| plexus lumbalis | A nervous plexus, formed by the ventral rami of the first four lumbar nerves; it lies in the substance of the psoas muscle, a lymphatic plexus formed of about twenty lymph nodes and connecting vessels situated along the lower portion of the aorta and the common iliac vessels. Synonym: plexus lumbalis. (05 Mar 2000) |
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| plexus lumbosacralis | The lumbar and sacral plexuses taken together. The fibres of the lumbosacral plexus originate in the lumbar and upper sacral spinal cord (l1 to s3) and innervate the lower extremities. (12 Dec 1998) |
| plexus lymphaticus | A plexus of lymphatic capillaries, usually without valves, that opens into one or more larger lymphatic vessels. Synonym: plexus lymphaticus. (05 Mar 2000) |
| plexus mammarius | A lymphatic plexus, including the parasternal; (internal thoracic) lymph nodes, with their vessels, situated along the course of the internal thoracic veins. Synonym: mammary plexus, plexus mammarius. (05 Mar 2000) |
| plexus mammarius internus | An autonomic plexus on the internal thoracic artery derived from the subclavian plexus. Synonym: internal mammary plexus, plexus mammarius internus. (05 Mar 2000) |
| plexus maxillaris externus | An autonomic plexus on the facial artery derived from the external carotid plexus; it sends a branch to the submandibular ganglion. Synonym: external maxillary plexus, plexus maxillaris externus. (05 Mar 2000) |
| plexus maxillaris internus | <anatomy, artery> An autonomic plexus on the maxillary artery derived from the external carotid plexus. Synonym: internal maxillary plexus, maxillary plexus, plexus maxillaris internus. (05 Mar 2000) |
| plexus meningeus | A nerve plexus on the cerebral meninges, derived from the external carotid plexus. Synonym: plexus meningeus. (05 Mar 2000) |
| plexus mesentericus inferior | An autonomic plexus, derived from the abdominal aortic plexus, surrounding the inferior mesenteric artery and sending branches to the descending colon, sigmoid, and rectum. Synonym: plexus mesentericus inferior. (05 Mar 2000) |
| plexus mesentericus superior | An autonomic plexus, a continuation of the abdominal aortic plexus, sending nerves to the intestines and forming with the vagus the subserous, myenteric, and submucous plexus's; this periarterial plexus is so dense that it results in the appearance of a characteristic perivascular "collar" distinguishing the superior mesenteric artery from the superior mesenteric vein in several imaging modalities such as with ultra sound. Synonym: plexus mesentericus superior. (05 Mar 2000) |
| plexus myentericus | One of two ganglionated neural networks which together form the enteric nervous system. The myenteric (auerbach's) plexus is located between the longitudinal and circular muscle layers of the gut. Its neurons project to the circular muscle, to other myenteric ganglia, to submucosal ganglia, or directly to the epithelium, and play an important role in regulating and patterning gut motility. (12 Dec 1998) |
| plexus nervorum spinalium | An intermingling of fibre fascicles from adjacent spinal nerves to form a network; the major plexus's are the cervical, brachial, and lumbosacral. Synonym: plexus nervorum spinalium. (05 Mar 2000) |
| plexus nervosus | A plexus formed by the interlacing of nerves by means of numerous communicating branches. Synonym: plexus nervosus. (05 Mar 2000) |
| plexus occipitalis | An autonomic plexus on the occipital artery derived from the external carotid plexus. Synonym: plexus occipitalis. (05 Mar 2000) |
| plexus oesophageus | One of two nervous plexus's, posterior and anterior on the walls of the oesophagus; the first is formed by branches from the right vagus and left recurrent, the second by the anastomosing trunks of the vagus after leaving the pulmonary plexus's; branches supply the mucous and muscular coats of the oesophagus. Synonym: plexus oesophageus, plexus gulae. (05 Mar 2000) |