A kind of Indian wheat. See Cerealia. Meatus, (from meo, to pass,) a duct, passage, or any open canal. The auditory passage is the meatus audi tortus; the Eustachian tube meatus a palato ad au-rem; the urethra meatus urinarius; the ducts which convey the bile from the gall bladder to the duodenum the meatus cystici.

Meatus auditorius externus is the external passage to the ear, beginning at the hollow of the outer ear, and ending at the drum. It was formerly a name for the Eustachian tube. See Auricula. Meatus caecus. See Tuba Eustachiana. Mecapatli. Theamerican name for one of the species of sarsaparilla.


(From Mecon 4863 bulk; from the largeness of its head). See Papaver.

Meconis And Meconium

(From Meconis And Meconium 4864 the hoppy). See Peplion.


(Syr.e.) (from the same). See Pa-paver Album.


(From the same). Opium is the juice flowing from the poppy head through artificial incisions; but meconium is the juice of the whole plant, first bruised, then pressed out. The excrement also contained in the intestines of a newly born infant, which has obtained its name from its resemblance to opium. See Infans.


A species of ulcer. Paracelsus. Medena vena; the same with medinensis vena. Castellus.

Mediana Vena

(From medius, middle). A remarkable vein on the inside of the flexure of the cubit, between the cephalic and basilic veins, called by the Arabians funis brachii. It is frequently opened in bleeding.

Mediana cephalica, (from the same). See Ce-phalica mediana.


(From the same). See Mediasmedianus, (from the same). See Cervicales.


(From the same). See Inflam-matio mediastini.

Mediastinae Arteriae

(From the same). The arteries of the mediastinum arise from the subclavian, and are spread on the mediastinum.

Mediastini.'n AE venae, (from the same). The right vein of the mediastinum comes out from the trunk of the superior vena cava anterior, a little above the azy-gos; the left from the subclavia.


(From the same,) medianum, is the membrane called the pleura, which, after covering the internal surface of the chest, rises from the spine, and is reflected on each side to cover the lungs. This double membrane between each lobe divides the chest into two cavities. It is commonly said, that at the sternum there is a cavity betwixt the laminae of the mediastinum, and that any matter may be discharged, if lodged there, by a perforation through the middle of that bone. This operation, however, if really required, would be very uncertain; for the mediastinum does not commonly terminate along the middle of the inside of the sternum, but from above, all the way down, it inclines to the left side; so that, if an instrument was thrust through the middle of the sternum, it would pass near an inch on one side of the membrane.

The mediastinum contains in its duplicature the heart, the pericardium, the vena cava, and the oesophagus.