What is congenital nonunion of the posterior arch of C1?
Congenital anomalies of the posterior arch of the atlas (C1) are relatively common anomalies. They may range from partial defects presenting as clefts to complete absence of the posterior arch (aplasia).
What is posterior arch defect?
Posterior arch defects of the cervical spine, including congenitally absent cervical spine pedicle and cervical spondylolysis, are complex of abnormalities in posterior arch development and occur rarely.
Does C1 have 2 Arches?
Introduction. The Atlas (the first cervical vertebra – C1) differs from the other cervical vertebrae in that it has no body or spinous process. It is comprised of two bony arches with two bony masses laterally.
What is the C1 arch?
Embryologically, the C1 vertebrae has 3 primary ossifications centers; the anterior tubercle and two lateral centers which extend forming the lateral masses and posterior arch. During the 7th week of gestations the lateral centers extend dorsally forming the posterior arch which are almost fused at birth.
Are neck problems hereditary?
Many cervical spine conditions — both common and rare — have a genetic component. Genetic conditions can be caused by inheritance (passed from parent to child), disrupted or abnormal development in utero, or unknown factors. Genetic conditions that affect the cervical spine vary widely.
What is C1 hypoplasia?
Abstract. Congenital hypoplasia of the posterior arch of the atlas (C1), a developmental failure of chondrogenesis, is a rare anomaly and may range from partial clefts to total agenesis of the posterior arch. Ossification of the posterior arch usually occurs between the 3rd and 5th years of life.
What is a C1 ring fracture?
The C1 vertebra (atlas) is a closed ring. A fracture of a closed ring necessarily results in at least two areas of ring disruption. These disruptions are customarily accompanied by a spread of the C1 ring fragments as a result of the axial loading mechanism of this injury and the weight of the head.
What makes C1 unique?
C1 and C2 form a unique set of articulations that provide a great degree of mobility for the skull. C1 serves as a ring or washer that the skull rests upon and articulates in a pivot joint with the dens or odontoid process of C2.
What is unique about atlas C1?
The C1, or first cervical vertebra, is commonly called the atlas due to its unique position in the spine. In Greek mythology, Atlas was the titan who held the Earth on his shoulders, just like the atlas holds the skull on top of the neck.
Why C1 is called atlas?
In anatomy, the atlas (C1) is the most superior (first) cervical vertebra of the spine and is located in the neck. It is named for Atlas of Greek mythology because, just as Atlas supported the globe, it supports the entire head.
Is C1 the same as atlas?
The atlas (plural: atlases) is the first cervical vertebra, commonly called C1. It is an atypical cervical vertebra with unique features. It articulates with the dens of the axis and the occiput, respectively allowing rotation of the head, and flexion, extension and lateral flexion of the head.
What is Klippel-Feil syndrome?
Klippel-Feil Syndrome is a rare disorder characterized by the congenital fusion of two or more cervical (neck) vertebrae. It is caused by a failure in the normal segmentation or division of the cervical vertebrae during the early weeks of fetal development.
Can you be born with cervical spondylosis?
Sometimes, an injury or illness can cause an upper cervical disorder, but you can also be born with one—this is known as a congenital disorder.
What is atlas hypoplasia?
Congenital atlantoaxial instability may be caused by multiple conditions, such as Down syndrome, Klippel-Feil malformation, and os odontoideum. Atlas Hypoplasia. Atlas hypoplasia occurs when you are born with an underdeveloped or incompletely developed atlas, which is the top bone in your cervical spine (C1).
Is a C1 fracture serious?
Complications in the management of C1 fractures range from minor discomfort to death. The primary concern with C1 fractures is establishing and maintaining cervical stability. Atlanto-occipital and atlantoaxial instability threatens the brainstem and spinal cord, potentially causing myelopathy and even mortality.
Is a C1 fracture fatal?
Injuries to the C1 and C2 vertebrae are rare, accounting for only 2% of spinal injuries each year. However, they are also considered to be the worst spinal cord injury that it is possible to sustain, and often fatal.
Why is C1 atypical?
C1 and C2 are considered atypical vertebrae because they have some distinguishing features compared to the rest of the cervical spine. The two vertebrae just below the skull are C1 (the atlas) and C2 (the axis).
How to classify congenital anomalies of the posterior atlas arch?
Congenital anomalies of the posterior atlas arch can be classified according to a system proposed by Currarino et al. in 1994 consisting of a combination of morphology and clinical presentation 1.
What is the incidence of C1 arch defects?
The overall incidence of C1 arch defects is 3.35%, with 2.6% type A, 0.54% Type B, and an anterior arch cleft only in one patient (0.09%) in a retrospective series (1). The majority of congenital C1 anomalies are asymptomatic and found incidentally on imaging.
What is a benign C1 anomaly?
Anomalies of the posterior arch of C1 are usually considered benign 4, but may give rise to severe neurological compromise. Especially groups C and D (i.e. isolated posterior ossicle) may be considered a risk factor for neurological morbidity rather than a developmental variant of normal 7.
What disorders affect the posterior arch of the Atlas?
Association with congenital anomaly of the posterior arch of the atlas has been reported in several disorders, including: 1 Arnold-Chiari malformation. 2 gonadal dysgenesis. 3 Klippel-Feil syndrome. 4 Down syndrome. 5 Turner syndrome.