Anatomy and Cerebral Circulation of the Rat
Yanlin Wang-Fischer in Manual of Stroke Models in Rats, 2008
The vertebral artery arises from the anterior surface of the subclavian artery, crosses the roots of the brachial plexus (Figure 4.2), and then runs upward under the carotid tubercle of the sixth cervical vertebra. Through the foramen magnum, it enters the skull and joins the vertebral artery of the contralateral side to form the basilar artery (BA) at the level of pons. The vertebral artery occasionally arises from the cervical trunk. The basilar artery is a component of the circle of Willis (discussed separately in this chapter).
Anatomy for neurotrauma
Hemanshu Prabhakar, Charu Mahajan, Indu Kapoor in Essentials of Anesthesia for Neurotrauma, 2018
The internal carotid artery, in its cranial part beyond the cavernous sinus, gives off the ophthalmic artery, the posterior communicating artery, the anterior choroidal artery, and the two terminal branches—anterior and middle cerebral arteries. The anterior choroidal artery is often referred to as the artery of thrombosis, as it has a narrow lumen and a long subarachnoid course, making it vulnerable to thrombosis. Above the optic chiasma, the anterior cerebral artery connects its corresponding artery from the opposite side via the anterior communicating artery. Just proximal to the anterior communicating artery, the recurrent artery of Heubner arises, which recurs backward to supply the internal capsule and head of the caudate nucleus. The anterior cerebral artery supplies the corpus callosum, medial parts of the frontal and parietal lobes (up to the parieto-occipital sulcus), including the sensorimotor cortex of the paracentral lobule, basal ganglia, and medial part of orbital surface. Motor weakness and sensory loss of the contralateral lower extremity is the commonest symptom of anterior cerebral artery occlusion. The middle cerebral artery gives off the lenticulostriate arteries, which are end arteries and supply the internal capsule. These arteries are sometimes referred to as the “Charcot’s artery of hemorrhage” as these are particularly prone to rupture during accelerated hypertension. The middle cerebral artery supplies the bulk of the supero-lateral surface of the cerebral hemisphere, including the sensori-motor areas around the central sulcus, and the Broca’s and Wernicke’s area. Occlusion of this artery, therefore, results in contralateral paresis affecting mostly the face and upper extremity, along with aphasia. Vertebral arteries form the posterior circulation in the brain. Each vertebral artery arises from the subclavian artery, enters the cranium through the foramen magnum, and unites with the corresponding artery from the opposite side, at the base of the pons, to form the basilar artery, between the two sixth cranial nerves. As the vertebrobasilar system, they supply the posterior part of the brain, cerebellum, brainstem and the spinal cord. The basilar artery ascends ventral to the pons and divides into a pair of posterior cerebral arteries at the cephalic border of the pons, close to the pituitary stalk. The vertebral artery gives off the posterior inferior cerebellar artery, which is its largest branch and supplies the cerebellum. The anterior and posterior spinal arteries also arise from the vertebral artery and supply the medulla in addition to the spinal cord. The basilar artery gives off the pontine arteries, the superior cerebellar artery, and the anterior inferior cerebellar artery to the cerebellum. The posterior cerebral artery gives off cortical branches supplying the inferior surface of the temporal lobe and occipital lobe; posterolateral striate branches supplying the caudal part of thalamus; and the posterior choroidal artery, supplying the choroid plexus, posterior part of the thalamus and midbrain. In the central nervous system, the capillary endothelium and the perivascular feet of the astrocytes of neurons, form a highly selective semipermeable membrane barrier, termed the blood–brain barrier, which helps in maintaining a chemically optimal environment for neuronal function. This blood–brain barrier controls movements of ions and metabolites, most importantly glucose, across the brain, and also prevents entry of harmful substances or toxins into the central nervous system. The blood–brain barrier may break down following infection or ischemia, leading to cytotoxic edema.
The Neck
Kenneth D Boffard in Manual of Definitive Surgical Trauma Care: Incorporating Definitive Anaesthetic Trauma Care, 2019
The proximal part of the vertebral artery is approached via the anterior sternomastoid incision, with division of the clavicular head of the sternomastoid. The internal jugular vein and common carotid artery are mobilized, the vein is retracted medially, and the artery and nerve are retracted laterally. The proximal vertebral artery lies deeply between these structures. The vertebral artery is crossed by branches of the cervical sympathetic chain and on the left side by the thoracic duct. The inferior thyroid artery crosses in a more superficial plane just before the vertebral artery enters its bony canal. Access to the distal vertebral artery is challenging and rarely needed. The contents of the carotid sheath are retracted anteromedially, and the prevertebral muscles are longitudinally split over a transverse process above the level of the injury. The anterior surface of the transverse process can be removed with a small rongeur, or a J-shaped needle may be used to snare the artery in the space between the transverse processes. The most distal portion of the vertebral artery can be approached between the atlas and the axis after division of the sternocleidomastoid near its origin at the mastoid process. The prevertebral fascia is divided over the transverse process of the atlas. With preservation of the C2 nerve root, the levator scapulae and splenius cervicus muscles are divided close to the transverse process of the atlas. The vertebral artery can now be visualized between the two vertebrae and may be ligated with a J-shaped needle. This area of dissection is more commonly the in province of a neurosurgeon if available. Neck exploration wounds are closed in layers after acquiring homeostasis.
Surgical considerations in posterior C1-2 instrumentation in the presence of vertebral artery anomalies: case illustration and review of literature
Published in British Journal of Neurosurgery, 2019
Lee A. Tan, Manish K. Kasliwal, Carter S. Gerard, Vincent C. Traynelis, Ricardo B.V. Fontes
Vascular anomalies involving the V3 segment of the vertebral artery are common and may complicate posterior atlantoaxial instrumentation. We report a patient with a fenestrated vertebral artery that underwent successful C1-2 instrumentation and fusion. Various vertebral artery anomalies are discussed with a review of pertinent literature.
New entry point for C2 screw, in posterior C1-C2 fixation (Goel-Harm’s technique) significantly reducing the possibility of vertebral artery injury
Published in Neurological Research, 2016
Objective: To reduce the chance of vertebral artery injury in posterior C1 lateral mass and C2 pedicle/pars screw–rod fixation (Goel–Harms technique ). Method: 49 patients, 30 males and 19 females, 12years - 82 years, underwent posterior C1–C2 fixation from February 2007 till June2013. A new entry point for the posterior C2 screw, 3mm below the midpoint of the C1–C2 joint which is directed medially and downwards into the C2 body , probably avoids the vertebral artery. As the screw now bypasses the pedicle/ pars , the chance of injuring the vertebral artery is probably reduced. Results: No case of intra-operative vertebral artery injury. Conclusion: The new technique of C2 screw fixation allows rigid immobilization of the C1–C2 joint without significant risk of vertebral artery injury.
Relation of the vertebral artery segment from C1 to C2 vertebrae: An anatomical study
Published in Alexandria Journal of Medicine, 2015
Ayman Ahmad Khanfour, Nancy Mohamed El Sekily
IntroductionThe anatomy of the vertebral artery (VA) at the cranio-vertebral junction is significantly different from the straightforward course in the transverse foramina from C6 to C2 vertebrae. Recent methods of fixation of C1 and C2 vertebrae due to different pathologies (trauma, tumors, or infection) are based on trans-articular procedures or direct screws for C1 and C2. These methods of fixation depend on a detailed knowledge of the osseous anatomy of C1 and C2 vertebrae, in addition to their relation to the vertebral artery. AimThe aim of this work was to obtain anatomical measurements of the vertebral artery segment between C1 and C2 to be considered during cranio-vertebral approaches. Materials and methodsTwenty five osseous specimens of C1 and C2 vertebrae were obtained from anatomy museum and ten adult cadaveric specimens were also studied. The anatomical measurements of vertebral artery were tabulated and graphically presented. The anatomical measurements obtained from C1 and C2 vertebra were statistically analyzed. ResultsTwenty five osseous specimens of C1 and C2 vertebrae were examined carefully. The anatomical measurements obtained from C1 vertebra were statistically analyzed. Different measurements of the vertebral artery groove including its length and diameter in addition to the distance between each of the medial and lateral edges of the inner and the outer cortices of the vertebral groove to the posterior tubercle of atlas respectively were measured and tabulated. The segment of VA between C1 and C2, the third and the fourth parts of vertebral artery were dissected in ten adult cadaveric specimens. The anatomical measurements of vertebral artery were tabulated and graphically presented. ConclusionThe vertebral artery adopts a serpentine course in relationship to C1 and C2 vertebrae, making it susceptible to injury during surgical procedures in this region. Comprehensive knowledge of the surgical anatomy is essential before performing surgery around the vertebral artery.
Related Knowledge Centers
- Basilar Artery
- Cervical Vertebrae
- Circle of Willis
- Artery
- Brain
- Subclavian Artery
- Circle of Willis