PNA 3 Flashcards
What is the basilar impression?
describes the condition of a relative cephalad position of the cervical vertebrae in relation to base of skull (vertebrae is positioned higher than normal)
What is occipitalzation of the atlas?
= fusion of atlas with occiput
Where are the sites of fusion in a complete fusion?
fusion of anterior + posterior arches with occiput & bilateral atlanto-occipital joint fusion
How is an incomplete fusion called and where does it occur?
= hemi-occipitalization
fusion of anterior OR posterior arch with occiput & fusion or asymmetry of C0-C1 articulations
What is agenesis of the atlas posterior arch?
lack of ossification of posterior arch of the atlas
What is the characteristic triad of a complete agenesis?
absence of atlas posterior arch, union of posterior tubercle to axis SP, (compensatory) enlargement and sclerosis of anterior arch
What can C1-C2 accessory joints result in?
limited flexion and extension, suboccipital pain
What is spina bifida occulta of atlas?
failure in midline ossfication of C1 neural arch
What is spondyloschisus?
non-union of the posterior arches of the atlas
What are ponticles of the atlas?
calcification of oblique portion of atlanto-occipital membrane
What does the atlanto-occipital membrane bridge?
posterior lateral mass and posterior arch
What is ossiculum terminale of Bergmann?
a single ossicle that lies adjacent to the tip of the odontoid process
What is os odontoideum?
non-union of the dens with axis body
What is a hypoplastic odontoid process?
the odontoid process is an abbreviated remnant stump
What indicates instability in the case of an hypoplastic odontoid process?
a lateral shift of atlas on axis
What is an agenetic odontoid process?
complete lack of an osseous odontoid process; no stump
When can instability be observed in the case of an agenetic odontoid process?
on flexion and extension; since the odontoid process is missing, atlas can translate significantly
Whats a block vertebrae?
failure of normal spinal segmentation which results in fusion of one ore more vertebral segments
What is arthrodesis?
surgically fused vertebrae
What is synostosis?
congenital fusion of vertebrae
What is Sprengel’s deformity?
shoulder fails to descend properly from neck to final position
What other conditions is Sprengel’s deformity usually associated with?
Klippel-Feil syndrome, congenital scoliosis, fused rubs, omovertebral bone (extra bone between scapula and cervical vertebra) and spina bifida
What is Klippel-Feil Syndrome?
congenital fusions of more than one segment
What else does it go along with?
short, webbed neck
low hairline
Sprengel’s deformity
reduced cervical ROM
What is cervical spondylolisthesis?
anterior or posterior translation of the vertebral body
What is it the result of?
congenital or traumatic separation between vertebral body and posterior neural arch
What is a cervical rib?
a bony process that originates from C7 and form articulations with TP and vertebral body
What is a nuchal bone?
ossification of the ligamentum nuchae
What is a butterfly vertebrae?
failure of regression of chorda dorsalis or failure of lateral ossification centers of vertebral bodies to unite
What is a hemivertebrae?
lack of formation of one half of a vertebrae
What does a lateral hemivertebrae result in?
scoliosis
What does a dorsal hemivertebrae result in?
focal angular kyphosis
What is the winking owl sign?
absence of one pedicle
What are Schmorl’s nodes?
when the NP breakes through the vertebral endplate into intraosseous areas
What is a limbus bone?
a triangular bony ossicle. its typically located anterosuperiorly or anteroinferiorly
What does it represent?
anterior herniation of disc material. it’s considered a type of Schmorl’s node
What is an intercalary bone?
small bony ossicle in the anterior vertebral interspace
What does it represent?
calcification of the ALL or outer annular fibers
What is a nuclear impression?
endplate depression or invagination secondary to notochordal remnant
What is agenesis of the lumbar pedicle?
absence of lumbar pedicle, which is a failure of ossification within the neural arch
What is spina bifida vera?
bony defect in posterior arch in more than one segment, with protrusion of spinal cord contents
What is a lumbosacral transitional vertebrae?
lowest lumbar or upper sacral vertebrae has characteristics of both areas
What is sacralization?
L5 has sacral characteristics, resulting in 4 lumbar vertebrae
What is lumbarization?
S1 has lumbar characteristics, resulting in 6 lumbar vertebrae
What is facet tropism?
variations in the plane of zygapophyseal joints of more than 5 degrees
What is a knife-clasp deformity?
elongation of L5 SP, invaginating into a spina bifida occulta
What is a von Luschka’s bifurcated rib?
anterior end of the upper rib is forked
What is a rib foramen?
a foramen in the posterior part of a lower rib develops
What is rib synostosis?
fusion between ribs (can be several segments)
What is a Srb’s anomaly?
partial or complete fusion of first and second ribs
What is pectus axcavatum?
exaggerated anterior concavity of sternum
What is pectus carinatum?
sternum bowed anteriorly and creates a pigeon breast chest
What is straight back syndrome?
similar to pectus excavatum
inferiorly angled ribs, horizontal posterior ribs, depressed sternum, thoracic kyphosis is reduced
What does straight back syndrome cause?
- ejection murmurs (decreases when sitting or inspiring)
- increased incidence of mitral valve prolapse
What is coxa vara & valga?
normal femoral angle between neck and shaft: 120-130
coxa vara: <120
coxa valga: >130
How is coxa vara caused?
by the failure of the medial growth of the physeal plate
