Atypical Cervical Vertebrae: C1/Atlas

Question 1

What is the name of the first cervical vertebra?

Answer 1

atlas

Question 2

What features are lacking at C1?

Answer 2

vertebral body, pedicles, a spinous process and the intervertebral disc

Question 3

What osseous modification is observed to the front of the anterior arch of C1?

Answer 3

the anterior tubercle

Question 4

What muscle attaches to the anterior arch of C1?

Answer 4

longus colli

Question 5

What ligaments will attach to the anterior arch of C1?

Answer 5

the anterior longitudinal, anterior atlanto-occipital and anteior atlanto-axial ligaments

Question 6

What is observed on the back of the anterior arch of C1?

Answer 6

the fovea dentis

Question 7

What is the morphology of the superior articular facet of C1?

Answer 7

they are elliptical, closer together in front and often demonstrate an elevation subdividing the facet surface into two separate surfaces

Question 8

What is the orientation of the superior articular facet of C1?

Answer 8

backward, upward, medial (BUM)

Question 9

What is the joint classification of the atlanto-occipital zygapophysis?

Answer 9

synovial (diarthrosis) ellipsoidal joint

Question 10

What are the morphological characteristics of the inferior articular facet of C1?

Answer 10

asymmetrical, slightly concave or flattened

Question 11

What is the orientation of the inferior articular facet of C1?

Answer 11

backward, medial, downward (BMD)

Question 12

What is the name of the rounded elevation on the medial aspect of the lateral mass of C1?

Answer 12

tubercle for the transverse atlantal ligament

Question 13

What muscles attach to the lateral mass of C1?

Answer 13

levator scapula, splenius cervicis and rectus capitis anterior

Question 14

What part of C1 represents the spinous process?

Answer 14

posterior tubercle of the posterior arch

Question 15

What is the distance from the posterior tubercle of the posterior arch to the skin in each gender?

Answer 15

males: about fifty millimeters; females: about thirty-seven millimeters

Question 16

What attaches to the posterior tubercle of the posterior arch of C1?

Answer 16

rectus capitis posterior minor muscle and ligamentum nuchae

Question 17

What superior surface modifications of the posterior arch of C1 are present?

Answer 17

groove/sulcus for the vertebral artery and arcuate rim

Question 18

What are the attachment sites of the posterior atlanto-occipital ligament?

Answer 18

it is attached to the arcuate rim of the posterior arch of atlas, to the superior articular process of the lateral mass of atlas and to the posterior margin of the foramen magnum of the occipital bone

Question 19

What is the earliest age of development where ossification of the anterior free margin of the posterior atlanto-occipital ligament was observed?

Answer 19

about age 7 years old

Question 20

Based on the amount of ossification of the anterior free margin of the posterior atlanto-occipital ligament what structures will form?

Answer 20

an incomplete ponticulus posticus or a complete ponticulus posticus

Question 21

What other name may be used to identify a ponticulus posticus?

Answer 21

Kimmerle’s anomaly

Question 22

What names are given to the opening formed by the ponticulus posticus?

Answer 22

arcuate foramen or retroarticular canal

Question 23

Ponticulus posticus has observed in what ethnic populations?

Answer 23

all ethnic populations studied thus far

Question 24

Wht is the general range of incidence of ponticulus posticus in the populations studied?

Answer 24

1%-41%

Question 25

What is the gender bias now associated with ponticulus posticus?

Answer 25

female

Question 26

What is the incidence of a complete ponticulus posticus versus and incomplete ponticulus posticus?

Answer 26

uthe incidence of a complete ponticulus posticus is aboue fifteen percent; the incidence of an incomplete ponticulus posticus may be as high as forty-one percent

Question 27

What is observed on the undersurface of the posterior arch of C1?

Answer 27

"inferior vertebral notch" and an attachment site for the posterior atlanto-axial ligament

Question 28

What is the location of the "zygapophysis" relative to the atlanto-occipital and atlanto-axial intervertebral foramina?

Answer 28

it forms part of the anterior boundary of the intervertebral foramen in both cases

Question 29

What is the general appearance of the transverse process of C1?

Answer 29

triangular

Question 30

What are the osseous parts of the transverse process of C1?

Answer 30

costal element, posterior tubercle, true transverse process

Question 31

What osseous parts of the transverse process are absent at C1?

Answer 31

anterior tubercle and costotransverse bar

Question 32

What muscles attach to the transverse process of C1?

Answer 32

rectus capitis anterior, rectus capitis lateralis, middle scalene, levator scapula, splenius cervicis, obliquus capitis superior, obliquus capitis inferior and intertransversarii muscles

Question 33

What suboccipital muscles are known to have fascial projections attaching to the spinal dura?

Answer 33

rectus capitis posterior minor, rectus capitis posteior major, obliquus capitis inferior

Question 34

What are the connections between suboccipital muscles and the spinal dura called?

Answer 34

myodural bridges

Question 35

What are the lateral bridges of atlas connected to?

Answer 35

the lateral mass and the transverse process of atlas

Question 36

What forms of the lateral bridges are observed in the population?

Answer 36

incomplete lateral bridges and complete lateral bridges

Question 37

What opening is identified when a complete lateral bridge is formed?

Answer 37

the retrotransverse foramen

Question 38

What are the possible contents of the retrotransverse foramen?

Answer 38

the vertebral artery, a brach from the suboccipital nerve and veins communicating with the venous sinuses of the neck

Question 39

What is observed in the transverse foramen of C1?

Answer 39

vertebral artery, vertebral venous plexus, postganglionic sympathetic motor nerve fibers

Question 40

What is the gender variation for measurements of the transverse diameter of C1?

Answer 40

males: 78 millimeters and females: 72 millimeters

Question 41

Is there gender variation for the distance from the posterior tubercle of the transverse process of C1 to the skin?

Answer 41

not a significant difference

Question 42

What is the distance from the posterior tubercle of the transverse process of C1 to the skin for each gender?

Answer 42

a little over 30 millimeters for both males and females

Question 43

How many synovial joint surfaces are observed at C1?

Answer 43

five

Question 44

What synovial joint surfaces are observed at C1?

Answer 44

two superior articular facets, two inferior articular facets and the fovea dentis