| primitive streak | An ectodermal ridge in the midline at the caudal end of the embryonic disk from which arises the intraembryonic mesoderm; achieved by inward and then lateral migration of cells; in human embryos, it appears on day 15 and gives a cephalocaudal axis to the developing embryo. Synonym: germinal streak. (05 Mar 2000) |
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| neuroectodermal tumour, primitive | A malignant brain tumour sharing common features and biologic properties with medulloblastoma. Some pathologists and clinicians use the terms interchangeably: they both can disseminate throughout the nervous system and, in some cases, systemically. most lesions arise from the posterior fossa in children under five years of age. The tumour often produces hydrocephalus and symptoms of increased intracranial pressure. Papilledema is often present. (12 Dec 1998) |
| vertebral part of the costal surface of the lungs | The part of the medial surface of the lung in contact with the vertebral bodies. Synonym: pars vertebralis faciei costalis pulmonis. (05 Mar 2000) |
| costal | <anatomy> Pertaining to the ribs. (27 Sep 1997) |
| costal angle | The rather abrupt change in curvature of the body of a rib posteriorly, such that the neck and head of the rib are directed upward. Synonym: angulus costae. (05 Mar 2000) |
| costal arch | That portion of the inferior aperture of the thorax formed by the articulated cartilages of the seventh to tenth (false) ribs. Synonym: arcus costalis, arcus costarum. (05 Mar 2000) |
| costal arch reflex | Contraction of the rectus abdominis muscle by tapping the costal margin inside the mammary line. (05 Mar 2000) |
| costal cartilage | The cartilage forming the anterior continuation of a rib, providing the means by which it reaches and articulates with the sternum. Synonym: cartilago costalis, costicartilage. (05 Mar 2000) |
| costal chondritis | <pathology> A condition that is caused by inflammation of the costochondral joints. This is perceived as chest pain with tenderness to one or both sides of the sternum (breast bone). Chest pains are often worse when taking a deep breath or moving the chest wall. Treatment includes warm, wet compresses to the anterior chest wall and oral anti-inflammatory agents. (27 Sep 1997) |
| costal facets | Articular surface on a vertebra for articulation with a rib. (05 Mar 2000) |
| costal fringe | An irregularly disposed collection of visible veins seen in the skin of people usually of or past middle age; it has no specific connection with any deep structure, such as the diaphragm, and no necessary connection with underlying visceral disease. Synonym: zona corona. (05 Mar 2000) |
| costal groove | A groove in the lower inner border of the rib, lodging the intercostal vessels and nerve. Synonym: sulcus costae, subcostal groove. (05 Mar 2000) |
| costal groove for subclavian artery | <anatomy, artery> A groove immediately posterior to the scalene tubercle on the upper surface of the first rib across which the subclavian artery passes. Synonym: sulcus costae arteriae subclaviae. (05 Mar 2000) |
| costal margin | The lower edge of the chest (thorax) formed by the bottom edge of the rib cage. (12 Dec 1998) |
| costal notch | One of the notches or facets on the lateral edge of the sternum for articulation with a costal cartilage. Synonym: incisura costalis. (05 Mar 2000) |