Atypical Cervical Vertebrae- C1 Flashcards
What is the name of the first cervical vertebrae?
Atlas
What features are lacking at C1?
4
Vertebral body
Pedicles
A spinous process
Intervertebral disc
What is thought to represent the pedicle at C1?
The Anterior Arch
What muscles attaches to the anterior arch of C1?
1
Longus Colli
What ligaments will attach to the anterior arch of C1?
3
Anterior longitudinal ligament
Anterior atlanto-occipital ligament
Anterior atlanto-axial ligament
What is observed on the back of the anterior arch of C1?
The Fovea Dentis
What joint classifications are observed on the anterior arch of C1?
(2)
Fibrous (Amphiarthrosis) Syndesmosis joint Synovial Pivot (Diarthrosis Trochoid) joint
What is the morphology of the superior articular facet of C1?
They are elliptical
Closer together in the front
Often demonstrate an elevation subdividing the facet surface into two separate surfaces
What is the orientation of the superior articular facet of C1?
Backward, upward, and medial (BUM)
What is the joint classification of the atlanto-occipital zygapophysis?
Synovial (Diarthrosis) Ellipsoidal joint
What are the morphological characteristic of the inferior articular facet of C1?
Asymmetrical, slightly concave, flattened
What is the orientation of the inferior articular facet of C1?
Backward, medial, downward (BMD)
What muscles attach to the lateral mass of C1?
3
Levator scapula
Splenius cervicis
Rectus capitis anterior
What part of C1 represents the spinous process?
Posterior tubercle of the posterior arch
What is the distance from the posterior tubercle of the posterior arch to the skin in each gender?
Males: About 50 millimeters
Females: About 37 millimeters
What attaches to the posterior tubercle of the posterior arch of C1?
(2)
Rectus Capitis Posterior Minor muscle
Ligamentum Nuchae
What superior surface modifications of the posterior arch of C1 are present?
(2)
Groove/sulcus for the vertebral artery
Arcuate rim
What attaches to the arcuate rim of the C1?
1
The posterior atlanto-occipital ligament
What are the attachment sites of the posterior atlanto-occipital ligament?
(3)
It is attached to:
- 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.
What is the joint classification of the atlanto-axial zygampophysis?
Synovial plane (diarthrosis arthrodia) joint
What is the earliest age of development where ossification of the anterior free margin of the posterior atlanto-occipital ligament was observed?
About age 7 years old
Based on the amount of ossification of the anterior free margin of the posterior atlanto-occipital ligament what structures will from?
An incomplete ponticulus posticus or a complete ponticulus posticus
What names are given to the opening formed by the ponticulus posticus?
(2)
Arcuate Foramen or Retroarticular Canal
Ponticulus Posticus has observed in what ethnic populations?
All ethnic populations studies thus far
What joint classification(s) may be observed on the posterior arch of C1?
(1)
Fibrous (Amphiarthrosis) Syndesmosis Joint
What are the osseous parts of the transverse process of C1?
3
Costal element
Posterior tubercle
True transverse process
What osseous parts of the transverse process are absent in C1?
Anterior tubercle and costotransverse bar
What muscles attach to the transverse process of C1?
8
Rectus capitis anterior Rectus capitits lateralis Middle scalene Levator scapula Splenius cervicis Obliquus capitis superior Obliquus capitis inferior Intertransversarii
What sub occipital muscles are known to have facial projections attaching to the spinal dura?
(3)
Rectus capitis posterior minor
Rectus capitis posterior major
Obliquus capitis inferior
What are the connections between sub occipital muscles and the spinal dura called?
Myodural bridges
What are the lateral bridges of the atlas connected to?
2
The lateral mass and the transverse process of atlas
What opening is identified when a complete lateral bridge is formed?
The Retrotransverse foramen
Which of the ponticles (bridges) of atlas is only observed in humans?
Lateral bridges
What is the distance from the posterior tubercle of the transverse process of C1 to the skin for each gender?
A little over 30 millimeters for both males and females
What is the gender variation for measurements of the transverse diameter of C1?
Males: 78 millimeters
Females: 72 millimeters
What joint classifications are observed at C1?
4
Fibrous (amphiarthrosis) syndesmosis joint Synovial (diarthrosis) ellipsoidal joint Synovial pivot (diarthrosis trochoid) joint Synovial plane (diathesis arthrodia) joint
How many synovial joint surfaces are observed at C1?
Five
What synovial joint surfaces are observed at C1?
3
Two Superior Articular Facets
Two Inferior Articular Facets
Fovea Dentis
