Lab 2.1 - Skull: Cranial and Facial Bones

Frontal Bone Features

Supraorbital foramen

Supraorbital foramen

opening located above the orbit of each eye for the supraorbital nerve and artery

Parietal Bone Features

None

Occipital Bone Features

1. Foramen magnum

2. External occipital protuberance

3. Occipital condyles

Foramen magnum

opening through which the spinal cord connects to lower brain

External occipital protuberance

projection at base of skull posterior to foramen magnum

Occipital condyles

rounded processes that articulate with the Atlas (C1)

Temporal Bone Features

1. External auditory meatus

2. Zygomatic process

3. Styloid process

4. Mastoid process

   1. Mandibular fossa

External auditory meatus

tube-like opening for the ear canal

Zygomatic process

projection that articulates with the zygomatic bone

Styloid process

long, thin proejction on inferior skull surface; attachment for muscles and ligaments of tongue and neck

Mastoid process

rounded projection posterior to external auditory meatus; attachment for msucles

Mandibular fossa

depression for articulation with condylar process (mandibular condyle)

Ethmoid Bone Features

1. Crista galli

2. Cribriform plates

3. Olfactory foramina

4. Perpendicular plate

5. Middle nasal conchae

6. Superior nasal conchae

Crista galli

projection for attachment of membranes covering brain

Cribriform plates

one on either side of crista galli; form roof of nasal cavity

Olfactory foramina

tiny holes that allow the passage of axons of the olfactory nerve to pass through the cribriform plate of the ethmoid bone and into the cranial cavity

Perpendicular plate

forms superior part of nasal spetum

Middle nasal conchae

scroll-like projections on each lateral wall of nasal cavity, located between the superior and inferior nasal conchae

Superior nasal conchae

scroll-like projections on each lateral wall of nasal cavity

• smallest of the nasal conchae and are situated above the middle nasal conchae, so they are not visible from the front

Sphenoid Bone Features

1. Sella turcica

2. Greater and lesser wings

3. Optic canal

Sella turcica

body projection that surrounds and protects pituitary gland

Greater and Lesser Wings

Form anterior and lateral floor of cranial cavity

Optic canal

passageway for cranial nerve ii (optic ii)

8 Cranial Bones

1. Frontal bone

2. Parietal bone (2)

3. Temporal bone (2)

4. Occipital bone

5. Sphenoid bone

6. Ethmoid bone

14 Facial Bones

1. Maxillae (2)

2. Mandible

3. Zygomatic bones (2)

4. Nasal bones (2)

5. Lacrimal bones (2)

6. Palatine bones (2)

7. Inferior nasal conchae (2)

8. Vomer

Maxillae Bone Features

• Alveoli

• Palatine process

Alveoli

Tooth sockets

Palatine process

Fused processes that form the anterior part of hard palate

Mandible Bone Features

1. Body

2. Rami

3. Condylar processes

4. Coronoid processes

5. Mental foramina

6. Alveoli

Body

curved, anterior portion of mandible

Rami

posterior branches, one on either side of the body of mandible

Condylar processes

rounded processes on rami that articulate with temporal bone at the mandibular fossa to form the TMJ

Coronoid processes

triangular projections of rami anterior to the condylar processes

Mental foramina

openings in chin for nerves and blood vessels

Zygomatic Bone Features

• Temporal process

Temporal process

projects posteriorly; temporal process of zygomatic bone and zygomatic process of temporal bone form the zygomatic arch (this is a composite feature)

Facial bones with no bone features

• Nasal bones

• Lacrimal bones

• Inferior nasal conchae

• Vomer

• Palatine bones