Axial Skeleton 1 Flashcards
Describe the bones of the skull. Describe the associated features (e.g., processes, foramina) of the skull bones.
what are most of the bones in the skull fused together by?
immovable joints called sutures
What are the main functions and features of the skull bones?
protect the brain (cranial cavity)
what is the purposed of the surface markings on the skull?
muscle attachment sites and passageways for blood vessels and nerves.
In addition to the cranial cavity, some skull bones form ____
the orbits and nasal cavity
Some skull bones also contain _____
smaller cavities (e.g., paranasal sinuses, middle and inner ear structures)
how many cranial bones are there?
How many facial bones are there?
8 and 14
purpose of cranial bones:
form the cranial cavity, in which the brain sits
purpose of facial bones:
for the structure of the face
list the cranial bones:
frontal
parietal (2)
temporal (2)
occipital
sphenoid
ethmoid
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what forms the frontal bone?
The forehead
The anterior portion of the cranial cavity
Part of each orbit
features of the frontal bone
Supraorbital margin (2)
Supraorbital foramen (2
what passes through the supraorbital foramen of the frontal bone?
artery and nerve
what forms the parietal bones (2)
The top and upper part of the sides of the head
Most of the superolateral portion of the cranial cavity
what forms the temporal bones (2)
The lower part of the sides of the head (“temples”)
Most of the inferolateral portion of the cranial cavity
what are the features of the temporal bone?
Styloid process
Mastoid process
Stylomastoid foramen
Carotid foramen
Jugular foramen
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what nerve passes through the stylomastoid foramen?
CN VII
what artery passes through the carotid foramen?
Internal carotid artery
what vein passes through the jugular foramen?
Internal jugular vein, CN IX, CN X, CN XI
features of the temporal bone:
Zygomatic process
Mandibular fossa
External auditory meatus
Internal auditory meatus
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Zygomatic process:
A finger-like projection that extends anteriorly to meet the zygomatic bone.
Mandibular fossa:
A depression that articulates or forms a joint with the condylar process of the mandible.
External auditory meatus:
A passage or opening leading to a canal for sound transmission.
Internal auditory meatus:
A passageway for cranial nerves 7 & 8.
What are the structures found between the external auditory meatus and internal auditory meatus in the temporal bone?
two cavities: the middle ear and inner ear.
The boundary between the external auditory meatus and the middle ear is covered by___
the tympanic membrane or eardrum.
There is a small opening between the middle and inner ears called:
the oval window.
The middle ear contains three small bones called the ____ and consists of ___, ____, and ___.
The middle ear contains three small bones called the auditory ossicles: the malleus, incus, and stapes.
The malleus is attached to ____, while the stapes is attached to the ____.
the tympanic membrane
membrane covering the oval window.
How are sound waves transmitted from the outer ear to the inner ear, and what is their significance?
Sound waves vibrate the tympanic membrane, which then vibrates the auditory ossicles in the middle ear.
where are vibrations in the ear transmitted?
These vibrations are transmitted to the cochlea in the inner ear, enabling us to hear. Damage to the tympanic membrane, auditory ossicles, or middle ear cavity can result in diminished hearing.
what is the structure of occipital bone?
The back of the head
The posteroinferior portion of the cranial cavity
features of the occipital bone:
Foramen magnum
Occipital condyle (2)
External occipital protuberance
Superior nuchal line (2)
Inferior nuchal line (2)
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External occipital protuberance:
A bump on the back of the head in the midline.
Superior nuchal lines:
Small ridges extending laterally from the external occipital protuberance.
Inferior nuchal lines:
Ridges located a couple of centimeters inferior to the superior nuchal lines.
Foramen magnum:
A large hole in the base of the occipital bone through which structures like the medulla oblongata (brain stem), cranial nerve 11, and vertebral arteries pass.
Occipital condyles:
Bony projections on either side of the foramen magnum that articulate with the superior facets of the first cervical vertebra (C1) to form the atlanto-occipital joints.
what is the structure associated with the sphenoid bone?
The middle part of the inferior portion of the cranial cavity
Part of each orbit
Part of the nasal cavity
_____ is derived from the Greek word for “wedge”, because it sits in the middle of the cranial cavity and articulates with every other cranial bone.
the sphenoid bone
what are the features of the sphenoid bone?
Body
Sella turcica (“Turkish saddle”)
Sphenoid sinus