| frontal sinus aperture | One of a pair of openings in the floor of the frontal sinuses in the nasal part of the frontal bone, through which the frontal sinuses communicate with the ethmoidal infundibulum via the frontonasal duct. Synonym: apertura sinus frontalis. (05 Mar 2000) |
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| frontal sinusitis | Inflammation of the frontal sinus; in most cases the infection is caused by the bacteria streptococcus pneumoniae and haemophilus influenzae. This condition may be acute or chronic. (12 Dec 1998) |
| frontal squama | The tabular or squamous portion of occipital bone. Synonym: squama occipitalis, occipital squama, frontal squama. (05 Mar 2000) |
| frontal suture | The suture between the two halves of the frontal bone, usually obliterated by about the sixth year; if persistent it is called a metropic suture. Synonym: sutura frontalis. (05 Mar 2000) |
| frontal triangle | A triangle bounded above by the maximum frontal diameter and laterally by lines joining the extremities of this diameter with the glabella. (05 Mar 2000) |
| frontal tuber | The most prominent portion of the frontal bone on either side. Synonym: tuber frontale, eminentia frontalis, frontal tuber. (05 Mar 2000) |
| frontal zone contraction theory | Model proposed to account for the movement of giant amoebae in which cytoplasmic contraction at the front of the leading pseudopod (fountain zone) pulls viscoelastic cytoplasm forward in the centre of the cell and forms a tube of more rigid cytoplasm immediately below the plasma membrane behind the active region. The peripheral contracted cytoplasm relaxes into a weaker gel at the rear and is pulled forward in its turn. Contrasts with the ectoplasmic tube contraction model. (18 Nov 1997) |
| accessory cephalic vein | <anatomy, vein> A variable vein that passes along the radial border of the forearm to join the cephalic vein near the elbow. Synonym: vena cephalica accessoria. (05 Mar 2000) |
| accessory hemiazygos vein | <anatomy, vein> Formed by the union of the fourth to seventh left posterior intercostal veins, passes along the side of the bodies of the fifth, sixth, and seventh thoracic vertebrae, then crosses the midline behind the aorta, oesophagus, and thoracic duct, and empties into the azygos vein, sometimes in common with the hemiazygos vein. Synonym: vena hemiazygos accessoria, vena azygos minor superior. (05 Mar 2000) |
| accessory saphenous vein | <anatomy, vein> An occasional vein running in the thigh parallel to the great saphenous vein which it joins just before the latter empties into the femoral vein. Synonym: vena saphena accessoria. (05 Mar 2000) |
| accessory vertebral vein | <anatomy, vein> A vein that accompanies the vertebral vein but passes through the foramen of the transverse process of the seventh cervical vertebra and opens independently into the brachiocephalic vein. Synonym: vena vertebralis accessoria. (05 Mar 2000) |
| accompanying vein | A vein accompanying another structure. Synonym: accompanying vein, companion vein. (05 Mar 2000) |
| accompanying vein of hypoglossal nerve | Runs with the hypoglossal nerve below and lateral to the hyoglossus muscle, emptying usually into the lingual vein. Synonym: accompanying vein of hypoglossal nerve. (05 Mar 2000) |
| angular vein | <anatomy, vein> A short vein at the medial angle of the eye, formed by the supraorbital and supratrochlear veins's and continuing as the facial vein. Synonym: vena angularis. (05 Mar 2000) |
| anterior auricular vein | <anatomy, vein> One of several veins draining the auricle and acoustic meatus and emptying into the retromandibular vein. Synonym: vena auricularis anterior, vena preauricularis. (05 Mar 2000) |