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, spinous process and intervertebral disc

Question 3

what is thought to represent the pedicle at C1?

Answer 3

anterior arch

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

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

Question 6

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

Answer 6

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

Answer 9

asymmetrical, slightly concave or flattened

Question 10

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

Answer 10

backward, medial, downward (BMD)

Question 11

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

Answer 11

tubercle for the transverse atlantal ligament

Question 12

what muscles attach to the lateral mass of C1?

Answer 12

levator scapula, splenius cervicis and rectus capitis anterior

Question 13

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

Answer 13

males: about 50 millimeters; females: about 37 millimeters

Question 14

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

Answer 14

rectus capitis posterior minor muscle and ligamentum nuchae

Question 15

what attaches to the arcuate rim of C1?

Answer 15

posterior atlanto-occipital ligament

Question 16

ossification of the free margin of the posterior atlanto-occipital ligament results in which atypical bone classification?

Answer 16

accessory bone

Question 17

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

Answer 17

about age 7

Question 18

what may be formed by ossification of the anterior free margin of the posterior atlanto-occipital ligament?

Answer 18

partial or complete ponticulus posticus

Question 19

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

Answer 19

Kimmerle’s anomaly

Question 20

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

Answer 20

arcuate foramen or retroarticular canal

Question 21

ponticulus posticus has observed in what ethnic populations?

Answer 21

all ethnic populations studied thus far

Question 22

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

Answer 22

1%-41%

Question 23

what is the gender bias now associated with ponticulus posticus?

Answer 23

female

Question 24

what is the location of the “zygapophysis” relative to the atlanto-occipital and atlanto-axial intervertebral foramina?

Answer 24

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

Question 25

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

Answer 25

costal element, posterior tubercle, true transverse process

Question 26

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

Answer 26

anterior tubercle and costotransverse bar

Question 27

what muscles attach to the transverse process of C1?

Answer 27

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

Question 28

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

Answer 28

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

Question 29

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

Answer 29

myodural bridges

Question 30

what are the lateral bridges of atlas connected to?

Answer 30

lateral mass and the transverse process of atlas

Question 31

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

Answer 31

retrotransverse foramen

Question 32

what are the possible contents of the retrotransverse foramen?

Answer 32

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

Question 33

which of the ponticles (bridges) of atlas is only observed in humans?

Answer 33

lateral bridges

Question 34

what is observed in the transverse foramen of C1?

Answer 34

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

Question 35

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

Answer 35

males: 78 millimeters and females: 72 millimeters

Question 36

what is the distances from the posterior tubercle of the transverse process of C1 to the skin for each gender?

Answer 36

a little over 30 millimeters for both males and females

Question 37

what joint classifications are observed at C1?

Answer 37

fibrous (amphiarthrosis) syndesmosis joint, synovial (diarthrosis) ellipsoidal joint, synovial pivot (diarthrosis trochoid) joint and synovial plane (diarthrosis arthrodia) joint

Question 38

how many synovial joint surfaces are observed at C1?

Answer 38

5

Question 39

what synovial joint surfaces are observed at C1?

Answer 39

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