Flashcards in Atypical Cervical Vertebrae - C1/Atlas Deck (45):
What is the name of the first cervical vertebra?
What features are lacking at C1?
Vertebral body, pedicels, a spinous process and the intervertebral disc
What is thought to represent the pedicle at C1?
The anterior arch
What osseous modification is observed to the front of the anterior arch of C1?
The anterior tubercle
What muscle attaches to the anterior arch of C1?
What ligaments will attach to the anterior arch of C1?
The anterior longitudinal, anterior atlanto-occipital and anterior atlanto-axial ligaments
What is observed on the back of the anterior arch of C1?
The fovea dentis
What is the morphology of the superior articular facet of C1?
There are elliptical, closer together in front and 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, medial (BUM)
What is the joint classification of the atlano-occipital zygapophysis?
Synovial (diarthrosis) ellipsoidal joint
What are the morphological characteristics of the inferior articular facet of C1?
Asymmetrical, slightly concave or flattened
What is the orientation of the inferior articular facet of C1?
Backward, medial, downward (BMD)
What is the name of the rounded elevation on the medial aspect of the lateral mass of C1?
Tubercle for the transverse atlantal ligament
What muscles attach to the lateral mass of C1?
Levator scapula, splenius cervicis and 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 mm; females: about 37 mm
What attaches to the posterior tubercle o the posterior arch of C1?
Rectus capitis posterior minor muscle and ligamentum nuchae
What superior surface modifications of the posterior arch of C1 are present?
Groove/sulcus for the vertebral artery and arcuate rim
What are the attachment sites offs the posterior Atlanto-occipital ligament?
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
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 form?
An incomplete ponticulus posticus or a complete ponticulus posticus
What other name may be used to ID a ponticulus posticus?
What names are given to the opening formed by the ponticulus posticus?
Arcuate Foramen or retro articular canal
Ponticulus posticus has observed in what ethnic populations?
All ethnic populations studied thus far
What is the general range of incidence of ponticulus posticus in the population studied?
What is the gender bias now associated with ponticulus posticus?
What is the incidence of a complete ponticulus posticus versus an incomplete one?
The incidence of a complete ponticulus posticus is about 15%; the incidence of an incomplete one may be as high as 41%
What is observed on the undersurface of the posterior arch of C1?
"Inferior vertebral notch" and an attachment site for the posterior Atlanto-axial ligament
What is the location o fate "zygapophysis" relative to the Atlanto-occipital and Atlanto-axial intervertebral foramina?
It forms part of the anterior boundary of the intervertebral Foramen in both cases
What are the osseous parts of the transverse process of C1?
Costal element, posterior tubercle, true transverse process
What osseous parts of the transverse process are absent at C1?
Anterior tubercle and cosstotransverse bar
What muscles attach to the transverse process of C1?
Rectus capitis anterior, Rectus capitis lateralis, middle scalene, levator scapula, splenius cervicis, obliquus capitis inferior and intertransversarii muscles
What sub occipital muscles are known to have faucial projections attaching to the spinal dura?
Rectus capitis posterior minor and major, obliquus capitis inferior
What are the connections between suboccipital muscles and the spinal dura called?
What are the lateral bridges of atlas connected to?
The lateral mass and the transverse process of atlas
What opening is IDed when a complete lateral bridge is formed?
The retrotransverse Foramen
What are the possible contents of the retrotransverse foramen?
The vertebral artery, a branch from the suboccipital nerve and veins communicating with the venous sinuses of the neck
Which of the ponticles (bridges) of atlas is most numerous?
Which of the ponticles (bridges) of atlas is only observed in humans?
What is observed in the transverse foramen of C1?
Vertebral artery, vertebral venous plexus, postganglionic sympathetic motor nerve fibers
What is the gender variation for measurements of the transverse diameter of C1?
Males: 78 mm and females :72 mm
What is the distance form the posterior tubercle of the transverse process of C1 to the skin for each gender?
A little over 30 mm for both males and females
How many synovial joint surfaces are observed at C1?
What synovial joint surfaces are. Observe red at C1?
Two superior articular facets, two inferior articular facets and the fovea dentis