| hiatus of facial canal | The opening on the anterior aspect of the petrous part of the temporal bone which leads to the facial canal and gives passage to the greater petrosal nerve. Synonym: hiatus canalis nervi petrosi majoris, fallopian hiatus, Ferrein's foramen, hiatus canalis facialis, hiatus of canal for greater petrosal nerve. (05 Mar 2000) |
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| hiatus sacralis | A normally-occurring gap at the lower end of the sacrum, exposing the vertebral canal, due to failure of the laminae of the last sacral segment to coalesce. It is closed by the sacrococcygeal ligament, and provides cannular access to the sacral epidural space for administration of anaesthetics (caudal nerve blocks). Synonym: hiatus sacralis. (05 Mar 2000) |
| hiatus saphenus | The opening in the fascia lata inferior to the medial part of the inguinal ligament through which the saphenous vein passes to enter the femoral vein. Synonym: hiatus saphenus, fossa ovalis, saphenous hiatus. (05 Mar 2000) |
| hiatus semilunaris | A deep, narrow groove in the lateral wall of the middle meatus of the nasal cavity, into which the maxillary sinus, the frontonasal duct, and the middle ethmoid cells open. Synonym: hiatus semilunaris, hiatus ethmoidalis. (05 Mar 2000) |
| hiatus subarcuatus | An irregular depression on the posterior surface of the petrous portion of the temporal bone just below its crest and above and lateral to the internal acoustic meatus. In the foetus, the flocculus of the cerebellum rests here; in the adult, a small vein enters the bone here. Synonym: fossa subarcuata, floccular fossa, hiatus subarcuatus. (05 Mar 2000) |
| hiatus tendineus | The aperture in the aponeurotic insertion of the adductor magnus that transmits the femoral artery and vein from the adductor canal to the popliteal space. Synonym: hiatus tendineus, hiatus adductorius, femoral opening, tendinous opening. (05 Mar 2000) |
| hiatus totalis sacralis | Developmental clefting in all sacral vertebrae; may also involve adjacent lumbar vertebrae. (05 Mar 2000) |
| HIB | <virology> A vaccination that is given to infants to protect against infection with haemophilus influenza b, an important cause of neonatal sepsis. Typically administered at 2, 4, 6 and 15 months. Children who are aged 15 months to 5 years, who have not received the vaccine, should be given a single injection of haemophilus b conjugate vaccine. Acronym: HIB (26 Mar 1998) |
| hib immunization | This vaccine is to prevent disease caused by the haemophilus influenzae type b (hib) bacteria. The h. Influenzae (h. Flu) bacteria can cause a range of serious diseases including meningitis with potential brain damage and epiglottitis with airway obstruction poisoning. The hib vaccine is usually given at 2, 4 and 6 months of age. A final booster is given at 12-15 months of age. Hib vaccine rarely causes severe reactions. (12 Dec 1998) |
| hib vaccine | A vaccination that is given to infants to protect against infection with haemophilus influenza b, an important cause of neonatal sepsis. Typically administered at 2, 4, 6 and 15 months. Children who are aged 15 months to 5 years, who have not received the vaccine, should be given a single injection of haemophilus b conjugate vaccine. (27 Sep 1997) |
| hibernacle | <plant biology, zoology> That which serves for protection or shelter in winter; winter quarters; as, the hibernacle of an animal or a plant. Origin: L. Hibernaculum a winter residence, pl. Hibernacula winter quarters: cf. F. Hibernacle. See Hibernate. (26 Mar 1998) |
| hibernacula | Caves or other structures used by bats for hibernation. (05 Dec 1998) |
| hibernaculum | <plant biology> A plant organ such as a bud, rhizome, turion, etc. Which allows a plant to live through adverse conditions. (26 Mar 1998) |
| hibernating gland | A thermogenic type of adipose tissue containing a dark pigment, and arising during embryonic life in certain specific areas in many mammals, including man. It is prominent in the newborn of all species in which it occurs and remains a distinct and conspicuous tissue in the adults of certain species, especially those that hibernate. It is also called brown adipose tissue. (12 Dec 1998) |
| hibernation | The dormant state in which some animal species pass the winter. It is characterised by narcosis and by sharp reduction in body temperature and metabolic activity and by a depression of vital signs. It is a natural physiological process in many warm-blooded animals. (12 Dec 1998) |