The Axial Skeleton Flashcards
What is the axial skeleton
Group of bones which is primarily involved in protecting, supporting and carrying other organs of the body
What does the axial skeleton support and protect
Supports the - head, neck and trunk
Protects - brain, spinal cord and thoracic organs
How many bones are there in the axial skeleton
80
What are the 3 regions of the axial skeleton
- skull
- vertebral column
- bony thorax (ribs) - thoracic cage
What is the skull comprised of
- cranium
- facial bones
What is the cranium
One of the components of the skull
It protects the brain and is the site of attachment for head and neck muscles
What are facial bones
One of the components of the skull
- Supply the framework of the face, the sense organs and the teeth
- provide openings for the passage of air and food
- Anchor the facial muscles of expression
What are the main bones in the skull
- maxilla
- Mandible
- Frontal bone
- Sphenoid bone
- parietal bone
- Temporal bone
What connects the mandible to the skull
temporomandibular joint (TMJ)
What is the temporomandibular joint
- Lies anterior to the ear
- Has a depression and elevation movement as well as a side to side grinding motion
What is the vertebral column
- Spine
Is relatively flexible, curved structure that runs from the skull to the pelvis
What is the function of the vertebral column
- Axial support for the trunk
- At the pelvis it transmits the weight of the trunk to the lower limbs
- Provides attachment points for the muscles of the back and neck
- Surrounds and protects the delicate spinal cord (has to be strong yet flexible)
How many vertebrae/irregular bones are there in the vertebral column
26 irregular bones (vertebrae) connected in such a way that a flexible, curved structure results
What are the 5 major divisions or regions of the vertebral column
- Cervicale vertebrae
- Thoracic vertebrae
- Lumbar vertebrae
- Sacrum
- Coccyx
Can Tigers Leap Swiftly, Super cool
How many bones and where are the cervical vertebrae
7 bones of the neck
How many bones and where are the thoracic vertebrae
12 bones of the torso
How many bones and where are the lumbar vertebrae
5 bones of the lower back
How many bones and where are the sacrum
formed from 5 fused vertebrae which articulates (joins ) with the hip bones of the pelvis
How many bones and where are the Coccyx
4 fused vertebrae
What are the ligaments in the vertebral column
Anterior and posterior longitudinal ligaments
What is the function of the anterior longitudinal ligaments
Is strongly attached to the bony vertebrae and the intervertebral disc
Prevents over extension (hyperextension) of the spine (bending too far back)
What is the function posterior longitudinal ligament
Resists hyperflexion of the spine (bending forward too sharply)
Its attaches only to the intervertebral discs - it is narrow and relatively weak
What is the structure which aids the posterior longitudinal ligament
Ligamentum flavum
What is the function of the ligamentum flavum
Contains elastic connective tissue making it especially strong
Stretches as we bend forward, then recoils when we resume an upright position
What is the intervertebral discs composed of
- Nucleus pulposus
- Annulus fibrosus
What is the nucleus pulposus
inner gelatinous nucleus that gives the disc its elasticity and compressibility like a rubber ball) - acts as a shock absorber
What is it called when the anulus fibrosus ruptures causing the nucleus pulposus to leak out of the intervertebral disc
Hernia
What is the impact of a hernia
The herniated portion of the disc can put pressure on the spinal nerve root resulting in spinal pain
What are the identifying features of the atlas
- no vertebral body
- no spinous process
- has transverse foramen (holes on the side for the vertebral artery)
- no intervertebral disc between atlas and axis
What’s the function of the atlas
carries the skull and has joints which lets you nod “yes”
What are the identifying features of the axis
- dens/ odontoid process (small bone which projects superiorly from the body and is cradled in the anterior arch of the atlas)
- small spinous process and body
what’s the function of the dens
provides pivot for the rotation of the atlas - joint lets you indicate “no”
What characterizes cervical vertebrae
- smaller body (carry east amount of weight)
- larger triangular vertebral foramen (carries most nerves)
- Y shaped spinous process - bifid
- U shaped transverse process
- has the transverse foramen (for vertebral artery and vein)
What characterises thoracic vertebrae
long spinous process which are sharp and projects inferiorly
- 2 partial facets (superior and inferior costal facets) on each side of the body for articulation with the head of its own rib and the head of he rib below
- Facet on each transverse process for articulation with the tubercle of its own rib
- Heart shaped vertebral body
What characterises lumbar vertebrae
short and blunt spinous process which projects directly posteriorly
- Largest vertebral body (carries the most weight)
- short, blunt spinous process
- thin and long transverse processes
- lacks facets for articulation with ribs
What characterizes the sacrum
triangular shaped bone formed by the fusion of 5 sacral vertebrae
What characterizes the coccyx
- its small size
- absence of vertebral arches and vertebral canal
fusion of 4 very small coccygeal vertebrae which articulates with the inferior tip of the sacrum
function of the thoracic cage
to protect the vital organs of the thorax - heart, lungs, major blood vessels
Also supports the shoulders and upper limbs as well as providing attachment point for many muscles of the neck, back, chest and shoulders
What are true ribs which which ones are the true ribs
the superior 7 pair
true ribs are the ribs which directly attach to the sternum via costal cartilage
What are false ribs and which ones are the false ribs
ribs 8-10 (interior 3)
flase ribs are ribs which indirectly attach to the sternum via costal cartilage
What are floating ribs and which ones are the floating ribs
ribs 11-12
Ribs which have no anterior attachment
How do most ribs connect to the vertebral column
connects to 2 facets - one joints with the body of the same numbered thoracic vertebra, whilst the other articulates with the superior vertebra
-articulates the the facet on the transverse process of the vertebra it takes its number from
what are the special characteristics of the first pair of ribs
- flattened (superior to inferior)
- quite broad - support the blood vessels that serve the upper limbs
What’s special about the articulation of ribs 1 and 10, 11,12
they only articulate with one vertebral body
what types of nerves do roots carry
Either sensory or motor (not both)
What type of nerves does the posterior/dorsal root carry
afferent (sensory) nerves
What type of nerves does the anterior/ventral root carry
Efferent (motor) nerves (both automatic and somatic)
What types of nerves do rami carry
both sensory and motor fibers
what are the different types of motor nerves
somatic - controls skeletal muscle
autonomic - controls cardiac muscle, smooth muscle and glands
What are somatic efferent nerves
Motor nerves which controls voluntary movements e.g. skeletal and muscles
What are autonomic efferent nerves
Motor nerves which controls involuntary body process e.g. Cardiac muscle and smooth muscle
e.g. blood flow and body temp
Where do afferent (sensory) nerves come from and terminates
comes from the dorsal root
terminates in the dorsal horn
where do somatic motor nerves start and terminate
comes from the the ventral horn
leaves through the ventral root to the skeletal and muscle
Where do autonomic motor nerves start and go
comes from the lateral horn
terminates at cardiac muscle, smooth muscle and glands
What types of nerves are in the spinal nerve
Both afferent (sensory) and efferent (motor) nerves
what nerve supplies the back muscle
posterior ramus
What muscles and organs does the posterior/dorsal rami supply
Skin and muscles of the back
What muscles and organs does the anterior/ventral rami supply
skin and muscle of the anterior trunk, upper and lower limbs
Where in the vertebral canal does the spinal nerve leave
intervertebral foramen
What comes out of the intervertebral foramen
vertebral artery
where do the C1-C7 nerves exit the vertebral canal
superior to vertebrae
where does the C8 nerve emerge
inferior to C7 vertebra
where do the thoracic, lumbar, sacral and coccygeal nerves emerge from
inferior to vertebrae that they take their name from
What does efferent nerves mean
the nerve fibers responsible for carrying signals from the brain to the peripheral nervous system in order to initiate an action and movement
What does afferent nerves mean
a nerve that passes sensory impulses from receptors toward or to the central nervous system.
What is the intervertebral foramen and what is its function
A gap formed between adjacent vertebral arches.
Its where each spinal nerve exists the vertebral canal laterally
How many cervical nerves are there
8
What is the intercostal space
The space which lies in between adjacent ribs and are filled by intercostal muscles
What is the function of intercostal muscle
They lift and depress the thorax
What is the knob like tubercle which the rib articulates with
facets on the transverse process of thoracic vertebra
