![]() The traditional diagnostic tool for vertebral injury is digital subtraction angiography however, CT angiography has also been demonstrated as a viable means of identifying symptomatic BVAI in the upper cervical spine. Nevertheless, occlusion of bilateral or dominant vertebral arteries can be devastating and the mortality rate in patients with BVAI without a neurological event is around 7 %. Most cases of BVAI remain asymptomatic and are often overlooked. They are subject to blunt vertebral arterial injury (BVAI) in cases of traumatic subluxation or fractures of the C1/C2 foramina. The vertebral arteries pass through the transverse foramina of the atlas. The dens articulates with the atlas via a facet on the posterior aspect of the anterior ring of the atlas, retained by the transverse ligament, providing the head with approximately 50 % of its lateral rotation. Posteriorly, the ring of the atlas is connected to the C2 by the posterior atlantoaxial ligament. ![]() At the anterior aspect of the ring, the joint is secured by the anterior atlantoaxial ligament. The C1-2 joint is highly mobile, with the dens of the axis secured to the anterior arch of the atlas by the transverse odontoid ligament. The atlas has two lateral masses with concavities that match the condyles of the occiput, forming the occipito-cervical articulations and allowing for movement of the skull. C1 lacks a vertebral body, consisting instead of a posterior and anterior arch that encircles the spinal cord, mostly posterior to the dens. This allows for lateral and vertical mobility of the head and upper spine. The atlas, or C1 vertebra, sits just inferior to the occiput and through its articulations with C2 and the occipital condyles joins the skull to the spine. Overall, a bimodal distribution is seen, with individuals aged in their mid-twenties and between 80–84 most at-risk for C1 fractures however, the mean age of diagnosis is 64 years and nearly three-quarters of cases occur in patients over 50 years of age. Pediatric patients with C1 fractures are rare, although the mortality rate among infants with this injury is approximately 16 %. This imbalance is reversed in the elderly where 52 % of patients are female, while in younger patients males account for upwards of 70 % of cases. There appears to be a male preponderance, with men accounting for 57–69 % of all cases. Classically, patients presenting with fractures of the atlas have sustained an injury due to diving into shallow water, falling, or a motor vehicle accident. In addition, violent rotational forces on the head and neck may infrequently cause atlas fractures. Atlas injuries occur due to a traumatic axial load and are typically associated with other damage to the upper cervical spine. Unstable spine fractures (wikem.Atlas fractures account for 2–13 % of acute injuries of the cervical spine and 1–2 % of all spinal injuries. Or hyperflexion causing the vertebrae bodies to collide and form a teardrop fragment of the superior vertebrae displacing the body and disrupting the posterior longitudinal ligament. Hyperextension of the anterior longitudinal ligament avulsing a teardrop fragment of the body. Bilateral C2 pedicle fracture, causing anterior dislocation of C2 vertebral body onto C3. Extreme hyperextension injury - MVC, diving, judicial hangings. Flexion injury with injury to ligaments stabilizing atlanto-occipital joint. Called "internal decapitation" because it is frequently fatal. Type III - extension of fracture to the upper portion of body Type II - fracture through waist, or base of odontoid near attachment to C2 ![]() Anterior and posterior ligaments are disrupted. Hyperflexion injury (rapid deceleration) causing anterior dislocation of superior vertebral body by 50% of the body's AP diameter. Associated with other cervical fractures, vertebral aa injury. Axial loading force (diving) transmitted to C1 causing a bilateral fracture of the ring. The mnemonic to remember unstable C-spine fractures and dislocations is "Jefferson bit off a hangman's thumb." Today's POTD is on trauma, which will be the topic every Tuesday.
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