The Axial Skeleton - Lecture 6 Flashcards
What is the Axial Skeleton Referring to?
Bones that make up the midline of the body
Name the bones of the Axial Skeleton. Which are anterior and which are posterior?
- manubrium (anterior)
- sternum (anterior)
- vertebrae (posterior)
- ribs (both)
- sacrum (posterior)
- coccyx (posterior)
What bones make up the Sternal body?
the manubrium and sternum
How many vertebrae are there? How many regions are they separated into and what are they named?
- 33 vertebrae (sg is vertebra)
- they are separated into 5 regions
- cervical
- thoracic
- lumbar
- sacrum
- coccyx
Where are the Cervical vertebrae on the vertebral coloumn? How many are there?
they are the top 7 vertebrae of the spine with the first cervical vertebrae articulating with the base of the skull and its occipital condyles
Where are the Thoracic vertebrae on the vertebral column? How many are there?
they are the vertebrae that articulate with the ribs and there are 12
Where are the Lumbar vertebrae? How many are there?
they are in the lower back and there is 5 of them
What important thing do the Lumbar vertebrae give to the spine?
the Lumbar vertebrae give the spine its flexibility
Where is the Sacrum? How many vertebrae does it have?
the sacrum is located below the lumbar vertebrae and is made up of 5-7 sacral bodies that fuse together as you age
Where is the Coccyx? What does it indicate about human lineage?
- below the sacrum and the last part of the vertebral column
- it also has small sections of bone that fuse together
- it is the vestigial tail which connects us to our ancestral lineage as primates
What are the main three sections of the vertebrae?
the cervical, thoracic, and lumbar vertebrae
Do each of the different sections of the vertebrae look the same?
no they each have different characteristics that make each section distinguishable from the other
Describe the 1st Cervical Vertebra.
- one of the most distinctive
- called the Atlas because of Greek mythology
- feature that characterize it as a cervical vertebrae are its transverse foramen
- large vertebral foramen (where the spinal column goes
- articulates with the occipital condyles it its superior articular facets
- articulates with the 2nd cervical vertebra’s superior articular facets with its inferior articular facets
- has a neural arch that is posterior which circles around the spine
Describe the 2nd Cervical Vertebra.
- another vertebra that looks distinguishable from the other cervical vertebrae
- called the Axis because the Atlas rotates around the Axis
- the Atlas does have a hollowed out bit that articulates with the Dens which allows you to rotate your head - most distinguishable trait is its Dens (Odontoid Process) that is a pointy bit on the vertebra’s anterior side
- a larger vertebral foramen than the other vertebrae but it is slightly smaller than the vertebral foramen of the Atlas
- has transverse foramen
- has a larger spinous process is a bit that sticks out and is formed when the neural arches meet
Why does the vertebral foramen get smaller in each descending vertebrae?
because the nerves within the spinal column will begin to spread out laterally through the transverse foramen
Describe Cervical Vertebrae 3-7.
- all look pretty much the same
- have a spinous process that can stick out into to halves also called a Bifid
- superior and inferior articular facets
- vertebral foramen (larger than the other vertebral sections and smaller than the atlas and the axis)
- transverse foramen
- clearer definition of the body than in the atlas and axis but are the smallest vertebral bodies out of all of the vertebral regions
What are the hallmarks of the Cervical Vertebrae?
- larger vertebral foramen
- transverse foramen
- small bodies
- can have a bifid spinous process
What animal do the Thoracic Vertebrae look like?
a giraffe
Describe the Thoracic Vertebrae.
- superior articular facets are sticking straight up
- thicker and larger vertebral body and a bit larger than the vertebral foramen
- smaller vertebral foramen
- transverse process (a bit that sticks out) that replaces the transverse foramen
- spinous process is longer and pointing down (overlap with each other)
- the shape of bipedal mammals - rib facets where the vertebrae articulate with the ribs
What are the hallmarks of the Thoracic Vertebrae?
- vertebral bodies getting larger
- longer spinous process pointing down
- transverse process instead of foramen
- smaller vertebral foramen
- rib facets
Describe the Lumbar Vertebrae. (these are all also the hallmarks of the Lumbar Vertebrae)
- superior articular facets are sticking up and curving medially
- inferior articular facets are curving convexly
- larger vertebral body which is also significantly larger than the vertebral foramen
- even smaller vertebral foramen
- spinous process is a lot shorter dorsally and is longer superiorly and inferiorly and is square shaped
- transverse processes that are short and stubby
What animal do the Lumbar Vertebrae look like?
a moose
Explain what the rib facets (or costal facets) are and what they do on the Thoracic Vertebrae.
- there are flat areas on both the left and right transverse processes
- there are half circles (demi-facets) on the right of left side of the body
What Thoracic Vertebrae has a complete rib facet?
the first Thoracic Vertebra because
