1. The Skeleton For descriptive purposes, the skeleton is divided into:
Axial Skeleton
Appendicular Skeleton
For descriptive purposes, the skeleton is divided into:
Axial Skeleton
Appendicular Skeleton
For descriptive purposes, the skeleton is divided into:
Axial Skeleton
Appendicular Skeleton

2. Structured from eighty bones segregated into three regions:
The Axial Skeleton
Structured from eighty bones segregated into three regions:
Skull
Vertebral column
Bony thorax

3. Axial Skeleton Supports the: Protects the: Head Neck Trunk Brain
spinal cord
Organs in the thorax

4. Bones of the Axial Skeleton
Figure 7.1

5. Most complex bony structure Formed by two groups of 22 bones :
The Skull
Most complex bony structure
Formed by two groups of 22 bones :
The cranial bones or cranium
Facial bones

6. Encloses and protects the brain Furnish attachment sites for:
The Cranium
Made of 8 bones
Encloses and protects the brain
Furnish attachment sites for:
Head muscles
Neck muscles

7. Anatomy of the Cranium
Eight cranial bones (Thin and remarkably strong for their weight):
Paired:
Two parietal
Two temporal
Unpaired:
Frontal
Occipital
Sphenoid
Ethmoid

8. Frontal Bone
Figure 7.2a

9. Forms anterior portion of the cranium
Frontal Bone
Forms anterior portion of the cranium
Articulates posteriorly with the parietal bones via:
The coronal suture (joint)
Major markings:
The supraorbital margins
The supraorbital foramen
The anterior cranial fossa
The frontal sinuses

10. Frontal Bone
Figure 7.2a

11. Frontal Sinuses:
Figure 7.11

12. Two large, curved, & rectangular bones Form most of :
Parietal Bones
Two large, curved, & rectangular bones
Form most of :
The superior aspect of the skull, and
The lateral aspects of the skull
Articulate with:
other cranial bones through:
Four large sutures (joints)

13. Parietal Bones & Major Associated Sutures
The four sutures marking the articulations of the parietal bones include:
Coronal suture: between parietal and frontal bones, anteriorly
Sagittal suture: between right and left parietal bones, superiorly
Lambdoid suture: between parietal and occipital bone, posteriorly
Squamous suture: where parietal and temporal bones meet

14. Parietal Bones and Major Associated Sutures
Form most of the superior and lateral aspects of the skull
Figure 7.3a

15. Occipital Bone and Its Major Markings
Forms most of skull’s posterior wall and base
Major markings:
The posterior cranial fossa
Foramen magnum
Occipital condyles
External occipital protuberance
Figure 7.2b

16. Temporal Bones Form: Divided into four major regions: Major markings:
The inferolateral aspects of the skull
Parts of the cranial floor
Divided into four major regions:
Squamous (bordering the parietals)
Tympanic (surrounds ext. ear opening)
Mastoid (posterior to ear)
Petrous (lateral portion of skull base)
Major markings:
Zygomatic, styloid, and mastoid processes
Mandibular fossa and external acoustic meatus

17. Temporal Bones
Figure 7.5

18. Sphenoid Bone Butterfly-shaped bone
Spans the width of the middle cranial fossa
Central wedge that articulates with all other cranial bones
Consists of central body & three paired processes:
Central body: contains paired sinuses
Greater wings: forms part of middle cranial fossa, dorsal walls of orbit, and skull wall
Lesser wings: forms part of anterior cranial fossa and medial walls of orbit
Pterygoid processes: projects ineriorly and forms attachment site for pterygoid muscles (chewing)

19. Sphenoid Bone Major markings: Major openings:
Sella turcica (pituitary gland location)
Major openings:
Optic canals
Superior orbital fissure
Foramen rotundum
Foramen ovale
Foramen spinosum

20. Break
Biol Oct 3rd

21. Sphenoid Bone
Figure 7.6a

22. Sphenoid Bone
Figure 7.6b

23. Lies between the sphenoid and nasal bones Forms:
Ethmoid Bone
Lies between the sphenoid and nasal bones
Forms:
most of the bony area between the nasal cavity and the orbits
Major markings:
Perpendicular plate
Lateral masses (riddled with ethmoid sinuses)
Nasal conchae (superior & middle)

24. Ethmoid Bone
Figure 7.7

25. Sutural (Wormian) Bones
Tiny irregularly shaped bones
Appear within sutures
Unknown functiom

26. Facial Bones Made of 14 bones Form the framework of the face
Contain cavities for special senses (sight, smell, taste)
Provide passageways for air and food
Secure teeth
Attachment site for facial muscles of expression
Made of 14 bones

27. Facial Bones Unpaired (two): Paired (six): Mandible Vomer Maxillae
Zygomatics
Nasals
Lacrimals
Palatines
Inferior conchae

28. Mandible and Its Markings
The lower jaw bone
largest, strongest bone of the face
Its major markings:
Coronoid process
Mandibular condyle
Alveolar margin
Mandibular foramen
Mental foramina

29. Mandible and Its Markings
Figure 7.8a

30. Maxillary Bones Medially fused bones Make up: Articulate with:
The upper jaw
Articulate with:
All other facial bones except the mandible
Major markings:
Palatine, frontal, and zygomatic processes
Alveolar margins
Inferior orbital fissure (junction with sphenoid greater wing)
Maxillary sinuses (largest of paranasal sinuses)

31. Maxillary Bone
Figure 7.8b

32. Paranasal Sinuses: Maxillary Sinuses
Figure 7.11

33. Zygomatic Bones (cheekbones)
Irregularly shaped bones
Form:
The prominences of the cheeks
The inferolateral margins of the orbits
Articulate with the zygomatic processes of the:
Frontal bone (superiorly)
Maxillae (anteriorly)
Temporal bones (posteriorly)

34. Other Facial Bones Nasal bones: Lacrimal bones:
Thin medially fused bones
Form the bridge of the nose
Lacrimal bones:
Contribute to the medial walls of the orbit
Contain a deep groove – the lacrimal fossa
The lacrimal fossa houses the lacrimal sac

35. Other Facial Bones Palatine bones:
Each is an L-shaped bone of two bony plates
One is horizontal and the other is perpendicular
Form:
The posterior portions of the hard palate
Part of posterolateral walls of the nasal cavity
Small part of the orbits

36. Inferior nasal conchae:
Other Facial Bones
Vomer:
Plow-shaped bone
Forms part of the nasal septum
Inferior nasal conchae:
Paired, curved bones
In the nasal cavity
Form part of the lateral walls of the nasal cavity

37. Orbits Bony cavities where eyes are firmly encased
Eyes are cushioned by fatty tissue
Formed by parts of seven (3 cranial & 4 facial) bones:
Frontal
Sphenoid
Ethmoid
Zygomatic
Maxilla
Palatine
Lacrimal

38. Orbits
Figure 7.9b

39. Nasal Cavity Constructed of bone and hyaline cartilage Roof formed by:
Cribriform plate of the ethmoid
Lateral walls formed by:
Superior and middle conchae of the ethmoid
Perpendicular plate of the palatine
Inferior nasal conchae
Floor formed by:
Palatine process of the maxillae and palatine bone

40. Nasal Cavity
Figure 7.10a

41. Nasal Cavity
Figure 7.10b

42. Paranasal Sinuses They are mucosa-lined, air-filled sacs
Found in five skull bones:
Frontal
Sphenoid
Ethmoid
Paired Maxillae
Air enters the paranasal sinuses from the nasal cavity
Mucus drains into the nasal cavity from the sinuses
They:
Lighten the skull
Enhance the resonance of the voice

43. Paranasal Sinuses
Figure 7.11

44. Not actually part of the skull
Hyoid Bone
Not actually part of the skull
Lies just inferior to the mandible in the anterior neck
Only bone does not articulate directly with another bone
Anchors to styloid process of temporal bone by stylo-hyoid ligament
Attachment point for neck muscles that raise and lower the larynx during:
Swallowing
Speech

45. The Following Slide Are:
Only for Reinforcement

46. Anterior Aspects of the Skull
Frontal bone
Parietal bone
Glabella
Frontal squama
of frontal bone
Frontonasal suture
Supraorbital foramen
(notch)
Nasal bone
Supraorbital margin
Sphenoid bone
(greater wing)
Superior orbital
fissure
Temporal bone
Optic canal
Ethmoid bone
Inferior orbital
fissure
Lacrimal bone
Zygomatic bone
Middle nasal concha
Perpendicular plate
Infraorbital foramen
Ethmoid
bone
Maxilla
Inferior nasal concha
Vomer bone
Mandible
Mental
foramen
(a)
Mandibular symphysis
Figure 7.2a

47. Posterior Aspects of the Skull
Sagittal suture
Parietal bone
Sutural
bone
Lambdoid
suture
Occipital bone
Superior nuchal line
External
occipital
protuberance
Mastoid
process
Inferior
nuchal
line
Occipitomastoid
suture
External
occipital
crest
Occipital
condyle
(b)
Figure 7.2b

48. External Lateral Aspects of the Skull
Coronal suture
Frontal bone
Sphenoid bone
(greater wing)
Parietal bone
Ethmoid bone
Temporal bone
Lacrimal bone
Lambdoid
suture
Lacrimal fossa
Squamous suture
Nasal bone
Occipital bone
Zygomatic process
Zygomatic bone
Occipitomastoid suture
Maxilla
External acoustic meatus
Mastoid process
Alveolar margins
Styloid process
Mandibular condyle
Mandible
Mandibular notch
Mental foramen
Mandibular ramus
(a)
Mandibular angle
Coronoid process
Figure 7.3a

49. Midsagittal Lateral Aspects of the Skull
(b)
Parietal bone
Coronal suture
Frontal bone
Frontal sinus
Sphenoid bone
(greater wing)
Crista galli
Nasal bone
Sphenoid sinus
Ethmoid bone
(perpendicular plate)
Vomer bone
Maxilla
Mandible
Alveolar margins
Incisive fossa
Lambdoid suture
Occipital
bone
Occipitomastoid
suture
External occipital
protuberance
Internal acoustic
meatus
Sella turcica
of sphenoid
Pterygoid
process of
sphenoid
Mandibular
foramen
Palatine
Squamous
Temporal
maxilla
Figure 7.3b

50. Inferior Portion of the Skull
Maxilla
(palatine process)
Incisive fossa
Medial palatine suture
Hard
palate
Infraorbital foramen
Palatine bone
(horizontal plate)
Maxilla
Zygomatic bone
Sphenoid bone
(greater wing)
Temporal bone
(zygomatic process)
Foramen ovale
Vomer
Foramen
lacerum
Mandibular
fossa
Carotid canal
External acoustic meatus
Styloid process
Stylomastoid
foramen
Mastoid process
Jugular foramen
Temporal bone
(petrous part)
Occipital condyle
Pharyngeal
tubercle of
basioccipital
Inferior nuchal line
Parietal bone
Superior nuchal line
External occipital crest
External occipital
protuberance
Foramen magnum
(a)
Figure 7.4a

51. Inferior Portion of the Skull
Olfactory foramina
Frontal bone
Anterior cranial fossa
Cribriform plate
Ethmoid
bone
Crista galli
Lesser wing
Sphenoid
Optic canal
Greater wing
Anterior clinoid process
Tuberculum sellae
Foramen rotundum
Hypophyseal fossa
Foramen ovale
Sella
turcica
Dorsum sellae
Posterior clinoid process
Foramen spinosum
Middle cranial
fossa
Foramen lacerum
Temporal bone
(petrous part)
Jugular foramen
Hypoglossal canal
Internal
acoustic meatus
Posterior
cranial fossa
Anterior
cranial
fossa
Parietal bone
Occipital bone
Middle
cranial
fossa
(b)
Foramen magnum
Posterior
cranial
fossa
(c)
Figure 7.4b