Bones of the Skull 21

Lateral aspect of the skull.

1 Frontal bone

2 Glabella

3 Supraorbital margin

4 Parietal bone

5 Temporal bone (squamous part)

6 Zygomatic process

(articular tubercle)

7 Mastoid process

8 Tympanic part (tympanic plate)

and external acoustic meatus

9 Occipital bone (squamous part)

10 External occipital protuberance

11 Occipital condyle

12 Sphenoidal bone (greater wing) 25 Condylar process

13 Infratemporal crest of sphenoid 26 Mental foramen

14 Pterygoid process (lateral pterygoid plate) 27 Mental protuberance

15 Nasal bone 28 Angle of the mandible

16 Ethmoidal bone (orbital part)

17 Lacrimal bone Sutures

18 Zygomatic bone 29 Coronal suture

19 Maxilla (body) 30 Lambdoid suture

20 Alveolar process and teeth 31 Squamous suture

21 Frontal process 32 Nasomaxillary suture

22 Anterior nasal spine 33 Frontosphenoid suture

23 Mandible (body) 34 Sphenosquamosal suture

24 Coronoid process 35 Occipitomastoid suture

30

22 Bones of the Skull

1 Frontal bone

2 Glabella

3 Supra-orbital margin

4 Supra-orbital notch

5 Trochlear spine

6 Parietal bone

7 Temporal bone

8 Nasal bone

Orbit

9 Lacrimal bone

10 Posterior lacrimal crest

11 Ethmoidal bone

Sphenoidal bone

12 Greater wing of sphenoidal bone

13 Lesser wing of sphenoidal bone

14 Superior orbital fissure

15 Inferior orbital fissure

16 Zygomatic bone

Maxilla

17 Frontal process

18 Infra-orbital foramen

19 Zygomatic process

20 Body of maxilla

21 Alveolar process with teeth

Nasal cavity

22 Anterior nasal aperture

23 Middle nasal concha

24 Inferior nasal concha

25 Nasal septum, vomer

Mandible

26 Body of mandible

27 Ramus of mandible

28 Mental foramen

29 Alveolar part with teeth

30 Base of mandible

31 Mental protuberance

Sutures

32 Frontal suture

33 Coronal suture

34 Frontonasal suture

35 Internasal suture

36 Nasomaxillary suture

37 Zygomaticomaxillary suture

38 Intermaxillary suture

Anterior aspect of the skull.

The skull comprises a mosaic of numerous complicated

bones that form the cranial cavity protecting the brain

(neurocranium) and several cavities such as the nasal and

oral cavities in the facial region. The neurocranium

consists of large bony plates that develop directly from the

surrounding sheets of connective tissue (desmo cranium).

The bones of the skull base are formed out of cartilaginous

tissue (chondrocranium), which ossifies secondarily. The

visceral skeleton, which in fish gives rise to the gills, has

in higher vertebrates been transformed into the bones of

the masticatory and auditory apparatus (maxilla, mandible,

auditory ossicles, and hyoid bone).

Bones of the Skull 23

1 Frontal bone

2 Frontonasal suture

3 Frontomaxillary suture

4 Supra-orbital margin

5 Internasal suture

6 Sphenofrontal suture

7 Optic canal in lesser wing

of sphenoidal bone

8 Superior orbital fissure

9 Lacrimal bone

10 Sphenoidal bone (greater wing)

11 Inferior orbital fissure

12 Nasomaxillary suture

13 Infra-orbital foramen

14 Maxilla

15 Vomer

16 Body of mandible

17 Parietal bone

18 Temporal bone

19 Sphenozygomatic suture

20 Ethmoidal bone

21 Zygomatic bone

22 Nasal bone

23 Zygomaticomaxillary suture

24 Middle nasal concha

25 Inferior nasal concha

26 Anterior nasal aperture

27 Mental foramen

28 Ramus of mandible

29 Base of mandible

30 Mental protuberance

Bones

Brown = frontal bone

Light green = parietal bone

Dark brown = temporal bone

Red = sphenoidal bone

Yellow = zygomatic bone

Dark green = ethmoidal bone

Yellow = lacrimal bone

Orange = vomer

Violet = maxilla

White = nasal bone

White = mandible

Anterior aspect of the skull (individual bones indicated by color).

The following series of figures are arranged so that the

mosaic-like pattern of the skull becomes understandable. It

starts with the bones of the skull base (sphenoi dal and

occipital bones) to which the other bones are added step by

step. The facial skeleton is built up by the ethmoidal bone to

which the palatine bone and maxilla are attached laterally;

the small nasal and lacrimal bones fill the remaining spaces.

Cartilages remain only in the external part of the nose.

24 Disarticulated Skull I: Sphenoidal and Occipital Bones

Sphenoidal and occipital bone (from above).

Sphenoidal and occipital bone in connection with the atlas and axis

(1st and 2nd cervical vertebrae) (left lateral view).

25

19

20

21

22

Disarticulated Skull I: Sphenoidal and Occipital Bones

Sphenoidal bone (anterior aspect).

Sphenoidal bone (posterior aspect).

Occipital bone (from below).

Sphenoidal bone

1 Greater wing

2 Lesser wing

3 Cerebral or superior surface of greater wing

4 Foramen rotundum

5 Anterior clinoid process

6 Foramen ovale

7 Foramen spinosum

8 Dorsum sellae

9 Optic canal

10 Chiasmatic groove (sulcus chiasmatis)

11 Hypophysial fossa (sella turcica)

12 Lingula

13 Opening of sphenoidal sinus

14 Posterior clinoid process

15 Pterygoid canal

16 Lateral pterygoid plate of pterygoid process

17 Pterygoid notch

18 Pterygoid hamulus

19 Orbital surface of greater wing

20 Sphenoidal crest

21 Sphenoidal rostrum

22 Medial pterygoid plate

23 Superior orbital fissure

24 Spine of sphenoid

25 Temporal surface of greater wing

26 Infratemporal crest

Occipital bone

27 Clivus with basilar part of occipital bone

28 Hypoglossal canal

29 Fossa for cerebellar hemisphere

30 Internal occipital protuberance

31 Fossa for cerebral hemisphere

32 Jugular tubercle

33 Condylar canal

34 Jugular process

35 Foramen magnum

36 Groove for transverse sinus

37 Groove for superior sagittal sinus

38 Squamous part of the occipital bone

39 External occipital protuberance

40 Superior nuchal line

41 Inferior nuchal line

42 Condylar fossa

43 Condyle

44 Pharyngeal tubercle

45 External occipital crest

26 Disarticulated Skull I: Temporal Bone

Sphenoidal bone

1 Greater wing

2 Lesser wing

3 Foramen rotundum

4 Foramen ovale

5 Foramen spinosum

6 Foramen lacerum

7 Anterior clinoid process

8 Hypophysial fossa (sella turcica)

9 Lingula

10 Dorsum sellae and posterior clinoid

process

11 Optic canal

12 Sphenoidal rostrum

13 Medial pterygoid plate

14 Lateral pterygoid plate

15 Pterygoid hamulus

16 Infratemporal crest

17 Body of the sphenoidal bone

Sphenoidal, occipital, and left temporal bone (from above). Internal aspect of the

base of the skull. The left temporal bone has been added to the preceding figure.

Left temporal bone (medial aspect). Left temporal bone (from above).