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
What is the only bone in the body that does not articulate with any other bone?
Hyoid bone
What bone is an attachment point for muscles responsible for speech and swallowing?
Hyoid bone
What does deglutination mean?
Swallowing
What are three holes in the bony orbit of the eye?
Superior & inferior orbital fissure, optic canal
What 7 bones make up the bony orbit (area eye sits in)?
Frontal, Maxillary, Ethmoid, Sphenoid, Lacrimal, Zygomatic, Palantine
What three bones form the bulk of the outer ring of the eye?
Frontal, zygomatic, and Maxillary bones
What is the nasal cavity lined with?
mucosa
What do the nostrils open up into?
nasal cavity
What does the lateral wall of the nasal cavity have?
Bumpy projections, conchae=turbinates
What are the superior & middle conchae a part of?
Ethmoid bone
What does the roof of the nasal cavity contain?
receptors from the olfactory nerve
What are the inferior conchae part of?
Nothing. They are individual bones derived from the maxilla and thus are considered facial bones
What are the two nostrils separated by at midline?
nasal septum consisting of perpendicular plate of the ethmoid, vomer, & cartilage (covered with mucosa)
What do the conchae of the nasal cavity do? What does the mucosa of the nasal cavity do?
Warm & filter inhaled air.
The mucosa serves an immune function by trapping foreign particles & exposing them to APCs (Ag presenting cells)
What is a suture?
Fibrous joints between the bones of the skull
What are the 4 sutures and what are their articulations?
Coronal: btwn frontal & parietal
Sagiattal: btwn parietals
Lambdoidal: btwn parietal & occiput
Squamosal: btwn parietal & temporal
What is the pteryion?
It is the meeting point of the frontal, parietal, greater wing of sphenoid, and sometimes temporal bones
What is the bregma?
Junction of the coronal and sagittal sutures
What is the lamda?
junction btwn. the lamdoidal & sagittal sutures
What are the sutural lig. that connect the cranial bones?
Remaining unossified sheets of mesenchyme from intramembranous ossification
What are the sphincter muscles of the facial expression?
Orbicularis Oculi & Oris
What are the two major divisions of the muscles of the face?
Muscles of facial expression and of mastication (eating)
Excluding the 2 sphincter muscles, what type of muscle are all the muscles of facial expression
Dilator muscles
What does the orbicularis oculi and oris surround respectively?
Oculi - eye
Oris - mouth
What is the innervation of the muscles of facial expression
Facial Nerve (Cranial Nerve VII)
What are the muscles of mastication?
Temporalis, Masseter, Medial & Lateral Pterygoid
What are the muscles of mastication innervated by?
Trigeminal N. (CN V)
What are the actions of the muscles of mastication?
Movements of the jaw: elevation, depression, protraction, retraction
What action does the medial pterygoid do?
elevation & protraction
What actions does the lateral pterygoid muscle do?
Depression & protraction
What actions do the temporalis do?
Elevation & retraction
What actions do the masseter muscle do?
elevation & protraction
What is the only muscle of mastication that depresses?
Lateral pterygoid
What is the only muscle of mastication that retracts?
Temporalis
What are the two divisions of the anterior neck?
Anterior triangle & posterior triangle
What borders the anterior triangle of the anterior neck?
sternocleidomastoid, inferior border of mandible, and anterior midline of neck
What borders the posterior triangle of the anterior portion of neck?
sternocleidomastoid, clavicle, and trapezius
What are the muscles of deglutition/speech
digastric, mylohyoid, sternohyoid, omohyoid, cricothyroid, thyrohyoid, sternothyroid
What is the ansa cervicalis
loop that links C 1 and 2 nerve roots
What muscles does the ansa cervicalis innervate
Sternohyoid, omohyoid, sternothyroid
What innervates the digastric
Anterior belly: trigeminal, Posterior belley: facial
What innervates the mylohyoid
trigeminal
What innervates the cricothyroid
Vagus
What innervates the thyrohyoid
1st cervical nerve, via the hypoglossal
What does CN VII generally innnervate
Motor innervation to the muscles of facial expression
What are the branches of CN VII
Temporal, zygomatic, buccal, mandibular, and cervical
What does CN V generally innervate
sensory innervation to the face
What are the branches of the common carotid
Internal carotid and external carotid, which gives of the temporal and facial aa
How does the blood drain from the brain
It flows through sinuses, no valves, just follows gravity and the path of least resistance
