Osteology of the Skull

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 S phenoid, 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

18. 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

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

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

21. 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

22. 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

23. 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 p osterior to the maxillary third molars

24. 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

25. 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

26. 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

27. 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.

28. 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

29. 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.

30. 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

31. Summary The skull contains 22 bones and divided into two groups 8 bones of the n eurocranium which forms the skull and protects the brain 14 bones of the v iscerocranium that comprise the face Additionally there is the hyoid bone which serves as an attachment for the tongue and neck

32. 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