Atypical Cervical Vertebrae: C1/Atlas

Question 1

What is the name of the first cervical vertebra?

Answer 1

atlas

Question 2

What muscle attaches to the anterior arch of C1?

Answer 2

longus colli

Question 3

What ligaments will attach to the anterior arch of C1?

Answer 3

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

Question 4

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

Answer 4

the fovea dentis

Question 5

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

Answer 5

backward, upward, medial (BUM)

Question 6

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

Answer 6

asymmetrical, slightly concave or flattened

Question 7

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

Answer 7

backward, medial, downward (BMD)

Question 8

What muscles attach to the lateral mass of C1?

Answer 8

levator scapula, splenius cervicis, and rectus capitis anterior

Question 9

What is thought to represent the pedicle at C1?

Answer 9

the anterior arch

Question 10

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

Answer 10

tubercle for transverse atlantal ligament

Question 11

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

Answer 11

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

Question 12

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

Answer 12

rectus capitis posterior minor muscle and ligamentum nuchae

Question 13

What attaches to the arcuate rim of C1?

Answer 13

the posterior atlanto-occipital ligament

Question 14

Ossification of the free margin of the posterior atlanto-occipital ligament result in which atypical bone classification?

Answer 14

accessory bone

Question 15

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

Answer 15

about age 7 years old

Question 16

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

Answer 16

a partial ponticulus posticus or complete ponticulus posticus

Question 17

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

Answer 17

Kimmerie’s anomaly

Question 18

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

Answer 18

arcuate foramen or retroarticular canal

Question 19

Ponticulus posticus has observed in what ethic populations?

Answer 19

all ethnic populations thus far

Question 20

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

Answer 20

1%-41%

Question 21

What is the gender bias now associated with the ponticulus posticus?

Answer 21

female

Question 22

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

Answer 22

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

Question 23

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

Answer 23

costal element, posterior tubercle, true transverse process

Question 24

What muscles attach to the transverse process of C1?

Answer 24

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

Question 25

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

Answer 25

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

Question 26

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

Answer 26

myodural bridges

Question 27

What are the lateral bridges of the atlas connected to?

Answer 27

the lateral mass and the transverse process of atlas

Question 28

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

Answer 28

the retrotransverse foramen

Question 29

What are the possible contents of the retrotransverse foramen?

Answer 29

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

Question 30

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

Answer 30

lateral bridges

Question 31

What is observed in the transverse foramen of C1?

Answer 31

vertebral artery, vertebral venous plexus, postganglionic sympathetic motor nerves

Question 32

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

Answer 32

males: 78 millimeters females: 72 millimeters

Question 33

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

Answer 33

a little over 30 millimeters for both males and females

Question 34

What joint classification are observed at C1?

Answer 34

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

Question 35

How many synovial joint surfaces are observed on C1?

Answer 35

five

Question 36

What synovial joint surfaces are observed at C1?

Answer 36

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