Atypical Cervical Vertebrae C1/Atlas Flashcards
What is the name of the first cervical vertebra
atlas
What features are lacking on C1 (atlas)
vertebral body, pedicles, a spinous process, and the intervertebral disc
What muscles attach to the anterior arch of C1
Longus colli
What ligaments attach to the anterior arch of C1
anterior longitudinal ligament, anterior antlato-occipital, and the anterior atlantal-axial ligaments
What is observed on the back of the anterior arch of C1
the fovea dentis
What is the morpology of the superior articular facet of C1
they are elliptical, closer together in the front and often demonstrate an elvation subdividing the facet surface into two separate surfaces
What is the orientation of the superior articular facet of C1
backward up and medial, BUM
What is the joint classification of the atlanto-occipital zygapophysis
synovial (diarthrosis) ellipsoidal Joint
What are the morphologial characteristics of the inferior articular facet of C1
asymmetrical, slightly concave or flattened
What is the orientation of the inferior articular facet of C1
BMD backward medial and down
What is the joint classification of the atlanto-axial zygapophysis
synovial plane (diarthrosis arthrodia) joint
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 capitus anterior
What is the contribution of the posterior arch to the circumference of C1
about 40%
What part of C1 represents the spinous process
posterior tubercle of the posterior arch
What is the sdistance 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
rectus capitus 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 attaches to the arcuate rim of C1
the posterior atlanto-occipital ligament
ossification of the free margin of the posterior atlanto-occipital-ligament results in which atypical bone classification
accessory bone
What is the earliest age of development where ossification of the anterior free margin of the posterior atlanto-occipital ligament was observed
about 7 years old
What may be formed by ossification of the anterior free margin of the posterior atlanto-occiptal ligament
a partial ponticulus posticus or a complete ponticulus posticus
What other name may be used to describe a ponticulus posticus
kimmerle’s anomaly
What names are given to the opening formed by the ponticulus posticus
arcuate foramen or retroarticular canal
ponticulus posticus has been observed in what ethnic populations
all ethnic 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 is the incidence of a complete ponticulus posticus versus an incomplete ponticulus posticus
the incidence of a complete is about 15%
the incidence of an incomplete can be as high as 41%
What joint classification(s) may be observed on the posterior arch of C1
fibrous (amphiarthrosis) syndesmosis joint
What is the location of the “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 costotransverse bar
What muscles attach to the Transverse process of C1 (a lot)
rectus capitis anterior, rectus capitis lateralis, middle scalene, levator scapula, splenius cervicis, obliquuis capitis superior, obliquus capitis inferior, and intertransversarii muscle
What suboccipital muscles are known to have fascial projections attaching to the spinal dura
rectus capitis posterior minor, rectus capitis posterior major, and obliquus capitis inferior
What are the connecutions between suboccipital muscles and the spinal dura called
myodural bridges
What are the lateral bridges of the 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 sinus of the neck
Which of the ponticles (bridges) of atlas is most numerous
ponticulus posticus
Which of the ponticles (bridges) of atlas is only identified 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
Male: 78 mm
females 72 mm
What is the distance from the posterior tubercle of the transverse process of C1 to the skin for each gender
a little over 30 mm for both male and females
What joint classifications are observed at C1
fibrous (amphiarthrosis) syndesmosis joint, synovial (diarthrosis) ellipsoidal joint, synovial piviot (diarthrosis trochoid) synovial plane (diarthrosis arthrodia) joint
how many synovial joint surfaces are observed at C1
5
