Axial Skeleton- Skull Flashcards
How many bones are in the axial skeleton?
80
How many bones are in the skull and associated bones?
29
How many bones are in the cranium?
8
How many bones are in the face?
14
How many bones are in the associated bones?
7
How many bones are in the auditory ossicles?
6
What are the three functions of the axial skeleton?
- Supports and protects body organs- brain, heart, and lungs
- Protects special sense organs- eyes, nerves for smell, auditory and balance structures
- Attachment sites for muscles- back muscles, intercostal muscles for breathing, facial expressive muscles
What is the skull composed of?
Face, cranium, and associated bones.
What are the facial bones? How many of each? Paired/unpaired? Location?
Maxillae (2)- Forms the upper jaw, anterior, articulates with the upper teeth
Palatine bones (2)- Forms the roof of the mouth
Nasal bones (2)- Forms the bridge of the nose
Inferior nasal conchae (2)- Forms the wall of the nasal cavity
Lacrimal bones (2)- Make up the medial portion of the ocular orbit (eye socket)
Vomer (1)- Sits deep to the zygomatic bones
Mandible (1)- Forms the lower jaw
Zygomatic bones (2)- Form the anterior portion of the cheekbone
What are the cranial bones? How many of each? Paired/unpaired? Location?
Occipital bone (1)- Back of skull
Parietal bones (2)- Middle of skull
Frontal bone (1)- Front of skull
Temporal bones (2)- Sides of skull, temples and ear
Sphenoid (1)- Deep
Ethmoid (1)- Deep
What are the associated bones? Location?
Hyoid bone (1)- Sits deep within the neck region, doesn’t articulate with other bones (ligaments and muscles attached to it)
Auditory ossicles enclosed in temporal bone (6)- Do auditory processes, transmit sounds from the air to the fluid-filled labyrinth of the inner ear
Where is the lambdoid suture located?
At the posterior (back) of the skull
Where is the sagittal suture located?
Down the midline of the skull, separates the right and left parietal bones
Where is the coronal suture located?
At the front of the skull (anterior)
What is the external occipital protuberance?
Serves as an attachment point, bomb at the back of the skull
What joint category do the skull sutures fall into? Would there be movement at these joints?
Synarthrotic joints. No, there is no movement.
Where is the chewing muscle located?
Inside the zygomatic arch.
What is the foramen magnum?
The large opening where the brain and spinal cord connect.
Describe the positioning of the palatine process of maxilla, the maxilla, and the palatine bone.
The palatine process of maxilla forms the anterior portion of the hard palate. The maxilla is most superficial, it makes up the outer part of the upper jaw and articulates with the teeth. The palatine bone sits posteriorly, near the back of the palate.
What is the temporalis?
Fan shaped muscle, helps with chewing
Where are the temporal process of zygomatic bone and zygomatic process of temporal bone located in relation to temporal bone?
The temporal process of zygomatic bone is located posteriorly, while zygomatic process of temporal bone is located anteriorly to temporal bone.
Which two components make up the bony nasal septum?
Vomer (inferior) and the perpendicular plate of ethmoid (superior)
What are the crista galli and cribriform plate?
Crista galli- Located on the superior surface of the ethmoid bone
Cribriform plate- Located just below the crista galli, many small holes that allow olfactory nerves to pass from the nasal cavity to the brain
What is the sella turcica?
Located in the sphenoid bone, shaped like a saddle and houses the pituitary gland (for production of hormones).
What sits laterally to the crista galli and cribriform plate?
The eyeballs and the muscles that surround them
What is the most structurally complex and intricate bone of the entire body?
The sphenoid
What major structure does the sphenoid contain?
Sella turcica- saddle shape, houses pituitary glands
What major structures does the ethmoid contain?
Cribriform plate (olfactory nerves sit here) and crista galli
What are the palatine bones and where are they located?
Two bones making up part of the roof of the mouth. Posterior to the palatine process of the maxilla.
Where are the nasal bones located?
Articulate with the frontal bone.
Where are the inferior nasal conchae located?
One on each side of the nasal septum attached to the lateral wall of the nasal cavity.
Where are the zygomatic bones located?
Articulate with the zygomatic process of the temporal bone. Form the zygomatic arch. Contain zygomaticofacial foramen- small opening, allows nerves and vessels to pass through.
Where are the lacrimal bones located?
Found in the medial portion of the orbit of the eye. Lacrimal groove leads to the nasolacrimal canal.
Where is the vomer located?
Forms the inferior portion of the nasal septum, separates left and right cavities.
With which bone does the mandible articulate/join?
Temporal bone (TMJ= temporo-mandibular joint)
Considered a sliding hinge joint, allows the mandible to protract and retract as well as depress and elevate (open and close) mouth. TMJ on both sides.
The Orbits
Protect the eyes
Formed from:
- Frontal bone makes the roof of the orbit
- Maxilla bones forms the floor of the orbit
- Lacrimal and ethmoid form the medial wall of the orbit
- Sphenoid bone forms the posterior wall of the orbit
- Zygomatic bone forms the lateral wall of the orbit
Consists of:
- Lacrimal gland (tear ducts)/adipose tissue/muscles that move
What is the purpose of the nasal conchae (superior, middle, and inferior)?
Churn the air to humidify and warm it, keep air moist and make mucus.
What are the paranasal sinuses?
Air-filled chambers that open into the nasal cavity.
- Frontal sinuses
- Sphenoidal sinuses
- Maxillary sinuses
- Ethmoid air cells
What category of bone do the paranasal sinuses fall into?
Pneumatized bones (they have hollow air-filled spaces)
What are the locations of the paranasal sinuses?
From top to bottom:
Frontal sinus
Ethmoid air cells
Sphenoidal sinus
Maxillary sinus
These sinuses connect to the nasal passages. During a cold, they can become blocked, and mucus can accumulate leading to pain
Do the paranasal sinuses lie in the same coronal plane?
No
What suspends the hyoid bone?
Stylohyoid ligaments. Does not articulate with any bones and is therefore extremely mobile.
What are the parts of the hyoid bone?
Greater and lesser horns. Serve as points for muscle and ligament attachments.
The cribriform plate is a feature of which bone?
Ethmoid bone.
Is the sternum part of the axial or appendicular skeleton?
Axial skeleton.
What general category of bone does the sternum fall into?
Flat bone.
What type of bone is the frontal bone?
Flat bone.
Another name for a diarthrotic joint is?
Synovial
The ear sits ______ to the mouth.
Lateral
The ______ is the connective tissue layer that wraps directly around a bone.
Periosteum
Osteons are primarily found in ________ bone.
Compact
True/False: Flexion and extension are movements that can occur at synarthrotic joints.
False; these occur at diarthrotic (synovial) joints.
Cartilage falls into which category of connective tissue?
Supporting connective tissue. Bone and cartilage are both in this group.
