Atypical Cervical Vertebrae: C1/Atlas Flashcards
What muscle attaches to the anterior arch of C1?
Longus Colli
What is the orientation of the superior articular facet of C1?
Backward, upward, medial (BUM)
What is the orientation of the inferior articular facet of C1?
Backward, meidal, downward (BMD)
What muscles attach to the lateral mass of C1?
Levator Scapula, splenius cervicis and rectus capitis anterior
What is the distance from the posterior tubercle of the posterior arch to the skin in each gender?
Males: about 50mm
Females: about 37 mm
What attaches to the posterior tubercle of the posterior arch of C1?
Rectus capitis posterior minor muscle and ligamentum nuchae
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
What names are given to the opening formed by the ponticulus posticus?
Arcuate foramen and retroarticular canal
Ponticulus posticus has been observed in what ethnic populations?
All populations studied thus far
What is the general range of incidence of ponticulus posticus in the populations studied?
1-41%
What is the gender bias now associated with ponticulus posticus?
Female
What muscles attach to the transverse process of C1?
Rectus capitis anterior, rectus capitis lateralis, middle scalene, levator scapula, splenius cervicis, obliquus capitis superior, obliquus capitis inferior and intertransversarii muscles
What suboccipital muscles are known to have fascial projections attaching to the spinal dura?
Rectus capitis posterior minor, rectus capitis posterior major, obliquus capitis inferior
What are the connections between suboccipital muscles and the spinal dura called?
myodural bridges
What are the lateral bridges of atlas connected to?
The lateral mass and the transverse process of atlas
What opening is identified 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 only obersved in humans?
Lateral bridges
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: 78mm; Females: 72mm
What is the distance from the posterior tubercle of the transverse process of C1 to the skin for each gender?
A little over 30mm for both males/females
How many synovial joint surfaces are observed at C1?
5
What synovial joint surfaces are observed at C1?
Two superior articular facets, two inferior articular facets and the fovea dentis
