Axial Skeleton Flashcards
What is the function of the skull?
supports facial structures and protects brain
How many bones does the skull consist of?
22
How many bones of the skull form the viscerocranium (framework of face/facial skeleton)?
14
What are the paired bones of the viscerocranium? (6)
lacrimal bone nasal bone zygomatic bone maxilla inferior nasal concha palatine bone
What are the unpaired bones of the viscerocranium? (2)
mandible
vomer
How many bones of the skull form the neurocranium (bony box that holds brain)?
8
What are the paired bones of the neurocranium? (2)
parietal bone
temporal bone
What are the unpaired bones of the neurocranium? (4)
frontal bone
occipital bone
sphenoid bone
ethmoid bone
What are sutures?
immobile joints that join all skull bones together, EXCEPT mandible (lower jaw)
What bone is the mandible connected to, and by what joint?
mandible articulates with temporal bone to form temporomandibular joint (mobile)
What is the cranium?
skull without mandible
Anterior View of Skull
What are the 5 bone cavities?
2 orbital cavities
2 nasal cavities
1 oral cavity
Anterior View of Skull
What are the orbital cavities?
four-sided pyramidal space, with apex pointing posteriorly
Anterior View of Skull
What are the 3 major openings in an orbital cavity, and what are they for?
- superior orbital fissure
- inferior orbital fissure
- optic canal
serves as passages for blood vessels and nerves
Anterior View of Skull
What is the nasolacrimal duct?
bony channel that connects medial corner of orbital cavity to nasal cavity
Anterior View of Skull
What are the 2 nasal cavities separated by?
vertical bony septum
Anterior View of Skull
What are the 3 curved bony plates on the lateral wall of each nasal cavity?
- superior nasal conchae (part of ethmoid bone)
- middle nasal conchae (part of ethmoid bone)
- inferior nasal conchae (individual bone)
Anterior View of Skull
What is the anterior nasal aperture?
anterior opening of each nasal cavity
Anterior View of Skull
What is the choana?
posterior opening of each nasal cavity
Anterior View of Skull
What are the main bones that can be seen in this view?
frontal bone nasal bones zygomatic bones maxillae mandible
Lateral View of Skull
What are the main bones that can be seen in this view?
parietal bone frontal bone occipital bone temporal bone zygomatic bone lacrimal bone (within orbital cavity) maxilla mandible
Lateral View of Skull
What are 3 main parts of the temporal bone?
external acoustic (auditory) meatus
mastoid process
styloid process
Lateral View of Skull
What is the zygomatic arch formed by?
processes of zygomatic and temporal bones
Lateral View of Skull
What are the 2 processes on the mandibular ramus?
coronoid process
condylar process
Posterior View of Skull
What are the main bones that form most of the posterior view?
occipital bone
2 parietal bones
Posterior View of Skull
What is the lambdoid suture?
suture between parietal bones and occipital bone
Posterior View of Skull
What is the external occipital protuberance?
bony projection on occipital bone, indicating the border between head and neck
Superior View of Skull
What are the main bones that form most of the superior view?
frontal bone
parietal bone
occipital bone
Superior View of Skull
What is the calvaria (vault)?
dome-shaped roof of skull, formed by frontal, parietal, and occipital bones
Superior View of Skull
What is the coronal suture?
between frontal bone and parietal bones
Superior View of Skull
What is the sagittal suture?
between left and right parietal bones
Superior View of Skull
What is the bregma?
junction of coronal and sagittal sutures
Superior View of Skull
What is the bregma called in infants?
anterior fontanelle
Superior View of Skull
What is the lambda?
intersection of sagittal and lambdoid sutures
Superior View of Skull
What is the lambda called in infants?
posterior fontanelle
Superior View of Skull
What is a fontanelle?
membrane of connective tissue that allows skull to grow proportionately
required for brain growth
Base of the Skull - Exterior View
Name the main bones from anterior to posterior.
maxillae, palatine bones, vomer, sphenoid bone, temporal bones, occipital bone
Base of the Skull - Exterior View
What are the main bony features?
- hard palate
- pterygoid processes of sphenoid bone
- choanae
- styloid and mastoid processes of temporal bones
- occipital condyles
Base of the Skull - Exterior View
What is the hard palate formed by?
maxillae and palatine bones
Base of the Skull - Exterior View
What are choanae?
What are they separated by?
posterior nasal openings, separated by vomer bone
Base of the Skull - Exterior View
What are occipital condyles for?
articulation with:
- vertebrae CI
- foramen magnum of occipital bone
Base of the Skull - Internal View
Divided into three fossae called…
anterior cranial fossa
middle cranial fossa
posterior cranial fossa
Base of the Skull - Internal View
What is the anterior cranial fossa formed by?
- frontal bone (orbital plate)
- ethmoid bone (crista galli and cribriform plate)
- sphenoid bone (lesser bones)
Base of the Skull - Internal View
What is the middle cranial fossa formed by?
- sphenoid bone (greater wings and body)
- temporal bone (petrous and squamous parts)
Base of the Skull - Internal View
What is the hypophyseal fossa?
boney landmark in anterior cranial fossa that houses pituitary gland
Base of the Skull - Internal View
What is the posterior cranial fossa formed by?
- occipital bone (squamous and basilar parts)
- temporal bone (petrous part)
Base of the Skull - Internal View
What forms the boundary between anterior and middle cranial fossae?
posterior border of lesser wings of sphenoid bone
Base of the Skull - Internal View
What forms border between middle and posterior cranial fossae?
superior border of petrous part of temporal bone
Anterior Cranial Fossa Openings
What structures pass through openings on cribriform plate?
olfactory nerve (CN I)
CN = cranial nerve
Anterior Cranial Fossa Openings
What structures pass through optic canal?
optic nerve (CN II)
Middle Cranial Fossa Openings
What structures pass through superior orbital fissure?
- oculomotor nerve (CN III)
- trochlear nerve (CN IV)
- ophthalmic division (VI) of trigeminal nerve (CN V)
- abducens nerve (CN VI)
Middle Cranial Fossa Openings
What structures pass through foramen rotundum?
maxillary division (V2) of trigeminal nerve (CN V)
Middle Cranial Fossa Openings
What structures pass through foramen ovale?
mandibular division (V3) of trigeminal nerve (CN V)
Middle Cranial Fossa Openings
What structures pass through foramen spinosum?
middle meningeal artery
Middle Cranial Fossa Openings
What structures pass through lacrum?
(filled with cartilage)
Middle Cranial Fossa Openings
What structures pass through carotid canal?
internal carotid artery
Posterior Cranial Fossa Openings
What structures pass through internal auditory (acoustic) meatus?
- facial nerve (CN VII)
- vestibulocochlear nerve (CN VIII)
Posterior Cranial Fossa Openings
What structures pass through jugular foramen?
- glossopharyngeal nerve (CN IX)
- vagus nerve (CN X)
- accessory nerve (CN XI)
Posterior Cranial Fossa Openings
What structures pass through foramen magnum?
- medulla oblongata
- vertebral arteries
Posterior Cranial Fossa Openings
What structures pass through hypoglossal canal?
hypoglossal nerve (CN XII)
What is the vertebral column?
forms axis of skeleton, starts from base of skull and rests on the pelvis
How many bones is the vertebral column composed of?
- 24 pieces of irregular bones (vertebrae)
- sacrum
- coccyx
join together to form flexible, rigid column for bearing and transferring body weight
What are the functions of the vertebral column?
- protects spinal cord
- provides passage for spinal nerves