9/8 Questions Exam 2 Flashcards
What is the number of coccygeal somites?
10
What is the typical number of segments that unite to form the adult coccyx?
4 segments
When is ossification of coccyx completed?
about age 30
What is the direction of fusion of coccygeal segments?
from caudal to cranial, the last segments to fuse together are Co1 and Co2
What is the direction of the coccygeal curve?
posterior (kyphotic)
What is the major motion and range of motion for coccyx?
flexion - extension, 5-20 degrees
How many coccygeal nerves are present in the fetus?
typically 5 pairs of coccygeal nerves are present
How many coccygeal nerves are present in the adult?
typically only one pair of coccygeal nerves remain in the adult
What forms the coccygeal nerve plexus?
S4, S5, Co1 nerves
What is the ganglion impar?
a midline sympathetic ganglion
What is the coccygeal glomus or coccygeal body?
an enlarged encapsulated arteriovenous anastomosis located near the last segment of coccyx
What innervates the coccygeal glomus or coccygeal body?
both sympathetic and parasympathetic fibers are identified
What muscles attach to the coccyx?
ischiococcygeus and levator ani
Superior articular facets of which vertebrae will be oriented backward, upward, and medial?
C1, C3-C7, L1-L5, S1
Superior articular facets of which segments will be oriented backward, upward, lateral?
C2, T1-T12
