Plexus

(pleks'-us). An aggregation of ve els or nerves forming an intricate network. A table of the nerve-plexuses is appended. P. articular is, a small venous plexus near the outer aspect of the temporo-maxillary articulation. P. cerebri, either of the choroid plexuses. P., Choroid, a fringe like membrane, occupying the margin of a fold of the pia mater in the interior of the brain. In structure, it consists of minute and highly vascular villous proce es, composed of large round corpuscles, containing, besides a central nucleus, several yellowish granules and fat-molecules, and covered by a single layer of flattened epithelium. P. ciliaris. Synonym of Canal of Schlemm. P. cirsoides. Synonym of P., Pam pin i form. P. digitalis, one of the venous plexuses on the anterior and posterior surfaces of the second and third phalanges. P., Fundamental. See P., Principal. P., Ganglionic, a nervous plexus in which ganglion -cells are found. P. gangliosus, one of the small plexuses formed at the junction of the spinal nerves and the inferior hypogastric plexus. They contain a number of ganglia. P. glandular is, P. glanduliformis. Synonym of P., Choroid. P., Hemorrhoidal, a plexus of veins surrounding the lower part of the rectum, beneath the mucous membrane, and giving origin to the inferior, middle, and superior hemorrhoidal veins. P., Hovius', a plexus of veins in the ciliary region of the eye. P., Interlaminar, a lymphatic plexus formed by the lymphatic ve els in the muscular coat of the intestines. P., Lymphatic, a plexus of lymphatic ve els. P. Malleal, P., Manubrial, a plexus of veins surrounding the handle of the malleus. P., Medulli-spinal, a venous plexus surrounding the spinal cord. P., mirabilis. Synonym of P., Choroid. P. nervorum spinalium, a plexus formed by the spinal nerves, e. g., the cervical, brachial, lumbar, or sacral. P., Pam pin i form, the spermatic plexus, collecting the blood from the testicle, and emptying by a single vein,: the spermatic, into the right renal vein on the right side, and into the inferior cava on the left. In the female, the plexus collects the blood from the uterus, the oviduct, and the ovary. P., Parotid. Synonym of Pes an serin us. P., Perineal, a superficial and a deep venous plexus are found in the perineum. The superficia formed by veins from the labia major a and some from the prepuce of the clitoris and the bulbs. Its blood is carried to the superficial epigastric, pudic and external obturator veins.