Chapter 7 | Th Axial Skeleton | Exam 2 | USF

What is another name for joints?

Articulations

The Axial Skeleton has how many bones?

80 bones

What is included in the Axial skeleton?

Skull, vertebrae column, & thoracic cage

What is the most complex bony structure?

The skull

The skull is formed by which bones?

The cranial and facial bones

What do bones of the cranium do?

-Enclose and protect the brain

-Provide attachment sites for some muscles of the head & neck

What forms the framework of the face?

Facial bones (also forms cavities for sense organs)

What do the facial bones do?

-Provide openings for passage of air & food

-Hold teeth in place

-Anchor muscles of the face

What are sutures best described as?

Interlocking, immovable joints

What do suture lines look like?

irregular saw toothed appearance

Bony ridges divide skull into what?

Distinct fossae

What 3 distinct fossae do the bony ridges divide into?

1. Anterior

2. Middle

3. Posterior

The brain sits within which fossae?

The cranial fossae, and it occupies the cranial cavity

What smaller cavities does the skull contain?

• Middle & inner ear cavities

• Nasal cavity

• Orbits

• Paranasal sinuses

How many openings does the skull approximately contain?

85 named openings

What are the openings in the skull for?

Spinal cord, blood vessels serving the brain, and twelve pairs of cranial nerves

How many cranial bones are there?

8 large bones

Paired cranial bones are…

Temporal & Parietal bones

Unpaired cranial bones are…

Frontal, Occipital, Sphenoid, & Ethmoid

Parietal bones form what parts of the skull?

Superior & lateral parts

What are the 4 sutures of the cranium?

1. Coronal suture

2. Squamous suture

3. Sagittal suture

4. Lambdoid suture

Coronal suture

located where parietal bones meet frontal bone

Squamous suture

occurs where each parietal bone meets a temporal bone inferiorly

Sagittal suture

occurs where right & left parietal bones meet superiorly

Lambdoid suture

occurs where the parietal bones meet the occipital bone posteriorly

Do sutural bones serve a purpose?

No they do not

What are sutural bones?

they are small bones that occur within sutures (especially lamboid suture)

All people have sutural bones

FALSE - not all people have sutural bones

A canal means…

tube

A foramen means…

hole

Frontal bone forms where?

The forehead & roofs of orbits

What is superior to the orbits?

Superciliary arches

What is a supraorbital margin?

super margin of orbits

What is a supraorbital foramen?

Passage for supraorbital nerve & artery

What is the glabella?

Smooth part of frontal bone between superciliary arches

What does the Occipital bone do?

holds the brain

-forms the posterior portion of the cranium

The foramen magnum is located at its base

Occipital bone (spinal cord comes out)

Occipital condyles do what?

Head nodding

Hypoglossal foramen do what?

houses cranial nerve & is hidden

External occipital protuberance does what?

secures the ligament nuchae (ligament of the neck)

Superior & Inferior nuchal lines do what?

Anchor muscles of the neck & back

Where does hair start to go gray first?

The temporal bone

Where do the temporal bones lie?

inferior to parietal bones & form inferolateral portion of the skull

The latin word temporal means what in latin?

time

What are the specific parts of the temporal bone?

Squamous, Tympanic, and Petrous

The Mastoid Process is what?

The site for neck muscle attachment & contains air sinuses

Petrous Part is where?

between occipital and looks like mountain ridge.

-projects medially, contributes to cranial base

What does the petrous part do?

Houses cavities of middle & internal ear

Where is the squamous part?

forms on the zygomatic arch

→ the mandibular fossa on its interior surface forms the temporomandibular joint

Where is the Tympanic part?

Surrounds the external acoustic meatus

The foramina of the temporal bone include…

• jugular foramen

• carotid canal

• foramen lacerum

• stylomastoid foramen

• internal acoustic meatus

Jugular foramen is what?

Is the passage for internal jugular vein & cranial nerves

Carotid canal is what?

The internal carotid artery passes through it

Foramen lacerum is what?

Closed by cartilage in living person

The stylomastoid foramen does what?

Is the passageway for a branch of cranial nerve VII (7)

The internal acoustic meatus does what?

Transmits cranial nerves VII & VIII (7&8)

Where is the sphenoid bone?

It is on the width of the cranial floor and resembles a bat

What does the sphenoid bone have?

a body and 3 pairs of processes with 5 openings

(Sella turcica, greater wings, lesser wings, and pterygoid processes)

What is the Sella Turcicia?

It is what holds the pituitary gland and it looks like a saddle. The saddle is called the hypophyseal fossa.

What are the Pterygoid processes?

Attachment sites for the pterygoid muscles that help close the jaw in chewing

The openings in the Sphenoid Bone?

Optic canal, superior orbital fissure, foramen rotundum, foramen ovale, foramen spinosum

The optic canal does what?

Let cranial nerve II pass through

The Superior orbital fissure does what?

Lets cranial nerves III, IV, VI pass through

The Foramen rotundum does what?

Lets the maxillary branch of cranial nerve V pass through

The Foramen ovale does what?

Lets the mandibular branch of cranial nerve V pass through

The Foramen spinosum does what?

Lets the middle meningeal artery pass through

Where is the ethmoid bone?

Between the nasal and sphenoid bones. It forms most of the medial bony region between nasal cavity and orbits.

What does the cribriform plate do?

Contains cribriform foramina through which filaments of cranial nerve I pass

What is Crista galli’s purpose?

It’s the attachment for falx cerebri; a fibrous membrane that helps secure the brain

What does the perpendicular plate form?

The superior part of nasal septum

What does the ethmoidal labyrinth contain?

It contains air cells

Superior & Middle Nasal Conchae are where?

Extend medially from lateral masses

The Facial unpaired bones include what?

The Mandible and Vomer

The Facial paired bones include what?

Maxillae, Zygomatic, Nasal, Lacrimal, Palatine bones, Inferior nasal conchae

How is the Mandible described?

It’s the lower jawbone and it’s the largest and strongest facial bone. It is the only movable bone of the skull.

What is the mandible composed of?

The horizontal body and 2 upright rami

Major landmarks in the Mandible include…

Mandibular fossa, Mandibular foramen, Alveolar process, mental foramen, condylar process, & ramus

Maxillary bones articulate with all other facial bones except for the…

Mandible

What are the maxillary sinuses?

The largest paranasal sinuses

Zygomatic bones do what?

form the lateral wall of orbits

Nasal bones do what?

form bridge of nose

Lacrimal bones do what?

located in the medial orbital walls

Palatine bones do what?

complete the posterior part of the hard palate

Vomer bone does what?

forms the inferior part of the nasal septum

Inferior nasal conchae does what?

forms the lateral walls of the nasal cavity.

The roof of the nasal cavity is what?

Ethmoid’s cribriform plates

The floor of the nasal cavity is what?

Palatine processes of maxillae & horizontal plates of palatine bones

Where are the Paranasal sinuses located within?

Frontal, ethmoid, sphenoid, and maxillary bones

What lines the paranasal sinuses?

Mucous membranes that are extensions of the nasal cavity.

→ help warm, moisten, & filter inhaled air

The Paranasal Sinuses do what

sinuses help lighten the skull

The Hyoid bone is what?

inferior to mandible and only bone with no direct articulation to any other bone

→ movable base for the tongue

How much bones are in the vertebral column?

26 bones in adults

What does the vertebral column transmit?

Weight of trunk to the lower limbs

What does the vertebral column do?

surrounds & protects the spinal cord

How many cervical vertebrae are there?

seven CV of neck (7am)

How many thoracic vertebrae are there?

12 TV (12pm)

How many lumbar vertebrae are there?

5 LV (5pm)

How many fused bones in the sacrum?

5 fused bones

Which parts of the spine concave posteriorly?

Cervical and lumbar curvatures

Which parts of the spine convex posteriorly?

Thoracic & sacral curvatures