| bell sound | In cases of a large pulmonary cavity or of pneumothorax, a clear metallic sound obtained by striking a coin, held against the chest, by another coin, or by flicking the chest wall with one's fingernail; the sound is heard on auscultating the chest wall on the same side anteroposteriorly. Synonym: anvil sound, bell sound, coin test. (05 Mar 2000) |
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| Bell's palsy | A condition that involves the facial nerve (VII cranial nerve) and results in the paralysis of one side of the face. Bell's (facial nerve palsy) can be differentiated from a central (stroke) deficit by the inability to raise the eyebrow on the affected side. (27 Sep 1997) |
| Bell's phenomenon | A patient with peripheral facial paralysis cannot close the eyelids of the affected side without at the same time moving the eyeball upward and outward. (05 Mar 2000) |
| Bell's respiratory nerve | <anatomy, nerve> Arises from the fifth, sixth, and seventh cervical nerves (roots of brachial plexus), descends the neck behind the brachial plexus, and is distributed to the serratus anterior muscle; it is somewhat unusual in that it courses on the superficial aspect of the muscle is supplies; its paralysis results in "winged scapula". Synonym: nervus thoracicus longus, Bell's respiratory nerve, external respiratory nerve of Bell, posterior thoracic nerve. (05 Mar 2000) |
| Bell's spasm | Involuntary twitching of the facial muscles, sometimes unilateral. Synonym: Bell's spasm, convulsive tic, facial spasm, histrionic spasm, mimic convulsion, mimic spasm, mimic tic, palmus, prosopospasm. (05 Mar 2000) |
| bell stage | Third stage of tooth development, wherein the cells form the inner enamel epithelium, the stratum intermedium, the stellate reticulum, and the outer enamel epithelium; the enamel organ assumes a bell shape. (05 Mar 2000) |
| syndrome, martin-bell | Better known as the fragile X syndrome, the most common heritable form of mental retardation. Fragile x syndrome is due to mutation (changes) at the fragile x site and so perforce is x-linked (carried on the x chromosome). Although it is usually more severe in males than females, the syndrome is due to a dynamic mutation (a trinucleotide repeat) that can change in length and hence in severity from generation to generation, from person to person, and even within a given person. The fragile x syndrome is known as the martin-bell syndrome in honor of their discovery of it in 1943. (12 Dec 1998) |
| external respiratory nerve of Bell | <anatomy, nerve> Arises from the fifth, sixth, and seventh cervical nerves (roots of brachial plexus), descends the neck behind the brachial plexus, and is distributed to the serratus anterior muscle; it is somewhat unusual in that it courses on the superficial aspect of the muscle is supplies; its paralysis results in "winged scapula". Synonym: nervus thoracicus longus, Bell's respiratory nerve, external respiratory nerve of Bell, posterior thoracic nerve. (05 Mar 2000) |
| acrocephalosyndactyly type 1 | <paediatrics> An inherited disease (autosomal dominant) or a spontaneously occurring disease characterised by a peaked head and unusual facial appearance, due to the premature closure of the cranial sutures. A skull X-ray can confirm the diagnosis and treatment is surgical. Inheritance: autosomal dominant. (27 Sep 1997) |
| Alzheimer type I astrocyte | Enlarged frequently multinucleated astrocytes, seen in progressive multifocal leukoencephalopathy. (05 Mar 2000) |
| Alzheimer type II astrocyte | Enlarged astrocytes with vesicular nuclei and one or more small basophilic nucleoli, seen in hepatocerebral disease and Wilson's disease. (05 Mar 2000) |
| American Type Culture Collection | <cell culture> A key resource for cultured cells, located in Rockville, USA. (12 Dec 1998) |
| Antoni type A neurilemoma | <tumour> Relatively solid or compact arrangement of neoplastic tissue that consists of Schwann cells arranged in twisting bundles and associated with delicate reticulin fibres; the nuclei of the Schwann cells are frequently grouped in parallel rows (so-called palisades), and the nuclei and fibres sometimes form exaggerated tactile corpuscles, called Verocay bodies. (05 Mar 2000) |
| Antoni type B neurilemoma | <tumour> Relatively soft or loose arrangement of neoplastic tissue that consists of Schwann cells in a haphazard or nondescript type of arrangement among reticulin fibres and tiny cystlike foci; fat-laden macrophages may be observed in some of the larger neoplasms. (05 Mar 2000) |
| arthus-type reaction's | Reaction's in man and other species that result from the same basic immunologic (allergic) mechanism which evokes, in the rabbit, the typical Arthus phenomenon. See: immune complex disease. (05 Mar 2000) |