Lecture 5 - Head & Neck Flashcards
What are the two major division in the skull bones?
Neurocranium (protects the brain) & viscerocranium (sense organ encased, face)
How many bones are in the skull? How many associated bones?
22 bones + 7 associated bones
What are the bones contained in the neurocranium (6)?
Frontal, Parietal, Occipital, Temporal, Sphenoid, Ethmoid
What are the bones of the viscerocranium (8)?
Mandible, Maxilla, Zygoma, Volmer, Lacrima, Nasal, Palatine, Inferior Nasal Concha
What is the top of the skull called?
Calvaria or Cranial Vault
What makes up the Calvaria?
The bones of neurocranium (frontal, parietal, & occipital bones)
How are the bones of the neurocranium formed? Why?
Intramembranous ossification (vs. incondyle ossification). Due to quick & large brain growth.
What does the convex shape of the Calvaria do?
Resist impact
Why in newborns do the cranial bones not articulate?
To allow for passage of the head through the birth canal and accommodate the growth of the brain.
What are the soft spots in a newborn head called and what are they?
Fontanelles, membrane covered parts of the skull where sutures will form
How long do fontanelles exist in babies?
Until about 7-19 months
What do bulging/tense fontanelles indicate?
Increased intracranial pressure
How many fossae are contained in the cranial base and what are their names?
Anterior, Middle, Posterior
What does the anterior fossa of the cranial base contain?
Frontal lobe, Cranial N. #1
What makes up the anterior fossa of the cranial base?
Frontal bone, crista galli, cribiform plate of ethmoid, lesser wings of sphenoid.
What makes up the posterior fossa of the cranial base?
Sphenoid, Temporal, & Occipital bones.
What does the posterior fossa of the cranial base contain?
Occipital lobe, cerebellum, brainstem.
Many holes: foramen magnum, hypoglossal canal, jugular foramen, & internal auditory meatus
What makes up the middle fossa of the cranial base?
sphenoid & temporal bones
What are the important landmarks in the middle fossa of the cranial base?
Sella tursica, chiasmic groove, optic canal, superior orbital fissure, foramen rotundum, foramen ovale, foramen spinosum, foramen lacerum, & cavernous sinus.
Where does the temporal lobe of the brain rest?
Middle fossa of the cranial base
What important structures are located in the middle fossa of the cranial base?
Pituitary, Optic chiasm, Optic nerve, Internal carotid artery, & cranial nerves III, IV, V1, V2, and VI
What does the mandible articulate with?
Temporal bones at the Temporomandibular joint (TMJ)
What is the percentage of facial injuries that involve mandibular fracture?
20% or 1/5
What does the Mandible do?
It holds the lower row of teeth in gomphosis joint at alveolar processes
What are the gums/teeth innervated by?
Inferior alveolar N.
Where does the inferior alveolar nerve travel through?
Mandibular foramen
What type of joint is the TMJ?
Synovial joint with an articular disc
What is the innervation of the TMJ?
Mandibular branch of the trigeminal N.
What is the articulation of the TMJ?
Between condylar process of the mandible & mandibular fossa & articular tubercle of the temporal bone.
What is the shape of the Hyoid bone?
U-shaped bone
What is the hyoid bone suspended by?
Stylohyoid lig. from the styloid processes of temporal bones.
What are the parts of the hyoid bone?
Body, 2 lesser cornua, 2 greater cornua