| nuclear pacemaker | A nuclear-powered unit used to generate the electrical current for artificially pacing the heart; replaced by units using long-life nickel-cadmium and other power sources. (05 Mar 2000) |
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| demand pacemaker | A form of artificial pacemaker usually implanted into cardiac tissue because its output of electrical stimuli can be inhibited by endogenous cardiac electrical activity. (05 Mar 2000) |
| diaphragmatic pacemaker | A device that paces the diaphragm, used in patients with chronic ventilatory insufficiency resulting from malfunction of the respiratory control centre on certain types of phrenic nerve malfunction. (05 Mar 2000) |
| ectopic pacemaker | Any pacemaker other than the sinus node. (05 Mar 2000) |
| electric cardiac pacemaker | An electric device that can substitute for the normal cardiac pacemaker, controlling the heart's rhythm by artificial electric discharges. Synonym: electronic pacemaker. (05 Mar 2000) |
| electronic pacemaker | An electric device that can substitute for the normal cardiac pacemaker, controlling the heart's rhythm by artificial electric discharges. Synonym: electronic pacemaker. (05 Mar 2000) |
| electronic pacemaker load | The impedance to the output, the standard load being 500 ohms resistance ± 1%. (05 Mar 2000) |
| transthoracic pacemaker | Artificial pacemaker delivering stimuli through the chest wall usually applied as a temporizing measure in patients with atrioventricular block. (05 Mar 2000) |
| fixed-rate pacemaker | An artificial pacemaker that emits electrical stimuli at a constant frequency. (05 Mar 2000) |
| abdominal external oblique muscle | <anatomy, muscle> Origin, fifth to twelfth ribs; insertion, anterior half of lateral lip of iliac crest, inguinal ligament, and anterior layer of the rectus sheath; action, diminishes capacity of abdomen, draws thorax downward; nerve supply, thoracoabdominal nerves. Synonym: musculus obliquus externus abdominis, abdominal external oblique muscle. (05 Mar 2000) |
| ambiguous external genitalia | External genitalia not clearly of either sex; most commonly designates external genitalia that are incompletely masculinised. (05 Mar 2000) |
| anterior scrotal branch of external pudendal artery | <anatomy, artery> Distribution, skin of anterior scrotum; anastomoses, posterior scrotal branches from internal pudendal artery. Synonym: rami scrotales anteriores arteriae pudendae externae. (05 Mar 2000) |
| aponeurosis of external abdominal oblique muscle | <anatomy> Broad, flat tendinous portion of the external abdominal oblique muscle. The fleshy fibres of the muscle end in the aponeurosis along a line descending vertically from the costochondral joint of the ninth rib then turning laterally just below the level of the umbilicus toward the anterior superior iliac spine. The fibres of the aponeurosis run medially and inferiorly, contributing to the anterior wall of the sheath of the rectus abdominis muscle and decussating with those of the contralateral aponeurosis at the median linea alba. Inferomedially, the aponeurosis is attached to the upper border of the pubic symphysis, the pubic crest and pubic tubercle. Between the anterior superior iliac spine and the pubic tubercle, it is thickened and turned under, forming the inguinal ligaments. The portion of the aponeurosis attached to the pubic bone forms the superficial inguinal ring by splitting into medial and lateral crura. See: external spermatic fascia, inguinal ligament, lacunar ligament, pectineal ligament, reflected inguinal ligament, superficial inguinal ring, rectus sheath. (05 Mar 2000) |
| bony part of external acoustic meatus | The medial two-thirds of the external acoustic meatus which is formed as the tympanic plate of the temporal bone develops; it extends approximately 16 mm. From its junction with the cartilaginous part to the tympanic membrane. (05 Mar 2000) |
| carotid artery, external | Branch of the common carotid artery which supplies the exterior of the head, the face, and the greater part of the neck. (12 Dec 1998) |