Head and Neck Anatomy

Question 1

How is the development of the skull related to the development of the brain?

Answer 1

The development of the skull is driven by the development of the brain.

Functional matrix theory.

Question 2

Why is there such a disproportionately smaller brain case relative to the face at birth?

Answer 2

Functional driver of facial skeleton is different to cranial skeleton.

Question 3

How is the cranial cavity divided?

Answer 3

3 fundametal parts:

Anterior cranial cavity

Middle cranial cavity

Posterior cranial cavity

Question 4

What are the important foramina of the cranial cavity?

Answer 4

Foramen magnum

Question 5

How is the spherical shape of the brain case produced?

Answer 5

Flat bits produced denovo from connective tissue via Intramembranous ossification.

Endochondral ossification produces the base of the brain case. (this continues until about the age of 25)

Question 6

What is the purpose of CSF?

Answer 6

It protects the brain and provides padding for it during collisions.

Question 7

How does the brain develop in young children?

Answer 7

Islands of bone form and then fuse

Question 8

What embryological structures form the cranial bones and which form the facial bones?

Answer 8

Cranial bones: Formed by the brain & vertebral development.

Facial Bones: formed by the foregut during development (via the pharyngeal arches)

Question 9

Which directions are facial bones strong?

Answer 9

Vertically, they are weak vertically

Question 10

What is the job of pharyngeal arches?

Answer 10

Each one is reponsible for the formation of one part of the head.

Question 11

What is the job of the 1st pharyngeal arch?

Answer 11

1st pharyngeal arch is important for formation of the bones of the jaw and maxilla

Question 12

Important to know about pharyngeal arches:

Answer 12

Each arch is highly specific for the structure that it ends up forming.

Question 13

How are facial bones arranged?

Answer 13

They are designed to create the maximum surface area of mucosa for air to travel for its air conditioning job.

Question 14

What are the muscles that close the jaw called?

Answer 14

The muscles of mastication.

Question 15

Where do the muscles that close the jaw come from?

Answer 15

The 1st pharyngeal arch (which is why they are supplied by the trigeminal nerve)

Question 16

Which muscles are produced from the 2nd pharyngeal arch?

Answer 16

Muscles of facial expression (by definition supplied by 7th cranial nerve)

Question 17

What is the main muscle that closes the jaw called?

Answer 17

The temporalis muscle

Question 18

How is biting stress directed though dense bone in the maxilla?

Answer 18

Via buttresses

Question 19

What structure separates the nasal cavity from the oral cavity?

Answer 19

The palatine process of the maxilla

Question 20

What is the name of the shelves of bone that hang out into the nasal cavity and what do they do?

Answer 20

Conchi, they create more folds of surface area for air to be modified on its way to the lungs.

Question 21

What bones make up the orbit?

Answer 21

Zygomatic bone laterally

Maxillary bone inferiorly

Frontal bone superiorly

Ethmoid bone posteromedially

Question 22

What does each pharyngeal arch contain?

Answer 22

1 arterial supply

1 piece of cartilage

&

1 nerve

Question 23

What are the 4 major muscles of mastication?

Answer 23

Masseter

Temporalis

Medial pterygoid

Lateral pterygoid

Question 24

What are the muscles of mastication that are needed for swallowing? (rather than chewing)

Answer 24

Mylohyoid muscle

Anterior belly of the digastric muscle. (posterior belly is made by 2nd arch and then they join to form 1 muscle)

Question 25

What non chewing muscles are derived from the 1st pharyngeal arch (these are also known as muscles of mastication)?

Answer 25

Tensor tympani Tensor palati

Question 26

What are the important parts of the masseter?

Answer 26

There is a deep part with vertical fibers and a superficial part with oblique fibers.

Question 27

What are the important parts of the temporalis muscle?

Answer 27

The fleshy part with fibers that form an arch with some fibers almost vertical and other fibers horizontal. Tendinous parts

Question 28

What are the important relationships with the medial pterygoid muscle?

Answer 28

Medially there are many peripheral nerves that arise from The peripheral nerves can be accidentally cut and this causes loss of sensation from tongue.

Question 29

What is the motion of the mouth during mastication called?

Answer 29

The mandible has an envelope of movement because the temperomandibular joint can move in several directions

Question 30

What nerve supplies the muscles of facial expression and which pharyngeal nerve do they come from embryologically?

Answer 30

CN7 supplies them and they are derived from the 2nd pharyngeal arch

Question 31

Which somite derived structures migrate to the areas where the pharyngeal arches are active?

Answer 31

Tongue Extrinsic muscles of the eye