Axial (Skull)

Question 1

• is made up of the frontal, parietal and temporal bones. These bones and the occipital bone are connected to each other via sutures.
• There are 14 facial bones—2 maxillary, 2 palatine, 2 nasal, 2 inferior conchae, 2 zygomatic, 2 lacrimal and 1 mandible and 1 vomer.
• Other bones that are associated with the ___ include the auditory ossicles and the hyoid bone. The auditory ossicles are found within the temporal bone, and the hyoid bone is connected to the __ by muscles.

Answer 1

The skull cap or calvarium

Question 2

• is clearly visible in this view. It is made up of two bones; the perpendicular plate of the ethmoid and the vomer.

Answer 2

The bony nasal septum

Question 3

• We mentioned previously that some of the bones of the skull are connected to each other by ___.
• means seam so you can think of ___ as a seam sewn between bones.
• In fact, __ are immovable joints found between certain bones of the skull.
• The articulating edges of __ are serrated and the interdigitations are held together with fibrous connective tissue.
• There are four __ in the adult skull
• are formed between 2-24 months after birth by intramembranous ossification

Answer 3

sutures

Question 4

• is between frontal bone and the two parietal bones.

Answer 4

the coronal (=crown) suture

Question 5

• cannot be seen in this lateral view of the skull, but is located between the two parietal bones.

Answer 5

The sagittal suture

Question 6

• named after the Greek letter lambda, is located between the parietal bones and the occipital bone.

Answer 6

The lambdoid suture

Question 7

• are between the parietal bones and the temporal bones on each side of the skull.

Answer 7

The squamosal sutures

Question 8

• “soft spots” called ___ between the bones.
• make the skull more pliable, and allow for rapid growth of the brain during infancy.

Answer 8

fontanels

Question 9

• is between the frontal and parietal bones.

Answer 9

the anterior or frontal fontanel

Question 10

• is located between the parietal and occipital bones.

Answer 10

The posterior or occipital fontanel

Question 11

• is outlined by the frontal, parietal, temporal and sphenoid bones

Answer 11

The anterolateral or sphenoid fontanel

Question 12

• is between the parietal, occipital, temporal bones.

Answer 12

the posterolateral or mastoid fontanel

Question 13

• there is an additional suture called the ___ ___ . This suture is not present after birth.

Answer 13

frontal suture

Question 14

• comprises the forehead and roof of the orbit.
• As stated previously, the fetal __ bones fuse during development but usually do not form a suture.
• However, in a small percentage of the population, there is a remnant of the __ ___ called the metopic suture.
• Some other features of the __ __ include the supraorbital foramen through which the supraorbital nerve & artery pass.
• From the inferior orbital surface there is a shallow depression in the __ __ called the lacrimal fossa. It houses the lacrimal or tear gland. The secretions of the lacrimal gland wash over the surface of the eye diagonally and are collected in the lacrimal sac located inferiorly and medially in the orbit (more on this later). Also visible is the frontal sinus which is lined with mucous membrane and contains air. Sinuses in general help to make cranium lighter and are important for sound resonation and hearing.

Answer 14

The frontal bone

Question 15

• through which the supraorbital nerve & artery pass.

Answer 15

the supraorbital foramen

Question 16

• From the inferior orbital surface there is a shallow depression in the frontal bone called the
• It houses the lacrimal or tear gland.
• The secretions of the lacrimal gland wash over the surface of the eye diagonally and are collected in the lacrimal sac located inferiorly and medially in the orbit (more on this later).

Answer 16

lacrimal fossa

Question 17

• Also visible is the __ __ which is lined with mucous membrane and contains air.
• Sinuses in general help to make cranium lighter and are important for sound resonation and hearing.

Answer 17

frontal sinus

Question 18

• make up the sides and roof of cranium.
• They fuse with each other in the midline forming the sagittal suture.
• Occasionally, Wormian or sutural bones are present. The superior and inferior temporal lines are attachment sites for the temporalis muscle which inserts on the mandible and functions to elevate the lower jaw. The insert on the lower right is a drawing of some of the features found on the inside of the __ __. The obvious grooves running on the inside of the bones are the impressions of the vessels that supply the outer brain covering called the dura mater.

Answer 18

parietal bones

Question 19

• makes up the back of the head and most of the base of the cranium.
• It has four main features: The foramen magnum, which literally means big hole, the occipital condyles, the external occipital protuberance, and the superior and inferior nuchal lines, two curved ridges of bone lying above and below the external occipital protuberance.

Answer 19

The occipital bone

Question 20

• This is the site where the spinal cord joins with the inferior most part of the brainstem called the medulla oblongata.
• On the inner aspect of the __ __ , two smaller foramina are visible. These are the hypoglossal canals through which cranial nerves XII (the hypoglossal nerves) pass to get to the muscles of the tongue which they control.
• it is through the __ __ that the vertebral arteries gain access to the base of the brain. They assist the internal carotid arteries in providing the blood supply to the brain.

Answer 20

foramen magnum

Question 21

• On either side of the foramen magnum are the __ __
• These articulate with the first cervical vertebra called the atlas and allow the skull to rock back and forth making the “yes” motion. The small pits in the bone are for small blood vessels such as nutrient arteries.

Answer 21

occipital condyles

Question 22

• Just superior to the foramen magnum is the medially located __ ___ __ which can be easily palpated—it is the big bump on the back of the skull.
• It is the insertion site for the ligamentum nuchae, a large, fibrous, elastic ligament that extends down to the 7th cervical vertebra. It helps to support the weight of the head and stabilize the neck. The superior and inferior nuchal lines are two prominent ridges which are attachment sites for muscles that move the head.

Answer 22

external occipital protuberance

Question 23

• make up the lower sides and part of the floor of the skull. There are several prominent features exhibited by these bones.

Answer 23

The temporal bones

Question 24

• are the thin, flat plates on the sides of the cranium.
• These are easily fractured if one receives a blow to the side of the head.

Answer 24

The temporal squama

Question 25

• is a bar of bone that articulates with the temporal process of the zygomatic bone to form the zygomatic arch or cheek bone.

Answer 25

The zygomatic process

Question 26

• The thick, bumpy and irregular part of the temporal bone is call the __ __
• means rock.
• It is the same word from which we get petrified and the name Peter.
• contains the external auditory (acoustic) meatus which channels sound waves to the eardrum. Internally, it contains the middle and inner ear which are used for hearing and balance.

Answer 26

petrous portion

Question 27

• is an important attachment site for muscles that flex, and rotate the head.

Answer 27

The mastoid process

Question 28

• From the base of the skull (shown in the upper left hand corner), the __ __ (red arrow) and the jugular foramen are visible. The internal carotid artery enters the skull to supply the brain via the __ __

Answer 28

carotid canal

Question 29

• serves as an entrance and exit point for cranial nerves IX, X, and XII and the internal jugular vein.

Answer 29

The jugular foramen

Question 30

• the mastoid process contains air cells that are lined with a thin epithelial membrane. Their normal function is to play a role in proper acoustics, however occasionally the membrane can become infected.
• The resulting inflammation is referred to as ___
• can be serious because infections of the throat can spread to the air cells and on to the inner ear and brain.

Answer 30

mastoiditis

Question 31

• Just posterior to the mastoid process is a sharp, pointed projection called the
• It is an important attachment site for muscles that raise the hyoid bone for swallowing and retract the tongue.

Answer 31

styloid process

Question 32

• Between the mastoid and styloid processes on the base of the skull, is a small foramen called the __ __.
• It transmits cranial nerve VII and the stylomastoid artery.

Answer 32

stylomastoid foramen

Question 33

• is visible on the inside of the temporal bone. The blue arrow in the photograph on the right is pointing to this opening. Through it passes cranial nerves VII and VIII, the facial and vestibulocochlear nerves.

Answer 33

internal acoustic meatus

Question 34

• is motor to the muscles of facial expression and carries taste fibers from the anterior 2/3 of the tongue

Answer 34

The facial nerve

Question 35

• brings information on balance and hearing to the brain from the inner ear.

Answer 35

The vestibulocochlear nerve

Question 36

• Clinically speaking, the articulation point between the mandible and the temporal bone, is very important. This joint is called __ ___ __.
• The joint is formed between the mandibular fossa and articular tubercle of the temporal bone and the condylar process of the mandible.
• Many people suffer from some aspect to ___ syndrome. Symptoms include, pain around the ear, sore jaw muscles, abnormal wearing of teeth, inability to open mouth all the way, and clicking and popping when opening and closing mouth. In severe cases, hearing loss can result due to excessive wearing down of the mandibular fossa and the proximity of the joint to the external auditory meatus and middle ear chamber.
• Some of the causes of ___ syndrome include, grinding the teeth when sleeping, clenching jaw, and arthritis.

Answer 36

the temporomandibular joint or TMJ

Question 37

• is known as the keystone of the cranial floor because it articulates with all the other bones of the cranium.
• It makes up the floor of cranium in the middle part of the base of the skull. When removed from the skull, the __ __ resembles a bat or a bird. There are numerous important bony features and foramina in this bone.
• is comprised of greater and lesser wings and a body. The superior surface of the body is visible when you are looking down into the skull. It has a saddle-shaped structure called the sella turcica or Turkish saddle. The “seat” of the saddle contains a depression called the hypophyseal fossa which cradles the pituitary gland. The greater wings project laterally forming parts of the middle cranial fossa, dorsal walls of the orbits and external wall of the skull. The lesser wings form a ridge of bone anterior and superior to the greater wings, and form part of the floor of the anterior cranial fossa, and part of the medial walls of the orbits.

Answer 37

The sphenoid bone

Question 38

• _ __ __ make up the inferior part of sphenoid, and serve as attachment sites for some of the muscles that move the mandible.

Answer 38

the pterygoid processes

Question 39

• The body of sphenoid contains the __ __that help to make the skull lighter.
• They are lined with mucous membrane and drain into the nasal cavity.

Answer 39

sphenoidal sinuses

Question 40

• are located between the body and lesser wing, and transmit cranial nerve II (optic nerve) and the ophthalmic artery.

Answer 40

The optic foramina or canals

Question 41

• lies between the greater and lesser wings and forms a large and triangular shaped slit which can be seen in the back of the orbit.
• transmits cranial nerves III (= oculomotor), IV (= trochlear), the ophthalmic branch of V (= trigeminal), and VI (= abducens). The foramen rotundum and foramen ovale provide passageways for the maxillary and mandibular branches of cranial nerve V, respectively.

Answer 41

The superior orbital fissure

Question 42

• transmits the middle meningeal vessels.

Answer 42

The tiny foramen spinosum

Question 43

• is located between the sphenoid and petrous portion of the temporal bone and transmits a branch of the ascending pharyngeal artery.

Answer 43

The foramen lacerum