Exam 1, DLA 1210

1. Osteology of the
Skull
CHAPTER 17

2. Neurocranium
The portion of the skull, comprised of 8 bones, that
houses and protects the brain
New terms associated with the skull
Suture is a jagged line where bones join
Foramen is a short opening through bone
Canal is a long opening through bone
Nerves and blood vessels travel through canals and foramina

3. Neurocranium

4. Neurocranium

5. Neurocranium - Occipital Bone
 Occipital Bone forms posterior aspect of
skull
Articulates with atlas (first cervical vertebra) by
way of occipital condyles
 Divided into four fossae housing brain
lobes
Hypoglossal nerve passes through the
hypoglossal canal on the sides of foramen
magnum

6. Neurocranium - Frontal Bone
Frontal bone forms
forehead and anterior
aspect of skull
Four sutures outline bone
 Coronal suture joins frontal and parietal
 Sagittal suture connects parietals
 Lambdoidal suture joins occipital and
parietal
 Squamous suture connects parietal and
temporal

7. Neurocranium – Frontal Bone
The prominent area of the forehead is
the frontal eminence
The glabella is the flattened area
between the eyebrows
A superciliary ridge is located above the
eyebrows

8. Bones of the Neurocranium

9. Neurocranium – Bones of the Orbit
Bones of the Orbit is comprised of 6 bones
Sphenoid, ethmoid, lacrimal, frontal, zygomatic, and maxilla
Optic foramen is opening for optic nerve and
ophthalmic artery
Nerves enter the orbit through the superior orbital fissure
The infraorbital nerve enters through the inferior orbital
fissure

10. Bones of the Neurocranium

11. Neurocranium – Parietal Bones
Parietal bones have two curving lines, the superior and
inferior temporal lines
Serve as attachment for temporalis muscle, a muscle of
mastication

12. Neurocranium – Temporal Bones
Temporal bones consist
of three parts
Squamous: flattened, fan-
shaped portion
Petrous
Tympanic, which encloses
essential hearing organs

13. Neurocranium – Temporal Bones
Temporal bones have several
portions
Zygomatic process, which extends
out to form zygomatic arch
Mandibular (glenoid) fossa, into
which mandible articulates
Articular eminence or tubercle,
“V”-shaped projection in front of
glenoid fossa

14. Neurocranium – Temporal Bones
External auditory (acoustic) meatus found
in the tympanic portion, opening for outer
ear
Posterior to this meatus is a rounded
prominence known as the mastoid process
Styloid process is a pointed bone spicule
Muscle/ligament attachment
Stylomastoid foramen is located between
styloid and mastoid processes
Small opening where the facial nerve exits skull

15. Jugular foramen just lateral to
occipital condyles and between
petrous portions of temporal
bone
Large opening where nerves exit
the skull
The carotid canal located in front
of the jugular foramen
Neurocranium – Temporal Bones

16. Bones of the Neurocranium

17. Neurocranium – Ethmoid Bone
 Ethmoid bone forms part of nasal cavity, nasal septum and
orbit
Located at base of cranium at cribiform plate
Perforated for olfactory nerves to pass between brain/nose
 Can be considered part of either neuro or viscerocranium
Considered neurocranium for dental purposes

19. Neurocranium – Sphenoid Bone
 Sphenoid bone looks like a bat; a body, two greater wings and two
lesser wings
 Articulates with all bones that form cranium
 Pterygoid process descends from each greater wing and comprised of
a
 Flattened latteral plate
 Thinner medial plate

20. Neurocranium – Sphenoid Bone
Pterygoid fossa between the
lateral and medial plates
Pointed pterygoid hamulus
which curves from the lower
end of the medial pterygoid
plate
The sella turcia is the
depression which houses the
pituitary gland

21. Viscerocranium
Viscerocranium of the facial skeleton contains
14 bones
Zygomatic bones form the cheeks
Vomer forms the posterior and inferior parts of
the nasal septum

22. Viscerocranium
Nasal bones form the bridge of the nose
Lacrimal bones located on the medial orbital wall are small
and fragile
Inferior nasal concha found in the nasal cavity, articulates
with the maxilla
Palatine bone forms the hard palate and vertical plate and
contain two foramina
Greater palatine foramen and lesser palatine foramen

24. Maxilla
 Comprised of two portions joined by a median suture
 Consists of a body and four processes
 Frontal process and zygomatic process join the frontal and
zygomatic bones
 Alveolar process surrounds and supports the maxillary
teeth
 Palatine process forms the major portion of the hard
palate

25. The body of the maxilla contains the:
 Canine eminence
 Elevation of bone over the canine root
 Infraorbital foramen
 Where the infraorbital nerve exits through the face, just below
the inferior margin of the orbit
 Maxillary sinus
 Largest of the paranasal sinuses and is located within the
maxilla, above the roots of the maxillary posterior teeth.
 Maxillary tuberosity
 A bulging of bone posterior to the maxillary third molars

26. The body of the maxilla contains the:
 Incisive foramen
 Aka Nasopalatine foramen; just behind the maxillary central incisors
 Opening for the Nasopalatine nerve to innervate the hard palate and
maxillary anterior region
 Covered by incisive papilla
 Median
 Marks the articulation of rhe right and left palatine process.
 Transverse palatine sutures
 Articulation between the palatine process and the horizontal plates of the
palatine bones

28. Mandible
 As horseshoe shaped bone that is comprised of a
horizontal body with right and left vertical rami
 Each ramus (singular) has a
 Condoyle
 Rounded knob that joins with the mandibular (glenoid) fossa
 Coronoid process
 A pointed, flat projection onto which the temporalis muscle inserts
 Mandibular notch
 The curved notch between the condyle and coronoid process

30. Mandible
 Pterygoid Fovea: triangular depression below the condyle where the
pterygoid muscle attaches
 Mental protuberance: tip of the chin
 Mental Foramen: external surface of the mandible near the apex of the
mandibular second premolar
 Exit point for the mental nerve and vessels branch from the inverior alveolar
nerve
 External Oblique Line: A line that extends from the mental foramen
along the external surface of the body
 Coronoid notch: concave curve near the posterior teeth
 Landmark for inferior alveolar nerve block

31. Mandible
 Internal Oblique Line: runs from molar region to midline, also known as the Mylohyoid ridge or line.
 is the attachment for the Mylohyoid muscle.
 Genial (chin) tubercles or spines: small projections of bone located on either side of the midline.
 Site of attachment for genioglossus and geniohyoid muscles
 Submandibular fossa: contains the submandibular gland is located in the premolar and molar
region below the Mylohyoid line
 The sublingual fossa is located on either side of the genial tubercles.
 Retromolar fossa: triangular area of bone distal to the mandibular third molar
 Mandibular foramen: large opening in the center of the ramus
 Opening into the mandibular canal through which passes the inferior alveolar nerve and artery
 The lingual is superior to the mandibular foramen
 Mylohyoid groove is visible leading away from the mandibular foramen.

33. Hyoid Bone
 Suspended in the neck below the mandible
 An attachment point for neck and tongue muscles
 Comprised of a body and two horns
 Greater and lesser cornu
Does not articulate with other bones

34. Summary- Neurocranium
 Occipital bone
 Posterior aspect of the sckull
 Frontal bone
 Forms the forehead and anterior aspect of the skull
 Ethmoid bone
 Forms the nasal cavity, nasal septum, and orbit
 Orbital bones
 Sphenoid, ethmoid, lacrimal, frontal, zygomatic, and maxilla
 Parietal bone
 Forms the sides of the skull
 Temporal bone
 House the hearing organs and help to comprise the temporomandibular joint.

35. Summary- Viscerocranium
 Zygomatic bone
 Form the cheek
 Nasal bones
 Form the bridge of the nose
 Lacrimal bones
 Medial corner of the eye
 Inferior nasal concha
 Lies in the nasal cavity and articulates with the maxilla
 Palatine bones
 Form the hard palate
 Maxilla
 Forms upper jaw
 Mandible.
 Forms lower jaw
 Vomer
 Forms posterior and inferior part of the nasal septum

36. Summary
The skull contains 22 bones and divided into two
groups
8 bones of the neurocranium which forms the skull and
protects the brain
14 bones of the viscerocranium that comprise the face
Additionally there is the hyoid bone which serves as an
attachment for the tongue and neck

37. Suggested Homework
Complete pages 219-222 in your textbook.
Watch https://youtu.be/c7_ZypQ94yQ
https://youtu.be/tlTGq8cDInY
Play this game:
https://www.purposegames.com/game/anatomy-of-
the-mandible