Lecture 16: Skull Flashcards
What is a chordate?
Animal/ human with a notochord
Where are the primary senses and the integration center (brain) concentrated in chordates
Front of the skull
What is the floor of the box called
chondrocranium
What does the bone of the chondrocranium develop from
a cartilagenous precursor
What different capsules are located in the chondrocranium
olfactory and optic capsules
What are the walls and roof of the box made of
dermal scales which developed into skin that eventually joins bone
What are the walls and roof of the box called
determatocranium
What bart of the skull does the notochord extend into
chondrocranium
What did the respiratory and feeding systems that attach to our skull evolve from
Gill arches (7 of them)
What composes the 1st gill arch
Upper and lower jaws, malleus, and incus
Is the upper jaw fused to the brain box
Yes
What are the malleus and incus a part of?
inner ear
How does the first gill arch attach to the brain box
cartilage attaches to the bottom of the brain box
What composes the 2nd gill arch
Middle ear bone, styloid process, stylohyoid ligament, and part of the hyoid bone
What composes the 3rd gill arch
Bony support for the tongue and hyoid
What do subsequent arches form
pharynx, larynx, and trachea
Modified gill arches that associate with the cranium form…
splanchnocranium
Which part of the skull has a lot of holes
chondrocranium
Which part of the skull consists of the jaw and face
Splanchnocranium
Where do vessels and nerve often emerge or enter into the skull
Foramina or between components of different origin
What is the internal coratid a. a branch of
common coratid a.
What does the internal coratid a. supply
brain, chondrocranium (including special senses)
What does the external coratid a supply
dermato- and splanchnocranium
What does CN V innervate (which gill arch)
first gill arch (jaw)
What does CN VII innervate (gill arch)
second gill arch (facial nerve)
What does CN IX innervate (gill arch)
3rd gill arch (hypoglossal)
What supplies the remaining 4 gill arches?
CN X (vagus)
Does CN V provide sensory and motor innervation to the upper and lower jaws
It only provides motor innervation to the lower jaw because you can not move the upper jaw
Where are the two frontal bones fused
At metopic suture
What do the frontal bones articulate with?
Nasals, sphenoids, zygomatics, parietals, lacrimals, ethmoids, and maxillaries
Where do the two nasal bones meet
internasal joint
What do the nasal bones articulate with
frontals and maxillaries
What bones form the orbits
lacrimals, ethmoids, greater and lesser wings of sphenoid
What bones articulate with the zygomatics
maxillae, sphenoids, frontals, and temporal
What are the sidewall bones of the nose?
Superior, middle, and inferior chonchae
What is another term for chin
mental protuberance
Pterigomaxillary fissure
Crack between the lateral pterigoid plates and the maxilla- place where n. and branch of external carotid artery exit.
The lateral pterygoid plates are a part of what bone?
Sphenoid
What attaches to the styloid process?
Ligament to the hyoid (2nd arch)
What are the functions of fontanelles
- Head to conform to shape of birth canal
- Clinical access to cerebrospinal fluid
Is the pterion junction a weak or strong joint?
Weak
Can you determine the rough age of a person based on how open/closed their sutures are
Yes more closed= older
What is bone growth in the skull determined by
brain size
Hydro and microcephaly
microcephally- small head (usually associated with small brain.
Hydrocephaly- Large head associated with large brain
Describe the bone arictecture in the skull
2 compact layers of bone with spongy bone in between
What is the spongy bone between the compact bone called?
Diploe
What are the names of the inner and outer layers of compact bone respectively
Inner and outer table
Diploic veins
veins that run in the diploe
Emissary veins
Penetrate the inner and outer tables to communicate with the diploes- Veins responsible for spreading infections throughout the head
In the splanchnocranium, structures are made of cartilage (Meckel’s cartilage) and does not ossify, whats the exception to this?
The upper and lower jaws.
What is the neocortex and what protects it?
Part of the cerebral cortex concerned with sight and hearing- protected by lofts over orbits
What is the cribriform plate
A sieve in the ethmoid bone where CN I enters along with anterior and posterior ethmoidal arteries and nerves
What attaches to the crista galli
falx cerebri
How many CN enter the middle cranial fossa?
5
What CN go through the superior orbital issue?
CN III, IV, V1, and VI
What is CN V1
CN V has 3 Branches: V1- is the ophthalmic branch which is sensory only to the forehead and scalp
What CN goes through the optic foramen
CN II
What is the junction between the brain box and face
Superior orbital fissure
Location of the optic foramen
lesser sphenoid
What goes through the foramen rotundum
CN V2- sensory to the maxilla
What goes through the foramen ovale
CN V3- Sensory and motor to the mandible
What runs through the foramen lacerum
internal carotid a. and pathway for greater superficial petrosal nerves (taste for preganglionic parasympathetic fibers from CN VII)
What runs through the coratid canal
internal carotid a
What does the internal coratid a cupply
chondrocranium, brain, and special senses
What goes through the foramen spinosum
meningeal a.
What does the meningeal a supply
meninges and dermatocranium
What junction does the foramen spinosum lie in
edge of dreamt- and chondrocranium
How many cranial nerves pass through the posterior cranial fossa
6
What runs through the internal acoustic meatus
CN VII and VIII
What runs through the jugular foramen
CN IX, X, and XI and internal jugular v.
What runs through the hypoglossal canal
CN XII exits
