| bell metal | A hard alloy or bronze, consisting usually of about three parts of copper to one of tin; used for making bells. Bell metal ore, a sulphide of tin, copper, and iron; the mineral stannite. Source: Websters Dictionary (01 Mar 1998) |
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| bell-shaped crown | A crown of a tooth with an exaggerated occlusogingival contour; human deciduous molars typify the bell-shaped crown. (05 Mar 2000) |
| Bell, Sir Charles | <person> Scottish surgeon, anatomist, and physiologist, 1774-1842. See: Bell's law, Bell-Magendie law, Bell's respiratory nerve, Bell's palsy, Bell's spasm, external respiratory nerve of Bell. (05 Mar 2000) |
| Bell's law | The ventral spinal roots are motor, the dorsal are sensory. Synonym: Bell-Magendie law, Magendie's law. (05 Mar 2000) |
| Bell's muscle | <anatomy> A band of muscular fibres, forming a slight fold in the wall of the bladder, running from the uvula to the opening of the ureter on either side, bounding the trigonum. (05 Mar 2000) |
| 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) |
| 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) |