Anatomy of the brainstem: a gaze into the stem of life.

The brainstem has an ectodermal origin and is composed of 4 parts: the diencephalon, mesencephalon, pons, and medulla oblongata. It serves as the connection between the cerebral hemispheres with the medulla and the cerebellum and is responsible for basic vital functions, such as breathing, heartbeat blood pressure, control of consciousness, and sleep. The brainstem contains both white and gray matter. The gray matter of the brainstem (neuronal cell bodies) is found in clumps and clusters throughout the brainstem to form the cranial nerve nuclei, the reticular formation, and pontine nuclei. The white matter consists of fiber tracts (axons of neuronal cells) passing down from the cerebral cortex--important for voluntary motor function--and up from peripheral nerves and the spinal cord--where somatosensory pathways travel--to the highest parts of the brain. The internal structure of brainstem, although complex, presents a systematical arrangement and is organized in 3 laminae (tectum, tegmentum, and basis), which extend its entire length. The motor pathway runs down through the basis, which is located at the most anterior part. The cranial nerve nuclei are settled into the middle layer (the tegmentum), just in front of the 4th ventricle and are placed, from medial to lateral, on the basis of their function: somatic motor, visceral motor, visceral sensory, and somatic sensory. All the somatosensory tracts run upward to the thalamus crossing the tegmentum in front of the cranial nerve nuclei. The tectum, formed by the quadrigeminal plate and the medullary velum, contains no cranial nuclei, no tracts and no reticular formation. The knowledge of precise anatomical localization of a lesion affecting the brainstem is crucial in neurological diagnosis and, on this basis, is essential to be familiar with the location of the mayor tracts and nuclei appropriately. Nowadays, current magnetic resonance imaging techniques, although still macroscopic, allow the fine internal structure of the brainstem to be viewed directly and make it possible to locate the main intrinsic structures that justify the symptoms of the patient. In this article we discuss the anatomy of the brainstem and highlight the features and landmarks that are important in interpreting magnetic resonance imaging.

[Internal carotid artery vasculitis originated by cervicofacial actinomycosis as a predisponing factor to stroke]. / Vasculitis de la arteria carótida interna originada por actinomicosis cervicofacial como factor predisponente de infarto cerebral.

Actinomycosis is a chronic, suppurative, fibrotic infection produced by a gram-positive anaerobic bacteria of the normal mouth flora, the infection having tendency to fistulate and to extend without respecting tissue layers. Initial diagnosis is usually delayed due to its painless evolution. Three clinical forms are known: cervicofacial, abdominal and thoracic. Occasionally, there is vascular involvement which is mainly associated with venous thrombotic phenomena with low clinical expresion and hematogenous dissemination that can result in a formation of abscess or meningitis in the central nervous system. We report the case of a 28 year old female patient with type I diabetes and microangiopathyc complication with a internal carotid artery stenosis adjacent to mandibular angle actinomicosis. A few months later and after a miscarriage she suffered from ischemic stroke. The anticardiolipin antibody were positive at the time of stroke with post-operative period and over the next two years. To our knowledge (Medline, 1984-2004), it is the first report of internal carotid vasculitis originated by cervicofacial actinomicosis. We discuss the neuroradiological aspects of our case.

Vasculitis de la arteria carótida interna originada por actinomicosis cervicofacial como factor predisponente de infarto cerebral / Internal carotid artery vasculitis originated by cervicofacial actinomycosis as a predisponing factor to stroke

La actinomicosis es una infección crónica, supurativa, fibrótica, con tendencia a la fistulización, que se extiende por invasión directa, sin respetar planos tisulares. Su evolución indolora suele retrasar el diagnóstico inicial. Existen tres formas clínicas: cervicofacial. torácica y abdominal. Ocasionalmente hay invasión vascular que se asocia a fenómenos trombóticos, principalmente venosos, y con escasa expresividad clínica y diseminación hematógena que a nivel cerebral se puede manifestar como absceso o meningitis. Comunicamos el caso de una paciente con diabetes tipo I con complicaciones microangiopáticas que presentó una afectación de la arteria carótida interna en el contexto de una actinomicosis mandibular objetivada como engrosamiento hipodenso de la pared en la tomografía computarizada cervical y que se asoció unos meses más tarde a accidente vascular cerebral isquémico en el postoperatorio de un aborto programado. los anticuerpos anticardiolipina resultaron ser positivos. En nuestro conocimiento es el primer caso comunicado en la literatura (Medline, 1984-2004), insistiendo especialmente en la descripción neurorradiológica del caso y el factor predisponente de la lesión arterial previa

Actinomycosis is a chronic, suppurative, fibrotic infection produced by a gram-positive anaerobic bacteria of the normal mouth flora, the infection having tendency to fistulate and to extend without respecting tissue layers. Initial diagnosis is usually delayed due to its painless evolution. Three clinical forms are known: cervicofacial, abdominal and thoracic. Occasionally, there is vascular involvement which is mainly associated with venous thrombotic phenomena with low clinical expresion and hematogenous dissemination that can result in a formation of abscess or meningitis in the central nervous system. We report the case of a 28 year old female patient with type I diabetes and microangiopathyc complication with a internal carotid artery stenosis adjacent to mandibular angle actinomicosis. A few months later and after a miscarriage she suffered fiom ischemic stroke. The anticardiolipin antibody were positive at the time of stroke with post-operative period and over the next two years. Io our knowledge (Medline, 1984-2004), it is the first report of internal carotid vasculitis originated by cervicofacial actinomicosis. We discuss the neuroradiological aspects of our case