| primary tuberculosis | First infection by Mycobacterium tuberculosis, typically seen in children but also occurs in adults, characterised in the lungs by the formation of a primary complex consisting of small peripheral pulmonary focus with spread to hilar or paratracheal lymph nodes; may cavitate or heal with scarring or may progress. Synonym: childhood type tuberculosis. (05 Mar 2000) |
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| primary tumour | <oncology> The mass of tumour cells at the original site of the neoplastic event from the primary tumour metastasis will lead to the establishment of secondary tumours. (18 Nov 1997) |
| primary union | Healing by fibrous adhesion, without suppuration or granulation tissue formation. Synonym: primary adhesion, primary union. (05 Mar 2000) |
| primary uterine inertia | True uterine inertia, uterine inertia that occurs when the uterus fails to contract with sufficient force to effect continuous dilation or effacement of the cervix or descent or rotation of the foetal head, and when the uterus is easily indentable at the acme of contraction, secondary uterine inertia, uterine inertia that occurs when the uterine contractions are vigorous but, as a result of the exhaustion or dehydration of the patient, decrease in vigor, and the progress of labour ceases. (05 Mar 2000) |
| primary vaccination | <virology> First or principal vaccination with the introduction of a vaccine into the body for the purpose of inducing immunity. (18 Nov 1997) |
| primary villus | The first stage of chorionic villus development, with columns of cytotrophoblastic cells covered by syncytiotrophoblast. (05 Mar 2000) |
| primary visual area | Area of the occipital lobe concerned with vision. (12 Dec 1998) |
| primary visual cortex | See: visual cortex. (05 Mar 2000) |
| 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) |