Chapter 7 Axial skeleton Flashcards
How many bones of the axial skeleton are?
Skeletal system: 206
1) axial skeleton: 80
2) appendicular skeleton: 126
The categories of the axial skeleton
1) skull and associated bones: 29
a) skull
cranium: 8/ face: 14
b) associated bones
auditory ossicles: 6/ hyoid: 1
2) thoracic cage: 25
a) sternum: 1
b) ribs: 24
3) vertebral column: 26
a) vertebrae: 24
b) sacrum: 1
c) coccyx: 1
what are skull and associated bones?
1) skull and associated bones: 29
a) skull
- cranium: 8
- face: 14
b) associated bones
- auditory ossicles: 6
- hyoid: 1
what is a thoracic cage?
2) thoracic cage: 25
a) sternum: 1
b) ribs: 24
*you can observe costal cartilages (cartilages of ribs)
what is a vertebral column?
3) vertebral column: 26
a) vertebrae: 24
b) sacrum: 1
c) coccyx: 1
*you can observe intervertebral discs (cartilages)
List the facial bones (8)
- maxillae: 2
- palatine bones: 2
- nasal bones: 2
- inferior nasal conchae: 2
- zygomatic bones: 2
- Lacrimal bones: 2
- vomer: 1
- mandible: 1
total= 14
List the cranium bones
- occipital bones: 1
- parietal bones: 2
- frontal bone: 1
- temporal bones: 2
- sphenoid: 1
- ethmoid: 1
total= 8
What do the associated bones contain?
1) Hyoid bone: 1
2) auditory ossicles enclosed in temporal bones: 6
total= 7
Make sure that you know the exact locations of those bones!
List 6 cranial bones and identify which have two
- frontal bone
- parietal bone = 2
- occipital bone
- temporal bone = 2
- sphenoid
- ethmoid
Name 3 sutures of the skull
sutures: fibrous joints that are unique to the skull.
- immovable and completely fuse around the age of 20.
1) coronal suture: runs from ear to ear, fusing the frontal bone to the parietal bones
2) sagittal suture: runs along the tops of the skull, fusing the two parietal bones together
3) squamosal suture: fuses the squamous part of the temporal bone to the parietal bones
6 process of the skull:
- the zygomatic process of temporal bones
- the temporal process of zygomatic bones
- Alveolar process: joints between the teeth
- condylar process (part of temporo-mandibular joints)
- mastoid process: a bony projection on the temporal bone located behind your ears on each side of your skull
- styloid process: a bony projection on the temporal bone that helps move the tongue, larynx, pharynx, mandible and hyoid bone
Where does sound enter?
External acoustic meatus
: a tube that carries sound waves from the outer ear to the eardrum
(the ear canal)
The bones of chin
Mandible
- mental protuberance: the front part
- mandibular angle: the triangular region where the lower back of the mandible curves upwards
The bones of the nasal complex: What is ethmoid sinus?
ethmoidal air cells in the ethmoid bone
- a hollow space in the bones around the nose
- cribriform plate in the ethmoid bone, which houses olfactory nerves for smelling
- shaped like butterflies
(related to the respiratory (nasal cavity))
The bones of the nasal complex: What is vomer
: the small, thin bone separating the left and right nasal cavities in humans and most vertebrates
(in the middle of nose)
what are the cranial vault and base of the cranial cavity?
cranial vault + the cranial base = neurocranium
cranial vault: the space in the skull within the neurocranium, occupied by the brain
(including frontal, parietal, occipital, and temporal bones and the greater wings of the sphenoid bone)
the cranial base:
1) posterial cranial fossa
2) middle cranial fossa
3) anterior cranial fossa
Can you see the frontal sinuses inside the frontal bone?
yes, but you can feel them by pressing upward just under your eyebrows
The frontal sinuses are located in the frontal bone, which is in the forehead, above the eyebrows and eye sockets.
Can you see the sphenoidal sinuses inside the frontal bone?
no, they are located behind the eyes and deeper into the skull, while the frontal sinuses are located above the eyes and in the forehead
What is the hyoid bone?
supports your tongue and plays a key role in speaking and swallowing
- the styloid process is connected to the hyoid bone
3 parts of the hyoid:
- greater horn
- lesser horn
- body
What is fontanelle?
a space between the bones of the skull in an infant or fetus, where ossification is not complete, and the sutures are not fully formed.
List 4 fontanelles:
1) sphenoid fontanelle
2) anterior fontanelle
3) posterior fontanelle
4) mastoid fontanelle
: close to the lower jaw associated w/ mastication or chewing
the anterior fontanelle
In picture…
the anterior fontanelle(“soft spot”) and associated sutures in the skull of an infant (sagittal/ coronal/ frontal sutures)»_space; typically after the age of 9 = adult head
how does occipital (posterior) fontanelle work?
In picture…
the occipital fontanelle and associated sutures in a posterior view of the skull of an infant (sagittal suture/ lambdoid suture)
How many bones in the vertebral column (spine)
consists of 26 bones (24 vertebrae, the sacrum, and the coccyx); designated to support the upper body and protect the spinal cord
5 regions of vertebrae
1) cervical region (curvature) (C1-C7) = 7 am
- atlas/ axis
2) thoracic region (curvature) (T1-T12) = 12 noon
3) lumbar region (curvature) (L1-L5) = 5 pm
4) sacrum (5 fused bones)
5) coccyx (4 fused bones)
The factors of the vertebrae
each region forms a curvature that allows flexibility & maximal weight-bearing
- to support the weight of your body
What is intervertebral discs?
vertebrae articulate with one another on their superior and inferior surfaces with a unique cartilage joint called an intervertebral discs
the distinguishable part of thoracic vertebrae
1) transverse process (side)
2) intervertebral foramen (fused to body)
3) spinous process (you can feel it on your spine)
also can see.
- a facet of superior articular process between the vertebrae
- an intervertebral disc
The term of vertebra
the general structure of each vertebra is conserved throughout the column. However, each region is specialized for specific functions
if you can imagine an animal through the shape = a superior view
What is vertebral foramen
where spinal cord is going in
= you can observe it through the superior view
what is transverse process
serve as muscle attachment sites.
the muscles will…
- maintain posture
- induce rotation and lateral flexion of single vertebrae and the spine as a whole
what is the spinous process
a bony projection that extends from the back of each vertebra in the spine, where it attaches to back muscles and ligaments
what is the superior/ inferior articular process
the superior and inferior articular processes of cervical vertebrae have fused on either or both sides to form articular pillars, columns of bone that project laterally from the junction of the pedicle and lamina
the structure of the cervical vertebra
C1 (atlas)
- groove for vertebral artery and first cervical nerve
C2 (axis)
- dens of the axis (odontoid process)
C7 (vertebra prominens)
- a bit thicker than the previous Cs
The first two cervical vertebrae
- atlas
- anterior arch of atlas
- ligament that enables rotation (as in shaking the head to indicate “no”)
- posterior arch of atlas
- joint that permits nodding (as in indicating “yes”) - axis
- dens (odontoid process)
what is atlas
: is specialized to articulate superiorly with the occipital condyles of the skull and permit nodding of the head
- anterior arch of atlas
- ligament that enables rotation (as in shaking the head to indicate “no”)
- posterior arch of atlas
- joint that permits nodding (as in indicating “yes”)
what is the axis
: acts as a pivot (central point) for the rotation of the atlas
- dens (odontoid process)
how do you distinguish which vertebral region?
- cervical
- transverse foramen (transverse process)
- bifurcated spinous process - thoracic: look-alike with giraffe
- articulating with ribs
- the body is smaller than the lumbar
- the spinous process of vertebra - lumbar: look-alike with moose
- the body is much larger
- the surrounding of the spinous process looks like a crown = 더 화려함
How herniated or slipped disc happens?
: occurs when the disc bulges abnormally or breaks apart as a result of injury, normal wear & tear, or disease
With 2 components:
- nucleus pulposus
- annulus fibrosus
(intervertebral disc - fibrocartilage)
causes…
- pain, numbness, weakness if pressed on nerve roots
- called sciatica if in the lower back; causes pain down the buttock & leg
treatment…
: rest/ ice and then light exercise
How many curves the vertebral column has?
the vertebral column has four (4) curves:
1) cervical
2) thoracic
3) lumbar
4) sacral
what are the primary curves?
the thoracic and the sacral curves - they present at birth
what are the secondary curves?
the lumbar and cervical curves
- they develop within the first few years of life
- is achieved by changes in the intervertebral discs rather than through changes in the vertebrae
what happens to the vertebrae during aging?
intervertebral discs tend to lose water, become…
- thinner/ less elastic
this can cause…
- the secondary curves to diminish, leading to postural abnormalities such as kyphosis (increased thoracic curvature)
» this is worsened by other factors such as osteoporosis
what is lordosis
: an exaggerated lumbar curvature
- temporary lordosis associated with a large/ heavy “front load”
» If you are pregnant/ if you have quite a larger beer belly, that can cause “lordosis”
