CANAL 



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CANAL 



cord), the small canal that extends through the center 

 of the spinal cord from the conus medullaris to the 

 lower part of the fourth ventricle. It represents the 

 embryonic ectodermal canal. C, Cerebro-spinal, 

 I. The neural or cranio-vertebral canal, formed by the 

 skull and the spine, and containing the brain and spinal 

 marrow. 2. The primitive continuous cavity of the 

 brain and spinal cord, not infrequently more or less 

 extensively obliterated in the latter, but in the former 

 modified in the form of the several ventricles and other 

 cavities. C, Cervical. See C. of Cervix Uteri. C, 

 Cervico-uterine. See C, Uterine. C. of Cervix 

 Uteri, that portion of the uterine canal that extends 

 between the internal and external os. C. of Chorda 

 Tympani, a small canal in the temporal bone, be- 

 tween its squamous and petrous portions, parallel with 

 the Glaserian fissure ; it transmits the chorda tympani 

 nerve. C, Chyleaqueous, in certain invertebrates, a 

 system of canals containing water and digestive pro- 

 ducts. C, Ciliary. See C, of Fontana. C, Cir- 

 cular, in the Echinodermata, a vessel surrounding the 

 esophagus, connected with the exterior by the madre- 

 poric canal, and giving off the ambulacral canals. C. 

 clavellaris, in biology, a cecal canal running into the 

 olfactory clubs of Medusa. C, Cloacal. See C, 

 Excurrent. C. of Cloquet. See C, Hyaloid. C, 

 Cochlear, the spiral and snail-like cavity of the 

 cochlea, 28 to 30 mm. long. The base is turned 

 inward toward the internal auditory meatus, and the 

 apex outward toward the tympanum. C. of Com- 

 munication, in the embryo of the fowl, canals that 

 run from the cavity of each protovertebra to the pleuro- 

 peritoneal space. C, Connecting, the arched or coiled 

 portion of a uriniferous tubule, joining with a collect- 

 ing tubule. C, Corona, in biology, the coronal in- 

 testine of MeduscB. Same as Pouch corona. C. of 

 Corti, the triangular canal formed by the pillars of 

 Corti, the base of which corresponds to the membrana 

 basilaris. It extends over the entire length of the 

 lamina spiralis. C. of Cotunnius. See Aqueduct 

 of the Vestibule. C, Cranio-vertebral. See C, 

 Cerebro-spinal, and C, Neural. C, Crural. See 

 C, Femoral. C, Ctenophoral, in the Clenophora, 

 eight canals connected at right angles with the tertiary 

 radial canals, and corresponding in their course with 

 the eight locomotive bands. C. of Cuvier, the ductus 

 venosus. C, Cystic, the cystic duct. C. of De 

 Candolle. See C, Medullary. C, Deferent, the 

 vas deferens. C, Demicircular. See C, Semi- 

 circular. C, Dental, Anterior, one extending 

 into the facial portion of the superior maxilla; it 

 transmits the anterior dental vessels and nerves. C, 

 Dental, Inferior, the dental canal of the inferior 

 maxilla; it transmits the inferior dental nerve and 

 vessels. C, Dental, Posterior, two canals in the 

 superior maxilla. They transmit the superior posterior 

 dental vessels and nerves. C, Dentinal, the minute 

 canals in dentine, extending approximately at right- 

 angles to the surface of a tooth from the pulp-cavity, 

 into which they open, to the cementum and enamel. 

 C, Digestive. See C, Alimentary. C. of Diploe, 

 canals in the diploe of the cranium transmitting 

 Breschet's veins. C, Efferent. I. See C, Excur- 

 rent. 2. In the Cestoda, canals connecting the testicles 

 with the deferent canals. C, Ejaculatory. See 

 Duct, Ejaculatory. C. of Epididymis, a convoluted 

 tube, about 20 feet long when straightened, forming 

 the epididymis and continuous with the vas deferens. 

 C, Eschricht's Yellow, in certain of the Cestoda, a 

 system of canals, opening into the fertilizing canal, 

 and terminating in round or oval sacs. C, Eth- 

 moidal, Anterior, one between the ethmoid and 



frontal bones ; it transmits the nasal branch of the 

 ophthalmic nerve, and the anterior ethmoidal ves- 

 sels. C, Ethmoidal, Posterior. See C. , Orbital, 

 Posterior, Internal. C, Eustachian, one in the 

 petrous portion of the temporal bone, containing a 

 portion of the Eustachian tube. C, Excurrent, in 

 sponges, the tubes that carry water from the ciliated 

 chambers to the exterior. C, Facial, the aqueduct 

 of Fallopius ; it transmits the facial nerve. C, Fal- 

 lopian. See Aqueduct of Fallopius. C, Femoral. 

 I. The inner compartment of the sheath of the femoral 

 vessels behind Poupart' s ligament ; a femoral hernia 

 descends through this. 2. See C, Hunter's. C. of 

 Ferrein, a triangular channel, supposed to exist 

 between the free edges of the eyelids when they are 

 closed, and to serve for conducting the tears toward 

 the puncta lachrymalia during sleep. C, Fertilizing, 

 in many cestoda, a tube connecting the vagina and the 

 uterus. C, Fibro-adipose, in certain fishes, a canal, 

 filled with adipose tissue, on the dorsal side of the neural 

 canal. C. of Fontana, a series of small spaces formed 

 by the interlacing of the connective-tissue fibers of 

 the framework of the peripheral processes of the 

 iris, situated in the angle of the anterior cham- 

 ber, and serving as a medium for the transudation 

 of the aqueous humor from the posterior to the 

 anterior chamber of the eye. They are also called C. 

 of Hovius, C, Ciliary, and Fontana's Spaces. C, 

 Galactophorous, the lactiferous tubules of the 

 mammary gland. C. of Gartner, in the female, a 

 relic of the main portion of the Wolffian duct of 

 the embryo ; it is a tube extending from the broad 

 ligament of the uterus to the wall of the uterus and 

 vagina. C, Gastro-vascular, in the Hydrozoa, 

 canals extending from the stomach into the substance 

 of the disc of the umbrella. C, Genital, in com- 

 parative anatomy, any canal designed for copulation 

 or for the discharge of ova. C, Gonocalycine, a 

 system of canals found in the gonocalyx of the Hy- 

 drozoa. C. of Groin. See C, Inguinal. C. of 

 Guidi. See C, Vidian. C, Gynecophoric, in 

 Bilharzia, a groove extending from a little below the 

 ventral sucker to the end of the tail. It lodges the 

 female during copulation. C. of Havers. See C, 

 Haversian. C, Haversian, canals in the compact 

 substance of bone forming a wide-meshed 

 network, and establishing communication between 

 the medullary cavity and the surface of the bone. 

 Their average diameter is -gfo inch, and they 

 are lined by a continuation of the endosteum ; they 

 transmit blood-vessels, lymph-vessels and nerves. 

 C, Hemal, one in the ventral surface of the vertebral 

 column, enclosed by the hemal arches ; it is incom- 

 plete in certain portions. C. of Henle, a portion of 

 the uriniferous tubules. C, Hepatic. I. The excre- 

 tory duct of the liver. 2. The radicles of the hepatic 

 duct. C, Hernial, one transmitting a hernia. C. 

 of Hovius. See C. of Fontana. C. of Huguier. 

 See C. of the Chorda Tympani. C, Hunter's, a 

 triangular canal formed in the adductor magnus 

 muscle of the thigh ; it transmits the femoral artery 

 and vein and internal saphenous nerve. C. of 

 Huschke, one formed by the junction of the tuber- 

 cles of the annulus tympanicus. This is generally 

 obliterated after the fifth year, but may persist through 

 life. C, Hyaloid, an irregularly-cylindrical canal 

 running antero-posteriorly through the vitreous body, 

 through which in the fetus the hyaloid artery passes, 

 Jto ramify on the posterior surface of the crystalline 

 lens. C, Hyapophyseal, in birds, that formed by 

 the inferior spinous processes of the upper cervical 

 vertebras; it transmits the carotid artery. C, Inci- 



