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Coverings of the central nervous system

The central nervous system (CNS) is supported and protected by bone and membranous coverings. The brain is located within the cranial cavity of the skull and the spinal cord lies in the vertebral, or spinal, canal within the vertebral column, or spine. Within their bony coverings, the brain and spinal cord are invested by three concentric membranous envelopes. The outermost membrane is the dura mater, the…

Peripheral nervous system

The peripheral nervous system consists of sensory and motor nerve endings, peripheral nerve trunks, plexuses and ganglia, which link the CNS with other parts of the body. Most of the neurones in the peripheral nervous system are, therefore, either afferent or efferent with respect to the CNS. Nerve endings include sensory receptors, that detect changes in the internal and external environments, and efferent endings, which control…

Cells of the nervous system

The functional unit of the nervous system is the nerve cell or neurone. These cells are highly specialised for the encoding, conduction and transmission of information. Neuroglial cells, or glia, are present in the nervous system in even larger numbers than neurones. Glia do not take part directly in information processing but are, nonetheless, crucial for normal neural function. Other cells are also present in the…

Introduction and overview

The nervous system of all animals functions to detect changes in the internal and external environments and to bring about responses in muscles, organs and glands that are appropriate for the preservation of the individual and the propagation of the species. In relatively primitive species such functions are focused primarily on: Maintenance of the internal environment (homoeostasis) Perception of, and response to, external stimuli/threats Finding food…

THERAPIES AND THERAPEUTIC PROCEDURES

PULMONARY PHARMACOLOGY Pulmonary pharmacology concerns the effects of drugs on the lungs and understanding how drugs used to treat patients with pulmonary diseases work. Much of this pharmacology concerns drugs used to treat obstructive airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Two types of drugs are used in the treatment of obstructive airway diseases: Relievers (bronchodilators) give immediate reversal of airway obstruction,…

DISEASES AND PATHOLOGY

Plate 4-1 Open full size image CONGENITAL DEFORMITIES OF THE THORACIC CAGE PECTUS EXCAVATUM Pectus excavatum is also called funnel chest, chonechondrosternon, or trichterbrust. It is a deformity of the anterior chest wall characterized by depression of the lower sternum and adjacent cartilages. The lowest point of the depression is at the junction of the xiphoid process and the body of the sternum. The trait is…

DIAGNOSTIC PROCEDURES

TESTS OF PULMONARY FUNCTION RADIOLOGIC EXAMINATION OF THE LUNGS Chest radiography remains the primary imaging modality for initial evaluation of patients with suspected chest disease and in many cases not only identifies abnormalities but also allows a specific determination of the nature of the disease present. ROUTINE EXAMINATION (see Plates 3-4 to 3-6 ) In most imaging centers, radiographs are no longer recorded on film but…

PHYSIOLOGY

PULMONARY MECHANICS AND GAS EXCHANGE The major function of the lung is to deliver oxygen to and remove carbon dioxide from the blood as it passes through the pulmonary capillary bed. This function is achieved through a series of complex and highly integrated series of processes. The first step in this essential gas exchange process is the contraction of the inspiratory muscles, producing the force (pressure…

ANATOMY AND EMBRYOLOGY

RESPIRATORY SYSTEM The respiratory system is made up of the structures involved in the exchange of oxygen and carbon dioxide between the blood and the atmosphere, so-called external respiration . The exchange of gases between the blood in the capillaries of the systemic circulation and the tissues in which these capillaries are located is referred to as internal respiration . The respiratory system consists of the…

Spine

Cervical Spine Axial 1 Pathologic Process Note on these images that the nasopharynx is often seen on cervical spine imaging. The neuroradiologist should always check for symmetry of the Eustachian tube opening and fossa of Rosenmüller just anterior to the longus capitis muscle to ensure that no nasopharyngeal lesion is present (see Chapter 13 ). Imaging Technique Consideration Spinal imaging can be daunting at first due…

Hypopharynx, Larynx, and Infrahyoid Neck

Hypopharynx, Larynx, and Infrahyoid Neck Axial 1 Diagnostic Consideration Axial 1 on the next page shows both a T2-weighted sequence (upper image) and a T1-weighted image (lower). Note that cerebrospinal fluid (CSF) around the spinal cord is bright on T2-weighted magnetic resonance imaging and dark gray on T1-weighted MRI. Usually the brightest structure on T1-weighted imaging is fat. Note that the fat is somewhat bright on…

Oral Cavity, Pharynx, and Suprahyoid Neck

Oral Cavity, Pharynx, and Suprahyoid Neck Axial 1 Normal Anatomy Note the enhancement of the mucosal surfaces of the aerodigestive tract on the lower magnetic resonance (MR) image in Axial 1 after gadolinium contrast administration. The subcutaneous adipose tissue and the adipose planes between the structures in the neck are visible on both the upper pre-contrast T1-weighted MR image and the lower post-contrast T1-weighted MR image.…

Temporal Bone (Middle Ear, Cochlea, Vestibular System)

Temporal Bone Axial 1 Normal Anatomy The temporal bone initially may seem a daunting area for magnetic resonance imaging because of the apparent structural complexity. To understand the temporal region better, trace the hearing pathway from auricle through external auditory canal, to tympanic membrane attached to small bones (ossicles; malleus, incus, and stapes) in the middle ear cavity, through stapes stirrup on oval window, then vestibule…

Mandible and Muscles of Mastication

Mandible and Muscles of Mastication Axial 1 Normal Anatomy Four paired muscles—temporalis, masseter, medial pterygoid, and lateral pterygoid—are the primary muscles of mastication, responsible for adduction and lateral motion. In the axial MR image on the next page, note the temporalis muscle superficial to the temporal lobe of the brain. These muscles are innervated by the mandibular branch (V 3 ) of the trigeminal nerve, cranial…

Orbits

Orbits Axial 1 Orbits Axial 1 Orbits Axial 2 Orbits Axial 2 Orbits Axial 3 Normal Anatomy The lenses are normally biconvex in shape. If this configuration is replaced by a thin line, the patient likely has had the lens removed because of cataracts and replaced with an artificial lens. Orbits Axial 3 Orbits Axial 4 Orbits Axial 4 Orbits Axial 5 You’re Reading a Preview…

Paranasal Sinuses

Paranasal Sinuses Axial 1 Normal Anatomy The paranasal sinuses are composed of the frontal sinuses, the ethmoid sinuses or ethmoid air cells, the maxillary sinuses or maxillary antra, and the sphenoid sinuses. The names are derived from the bones that form the walls of the sinuses. Paranasal Sinuses Axial 1 Paranasal Sinuses Axial 2 Normal Anatomy The sphenoid sinuses are at the center of the skull…