Lecture 4: Axial Skeleton Flashcards
What are the functions of the Axial Skeleton?
- Supportive and protective framework for internal organs
- Skull houses special sensory organs
- Vertebral column and ribs provide extensive attachment for muscles moving the head neck, trunk and limbs
- Thoracic cage performs movement for respiration
What are the 3 bones in the ear?
- Malleus
- Incus
- Stapes
What are the only bones fully formed at birth?
The bones of the middle ear
Where does the Hyoid bone sit?
Under the mandible
What is interesting about the Hyoid bone?
It only articulates with muscles and ligaments
What does the Nasal Concha do?
Warms the air as you breath
What is a Fossa?
A depression in bone
What does the Ramus of the Mandible articulate with?
The temporal mandibular bone
What are the parts of the Mandible?
- Body
- Ramus
- Coronoid process
- Mandibular condyle
What are the bones of the Neurocranium?
- Occipital
- Temporal
- Parietal
- Sphenoid
- Ethmoid
- Frontal
What are the bones of the Viscerocranium/face
‘
- Mandible
- Maxilla
- Zygomatic
- Palatine
- Vomer
- Nasal
- Lacrimal
- Inferior Nasal Concha
What are the 4 cavities of the skull?
- Cranial cavity
- Orbit
- Nasal cavity
- Oral cavity
What is housed in the Cranial Cavity?
The brain
What are the two divisions of the Skull?
- Neurocranium/cranium
* Viscerocranium/face
Which bones are part of the Neurocranium/Cranium?
- Occipital
- Temporal
- Parietal
- Sphenoid
- Ethmoid
- Frontal
Which bones are parts of the Viscerocranium/face?
- Mandible
- Maxilla
- Zygomatic
- Palatine
- Vomer
- Nasal
- Lacrimal
- Inferior nasal concha
How did the bones of the skull develop?
Intramembranous ossification
What is housed in the Oral cavity?
Tongue
What are the 4 Paranasal Sinuses?
Frontal Sinus
Ethmoid air cells
Sphenoidal sinus
Maxillary sinus
What are the 4 Paranasal sinuses lined with?
Mucus
What is the Fontanelle?
The spot where two sutures join on the skull to form the babies soft spot
What are the names of the Fontanelles?
- Anterior
- Posterior
- Sphenoid
- Mastoid
How many bones are in the Vertebral column?
26 bones
What are the 5 divisions of the Vertebrae?
- Cervical
- Thoracic
- Lumbar
- Sacral
- Coccygeal
How many Cervical vertebrae are there?
7
How many Thoracic vertebrae are there?
12
How many Lumbar vertebrae are there?
5
How many Sacral vertebrae are there?
5 fused to make 1 sacrum
How many Coccygeal vertebrae are there?
3-5 fused to make one coccyx
Which curves of the spinal cord change direction after birth?
Cervical and Lumbar
What is the function of the Articular process of the Vertebrae?
It articulates with the vertebrae on top and below
What is the function of the Vertebral Foramen?
It is where the spinal cord goes through
What is the Intervertebral joint?
The intervertebral disc attached between two adjacent vertebrae (secondary cartilaginous joint)
What kind of cartilage is the intervertebral joint made of?
Fibrocatilage
What kind of joint is the Zygapophyseal joint?
A synovial joint
What is the Zygapophyseal joint?
A joint between two adjacent articular processes (synovial joint) superior and inferior articular processes
What does the Vertebral Canal house?
The spinal cord and meninges
Where do the spinal nerves exit the spinal cord?
the Intervertebral foramen
What occurs in Herniation?
A herniated intervertebral disc compresses a spinal nerve
What is the outer part of the intervertebral disc?
Annulus fibrosus
What is the innter part of the intervertebral disc?
Nucleus pulposus, more watery and contain more ground substance
What is the size of the Vertebral cana in the Cervical vertebrae?
It is very large because at that point the spinal cord is very large
What does the Transverse Foramen allow for?
Allows for the passage of vertebral artery going up to supply the brain
Why do Cervical vertebrae have holes?
To allow for arteries to pass to be able to feed the brain
What is different about the Spinous process of Cervical Vertebrae?
They are bifid (split in two)
What does having a Bifid spinous process allow for?
The movement of the neck
What is the exception to the Bifid spinous process of Cervical vertebrae?
C7 has a single long prominent spinous process
Why does C7 have a single spinous process?
It serves as a transition to the thorax
What are the names of the first 2 Cervical vertebrae?
- Atlas (C1)
* Axis (C2)
What does C1 (Atlas) articulate with?
The condyle
What is C1 lacking?
It lacks a body
What does C2 have extra of?
It has a body and an extra process called a dens
What is the Dens?
The extra process that C2 has
What joint is at the Atlas?
A synovial joint
What movement of the next does the Atlas allow?
Flexion of the neck to move yes or no
What is the Joint that the Atlas has?
The Atlanto Occipital joint
Describe the Atlanto-Occipital joint
A synovial joint between occipital condyles and C1 which allows flexion of the neck (up and down)
What movement does the Atlanto-Occipital joint allow for?
Allows flexion of the neck (up and down)
What is the joint between C1 and C2 known as?
The Atlanto-axial joint
What is the Atlanto-Axial joint?
A synovial joint between C1 and C2 that allows the head to turn side to side
What movement does the Atlanto-Axial joint allow for?
Movement of the head side to side
What are all the cervical joints after C1 and C2 known as?
Zygapophyseal joints
Describe Zygapophyseal joints?
They are Synovial joints sloped from anterior ro posterior
What are the joints between vertebrae called?
Zygapophyseal joints
What kind of Movement do Zygapophyseal joints allow for?
Lateral flexion
How many Thoracic vertebrae are there?
12 Thoracic vertebrae
What is each thoracic vertebrae associated with?
A rib
Which vertebrae are associated with ribs?
Thoracic vertebrae
Why do Thoracic vertebrae need two joints?
One is associated with the ribs and one is associated with the next vertebrae
What are the two joints that Thoracic vertebrae have?
- Costovertebral joints
* Zygapophyseal joints
What is the size of the Vertebral foramen in Thoracic vertebrae?
They have a smaller foramen for lesser amounts of spinal cord
Describe the spinous process of Thoracic vertebrae?
It is NOT bifid it is just a singular process
What is the slope Thoracic Vertebrae?
They slope down
Why do Thoracic Vertebrae slope down?
To limit movement
Describe the joints of the Thoracic Vertebrae?
They are vertical (straight up) to allow for rotation of the Thorax
What are Costovertebral joints?
Two synovial joints between thoracic vertebra and associated rib
What do Costal Facets allow for?
They allow the rib to move during respiration by changing thoracic cage volume
What are the thoracic Zygapophyseal joints?
The joints between the Thoracic vertebrae that allow for some rotation of the thorax
What type of joints are Costovertebral joints?
Synovial joints
What are the three bones that make up the Sternum?
- Manubrium
- Body
- Xiphoid process
What makes of the Thoracic cage?
- Sternum
- Ribs and Costal Cartilage
- Thoracic vertebrae
What is the Xiphoid process?
The very end of the sternum
How many ribs are there?
24 ribs
What is the most common cartilage found in the body?
Hyaline cartilage
What kind of cartilage is the Costal cartilage made of?
Hyaline cartilage
What do the first 7 ribs attach to?
The Sternum
What are the first 7 ribs known as?
True ribs
What are true ribs?
Ribs 1-7 that attach to the sternum
What are true ribs?
Ribs 1-7 that attach to the sternum
What forms the Costal margin?
Where ribs 8-10 merge
What are the False ribs?
Ribs 8, 9 and 10
What do ribs 11-12 attach to?
Only to the thoracic vertebrae they have no cartilage
What does the Head of the rib articulate with?
Thoracic vertebrae
Where does the Tubercle of the rib attach to?
The facet of the transverse process
What is in the Costal groove?
•Nerve
•Artery
•Vein
That run under the rib from the intervertebral foramen
Why is the Lumbar vertebrae body so large?
Because it supports a lot of the body weight
Why do lumbar vertebrae have large processes?
For strong muscles
What is the shape of Lumbar Facets?
They are pretty much curved
What do the curved facets of lumbar vertebrae cause?
Very little rotation
How many vertebrae did the sacrum have before fusing together?
5
What is the Sacral Promontory?
The stage where the 5th lumbar vertebrae articulates with the Sacrum
What is the Auricular surface?
The part of the Sacrum that articulates with the Pelvis
