Intracranial region of the vertebral artery: morphometric study in the context of clinical usefulness

Abstract

The presented knowledge of anatomical variation and abnormali-ties of vertebral circulation can improve the accuracy and "safety" of the surgical procedures in this region, help to determine the range of surgical approach and avoid associated complications. The radiological examinations using 3D CT, DSA reveal unlimited observation of anatomical structures in contrast to studies based on cadavers, and can complement the morphometry in anatomical preparations.

Anatomical Variations and Dimension of the Intracranial Vertebral Artery: Evaluation With Multidetector Computed Tomography Angiography

“…3b) and the proximal part of the basilar artery in another patient. Our observation is similar to the report of Dzierzanowski et al, which reported two fenestrations in the Caucasians 1 . Fenestration of the vertebrobasilar artery is a congenital anomaly that involves lumina division of an artery with a single origin into two separate channels that later reunite distally.…”

“…The vertebral artery (VA) emanates from the superior-posterior part of the subclavian artery and proceeds through the foramen transversarium of the cervical vertebra. The left and right VA penetrates the dura mater to enter the intracranial space through the foramen magnum, where they converge to form the basilar trunk at the pontomedullary junction 1 . Anatomically, the VA is divided into four segments.…”

Clinical Importance of the Posterior Inferior Cerebellar Artery: A Review of the Literature

“…The first three segments were extracranial and the fourth segment is entirely intracranial and terminates with forming the basilar artery (BA). It is the fourth segment of VA that gives off the PICA, which is the largest branch of VA 3 - 5 . The trunk of PICA is divided into five segments (Figure 1 ): (1) the anterior medullary segment, which begins at the origin of the PICA and ends at the level of a rostrocaudal line that passing through the most prominent part of the inferior olive; (2) the lateral medullary segment, which extends from the level of the most prominent point of the olive to the level of the origin of the glossopharyngeal (CN Ⅸ), vagus (CN Ⅹ), and accessory (CN Ⅺ) rootlets; (3) the tonsillomedullary segment, which begins where the PICA passes posterior to the CN IX-XI and ends at the midpoint of the PICA's ascent toward the roof of the fourth ventricle along the medial surface of the tonsil; (4) the telovelotonsillar segment, which begins where the PICA ascends to the mid-level of the medial surface of the tonsil and ends where the artery exits the fissures between the tonsil, vermis, and hemisphere to reach the suboccipital surface; (5) the cortical segment, this segment begins where the PICA leaves the groove between the vermis, tonsil and hemisphere, and includes the terminal cortical branches 1 , 6 .…”

“…The incidence of PICA fenestration is reported to be 0.3% 18 . Some investigators hold the view that variations such as duplications and fenestrations were prone to the coexistence of vascular anomalies including aneurysms, vascular malformations, dissections due to the abnormal vascular structure and hemodynamics 5 .The VA terminating in the PICA is reported in 2.8 - 7% patients, which is also one of the most common variations of VA 3 , 18 - 20 . This variation may have a detrimental impact on cerebral hemodynamics 21 .…”

Anatomical location of the vertebrobasilar junction: computed tomography morphometrics for planning endoscopic transsphenoidal transclival approaches

“…VA is divided into four segments during its course and the fourth segment, known as the intracranial segment, starts from the foramen magnum level, merges with the corresponding segment at the pontomedullary level and forms VBJ. Although the anatomy of the structure is well known, especially starting with VA 4th segment and ending with VBJ, it is important to have information about the anatomical variability of these structures, especially in terms of planning for brain surgery, head and face surgery, and vascular surgery [5,6]. Songur et al described the position of VBJ associated with the bulbopontin sulcus and found that 20% of VBJ was at this level, 67% was below this level, and 12% was above this level [7].…”