Mod 4: Lecture 3 - Overview of the Skull and Tempromandibular Joint Flashcards Preview

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Flashcards in Mod 4: Lecture 3 - Overview of the Skull and Tempromandibular Joint Deck (34)
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Divisions of the Cranium

- Neurocranium
- Viscerocranium



- cranial vault
- bony covering of the brain and the cranial meninges
- contains proximal parts of the cranial nerves and the vasculature of the brain
- calvaria: dome-like roof
- cranial base: floor



- facial skeleton
- forms the anterior parts of the cranium
- consists of the bones
---- surrounding the mouth (upper and lower jaws)
---- surrounding the nose/nasal cavity
---- comprising most of the orbits (eye sockets or orbital cavities)


Superior View of the Skull

- somewhat egg-shaped outline
----- small end is anterior
- four bones visible
---- anteriorly: frontal bone
---- laterally both right and left: parietal bones
---- posteriorly: occipital bone


Sutures of the Top of the Skull

- Coronal: separates frontal bone from parietal bones
- Sagittal/Interparietal: separates the right and left parietal bones
- Lambdoidal: separates the parietal and temporal bones from the occipital bone
- Bregma: the intersection of the sagittal and coronal sutures
- Lambda: the intersection of the lambdoidal and sagittal sutures


Posterior View of the Skull

- Bones visible: occipital, both parietals
- Sutures visible: sagittal, lambdoidal, lambda
- External Occipital Protuberance: a bump in the center about 2/3 down the occipital bone
- Occipital Condyles: on either side of the foramen magnum
- Superior and Inferior Nuchal Lines: areas of attachment for some neck and back muscles
- Mastoid Process: big sticking down thing by the jaw
- Styloid Process: thin sticking down thing anterior to the mastoid process


Frontal View of the Skull

- Bones:
---- right and left maxillae
---- right and left nasal
---- right and left zygomatic
----- vomer: nasal septum
----- frontal bone of skull
---- mandible


Apertures in the wall of the orbit

- Superior Orbital Fissure
---- CN III, IV, VI, V1 (1st branch of V)
- Inferior Orbital Fissure
---- CN V2 (2nd branch of V), infraorbital vessels
- Optic Canal
---- CN II, Ophthalmic artery


Lateral View of the Skull

- Temporal Lines
- Pterion
- Temporal Fossa
- External Auditory Meatus
- External Occipital Protuberance or Inion
- Styloid Process
- Mastoid Process


1. Temporal Lines
2. Temporal Fossa

1. - curved ridge in the frontal and parietal bones that serves as the superior limit of the curved origin of the temporalis muscle
---- superior and inferior
2. - slightly depressed area on the anterolateral aspect of the skull inferior to the temporal lines
---- filled in by the temporalis muscle


1. Pterion

- the H shaped (H is on its side) region where the frontal, parietal, temporal, and greater wing of the sphenoid bones intersect


Styloid Process

- sharp slender process that angles inferiorly, medially, and anteriorly
- provides attachment for a number of muscles and two ligaments
---- stylohyoid ligament
- a portion of the tympanic plate wraps itself around the base of the styloid like a scroll
- this is the vaginal process of the temporal bone


1. External Auditory Meatus
2. External Occipital Protuberance or Inion

1. - forms the entrance to the middle ear within the temporal bone
2. - occupies the central external aspect of the occipital bone


Mastoid Process

- lump of bone immediately posterior and inferior to the external auditory meatus
- serves as part of the insertion of the sternocleidomastoid muscle`


Skull Base

- Anterior Cranial Fossa
- Middle Cranial Fossa
- Posterior Cranial Fossa


Location and Nerves Going Through the Opening:
1. Cribiform Plate
2. Optic Canal
3. Superior Orbital Foramen

1. - center of anterior fossa
- CN I
2. - center border of anterior and middle fossa
3. - medial curved border of the anterior and middle fossa, on the side of the middle fossa
- CN III, IV, V1, VI


Location and Nerves Going through the Opening:
1. Foramen Rotundum
2. Foramen Ovale
3. Foramen Lacerum and Foramen Spinosum

1. - little circle directly below the superior orbital fissure
- CN V2
2. - biggish circle below the foramen rotundum
- V3
3. - tiny holes right below the foramen ovale
- one on each side of it
- no nerves


Location and Nerves Going through the Opening:
1. IAM: internal auditory meatus
2. Jugular Foramen
3. Hypoglossal Canal

1. - in the medial curved border of the middle and posterior fossa on the posterior side
2. - big hole in the posterior fossa, below the IAM
- CN IX, X, XI
3. - in the rim of the foramen magnum



- the slope of bone going up from the foramen magnum to the center of the middle fossa


Normal Basalis: Anterior Region

- the bottom of the skull, if the lower jaw is removed
- Hard palate: roof of the mouth
---- two bones
- Posterior Nasal Spine: a midline posterior projection from the posterior border of the bony plate


Hard Palate

- roof of the mouth
- Maxillae: palatal processes
---- the anterior 2/3
---- where the teeth fit in
---- incisive foramen: transmits the nasopalatine nerve and vessels
- Palatine Bones: horizontal processes
----- the posterior 1/3
---- ending as a double crescent shaped posterior free border (no bones in the back of it)
---- greater palatine canal


Greater Palatine Canal opens as the....

- greater palatine foramen onto the horizontal process of the palatine bone
---- in line with the last maxillary molar
---- transmits the greater palatine nerve and vessels
- lesser palatine foramen
---- posterior to the greater palatine foramen
---- transmits the lesser palatine nerve and vessels


Features of the Norma Basalis From Lateral to Medial

- mastoid process of the temporal bone
- stylomastoid foramen: lies between the styloid and the mastoid processes
---- allowing passage of the facial nerve (CN VII) from within the temporal bone
- styloid process
- Foramen Ovale


Intermediate area of the Norma Basalis

- mandibular fossa: which accommodates the condyle of the mandible
---- mandible not seen, just a big dent where it should be
- tympanic plate: forms the anterior wall of the external auditory meatus and the posterior wall of the mandibular fossa
- external auditory meatus: lies behind the mandibular fossa


Middle area of the Norma Basalis

- Jugular Foramen: a large opening through which the internal jugular vein and cranial nerves IX, X, and XI pass
- Carotid Canal: immediately anterior to the jugular foramen and separated from it only by a small wedge of bone


Posterior Section of the Norma Basalis

- Foramen Magnum
- Occipital Condyles: bumps on each side of the foramen magnum
- Hypoglossal canal: in the rim of the foramen magnum


Temporomandibular Joint (TMJ)

- named for the two bones that comprise the joint
---- temporal and mandible
- modified hinge joint
- articular tubercle: a jutting out of the zygomatic process of the temporal bone right next to the mandibular fossa
---- keeps the condyle in the fossa
- mandibular fossa: where the mandible connects to the temporal bone
- condyle of the mandible: the part of the mandible that fits into the fossa


Mandible Features

- condyle: the posterior process, the one that fits into the fossa
- coronoid process: the smaller anterior process
- Ramus: the body


Movements of the Mandible

- elevation/depression: closing/opening the jaw
- protrusion/retrusion: overbite/underbite
- lateral excursion: side to side motion of teeth grinding


Muscles of Mastication

- Masseter
- Lateral Pterygoid