MSK Flashcards
What is myotonia congenita?
What are its aggravating and relieving factors?
Myotonia = inability to relax muscles at will
- Caused by mutation in chloride channels - can be recessive or dominant
- Leads to muscle stiffness, particularly in legs - may be enhanced by cold and inactivity and often relieved by exercise
What is syndactyly?
Fusion of digits
What is polydactyly?
Extra digits (genetic recessive trait)
What is the name for the complete absence of a limb?
Amelia
What is meromelia?
Partial absence of one or more limb structures e.g. A humerus
What is phocomelia?
A type of meromelia whereby hands and feet are attached directly to trunk
Define malformation
Intrinsic error in coordination of morphogenetic - things don’t form correctly
Define deformation
A formed limb or digit is cut off by constriction bands - strands of amniotic tissue
No genetic abnormality
Define disruption (in context of morphogenesis)
Caused by an external agent e.g. Thalidomide, or viruses such as rubella and herpes
Disrupts AER so stops elongation of the limbs
What are the four stages of disk herniation?
- Disc degeneration = This is chemical changes which occur with aging – causes disc to weaken but without herniation.
- Prolapse = Protrusion of nucleus pulpous with slight impingement of spinal canal.
- Extrusion = Nucleus pulpous breaks through annulus fibrosus but does not leave disc space.
- Sequestration = Nucleus pulpous breaks through annulus fibrosus and lies outside of disc space, in the spinal canal.
What is cervical spondylosis? What does it result in?
Effectively arthritis of the cervical spine
- NARROWER DISCS (age –> loss of water and pressure) - osteophytes form at front and back to bear weight
- Pressure on nerve roots –> RADICULOPATHY
Dermatomal paraesthesia and pain, motor weakness - MYELOPATHY - Pressure on cord (rare)
Leads to global weakness, gait dysfunction, loss of balance, loss of bladder and bowel control
What is a C1 (atlas) fracture called?
What can it be caused by?
What does it result in?
JEFFERSON’S FRACTURE
- Fracture of anterior and posterior arches
- Caused by axial load e.g. Diving into shallow water, impact against roof of vehicle
- Typically caused by pain but no neurological signs - vertebral foramen is so big
- BUT may damage arteries at the base of the skull with secondary neurological consequences e.g. Ataxia (loss of coordination)
What is a fracture of C2 (axis) called?
What causes it?
What can it lead to?
HANGMAN’S FRACTURE
- Fractures through pars interarticularis
- Caused by hyperextension of head or neck
- Unstable fracture –> displacement of C1 and body of C2 on C3 - can transact SPINAL CORD
What causes a fracture of the odontoid process?
What imaging technique would you use to confirm?
FLEXION - blow to the back of the head e.g. Falling back against a wall
HYPEREXTENSION - old person falling forward and hitting chil/forehead (will also see bruising of face)
Would use AP x-ray or MRI
What is whiplash? What can it lead to in serious cases?
Hyperextension followed by hyperflexion
C spine is very mobile so can lead to cord injury
What is neurogenic claudication?
Pain upon walking due to stenosis of foramina where nerve roots exit spine - narrowing around nerve roots
What is spondylolysis?
Why is spondylolysthesis?
Fracture in pars interarticularis
Movement of one vertebra relative to the ones above/below it (caused by spondylolysis)
Describe the anatomical abnormality in the bones in spina bifida occulta.
What is meningocele spina bifida?
Laminae of lower lumbar vertebrae and upper sacral vertebrae fail to fuse completely.
‘Occulta’ because no resulting disability so often never detected
Meningocele: Meninges protrude through cleft in vertebrae.
Spinal fluid often fills these protrusions causing cysts - can often be removed by can still result in some spinal cord damage - weakness to lower limbs, faecal and urinary incontinence
At what level do you do a lumbar puncture? What structures must the needle pass through to reach the subarachnoid space?
L3/4 or L4/5
Skin, subcutaneous fat
Supraspinous ligament, interspinous ligament, ligamentum flavum,
Epidural space, dura, subdural space, and arachnoid.
