Axial Skeleton I Flashcards
How many bones does the human body have?
206
In what two parts is the human skeleton divided?
The axial skeleton and the appendicular skeleton
What is the axial skeleton?
Runs on longitudinal axis
What is the appendicular skeleton?
Extremities and their girdles that hold them to the trunk
How many bones are in the skull and how are they divided?
28
Cranium: 8
facial bones: 14
Auditory ossicles: 6
The body has ____ ribs and ____ vertebrae
24
26
The _______ is a small bone in the neck, and the ______ connects the ribs anteriorlly.
Hyoid
Sternum
What are some of the anatomical features of bone?
Anatomical features in bone: ridges, spines, bumps, depressions, canals, sinuses and foramen
What is the purpose of the anatomical features of bone?
These provide places for muscle and ligament attachment, and routes for blood vessels and nerves.
What cavity encloses the brain?
The cranial cavity
What is the calveria?
Dome of the top of the skull OR skullcap
What are the three areas in the cranial floor?
Anterior cranial fossa
Medial cranial fossa
Posterior cranial fossa
Describe the anterior cranial fossa
holds the frontal lobe of the brain; crescent shaped
Describe the medial cranial fossa
the the temporal lobes of the brain (2); bat wing shaped
Describe the posterior cranial fossa
Deepest; holds the cerebellum
Name the cranial sutures
Saggital
Lambdoid
Coronal
Squamous
What is a fontanel?
Spaces between unfused cranial bones
Depressed fontanels can indicate _______, while bulging fontanels may indicate ________ _______.
Dehydration
Increasing ICP
What may wide fontanels indicate?
Wide fontanels may indicate hydrocephalus- excessive amounts of CSF
What cavities/areas are in the skull?
1- cranial cavity 1 oral cavity 2 nasal cavities 2 orbits 4 sinuses 2 middle ear and 2 inner ear areas
What is the frontal bone?
Forms the forehead, the roof of the orbits, and the anterior cranial fossa
What is the supraorbital margin of the frontal bone?
Forms the top of the orbit
What is the supraorbital foramen/notch of the frontal bone?
Notch where supraorbital nerve passes through
What is the frontal sinus of the frontal bone?
2, are supraorbital
What is the zygomatic process of the frontal bone?
“Of the” the part of the frontal bone that meets the zygomatic bone
What is the glabella of the frontal bone?
Smooth area of frontal bone, just above the nose
What is the parietal bone?
2, forms the greater portion of the sides and roof of the cranium
What are the temporal tines of the parietal bone?
2, inferior and superior- form an arc, one higher than the other, across the parietal (and some frontal) bone; origin of temporalis muscle
What are the temporal bones?
2, It forms the inferior sides of the cranium, and part of the middle cranial fossa
The flat area of the temporal bone is called what?
The squamous portion of the temporal bone.
What is the petrous portion of the temporal bone?
“Rock like” portion that houses the inner ear
What is the mastoid process of the temporal bone?
Prominent lump behind ear lobe, filled with small air sinuses
The opening of the ear canal is called what?
External auditory meatus of the temporal bone.
What is the mandibular fossa of the temporal bone?
A depression where the mandible articulates, one on each side
What is the styloid process of the temporal bone?
The attachment of the muscles of the tongue, pharynx, and hyoid bone
What is the zygomatic process of the temporal bone?
Where the temporal bone meets the zygomatic bone
What is the temporal fossa?
A wide depression where the body of the temporalis muscle lies
What is the occipital bone?
Forms the posterior part of the skull and most of the posterior cranial fossa
What is rounded and articulates with the C1 vertebra?
Occipital condyle
What is the foramen magnum? What travels through it?
A large hole. Medulla oblongata meets the spinal cord here, also houses the vertebral arteries that supply the brain
What is the external occipital protuberance, and what attaches here?
Prominent medial bump, the nuchal ligament attaches here
What holds up the head?
The nuchal ligament
What do neck muscles attach to?
The superior nuchal line of the occipital bone.
What is below the superior nuchal line?
The inferior nuchal line
What is the sphenoid bone?
Lies in the middle part of the skull. Is the “keystone” of the skull because it articulates with all other cranial bones. Looks like a bat with outstretched wings.
What is the sella turcica?
The “turkish saddle” this depression houses the pituitary gland (master gland)
What is the sphenoid sinus?
Drains into the nasal cavity
Name the plates of the pterygoid process of the sphenoid
Medial plate
Lateral plate
How many processes does the pterygoid process of the scaphoid have?
2
Which plate of the pterygoid has the hamulus, and what is it?
The medial plate
The hamulus is a slight bump at the end
Which plate of the pterygoid is shorter and wider?
The lateral plate
What is the hole where optic nerve passes through
The optic foramen of the sphenoid bone
What divides the divides the middle and anterior cranial fossa?
The lesser wing of the pterygoid process of the sphenoid bone
What is the greater wing the of the pterygoid process?
It’s larger can see it on a lateral view of the skull
What is the ethmoid bone?
A light, sponge-like bone that’s very delicate, located between the eyes. Contributes to the medial wall of the orbit, and roof and walls of the nasal cavity. Part of the nasal septum.
What is the cribriform plate of the ethmoid?
Forms the roof of nasal cavity.Has many foramina (holes) in it. Holes allows nerve fibers of the olfactory nerve to pass through.
What is the crista galli of the ethmoid?
Projects upwards from the 2 cribriform plates, point of attachment for the membranes that cover the brain.
What are the superior and middle conchae of the ethmoid?
they stick out medially into the nasal cavity
What do the conchae of the ethmoid do?
Both cause turbulence in inhaled air: 1) to warm air as it slows down, makes air more humid; 2) results in inhaled particles striking and becoming trapped in mucus; forms superior part of nasal septum
What is the Perpendicular plate of the ethmoid?
Only visible only in a parasagittal cut
What are the ethmoid sinuses?
Light, airy bone, has air cells
How many facial bones are there? Do they enclose the brain?
14
No
How does the face change in the first two postnatal years?
1-Brain and cranial bones expand
2-Teeth form and erupt
3-Paranasal sinuses increase in size
What are the nasal bones?
Are 2. Meet to form the bridge of the nose. Major portion of the nose is cartilage. Will hide the superior nasal conchae.
What is the maxilla?
Are 2. Forms the floor of the orbit. Meet to form the upper jawbone. Maxillae articulates with every bone of the face except the mandible.
What is the palatine process of the maxilla?
Makes up the anterior ⅔ ds of the hard palate
What is the infraorbital foramen of the maxilla?
Passage of blood vessels and nerves to and from the face (infra = below)
What is an alveolus?
Socket for tooth, deep sockets in the bone for the upper teeth
What is the alveolar process?
Small projections of bone between the bases of the teeth
What is the maxillary sinus?
Space in the maxilla that drain into the nasal cavity (all 4 do)
What are the zygomatic bones?
Commonly called the cheekbone. Forms the angle of the cheeks and part of the lateral wall of the orbit.
What is the frontal process of the zygomatic bone?
Where zygomatic bone meets frontal bone
What is the temporal process of the zygomatic bone?
Where zygomatic bone meets the temporal bone
What is the zygomatic arch?
Two processes joining:
1- zygomatic process of the temporal bone; and
2- temporal process of the zygomatic bone
What is the mandible?
Lower jaw bone. Only bone in the skull that moves. Has a body and two rami/ramus. Strongest bone of the skull.
What are the angle, body and ramus of the mandible?
Refer to a diagram.
What is the coronoid process of the mandible?
A projection of bone, temporalis muscle inserts here. Shaped like a crow’s beak.
What is the condylar process of the mandible?
Projection of bone supporting the mandibular condyle
What is the mandibular condyle?
Articulates with the mandibular fossae of the temporal bones
What is the mental foramen of the mandible?
Foramen for the nerves and blood vessels to the chin
The mandibular notch is between the ________ and ________ processes
Coronoid
Condylar
What is the mandibular foramen?
Inner aspect of the mandibular ramus, nerves and blood vessels that supply the lower teeth
What are the lacrimal bones?
Are 2.
Thin, resembling a fingernail. Smallest bone in the face. Forms part of the medial wall of the orbit
What is the lacrimal sulcus?
Depression/dent, area for tear drainage into the nasal cavity when not crying
What is the palatine bone?
L-shaped, forms posterior ⅓ of hard palate and part of the floor and lateral wall of the nasal cavity
What is the vertical plate of the palatine bone?
Part of the lateral wall of the nasal cavity and slight orbit
What is the horizontal plate of the palatine bone?
Posterior ⅓ of hard palate
Describe the vomer
Slender, ruffled, triangular bone, looks like a plow
What does the vomer form?
Forms the inferior and posterior portions of the nasal septum
Is the medial division of the nasal cavities
What is the vertical plate of the vomer?
forms the inferior and posterior part of the nasal septum
What part of the vomer is frequently deviated?
The nasal septum
What is the ala of the vomer?
“wing” superior portion of the comer attachment area to the sphenoid bone
The orbot is called the _____ _____
Eye socket
What seven bones comprise the orbit?
Frontal Maxilla
Sphenoid Ethmoid
Zygomatic Lacrimal
Palatine
What bones does the hyoid articulate with?
None
The hyoid is suspended from what?
Styloid process of the temporal bone
The hyoid is located in the neck between the ________ and ______.
Mandible
Larynx
How is the hyoid often fractured?
During strangulation
The hyoid looks like a mini ______.
Mandible
What does the hyoid support?
The tongue and larynx
