The back; Bones, Ligaments and Muscles Flashcards
How many bones makes up the vertebral column?
33 bones
What is special about the bones in the vertebral column?
The vertebral column consists of a series of irregular bones
What are the different vertebra separated by?
The vertebra are separated from each other by fibrocartilaginous intervertebral disks
What are the 5 regions of vertebra and how many vertebra are in each region?
Cervical Vertebra - x7 Thoracic Vertebra - x12 Lumbar Vertebra - x5 Sacral Vertebra - x5 Cocygeal Vertebra - x1 - 4
Remember; Breakfast at 7, Lunch at 12 and Dinner at 5
Why does the number of vertebra in the Cocygeal region vary?
As the number of vertebra that fuse together varies from one person to another.
Some people all 4 of their Coccygeal vertebra have fused together giving them only 1 bone and in others none have fused giving them 4 bones
What are the 6 primary functions of the vertebral column?
The vertebral column; - Enables upright posture - Supports body weight - Protects and transmits spinal cord and spinal nerves - Supports the skull and allows for its movement - Contributes to the rib cage - Locomotion: Provides attachment for trunk muscles
What are primary curvatures, when are they present and in what regions?
Primary curvatures are;
- Present in-utero where the foetus’ spine is fully curved dorsally (Kyphosis)
- Concave anteriorly (Kyphosis)
- Remains in thoracic and sacral regions after birth
What does Kyphosis mean?
A concave anteriorly
The curved part is pointing dorsally
What does Lordosis mean?
A concave posteriorly
The curved part is pointing anteriorly
What are secondary curvatures, when are they present and in what regions?
Secondary curvatures;
- Are not present in a foetus in-utero
- Are in the cervical and lumbar regions
- Do not develop until an infant lifts their head and stands to walk
What are the 10 main components to any typical vertebra, their functions?
Vertebral body - chunky bit at the front that takes most of the weight from the body/supportive function
Vertebral endplate/Intervertebral surface - part that is taking part in the joint between 2 vertebral bodies, covered in hyaline cartilage (secondary Cartilaginous) it will articulate with an intervertebral disk to form a intervertebral joint
Vertebral arch - Behind vertebral body
Sub parts;
- Pedical, means foot of vertebral arch - articulating / connected to vertebral body
- Lamina, plate or flat area used for ligament and muscle attachment
This vertebral arch encloses a vertebral foramen and when lots of these are stacked together these become continuous and for a vertebral canal in which our spinal cord runs in
Transverse processes - sticky bits out of sides
Spinous process - sticky bit out of back
Superior articular facet and inferior articular facet articulate with one another - vertebrae are a synovial joint and are prone to wear and tear these facet joints, arthritis (osseo and rhemetoid arthritis)
These facet joints are also known as zygapophyseal joints
Inferior veritable notch and superior veritable notch - when 2 stack together form an intervertebral foramen
Draw this diagram
What is bone-bone separated by in the vertebral column?
Bone to bone is separated by a fibrocartilaginous disk (secondary cartilaginous joint between vertebral bodies)
What are articular facets and joints susceptible too?
Articular facets and joint are susceptible to arthritis and back pain
What are the 4 main characteristics of the Cervical Vertebra?
They have Uncinate processes at lateral edges for synovial articulation with vertebra above. They help to deepen the socket between 1 cervical vertebrae and another
Transvers foramen - a whole in the transverse process which contains the vertebral artery and vein , going up through the holes in these vertebrae, being one of the ways to get blood to the brain
Its spinous process is bifid - bifocated at back - Main way to recognise a cervical vertebra
Superior Articular facets are flat, facing superiorly and posteriorly. They are directed postero-laterally.
- Movements can occur here due to the Superior articular facets being flat
What kind of movements can occur in the Cervical region?
Flexion, extension, rotation and lateral flexion
What are the 3 irregular vertebrae found in the cervical region?
C1 (the Atlas), C2 (Axis) and C7
What makes the Atlas/C1 vertebrae irregular?
No vertebral body
Has very big superior articular facets articulate with the occipital condyles (base of skull)
Its inferior articular facets articular with the Axis (C2)
Around back there is a groove behind the articular facets for vertebral artery which will come up and pass around the back of the articular facet to go up into the skull
What kind of joint occurs from the occipital bone in the head to the C1 vertebra and what kind of movement does this allow for?
The Atlanto-occipital joint allows for a little flexion extension in neck
What is unique about the Axis/C2 vertebra, what kind of joint occurs from here and what kind of movement does this allow for?
The Axis/C2 vertebra. has an Odontoid process/Dens which is a tooth-like, sticky up bit at front of C2 vertebra and is used for articulation with the anterior arch of the Atlas
Odontoid process/Dens - allows for rotation of head and neck at the Atlanta-axial joint (making up one of our pivot joints)
Odontoid peg takes the place of the vertebral body of C1, odontoid peg is derived form the vertebral body of C1
It superior articular facets are quite flat to articulate with the inferior facets of the atlas (atlanto-axial joint)
What are the 5 main characteristics of the Thoracic Vertebra?
Has a Heart shaped body and circular vertebral canal
Has a long, downward/inferiorly projected,
spinous process which overlaps 2 vertebrae points
Vertebral Body contains superior and inferior costal demi facets for the articulation with the heads of 2 pairs
of ribs because one rib articulates with half of a facet on the vertebrae above and half of a facet on the vertebra below itself - hence demi facets
Transverse processes has transverse costal facet that articulates with the tubercle of rib - Its transverse processes are very long and stick way out the side
Superior articular facets are flat and point straight backwards/postero-laterally, on a the arc of the circle
- This allows for 1 of the thoracic vertebra to rotate on the articular facets of another
What kind of movement occurs in the Thoracic vertebra and why doesn’t it have any different types of movement?
Main movement in thoracis vertebra is rotation, Due to them being packed very closely together you cannot flex or extend them
What are the 3 atypical vertebrae found in the Thoracic region and what makes them atypical?
T1, T11 and T12 because they have a full articular facet, not a demi articular facet like other thoracic vertebrae because the rib just articulates with 1 vertebrae at the top and bottom
What parts of the Thoracic vertebrae does the ribs articulate with?
Rib articulates with the;
- Demi facet on the body
- Facet on the transverse process (it has a long transverse process with a facet for articulation with the tubercle of its own rib)
What are the 3 main characteristics of the Lumbar Vertebra?
Lumbar vertebrae contain the largest vertebral body compared to the rest of the vertebra
Its Superior Articular Facets are concaved and facing postero-medially, interlocking with
inferior facets so if we stack 1 lumbar vertebrae on top of another this stops rotation, so we only get flexion and extension
Lumber spinous process is short, stumpy and thick quadrangular spinous process
Why should we avoid trying to distinguish lumbar vertebral from their large vertebral bodies when in the Dissection Room?
Between individuals don’t rely on the size of the lumbar vertebra being bigger as it wont coincide (our vertebrae all vary in size but are proportional to our own vertebrae)
I.e - Some people have larger thoracic vertebra than others lumber vertebra
What kind of movement is found in the lumbar vertebra and why?
Flexion and extension as its Superior Articular Facets are concaved and facing postero-medially, interlocking with inferior facets so if we stack 1 lumbar vertebrae on top of another this stops rotation
Extension is greatest movement, flexion and some lateral flexion, but no rotation
What are the 8 main characteristics of the Sacrum Vertebra?
Formed by fusion of 5 vertebrae
On the anterior surface we have the sacral promontory - When you look at the sacrum from above you can see that it sticks out quite a bit and this is the anterior projection of S1
At either side of the sacral promontory we have the Sacral ala (looks like wings)
Median, intermediate, lateral crests: Union of spinous,
articular and transverse processes, respectively
Anterior and Posterior foramen on the front and back of the sacrum and nerves go in and out foramena
On the Anterior foramen we have ventral rami (contains nerves) coming out
On the Posterior foramen we have dorsal rami (contains nerves) coming out
Sacral hiatus is where veritable arch of the of the lower sacral vertebrae hasn’t fused and has left a little gap
Cornu (meaning horn) parts at either side of hiatus
What would you expect to see in a scan of a juveniles sacrum?
In juvenile will see what looks like a fracture, just growing bones - don’t fuse until late teens early 20’s
What potential procedures does the Sacral Hiatus allow us to do?
Can use as a route to enter the vertebral canal - can stick a needle up and sample CSF, especially in juveniles
What is the Cauda equina?
frayed part spinal cord turns into
What hangs from the Sacrum?
The Coccygeal Vertebra
How many bones are in the Coccygeal vertebra?
Between 1-4 vertebrae a there is a great deal of variation in fusion
In a lot of people the lower coccygeal vertebrae never ossify and remain as cartilaginous masses
What are the 2 types of joints found in the vertebral column?
1). Zygapophyseal (facet) joints - synovial joints between articular processes
2). Symphysis or secondary
cartilaginous joint between
endplates and the intervertebral
discs
What is the intervertebral foramen?
Spinal nerves emerge from the intervertebral foramen
The intervertebral foramen a small space formed when the superior vertebral notch of one vertebra aligns with the inferior vertebral notch above of another vertebra with contribution from the intervertebral disc which forms part of the anterior border of the intervertebral foramen
What is the intervertebral disk composed of and what is its function?
Consists of an outer anulus fibrosus, which surrounds a central nucleus
pulposus
Nucleus pulposus;
• Gelatinous layer (made from 70-90% water)
• Absorbs compressive forces between
vertebrae (acts as a shock absorbent)
• Relative collagen content increase with age and dehydration of this mass.
Anulus fibrosus;
• Very strong, concentric lamellae (layed down one layer on top of another) of fibrocartilage
- Attached strongly and is kept in place by anterior and posterior longitudinal ligaments (which attach to the vertebral bodies of the vertebral column).
- It keeps the nucleus pulposus in place
Why do people shrink as they get older?
As you get older the nucleus pulposus will dehydrate causing a loss in mass and increase in collagen content
A great deal of the length of the vertebral column (20-25%) is made up by these intervertebral disks, so when they dehydrate we shrink
At what time of the day are we taller and why?
During day you are taller than you are at night, as you’ve been on your feet all day putting pressure through your intervertebral disks - only by a few cm
What else does the intervertebral contribute to in the spine?
The intervertebral disc also contributes to the shape of spinal curvatures
What happens when force is transmitted through the vertebrae?
The nucleus pulposus is being squeezed like squashing a tennis ball
What are bone and intervertebral discs an example of and what does this mean they require?
Bone and intervertebral disks are living tissues and need a blood supply
How are the different parts of the intervertebral disc supplied with blood?
We have a segmental blood supply to the vertebral bodies. From that segmental supply we get some little arteries that comes through into the periphery of disk, not through the centre of disk.
The annulus fibrosis is supplied by neighbouring capillaries
The nucleus pulposus is nourished by
diffusion from the periphery arteries located in the body of the vertebra
What may happen to the intervertebral discs to allow for movement between the vertebral bodies and what can this lead to?
Discs may deform to allow movement between the vertebral
bodies
This may put pressure on the nucleus pulposus
