Atypical Cervical Vertebrae: C1/Atlas Flashcards Preview

Spinal Anatomy I - Exam 2 > Atypical Cervical Vertebrae: C1/Atlas > Flashcards

Flashcards in Atypical Cervical Vertebrae: C1/Atlas Deck (56)
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1
Q

What is the name of the first cervical vertebra?

A

Atlas

2
Q

What features are lacking at C1?

A
  • Vertebral body
  • pedicles
  • a spinous process
  • intervertebral disc
3
Q

What is thought to represent the pedicle at C1?

A

The anterior arch

4
Q

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

A

The anterior tubercle

5
Q

What muscle attaches to the anterior arch of C1?

A

Longus colli

6
Q

What ligaments will attach to the anterior arch of C1?

A
  • anterior longitudinal
  • anterior Atlanta-occipital
  • anterior atlanto-axial
7
Q

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

A

the fovea dentis

8
Q

What joint classifications are observed on the anterior arch of C1?

A

fibrous (amphiarthrosis) syndesmosis joint and synovial pivot (diarthrosis trochoid) joint

9
Q

What is the contribution of the lateral mass to the circumference of C1?

A

forty percent - twenty percent for each lateral mass

10
Q

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

A

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

11
Q

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

A

backward, upward, medial (BUM)

12
Q

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

A

synovial (diarthrosis) ellipsoidal joint

13
Q

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

A

asymmetrical, slightly concave or flattened

14
Q

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

A

backward, medial, downward (BMD)

15
Q

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

A

synovial plane (diarthrosis arthrodia) joint

16
Q

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

A

tubercle for the transverse atlantal ligament

17
Q

What muscles attach to the lateral mass of C1?

A
  • levator scapula
  • splenius cervicis
  • rectus capitis anterior
18
Q

What is the contribution of the posterior arch to the circumference of C1?

A

about forty percent

19
Q

What part of C1 represents the spinous process?

A

posterior tubercle of the posterior arch

20
Q

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

A
  • male: about fifty millimeters

- female: about thirty-seven millimeters

21
Q

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

A
  • rectus capitis posterior minor

- ligamentum nuchae

22
Q

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

A
  • groove/sulcus for the vertebral artery

- arcuate rim

23
Q

What attaches to the arcuate rim of C1?

A

the posterior atlanto-occipital ligament

24
Q

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

A
  • arcuate rim of the posterior arch of atlas
  • superior articular process of the lateral mass of atlas
  • posterior margin of the foramen magnum of the occipital bone
25
Q

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

A

accessory bone

26
Q

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

A

about age 7 years old

27
Q

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

A

an incomplete ponticulus posticus or a complete ponticulus posticus

28
Q

What are the attachment sites of the ponticulus posticus?

A
  • arcuate rim of the posterior arch of atlas

- superior articular process of the lateral mass of atlas

29
Q

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

A

Kimmerle’s anomaly

30
Q

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

A

arcuate foramen or retroarticular canal

31
Q

Ponticulus posticus has been observed in what ethnic populations?

A

all ethnic populations studied thus far

32
Q

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

A

1% - 4%

33
Q

What is the gender bias now associated with ponticulus posticus?

A

female

34
Q

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

A
  • the incidence of a complete ponticulus posticus is about 15%
  • the incidence of an incomplete ponticulus posticus may be as high as 41%
35
Q

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

A
  • inferior vertebral notch

- an attachment site for the posterior atlanto-axial ligament

36
Q

What joint classification(s) may be observed on the posterior arch of C1?

A

fibrous (amphiarthrosis) syndesmosis joint

37
Q

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

A

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

38
Q

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

A

triangular

39
Q

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

A
  • costal element
  • posterior tubercle
  • true transverse process
40
Q

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

A
  • anterior tubercle

- costotransverse bar

41
Q

What muscles attach to the transverse process of C1?

A
  • rectus capitis anterior
  • rectus capitis lateralis
  • middle scalene
  • levator scapula
  • splenius cervicis
  • obliquus capitis superior
  • obliquus capitis inferior
  • intertransversarii
42
Q

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

A
  • rectus capitis posterior major
  • rectus capitis posterior minor
  • obliquus capitis inferior
43
Q

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

A

myodural bridges

44
Q

What are the lateral bridges of atlas connected to?

A

lateral mass and transverse process of atlas

45
Q

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

A

incomplete lateral bridges and complete lateral bridges

46
Q

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

A

the retrotransverse foramen

47
Q

What are the possible contents of the retrotransverse foramen?

A
  • vertebral artery
  • branch from the suboccipital nerve
  • veins communicating with the venous sinuses of the neck
48
Q

Which of the ponticles (bridges) of atlas is most numerous?

A

ponticulus posticus

49
Q

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

A

lateral bridges

50
Q

What is observed in the transverse foramen of C1?

A
  • vertebral artery
  • vertebral venous plexus
  • postganglionic sympathetic motor nerve fibers
51
Q

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

A
  • males: 78 millimeters

- females: 72 millimeters

52
Q

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

A

not a significant difference

53
Q

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

A

a little over 30 millimeters for both male and female

54
Q

What joint classifications are observed at C1?

A
  • fibrous (amphiarthrosis) syndesmosis joint
  • synovial (diarthrosis) ellipsoidal joint
  • synovial pivot (diarthrosis trochoid) joint
  • synovial plane (diarthrosis arthrodia) joint
55
Q

How many synovial joint surfaces are observed at C1?

A

five

56
Q

What synovial joint surfaces are observed at C1?

A
  • two superior articular facets
  • two inferior articular facets
  • fovea dentis