Skeleton (Axial) Flashcards
How many bones are in the axial skeleton?
80 bones
What are the 3 major regions of the axial skeleton?
skull
vertebral column
thoracic cage
What are the 2 divisions of the skull?
cranial bones (cranium) facial bones
What is the function of the cranial cavity?
enclose brain in cranial cavity
provides site of attachment for head and neck muscles
cranial vault - calvaria
cranial base - made up of 3 cranial fossae
What is the function of the facial bones?
framework of the face anchor facial muscles sites of attachment for teeth and muscles cavities for special sense organs openings for air and food passage
What are the 3 fossae of the cranium?
anterior cranial fossa
middle cranial fossa
posterior cranial fossa
What are the 8 bones of the skull?
frontal bone parietal bones occipital bone temporal bones sphenoid ethmoid
What is the foramen magnum?
the passage of the spinal cord through the occipital bone
What are the 3 major regions of the temporal bone?
squamous region
- zygomatic profess
- mandibular fossa
petrous region
- mastoid process
- styloid process
tympanic region
- external acoustic meatus
Carotid canal (of the temporal bone)
for the internal carotid artery
smaller holes to the jugular foramen
stylomastoid foramen
for the facial nerve CN VII
near the styloid and mastoid process
internal acoustic meatus
for facial nerve (CN VII) and vestibulocochlear (CN VII) nerves
jugular foramen
larger holes on the side of the foramen magnum
for internal jugular vein and CN IX, X, XI
what is the function of the mastoid air cells?
to lighten the skull
what are the 3 processes on the sphenoid bone?
lesser wings greater wings pterygoid processes - medial pterygoid plates - lateral pterygoid plates
Where is the sella tucica
part of the sphenoid bone
looks like the vertebral column of the sphenoid
contains the hypophyseal fossa
what are the 5 sphenoid bone passageways?
superior orbital fissure (control eye movement)
optic canal (for optic nerve)
foramen rotundum (for trigeminal nerve)
foramen ovale (for trigeminal nerve)
foramen spinosum (for middle meningeal artery)
what are some of the characteristics of the ethmoid bone?
deepest skull bone
contributes to the medial wall of orbits
superior part of nasal septum, roof of nasal cavities, and 2 nasal conchae
Where is the cribriform plate and what is the function?
in the ethmoid bone
for the olfactory foramina
the crista galli is also a part of the cribriform plate - attaching dura mater
what are the characteristics of the mandible?
lower jaw
largest, strongest bone of the face
contains sockets for lower teeth
what 2 bones form the temporomandibular joint?
the mandibular fossa of the temporal bone and the mandibular condyle of the mandible
**only freely moveable skull joint
what are the 2 main points of the mandible?
mandibular condyle - where the jaw connects to the skull
mandibular angle - the jaw line
what are the 2 points of the maxillary bones?
palatine process - the top palette of the mouth (medially fused to form the upper jaw)
maxillary sinus (in the cheeks but closer to the nose)
zygomatic bones
has the zygomatic arch - the cheek bones
nasal bones
forms the bridge of the nose and attaches to nose cartilage
lacrimal bones
form the medial orbital walls
lacrimal fossa houses lacrimal sac
Vomer bone
plow shaped
lower part of nasal septum
palatine bones
L-shaped bones
posterior 1/3 of hard palate
psterolateral walls of nasal cavity
inferior nasal conchae
form parts of lateral walls of nasal cavity
the superior nasal concha and middle nasal concha are part of the ethmoid bone
hyoid bone
**not really a skull bone
does not articulate directly with another bone - anchored by ligaments
acts as a moveable base for tongue and site of attachment for muscles of swallowing and speech
C3 vertebrae
paranasal sinuses function
mucosa-lined, air-filled cavities in skull bones
Functions:
- warm and humidify air
- lighten skull
- enhance vocal response
what are the 4 paranasal sinuses
frontal sinus (frontal bone)
ethmoidal air cells
sphenoidal sinus (posterior to ethmoid)
maxillary sinus (in the cheeks but close to the nose)
what are the 5 major sutures of the cranium?
coronal suture squamous suture pterion sagittal lambdoid
what bones form the coronal suture
frontal and parietal
what bones form the squamous suture
parietal and temporal bones
what bones form the pterion?
frontal
parietal
occipital
temporal
what bones form the sagittal suture?
between the 2 parietal bones (left and right)
what bones form the lambdoid suture?
parietal and occipital
which bones make up the hard pallet?
maxilla and palantine
what bones form the zygomatic arch?
maxilla, zygomatic, temporal
fetal skull main points
- the infant skull has more bones than the adult skull
- fetal skull is connected by 4 fontanels
1. anterior fontanel
2. posterior fontanel
3. mastoid fontanel
4. sphenoidal fontanel
What is the function of the vertebral column?
extends from the skull to pelvis
transmits the weight of trunk to lower limbs
surrounds and protects spinal cord
formed from 26 bones
serves as attachment site for muscles of neck and back
held in place by ligaments
body of the vertebrae
disc shaped, weight bearing region
vertebral arch
composed of both pedicles and laminae
vertebral foramina
make up the vertebral canal for spinal cord
Where are the pedicles vs laminae of the vertebrae?
pedicles are closest to the body
lamina is between the 2 processes
transverse vs spinous processes
transverse - project laterally
spinous - project posteriorly
superior and inferior articular processes (with facets)
protrude superiorly and inferiorly from pedicle-lamina junctions
intervertebral foramina
lateral openings for passage of spinal nerves
what is the nucleus pulposus
inner gelatinous nucleus that gives the disc its elasticity and compressibility (Intervertebral disc)
no IV discs between C1 and C2
what is the annulus fibrosus?
surrounds nucleus pulposus with a collar composed of collagen and fibrocartilage
cervical vs thoracic vs lumbar
cervical - 7 bones
thoracic - 12 bones
lumbar - 5 bones
sacrum vs coccyx
the sacrum is 5 fused vertebrae, whereas the coccyx is 3-5 fused vertebrae (Tail bone)
coccyx is made up of 3-5 fused vertebrae
articulates superiorly with sacrum
serves little function
thoracic cage function
protects vital organs of thoracic cavity
supports shoulder girdle and upper limbs
provides attachment sites for many muscles
what is the thoracic cage composed of
thoracic vertebrae
sternum
ribs and costal cartilages
what is the sternum made up of
manubrium - articulates with clavicles and costal cartilages of ribs 1-2
body - costal cartilages of robs 2-7
xiphoid process: not ossified until age 40
anatomical landmarks of the sternum
jugular notch (top notch of the sternal angle xiphisternal joint (in between the xiphoid process and body)
how many true ribs are there
there are 7 true ribs that attach directly to sternum via costal cartilages
how many false ribs are there?
there are 3 false ribs that attach indirectly to sternum via costal cartilage of rib 7
how many floating ribs are there
there are 2 floating ribs with no anterior attachment
what are the spaces between each rib called?
intercostal spaces
what are the landmarks of a typical true rib?
head articular facets neck tubercle angle costal groove
is the bumpy or smooth/flat end of the rib connect to the vertebrae?
the head of the rib connects to the vertebrae (back) and the flat/smooth end is at the ribs (your ribs are not bumpy but your back is)
what pair of ribs is atypical?
first pair
