement between any two vertebrae is limited,
the effects between vertebrae are additive along the length of the column.
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More important function:
Protection of the
spinal cord
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Bones
7 cervical, 12 thoracic, 5
lumbar, 5 sacral and 3-4
coccygeal vertebrae.
Sacral vertebrase fuse
into a single bony
element, the sacrum.
Coccygeal vertebrae
are rudimentary (loss of
use) in structure, vary in
number, and often fuse
into a single coccyx.
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A typical vertebra
Consists of a Body and a Vertebral arch.
1. Body: the major weight-bearing component, increase in size
from C1 to L5.
2. Arch: anchored to the body by two pedicles, two laminase
form the roof of the arch and fused in the middle.
3. Body and Arch form a bony canal, vertebral canal
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Projections from the Arch
1. Spinous process, posterioly
2. Transverse process, laterally
3. Superior and Inferior articular process, with similar
processes on adjacent vertebrae.
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Intervertebral foramen
1. Allows spinal nerve and blood vessel, to pass in and out of
the vertebral canal.
2. Formed by the adjacent sup. notch and inf. notch.
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A typical vertebra
Consists of a Body and a Vertebral arch.
1. Body: the major weight-bearing component, increase in size
from C1 to LV.
2. Arch: anchored to the body by two pedicles, two laminase
form the roof of the arch and fused in the middle.
3. Body and Arch form a bony canal, vertebral canal
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A typical cervical vertebra
1. Body: short in height and square shaped.
2. Transverse process perforated by a round foramen
transversarium (for a artery going into skull)
3. Spinous process: short and bifid
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C1 (atlas) and C2 (axis)
C1: lacks the body, ring-
shaped, two large lateral mass
(facet for occipital condyle)
interconnected by an ant. arch
and post. arch.
Atlanto-occipital joint: allows the
head to node up or down.
C2: a Dens from the body,
which form atlanto-axial joint
with facet for dens in C1, allows the
head to rotate.
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Vertebra prominens
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A typical thoracic vertebra
1. Articulation with ribs:
Body: with head of ribs, superior or inferior demifacet
Transverse process: facet for articulation with tubercle of rib
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Sacrum
1. Triangular in shape with the apex pointed inferiorly.
2. Two large L-shaped facet on each lateral surface, for
articulation with pelvic bone.
3. Ant. and Post. Sacral foramen (foramina).
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Joints
Symphysis (fused) between the bodies: inter-vertebral joint
Synovial joints between articular processes.
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Intervertebral disc:
Intervertebral joint
Anulus fibrosus: circular fibrocartilage
Nucleus pulposus: gelatinous, absorbs compression forces
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Intervertebral joint
Clinical Note:
Degenerative changes in the anulus fiberosus can lead to herniation
of the nucleus, and posteriolateral herniation can impinge the spinal
nerve root leading to back pain.
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Ligaments
Ant. & post. longitudinal
ligaments
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Ligaments
Ligament flava (yellowish): on each side, pass between the laminae of
adjacent verbebrae.
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Supraspinous
ligament
Connect and passes along
the tips of the spinous
processes
Ligamentum nuchae:
(nucha --- nape)
The most predominant one, a
triangular, sheet-like structure in
the median sagittal plane
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