| primary vitreous | The vitreous first formed in the embryo between the optic cup and the lens vesicle, and later vascularised by the hyaloid artery and its branches. (05 Mar 2000) |
|---|---|
| hyperoxaluria, primary | Either of two genetic disorders characterised by urinary excretion of large amounts of oxalate, with nephrolithiasis, nephrocalcinosis, early onset of renal failure, and often a generalised deposit of calcium oxalate, resulting from a defect in glyoxalate metabolism. (12 Dec 1998) |
| neoplasms, multiple primary | Two or more abnormal growths of tissue occurring simultaneously. The neoplasms are histologically different and may be found in the same or different sites. (12 Dec 1998) |
| neoplasms, second primary | Abnormal growths of tissue that follow a previous neoplasm but are not metastases of the latter. The second neoplasm may have the same or different histological type and can occur in the same or different organs as the previous neoplasm but in all cases arises from an independent oncogenic event. The development of the second neoplasm may or may not be related to the treatment for the previous neoplasm since genetic risk or predisposing factors may actually be the cause. (12 Dec 1998) |
| neoplasms, unknown primary | Metastases in which the tissue of origin is unknown. (12 Dec 1998) |
| dentition, primary | The teeth first in order or time of development that will be replaced by permanent dentition upon their loss. (12 Dec 1998) |
| dorsal primary ramus of spinal nerve | <anatomy, nerve> The smaller, posteriorly-directed major terminal branch (with the ventral primary ramus) of all 31 pairs of mixed spinal nerves, formed at the intervertebral foramen and turning abruptly posteriorly to divide into lateral and medial branches, both of which will supply the deep (true) muscles of the back. The medial branch (rami medialis ) of the dorsal primary ramus also supplies articular branches to the zygopophyseal joints and the periosteum of the vertebral arch. In the neck and upper back, the medial branch continues through the deep and superficial back muscles to supply overlying skin; in the lower back, the lateral branch does this. Nomina Anatomica lists dorsal primary rami as "rami dorsales" for each group of spinal nerves: 1) cervical (nervorum cervicalium ), 2) thoracic (nervorum thoracicorum ), 3) lumbar (nervorum lumbalium ), 4) sacral (nervorum sacralium ), and 5) coccygeal (nervi coccygei ). Synonym: ramus dorsalis nervorum spinalium, ramus dorsalis, rami posteriores nervorum spinalium, dorsal branch, posterior primary division. (05 Mar 2000) |
| International Classification of Health Problems in Primary Care | A classification of diseases, conditions and problems arranged for use in primary care where diagnostic precision is seldom possible. (05 Mar 2000) |
| osteoarthropathy, primary hypertrophic | A conditioned chiefly characterised by thickening of the skin of the head and distal extremities, deep folds and furrows of the skin of the forehead, cheeks, and scalp, seborrhoea, hyperhidrosis, periostosis of the long bones, digital clubbing, and spadelike enlargement of the hands and feet. It is more prevalent in the male, and is usually first evident during adolescence. It is believed to be inherited as an autosomal dominant trait. (12 Dec 1998) |
| lateral cutaneous branches of ventral primary ramus of thoracic spinal nerves | Branches arising in approximately the anterior axillary line at the level of the second through sixth intercostal spaces. Synonym: rami mammarii laterales nervorum intercostalium, lateral cutaneous branches of intercostal nerves. (05 Mar 2000) |
| absolute system of units | A system based on absolute units accepted as being fundamental (length, mass, time) and from which other units (force, energy or work, power) are derived; such system's in common use are the foot-pound-second, centimeter-gram-second, and meter-kilogram-second system's. (05 Mar 2000) |
| absorbent system | <anatomy> The tissues and organs (including the bone marrow, spleen, thymus and lymph nodes) that produce and store cells that fight infection and the network of vessels that carry lymph. (12 May 1997) |
| alimentary system | The organs that are responsible for getting food into and out of the body and for making use of food to keep the body healthy. These include the mouth, oesophagus, stomach, liver, gallbladder, pancreas, small intestine, colon, and rectum. (12 Dec 1998) |
| anterolateral system | A composite bundle of fibres, located in the ventrolateral part of the lateral funiculus, containing spinothalamic, spinohypothalamic, spinoreticular, and spinomesencephalic (spinotectal, spinal to periaqueductal grey, etc.) fibres; occupies the combined areas of the spinal white matter historically divided into anterior and lateral spinothalamic tracts; located in white matter ventral to the denticulate ligament, hence the anatomical basis for the anterolateral cordotomy; concerned with the transmission of nociceptive and thermal information and with crude (nondiscriminative) touch. (05 Mar 2000) |
| anti-allergic and respiratory system agents | A collective term for drugs used to treat allergic reactions as well as those drugs that produce an effect on the respiratory system. (12 Dec 1998) |