The Nose and Paranasal Air Sinuses 1

Question 1

What part of the skull does the maxilla occupy?

Answer 1

It occupies a large region of the skull in the angle between the orbit and the nose. It therefore forms a great part of the framework of the face.

Question 2

Describe the strength of the maxilla.

Answer 2

It is a rather frail bone because the inside the excavated by a large air sinus.

Question 3

What is the large air sinus in the maxilla called?

Answer 3

This is called the maxillary air sinus or antrum.

Question 4

What part of the orbit does the maxilla form?

Answer 4

It forms most of the floor of the orbit.

Question 5

What part of the nose does the maxilla form?

Answer 5

It forms the lateral wall of the nose.

Question 6

What is the infraorbital canal?

Answer 6

This is a bony tunnel that runs through the floor of the orbit.

Question 7

Where does the infraorbital canal open onto the face?

Answer 7

Opens onto the face at the infraorbital foramen.

Question 8

What are the 2 bones that articulate with the maxilla?

Answer 8

• zygomatic bone
• sphenoid bone

Question 9

What bone forms most of the cheek bone?

Answer 9

The zygomatic bone forms most of the cheek bone therefore it is easily palpable on the face.

Question 10

What does the zygomatic bone take part in the formation of?

Answer 10

It takes part in the formation of the lateral wall of the bony orbit and also of the zygomatic arch.

Question 11

Where can we see the greater and lesser wings of the sphenoid bone?

Answer 11

At the back of the orbital cavity.

Question 12

What does the greater wing of the sphenoid bone contribute to?

Answer 12

It extends laterally and contributes to the side of the cranium.

Question 13

Describe the undersurface of the sphenoid bone.

Answer 13

It is irregular.

Question 14

What does the undersurface of the sphenoid bone extend down to?

Answer 14

It extends down to the level of the sides of the soft palate in the form of 2 plates which are the lateral and medial pterygoid plates.

Question 15

What do we have between the sphenoid and the maxilla?

Answer 15

There is a slit where the 2 bones do not quite meet.

This slit is called the pterygomaxillary fissure.

Question 16

What is the deepest part of the pterygomaxillary fissure called?

Answer 16

It is called the pterygopalatine fossa.

Question 17

Why is the pterygopalatine fossa so named?

Answer 17

Because deeper within the pterygomaxillary fissure there is another bone that lies opposite the pterygoid plates of the sphenoid bone and this bone is a part of the palatine bone.

Question 18

How many bony tunnels lead to the deepest part of the pterygomaxillary fissure?

Answer 18

There are several bony tunnels.

Question 19

From the inside of the skull, how many entrances are there leading into the pterygopalatine fossa?

Answer 19

There is one larger entrance and one smaller entrance.

Both entrances lead out of the middle cranial fossa.

Question 20

What is the foramen rotundum?

Answer 20

This is a round hole in the sphenoid bone.

Question 21

Where does the foramen rotundum lie?

Answer 21

It lies below the superior orbital fissure.

Question 22

Where is the opening of the smaller pterygoid canal?

Answer 22

This is below the level of the foramen rotundum.

Question 23

Describe the course of the pterygoid canal.

Answer 23

It passes through the sphenoid bone from its posterior surface and then opens into the pterygopalatine fossa anteriorly.

Question 24

Where do the pterygoid canal and foramen rotundum both open into?

Answer 24

They both open into the pterygopalatine fossa.

Question 25

What do the infraorbital fissure and canal run onwards towards?

Answer 25

They run onwards to the infraorbital foramen and the front of the maxilla.

Question 26

What is the sphenopalatine foramen?

Answer 26

This is a round foramen that can be seen when we look at the pterygomaxillary fissure from the side, deep within the pterygopalatine fossa.

It leads further inwards to the lateral wall and roof of the nose.

This foramen is part of the sphenoid and the palatine bone.

Question 27

What is the palatine canal?

Answer 27

This runs from the pterygopalatine fossa down into the side of the hard palate.

Question 28

What does the palatine canal divide to?

Answer 28

It divides to open as 2 foramina which are called the greater and lesser palatine foramine on the hard palate.

Question 29

Where do the greater and lesser palatine foramina lie?

Answer 29

The lie opposite to the last molar tooth on the hard palate where the palatine bone sutures with the maxilla.

Question 30

Describe the path of the large maxillary division of the trigeminal nerve (Viii).

Answer 30

• leaves skull through foramen rotundum
• enters the infraorbital canal
• emerges at the infraorbital foramen
• in the pterygopalatine fossa
  
  • several branches either diverge medially into the nose through the sphenopalatine foramen
  • or forwards through the orbit
  • downwards towards the palate through the bony canals

Question 31

What nerves does the pterygoid canal of the sphenoid bone transmit?

Answer 31

It transmits autonomic nerves to the pterygopalatine fossa.

Question 32

Why is the pterygopalatine fossa important?

Answer 32

Because it contains many nerves and blood vessels and is an important point of relay for nerves and vessels in the nose and mid face.

Question 33

Where do the nasal bones lie?

Answer 33

They lie in front of the maxilla.

Question 34

What do the nasal bones form?

Answer 34

They form the bridge of the nose.

Question 35

Where is the ethmoid bone positioned?

Answer 35

It is positioned between the orbital cavities.

Question 36

What does the nasolacrimal canal contain?

Answer 36

It contains the nasolacrimal duct.

Question 37

What is the path of the nasolacrimal duct?

Answer 37

It runs from the orbit to the floor of the nose.

Question 38

What bone form the lateral wall of the nose?

Answer 38

• palatine bone
• nasal bone
• ethmoid bone
• lacrimal bone
• maxilla

Question 39

What is the roof of the nose formed by?

Answer 39

It is formed by the ethmoid bone at the front and the sphenoid bone at the back.

Question 40

What does the body of the sphenoid bone contain?

Answer 40

It contains the sphenoid air sinus.

Question 41

In front, what is the floor and lateral wall of the nose formed by?

Answer 41

Maxilla.

Question 42

Behind, what is the floor and lateral wall of the nose formed by?

Answer 42

It is formed by the palatine bone.

Question 43

When views from the front, what is the palatine bone shaped like?

Answer 43

It is shaped like an L

Question 44

What does the palatine bone take part in the formation of?

Answer 44

It takes part in the formation of the floor of the nose (hard palate) and of the lateral wall of the nose.

Question 45

Describe the vertical part of the palatine bone.

Answer 45

It is forked at the top.

Question 46

What does the vertical part of the palatine bone make up?

Answer 46

It makes up the lower part of the sphenopalatine foramen.

Question 47

Where does the maxillary air sinus lie?

Answer 47

It lies in front of the pterygopalatine fossa.

Question 48

What does the sphenopalatine foramen lead from, to?

Answer 48

It leads from the fossa into the nose.

Question 49

What does the sphenopalatine foramen pass between?

Answer 49

It passes between the fork at the top of the perpendicular plate of the palatine bone.

Question 50

What bone forms a large part of the lateral wall of the nasal cavity?

Answer 50

The maxilla.