Back Osteology Flashcards
The axis (C2) is susceptible to fracture in two places. What are these two spots?
The odontoid process (dens) and vertebral arch
What is a Hangman’s fracture?
Fracture of the vertebral arch or odontoid process of the axis (C2)
A hangman’s fracture of the vertebral arch occurs as a result of what?
Hyperextension of the head on the neck
A hangman’s fracture of the odontoid process occurs after what?
A horizontal blow to the head and since the transverse L is stronger than the odontoid process it breaks
What is a type I odontoid fracture?
If the tip of the odontoid process is fractured
What is a type II odontoid fracture?
The entire dens is broken off
What is a type III odontoid fracture?
Dens + part of the vertebral body is broken off
When will an odontoid fracture not heal?
If the odontoid process breaks at its base because the transverse L is holding it away from its blood supply
When is the odontoid process much more likely to heal after fracture?
If the odontoid process breaks at the inferior to the base
What is a Jefferson or burst fracture?
Fracture of both arches of the atlas due to a blow to the top of the head from a falling object or driving accident
Does a Jefferson fracture injure the spinal cord?
Not typically however if the transverse L is ruptured to odontoid process may injure the spinal cord
Explain why it takes less force to dislocate cervical vertebra?
Since the articulating facets are most horizontal compared to other vertebra it takes less force to dislocate cervical vertebra
However due to the large vertebral foramen this doesnt usually result in injury to the spinal cord
What is spina bifida occulta?
A bony defect that occurs in 24% of the population
A developmental abnormality in which the vertebral lamina fails to fuse and close off the vertebral canal
Where does spina bifida occulta commonly occur?
At L5 and S1 where it can go undetected due to the overlying skin
Often a tuft of hair exists over the defect
What is spina bifida cystica?
A form of spina bifida that also incorporates neural tissue and meninges
What is spondylosis?
A degenerative joint disease which involves calcification of the edges of the vertebral body and can cause localized pain and stiffness
What is spondylolysis?
Separation of the vertebral arch from the vertebral body
What is spondylolisthesis?
Anterior displacement of the vertebral body on the inferior vertebral segment
What can occur secondary to spondylolysis?
Spondylolisthesis
What is lumbar spinal stenosis?
Narrowing of the lumbar vertebral foramen
May cause compression of one or more spinal nerve roots
What happens when lumbar spine stenosis is further compounded with intervertebral disc bulging?
Arthritic proliferation and ligamentous degeneration of the vertebral canal is considerably more compromised
What is a lumbar puncture (spinal tap)?
An important diagnostic procedure for evaluating a variety of CNS disorders
Describe how a lumbar puncture is performed
A needle is inserted between either L3/4 or L4/5 at the level of the iliac crests
As the needle passes through the ligamentum flavum it “pops” and passes into the lumbar cistern deep into the spinal dura and arachnoid mater
CSF can then be drawn out and evaluated for CNS disorders
Why is a lumbar puncture typically done at the levels of L3/4 or L4/5?
To avoid the needle injuring the spinal cord
What is sacrilization of L5 (hemisacrilization)?
The partial or complete incorporation of the L5 vertebral segment into the sacrum
What is lumbarization of S1?
The separation of the S1 vertebra from the sacrum
What is coccygeal trauma?
May occur due to low falls on the lower back or difficult child birth
Results in bruising, dislocation or fracture of the coccyx
Coccygodynia (pain) can follow trauma
Painful and difficult to treat
What are the primary curvatures of the vertebral column?
The thoracic and sacral kyphoses
What are the secondary curvatures of the vertebral column?
The cervical and lumbar lordoses as they result from extension from the fetal position
What is an exaggerated kyphosis?
Exaggerated curving of the thoracic vertebral column resulting in hump back
What is an exaggerated lordosis?
Refers to exaggerated curving of the lumbar vertebral column resulting in sway back
What is scoliosis?
Refers to lateral curving of the spine either to the right or left
What are features of a typical vertebra?
Lamina, spinous process, transverse process, vertebral arch, vertebral foramen, vertebral body, pedicle, vertebral notch and articulating processes
What are some unique features of cervical vertebra?
Bifed spinous process, large triangular vertebral foramen, anterior and posterior tubercles on transverse processes, uncinate processes, transverse foramen and costotransverse bar
What are some unique features of thoracic vertebra?
Small round vertebral foramen, well pronounced lamina, heart shaped vertebral body, superior, transverse and inferior costal facets, and strongly inferiorly directed spinous process
What are some unique features of lumbar vertebra?
Large oval shaped vertebral foramen, long slender transverse process, large kidney shaped vertebral body, mammillary process, accessory process and short sturdy hatchet shaped spinous process