MEMBRANACEOUS 



742 



MEMBRANE 



glottic folds. M. ruyschiana, the middle or capillary 

 layer of the choroid. M. semilunaris conjunctivae. 

 See Membrane, Nictitating. M. serotina, that part 

 of the decidua which enters into the formation of the 

 placenta. M. sinuosa, M. spongiosa, the decidua. 

 M. tectoria, a delicate membrane of the internal 

 ear, extending from the upper lip of the limbus above 

 the sulcus spiralis and the organ of Corti as far as 

 the last row of the outer hair cells. It is also known 

 as Corti's membrane. M. tensa, the tympanic mem- 

 brane proper, exclusive of Shrapnell's membrane. 

 M. tenuis, the arachnoid. M.tympani. See Mem- 

 brane, Tympanic. M. tympani, Artificial. See 

 Membrane, Tympanic. M. tympani secundaria. 

 See Membrane, Secondary Ty?npanic. M. urinaria, 

 the allantois. M. vasculosa cerebri, the pia. M. 

 vibrans. Synonym of M. tensa. M. virginalis, 

 the hymen. M. vocalis, the portion of the laryngeal 

 mucosa investing the vocal bands. 



Membranaceous (mem-bran-a' '-ce-us) \membranaceus, 

 from membrum, member]. Pertaining to, consisting 

 of, or of the nature of, a membrane. 



Membrane (inem r -brati) \_membrana, from membrum, 

 member]. In anatomy, a term applied to almost any 

 thin, enveloping or lining substance. In the plural 

 it usually signifies the fetal membranes. M., Adven- 

 titious. See Adventitia. M., Albugineous. See 

 Albuginea. M., Amphiblestroid, the retina. M., 

 Animal, a membrane made from animal tissues, used 

 in dialyzing; also, in the plural, the fetal membranes. 

 M., Arachnoid. See Arachnoid. M. of Arnold, the 

 pigmented layer of the iris. M. of Ascherson. See 

 M. , Haptogenous. M., Bacillar. See M., Jacob's. 

 M., Basement or Basal, in histology, a delicate 

 membrane, made up of flattened cells, and underlying 

 the epithelium of the mucous surfaces. M.-bone, 

 any bone that originates, not in cartilage, but in mem- 

 brane, such as some of the cranial and facial bones. 

 M., Bowman's. See Bowman. M. of Bruch, 

 a thin, transparent, homogeneous membrane, the 

 external or vitreous lamina of the choroid of the eye. 

 M., Caducous, the decidua. M., Cell, the mem- 

 brane surrounding a cell ; the cell- wall. M. of 

 Corti. See Membrana tectoria. M., Costo-cora- 

 coid, a dense layer of fascia extending between the 

 subclavius muscle and the pectoralis minor, and form- 

 ing the anterior portion of the sheath of the axillary 

 vessels. M., Crico-thyroid, the triangular mem- 

 brane connecting the thyroid and cricoid cartilages of 

 the larynx. M., Croupous. See M., Diphtheric. 

 M., Debove's, a deep, germinal layer of flattened 

 cells in the mucosa of the trachea and extra- 

 pulmonary bronchi. M. of Descemet. See 

 Descemef s Membrane. M., Diphtheric, a fibrinous 

 layer formed on the surface of mucous membranes and 

 extending downward for a variable depth. It is due 

 to a process of coagulation-necrosis. The most com- 

 mon cause of its formation is the bacillus of diph- 

 theria; irritant poisons also may produce it. M., Drum. 

 Synonym of the tympanic membrane. M., Elastic, 

 a membrane largely composed of elastic fibrous tissue. 

 M., Elytroid, the fibers of the cremaster muscle 

 covering the testicle. M., False. See M. , J)iph- 

 theric. M., Fenestrated. See Fenestrated Mem- 

 brane of Henle. M., Fetal, a name given to 

 the chorion, amnion, and allantois. M., Germinal, 

 the blastoderm. M., Glassy, the hyaloid mem- 

 brane. M., Granular. See Membrana granulosa. 

 M., Haptogenous, a delicate albuminous pellicle 

 supposed to envelop the fat-globules of milk and of 

 other fluids containing fat and albumin. M., Homo- 

 geneous, a delicate layer of connective tissue cover- 



ing the placental villi. M., Huxley's, a sheatl 

 peculiar to hair and surrounding the proximal part o 

 the shaft. M., Hyaloid, a delicate areolar membra 

 investing the vitreous humor of the eye. M., Inor- 

 ganic, a membrane used in dialyzing fluids ; it i- 

 composed of silicic acid. M., Internal, the endyma. 

 q. v. M., Interosseous, a thin aponeurosis of parallel 

 fibers extending between contiguous borders of tin 

 tibia and fibula, and the ulna and radius. M., 

 Jacob's, the layer of rods and cones of the retina. 

 M., Krause's, a thin, transverse, dark disc bisecting 

 the light substance of the striped muscle fibers ; ii 

 divides the fibers into muscular compartments. M., 

 Meconic, a layer within the rectum of the fetus. 

 supposed to invest the meconium. M., Mucous, the 

 continuation of the skin lining those internal cavities 

 and organs exposed to or communicating with the air. 

 It is kept moist by the mucus secreted by the goblet- 

 cells and mucous glands. M. of Nasmyth, a delicate 

 but firm membrane covering the ectal surface of the 

 enamel for a short time after birth. M., Nictitating, 

 the plica or third eyelid, a mucous fold at the nasla 

 canthus of the eyes of birds and certain quadrupeds. 

 M., Nuclear, the membrane surrounding the nucleus 

 of a cell. M., Obturator, the fibrous membrane clos- 

 ing the obturator foramen. M., Olfactory. 

 Schneiderian . M., Ovular. See M., Vitelline. M., 

 Perforated (of Henle), the ental elastic layer of an 

 artery. M., Perifibril, a special membrane surround 

 ing the skeletal threads of some sponges ( Chalinula > 

 it is composed of epithelial cells, either transparent 01 

 deeply-colored with granules (Hyatt). M., Perio- 

 dontal, a fibrous layer covering the cement of teeth 

 M., Pharyngeal, the oral plate separating the primi I 

 tive oral and pharyngeal cavities in the embryo. 1 

 formed of an anterior ectodermic and posterior entoder ; 

 mic layer. M., Pituitary. Same as M. , Schih 

 M., Primary, the basement membrane. M., Pre 

 formation, a doubtful membrane supposed to cow J 

 the dentine papilla. M., Proligerous. S> 

 proligerus. M., Pseudo. See A/., Diphtheric. M.i 

 Pupillary, a delicate, transparent membram 

 the pupil in the fetus. It disappears betw 

 seventh and eighth months. M., Pyogenic, the fibrou 

 membrane forming the lining of abscess cavities 

 instead of being a pus-producing membrane, it 1 

 really a protective layer, limiting the spread of th 

 abscess, although it may form pus under 

 circumstances. M., Pyophylactic, a tern 

 gested by Roswell Park for the so-called " | 

 membrane." M., Reichert's. See J/., /■' 

 M. of Reissner, a delicate membrane stretchin 

 across the outer wall of the cochlea. M., Reticulai 

 the membrane covering the space of the outer hau 

 cells of the cochlea. M. of Ruysch. See A/emir 

 ruyschiana. M., Schneiderian, the mui 

 ing the nasal fossse. M. of Schwann. 

 Neurilemma. M., Serous, a delicate membrai 

 covered with flat endothelial cells lining 

 cavities of the body, e.g., the peritoneum, tl 

 pleura. M., Shell. See A/embrana putaminit. M 

 Shrapnell's, a small portion of the drum -membrai 

 filling the notch of Rivini. It differs from the r 

 mainder of the drum-membrane in that it contaii 

 none of the fibrous tissue proper to the drum, it 

 also called Membrana flaccida. M., Synovial, 

 membrane covering the articular extremities 

 and the inner surface of ligaments entering into the fa 

 mation of a joint. M., Tectorial. See M»i 

 tectoria. M., Tenon's. See Tenon's Capsule. M 

 Thyro-hyoid, the broad membrane joining ' 

 thyroid cartilage and the hyoid bone. M., Tubula 



