Anatomy Test #3 Lecture #1 Material Flashcards
How many bones are there in the skull?
22 bones attached to each other by sutures
What are the two parts that the skull can be divided into
- the neurocranium (the upper part). It’s the cranium vault (cavity) and the skull cap (calvaria)
- the viscerocranium (the lower part, bones around the mouth). It’s the fascial skeleton
What is the function of the neurocranium?
It houses and protects the brain
Describe the dividing line between the neurocranium and the viscerocranium
The dividing line for these two components passes through the lower 1/3rd of the orbits, the nasal cavity, and external auditory meati
The term cranium may be used to describe
the skull minus the mandible
Neurocranium bones:
PEST OF 6 Parietal bones (2) Ethmoid bone Sphenoid bone Temporal bones (2) Occipital bone Frontal bone
Viscerocranium bones:
Nicole Loves Zesty INC ‘s Magenta Velvet Pants Nasal bones (2) Lacrimal bones (2) Zygomatic bones (2) Inferior Nasal Conchae Maxilla Vomer (unpaired) Palatine bone
what forms the cranial vault?
the calvaria and the cranial cavity floor
divide the nose into left and right, and when you deviate the septum you deviate these:
vomer and the perpendicular plate
cranial bones are separated by
FIBROUS SUTURES which form FIBROUS JOINTS
A younger individuals suture joints would
have more joint integrity, so they would be more defined and clear. Older peoples suture joints have poor to no integrity as they are fused so they won’t have the joints.
Neurocranium
formed by the bones making the calvaria (or “skull cap”), which are the fused frontal bones, paired parietal bones, the squamous portion of the temporal bones, and the occipital bones. These bones are separated from one another by sutures, which become ossified in old age
the coronal suture
between frontal bone and parietal bone, it runs through the frontal plane
helps form “soft spot” or bregma in the infant
the sagittal suture
separates the parietal bones from each other. Runs through the sagittal plane (left and right)
the lamboid / lambdoidal suture
separates the occipital bone and two parietal bones
the squamosal suture
between parietal bone and the squamous portion of the temporal bone
Wormian bones or sutural bones
found within sutures / sutures of individual calvaria bones; Also known as Inca bones
Metopic suture
- separates the frontal bones prior to their fusion around six to eight months of age. Fastest suture to ossify
fontanelles
large unossified gaps between bones filled with fibrous tissue
They close in the first year after birth
complete ossification occurs later in life
anterior fontanelle vs posterior fontanelle
anterior is between the frontal and coronal sutures. It is also called the bregma. It has a diamond shape
the posterior fontanelle is between the occipital bone and the parietal bones. It is diamond shaped
infant skull vs adult skull
as an infant the neurocranium is disproportionately huge. It takes up most of our skull
adult skull the viscerocranium elongates so that it is pretty equal in size to the neurocranium
Eustachian tube
a little tiny tube (1.4 inches in length) that is partially cartilage partially bone, that runs from your middle ear (deep to eardrum), and then terminates in your nasal pharynx (behind nasal cavity)
Why do we have Eustachian tubes?
to equalize the pressure in your middle ear
Infant vs Adult Eustachian tube?
in the baby its more horizontal. In an adult when it goes medially it runs down and forward (bc of the viscerocranium elongating).
Why do infants get more ear infections?
If an Infection in the pharynx reflexes up to middle ear, an adult is more likely to be able to drain it back out through their Eustachian tube. But in infants it can’t as easily drained because of the anatomical orientation of their Eustachian tube (which is more horizontal than adults, causing less drainage)
Kids might get tubes in their ears to help it drain out
describe the neurocranium boney make up:
Calavaria:
- Deep Inner Table – Compact Bone
- Periosteuim attaches to Dura Mater - Diploe – Cancellous Bone (soft and squishy).
- Cancellous bones contains veins which are named for the area where they are located. Ie: occipital - Superficial Outer Table – Compact Bone
- Periosteuim attaches to scalp
The diploe layer of neurocranium has spaces which hold and protect
red bone marrow
Other than red bone marrow, what else runs in the diploe layer of scalp?
blood vessels! Specifically, diploic veins
Diploic veins are named for
the bone that they reside in
Diploic veins course within the cancellous bone - these are the ___ veins, ____ ___ veins, the ___ ___ veins, and the ___ veins.
frontal, anterior temporal, posterior temporal and occipital
what do diploic veins do?
drain the neurocranium, so they drain the scalp
a scalp vein joins into an _____ vein to go from the outer table, through the diploe layer, through the internal table. The emissary vein also picks up the ____ veins
emissary vein
emissary vein also picks up diploic veins
emissary vein plus veins it picks up drain into
The superior sagittal sinus
Diploic veins terminate in the
dorsal venous sinuses
the superior sagittal sinus picks up majority of the your intercranial blood. It flushes out into the ____ direction to make it back to the heart
posterior
emissary veins, and what could be bad about them…
pass from the scalp and diploic veins to the venous circulation of the brain
THESE COMMUNCATIONS MAY PROVIDE A ROUTE FOR THE SPREAD OF INFECTION
encephalitis
a scalp infection that can be caused by the emissary veins. It is a swelling and infection throughout the brain veins. It can cause the brain to compress and the blood vessels to be smooshed
The orbit of the skull is a pyramidal shaped socket. Name its borders
How to Remember:
MS. ELFZ
Roof: frontal bone Medial wall: lacrimal and ethmoid bones (orbital plate) Lateral wall: zygomatic bones Floor: maxilla Apex: greater wing of sphenoid bone
The orbit is a pyramid-shaped cavity which lies above the
maxillary sinus and just lateral to the nasal cavity
Optic Canal function
Transmits:
- the optic nerve (CN II)
- the ophthalmic artery
Superior orbital fissure function
Transmits:
- the ophthalmic division of CN V (trigeminal nerve)
- superior and inferior ophthalmic veins
- cranial nerves III (oculomotor), IV (trochlear), and VI (abducens)
Orbit-Foramina
- Optic canal
- Superior Orbital fissure
- Inferior Orbital fissure
- Infraorbital groove
Lefort fractures 1, 2, and 3
also referred to as a dashboard injury - the car stops, but you keep going because you’re not wearing a seatbelt. fractures in the face.
1- an arch right over maxilla and inferior portion of piriform fossa
2. an arch that comes up higher in maxilla and skirts along the inferior edges of the orbits
3. goes transversely through orbits (worst one)
pterion (p is silent)
a landmark- go from top of the ear and go forward about an inch and a half. It is the point of articulation between 4 bones of the skull : the frontal bone, the parietal bone, the temporal bone, and the sphenoid bone. It is a weak spot because it is the thinnest portion of the skull.
Why is it bad to have your pterion fractured?
because it houses the middle meningeal artery. This mostly effects the anterior branch of the middle meningeal artery. CAUSES AN EPIDURAL HEMATOMA which is bleeding in the epidural space)
the middle meningeal artery branches off into
anterior and posterior meningeal artery
the middle meningeal artery supplies blood to the
dura mater of the brain, and it runs in the epidural space
the middle meningeal artery is between
the dura mater and the bones of the skull. When there is a hematoma a big blood clot forms in this space
Bones of your cranial vault - the frontal bone - forms your
orbital plates- which cover your orbits
it also forms your forehead
your frontal bone contains
the frontal lobes - cerebral cortex
your occipital bone forms the
posterior portion & floor of the cranial vault
Bones of your cranial vault - your occipital bone - contains your
contains the foramen magnum
contains your brainstem and cerebellum
3 parts of the floor of the cranial vault
the frontal bone
the sphenoid bone
the occipital bone
what lives in the hypophyseal fossa?
the pituitary gland
the sella turcica / Turks Saddle
part of the sphenoid bone that includes the hypophyseal body and shenoid body the bump out in front called the tuburculum sellae the dorsum sellae the posterior clinoid processes
the clivus of the occipital bone articulates with the
sphenoid bone
what do the occipital condyles do?
make the Atlanto-Occipital joint. They protrude down and fit into transverse faucets of the atlantis
Medial and Lateral pterygoid plates
project downward and are an important attachment for the pterygoid muscles that move the mandible
Body of the sphenoid bone includes the
- Hypophyseal Fossa
- Posterior Clinoids (Anterior Clinoids are part of lesser wing)
- Sellae Turcica
What is the importance of the mastoid part of the temporal bone?
Babies don’t have it. Muscles originate here which pull the bone down to create it
petrous portion of temporal bone
This is a very hard boney part of the temporal bone. It houses the cochlea, the 3 semicircular canals and vestibule.
3 sensory receptors of inner ear
1- cochlea
- 3 semicircular canals
- vestibule
The 3 inner Ear houses structures are responsible for
Hearing (Cochlea)
- Balance (Semicircular Canals)
- CN VIII (Vestibulocochlear) carries these to brain
What nerve runs through the inner ear?
The vestibulochlear nerve AKA Cranial nerve 8. It carries hearing and balance information to the brain
What is the cochlea responsible for?
It has sensory receptors in it that pick up vibrations in ear and convert them to electrical pulses for the brain to hear (auditory)
the inner ear houses structures for auditory and ____
equilibrium! and balance!
- senses changes in the head position (moving head left and right)
- 3 semicircular canal sense head movement in the 3 planes - the vestibule senses static head positioning, so like on a carnival ride. It tells you some movement isn’t good
Vestibulocochlear nerve 8
carries auditory and equilibrium/balance information to brain from inner ear
stylomastoid foramen
between the styloid process and mastoid process, it transmits cranial nerve 7 which does the face (Smile, frowning, winking)
bells palsy
temporary peralosis of nerve 7
After removing the calvaria, look into the cranial cavity and note the
three paired cranial fossae
names of three paired cranial fossa
(1) the anterior cranial fossa, (2) the middle cranial fossa, and (3) the posterior cranial fossa
Posterior cranial fossa
Contains cerebellum and brainstem Formed by: Occipital bone Petrous part of temporal Parietal bone
TO REMEMBER:
Oh, Please Patrick
Middle cranial fossa
Contains temporal lobes of cerebral cortex Formed by: Greater wing of sphenoid Parietal bone Squamous and petrous temporal bone
TO REMEMBER:
GPS
You use GPS when you’re lost in the MIDDLE of nowhere
Anterior cranial fossa
Contains frontal lobes of cerebral cortex Formed by: Lesser wing of sphenoid Orbital plates Cribriform plates and crista galli
TO REMEMBER:
LOC: med abbrev for loss of consciousness
If you get punched anteriorly, you pass out aka LOC
Christa galli
a ridge on ethmoid bone- it helps anchor the dura matter
“Rooster’s Comb” protruding up between the cribriform plates
cribriform plates
little openings that allow cranial nerve 1 , which is your olfactory nerve to pass through nasal cavity into cranial cavity. It’s not a solid nerve. Its a bunch of little units that pass through these openings
temparomandibular joint
The TMJ is formed by the articulation of the mandibular fossa and the head of the mandible
The mandible forms the lower jaw and articulates with the skull via the
temporomandibular joint
what kind of joint is the TMJ
Its a combination of a hinge and a ball and socket joint
Multiaxial joint: Protrude, Retract, Elevate, and Depress
what protects the TMJ from wearing down due to overuse?
an articular disk - its acts like a mattress
mental foramen are found on either side of the chin. What runs through them?
the inferior alveolar nerve
It enters through the mandibular foramen, then gives off sensory endings to your lower row of teeth, then exits through the mental formen, where it turns into your mental nerve.
What do they do at the dentist to num lower mouth?
they give a shot to the inferior alveolar nerve
layers of the scalp
Superficial to Deep
Skin
Connective tissue (Dense-contains blood vessels and sensory nerve endings)
Aponeurotic layer (galea aponeurotica)
Loose connective tissue
Periosteum (fibrous layer that covers outer table of bone)
Mandibular foramen - site for a dental block (inferior alveolar nerve passes through and terminates as
mental nerve
why is it dangerous to get infection in the loose connective tissue of skin?
because the infection can travel!
The aponeurosis of the scalp is also known as the
Galea Aponeurotica. It goes from the frontal bones to the occipital bones. Aponeurosis = two muscles attached.
Viscerocranium - formed by the union of the ____ bones and the _____ bones
maxillary bones and the zygomatic bones
Squamosal - parietal from squamous portion of ___ ___
of temporal bone
