Transition Zones Flashcards
What is/are the characteristic(s) of occipitalization of C1
The atlas may be partially fused to the occiput
What is another way of implying occipitalization of C1
Atlas assimilation
What is the incidence of occipitalization of C1
0.1% to 0.8%
When do the centers of ossification for the odontoid process first appear?
Last trimester in utero
When do the bilateral ossification centers for the odontoid process fuse
At or shortly after birth
What joint is formed between the odontoid process ossification centers and the centrum of C2
The subdental synchondrosis
Ossification between the odontoid process and centrum joint of C2 first appear at what age
4 years old
A joint between the odontoid process and centrum of C2 is last identified at what age
7 years old
What is the name given to the condition in which the joint formed between the odontoid process and centrum of C2 persists beyond age 7
Os odontoideum
What is the name given to the joint between the odontoid process and the centrum of C2 which is still evident beyone age 7
Persistent subdental synchondrosis
What is the name given to the joint formed between the tip of the dens and the odontoid process centers of ossification
Tip of the dens synchondrosis
At what age will the tip of the dens center of ossification appear
Sometime in early adolescence
at what age will the tip of the dens fuse with the odontoid process
Before age 12
if the joint formed between the tip of the dens and odontoid process centers of ossification persists beyond age 12, what is the condition called
Terminal ossicle
What is a basilar impression
persistence of the nonunion of the basilar and condylar parts of the chondrocranium such that the cartilage defoms due to the weight of the brain
What is a basilar invagination
The upper cervical spine appears to be invaginated into the skull on x-ray analysis
What is the incidence of rib-related changes following dorsalization of C7
.5% - 1.5%
Do patients typically present with symptoms specific for dorsalization of C7
no, they are typically asymptomatic
What is the gender bias suggested in dorsalization of C7
Female
What alteration in C7 facet orientation may accompany dorsalization
The superior articular facet of C7 may change from back, upward and medial to that of a typical thoracic facet…. Back, up and lateral; the inferior articular facet is unchanged
What percentatge of the population may demonstrate thoracic-like features at C7
up to 46%
What T1 facet orientation changes may accompany cervicalization
The superior articular facet may change from back, upward and lateral to back upward and medial;
the inferior articular facet is unchanged
What is the incidence of cervicalization of T1 in the population
up to 28% of the population
What is the incidence of lumbar ribs in the population
Over 7% of the population demonstrates lumbar ribs
What L1 facet orientation changes may accompany dorsalization
The superior articular facet may change from concave, back, upaward and medial to flat, back, upward and lateral
Inferior articular facet is unchanged
What is the gender bias associated with dorsalization of L1
Males are two to three time more affected
What T12 facet orientation changes may accompany lumbarization
The superior articular facet may change from flat, back, upward and lateral to concave, back, upward and medial
the inferior articular facet is unchanged
