Day 34 (Transition zones) Flashcards
What is/are the characteristic(s) of occipitalization of C1?
the atlas may be partially or completely 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?
during the 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 appears 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 centrum of C2 which is still evident beyond 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 condrocranium such that the cartilage deforms due to 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?
from one-half to 2 and one-half percent of the population
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, upward, and lateral; the inferior articular facet is unchanged
What percent 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, upward, and medial to flat, back, upward, and lateral; the inferior articular facet is unchanged
What is the gender bias associated with dorsalization of L1?
males are two to three times 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
