Lecture 2: Human Skull

Question 1

Skull Anatomy

Answer 1

1. Bone composition
   - The neurocranium consists of 8 bones (2 parietal, 2 temporal, frontal, occipital, sphenoid, and ethmoid)
   - The viscerocranium consists of 14 bones
2. Sutures
   - Most skull bones are joined by immovable joints
3. Foramina
   - Several openings in the skull allow for passage of nerves and blood vessels
4. Mandible
   The lower jaw, the only moveable bone of the skull

Question 2

What is the cranium?

Answer 2

The bones that form the head.
- Made up of cranium and facial bones

Question 3

Viscerocranium

Answer 3

facial skeleton
- Gives you your face

Question 4

Neurocranium

Answer 4

The part of the skull that surrounds and protects the brain.
- Dorsal: calvaria
- Ventral: floor of cranial cavity

Question 5

What structures are in the viscerocranium?

Answer 5

There are 15 bones.
- Ethmoid
- Inferior nasal conchae (2 bones)
- Vomer
- Nasal bones (2 bones)
- Lacrimal bones (2 bones)
- Zygoma (2 bones)
- Maxilla (2 bones are fused)
- Palatine (2 bones)
- Mandible

Question 6

Label the structures of the ethmoid.

Answer 6

• Superior nasal septum
• Superior and middle conchae (turbinates)
• Posteromedial orbit

Question 7

What structure is the inferior nasal conchae inferior to?

Answer 7

ethmoid

Question 8

Label the structures of the vomer.

Answer 8

• Inferior nasal septum
• Much larger posteriorly

Question 9

Medial

Answer 9

middle or center

Question 10

Where can you find the nasal bones?

Answer 10

They are superior to the ethmoid and vomer

Question 11

How do the nasal bones and lacrimal bones relate to each other?

Answer 11

Both the lacrimal bones are found medial to the ethmoid posteromedial orbit, and it lies lateral to the nasal bones

Question 12

Lacrimal bone

Answer 12

A small fragile bone in the front of the medial wall of the orbit, and helps to keep eyes moist.
- This supports the structures of the lacrimal apparatus
- The lacrimal bone helps form the nasolacrimal canal which drains tears into the nasopharynx

Question 13

Medial orbit

Answer 13

The location of the lacrimal bone.
- Contains gland n7

Question 14

Zygoma

Answer 14

This is the cheekbone.
- This placement is lateral and caudal to the nasal bones
- Becomes an extension of the temporal bone

Question 15

Maxilla structures

Answer 15

• Inferior orbit
• Anterior hard palate
• Inferior orbital foramen (nV2)

Question 16

Palatine structures

Answer 16

• Posterior hard palate
• Pesteroinferior orbit (VERY SMALL)

Question 16

Maxilla

Answer 16

This is the jawbone, specifically in the upper jaw.
- This is comprised of 2 bones which fuse during embryological development
- The nerve nV2 transmits sensory information from the teeth to the brain

Question 17

What are the two main parts of the mandible?

Answer 17

• Ramus
• Body

Question 18

Mandible ramus strcutures

Answer 18

• Coronoid process
• Condylar process (articulates with the temporal bone)

Question 19

Manible body structures

Answer 19

• Foramen
  
  • mandibular and mental (nV3)
  • mandibular branch
• Fossa
  
  • sublingual and submandibular (glands n7)
  • Innervated by the facial nerve

Question 20

Describe the basic anatomy of the external skull regions and reference points.

Question 21

Describe the important external locations where nerves or vessels enter or exit the skull.

Question 22

What are the bones found in the dorsal view of the skull?

Answer 22

frontal, parietal, and occipital bones

Question 23

Identify the 3 fossa on the floor of the cranium.

Question 24

What are the sutures found in the dorsal view of the cranium?

Answer 24

coronal, labdoid, and sagittal sutures

Question 25

What are the two reference points in the dorsal view of the skull?

Answer 25

These are the intersection of sutures which run laterally and longitudinally. - Bregma and Lambda

Question 26

Which suture is in front of the other through the dorsal view?

Answer 26

bregma: coronal suture + sagittal suture lambda: lamboid suture + sagittal suture

Question 27

Anterior and posterior fontanelle in newborns

Answer 27

Right after birth, the sutures in newborns have not fully formed yet. Their bones are soft, forming a soft spot on their head where the bones have not fused together. - Anterior: front - Posterior: back

Question 28

What major bones/structures are seen in the lateral view of the skull?

Answer 28

Temporal bone, pterion, and other facial bones

Question 29

Describe in "layman's terms" the lateral view of the skull.

Answer 29

It is the side of the skull, like a side profile where you can only see one ear.

Question 30

Name the important structures of the temporal bone.

Answer 30

- Squamous and petrous parts - External auditory meatus - Styloid and mastoid processes

Question 31

Name the important structures of the pterion.

Answer 31

- "Temple" -weak point - Frontal, parietal, temporal, and sphenoid

Question 32

Name the important structures of the lateral view of facial bones.

Answer 32

- Zygoma - Maxilla - Mandible (TMJ -> temperomandibular joint)

Question 33

Describe the anterior view of the skull in "layman's terms."

Answer 33

This is the front of your face, where you see all your facial features: eyebrows, eyes, ears, nose, lips, and chin.

Question 34

What bones/major structures can you see in the anterior view?

Answer 34

Frontal bone, maxilla, and mandible

Question 35

What are the major structures of the frontal bone seen from the anterior view?

Answer 35

- Supraorbital notch (contains distal V1 -> first vertebral artery)

Question 36

What are the major structures of the maxilla seen from the anterior view?

Answer 36

- The infraorbital foramen (contains the distal V2 -> second vertebral artery)

Question 37

What are the major structures of the mandible seen from the anterior point of view?

Answer 37

- Mental foramen (contains the distal V3 -> third vertebral artery)

Question 38

Describe the ventral view using "layman's terms."

Answer 38

This view is as if you took the skull and looked at the bottom of the skull directly at your lymph nodes near your throat.

Question 39

What are the bones/major structures seen from the ventral view?

Answer 39

- Foramen magnum - Stylomastoid formamen - Carotoid formen and canal - Foramen lacerum

Question 40

Describe the floor of the skull in "layman's terms."

Answer 40

This is as if you took a bone saw and sawed off the top half of your scalp and turned it over to see the crevices inside the top of your brain.

Question 41

What are the bones/major structures found at the floor of the skull.?

Answer 41

- Anterior Fossa - Middle Fossa - Posterior Fossa

Question 42

What are the major fossa of the floor of the skull?

Answer 42

Anterior, middle, and posterior

Question 43

What are fossa?

Answer 43

Depressions in the skull

Question 44

What are the major structures found in the anterior fossa in the floor of the skull?

Answer 44

- Cribiform plate and crista galle - Optical canal - Carotid canal (exit)

Question 45

What are the major structures found in the middle fossa in the floor of the skull?

Answer 45

- Sella turcica "Turkish saddle" (houses the pituitary fossa -> pituitary gland) - Superior orbital fissure - Foramen ovale, spinosum and rotundum

Question 46

What are the major structures found in the posterior fossa in the floor of the skull?

Answer 46

- Foramen magnum - Internal auditory meatus - Jugular foramen - Hypoglossal canal