PORTIPLEX 



1161 



POSITION 



laterally to the head of the pancreas. It lies behind 

 the transverse colon and in front of the right kidney. 

 The ductus communis choledochus empties into it. P., 

 Iliac {of the fascia lata), the portion of the fascia lata 

 to the outer side of the saphenous opening. P., 

 Infra-vaginal, P., Intravaginal, the portion of 

 the uterine cervix projecting into the vagina. P., 

 Membranous {of the urethra), the portion of the 

 urethra enclosed between the two layers of the tri- 

 angular ligament. P., Pes, the lower surface of a 

 cms cerebri (Spitzka). P., Prostatic {of the 

 urethra), the part of the urethra surrounded by the 

 prostate gland ; it is the most dilatable portion and is 

 rarely, if ever, the seat of stricture. P., Spongy 

 {of the urethra), the part of the urethra anterior to the 

 anterior layer of the triangular ligament, and extending 

 from the latter to the glans. P., Vaginal (of the 

 uterus), the part of the neck of the uterus projecting 

 into the vagina. 



Portiplex, Portiplexus {por'-tip-leks, por-tip-leks'-us) 

 \_ porta, gate ; plexus, plexus]. The plexus or vas- 

 cular fringe that connects the two lateral choroid 

 plexuses. It passes through the porta, or foramen of 

 Monro, whence the name. 



Porus ( po'-rus) [tvo/joc, porus, a pore : //. , Pori ] . 

 A callosity. Also a canal, duct, or pore. P. acusti- 

 cus externus, the external opening of the external 

 auditory canal. P. acusticus internus, the open- 

 ing of the internal auditory canal. P. auditorius 

 externus. Synonym of P. acusticus externus. P. 

 biliaris, one of the biliary ducts. P. centralis, the 

 canal in the optic nerve through which the central 

 artery of the retina passes. P. cranio-nasalis, the 

 foramen caecum of the frontal bone. P. deferens. 

 Synonym of J as deferens. P. opticus, the large 

 opening in the center of the lamina cribrosa, trans- 

 mitting the central artery of the retina. P. pul- 

 moneus, an air-cell. 



Posis ipo'-sis) [-oar, a drinking]. A potion. 



Position {po-zish'-un)\_ponere, to place], i. Location; 

 situation ; attitude ; posture. See Posture. See, also, 

 Table of Position and Direction, appended. 2. In 

 chemistry, a term corresponding to that of ' ' union ' ' 

 ing), formerly used. P., Articulation. See 



" 



Consonants. P., Cadaveric, of the vocal bands, the 

 position which they assume in paralysis of the recurrent 

 laryngeal nerve. The affected band is in the median 

 position, and is perfectly motionless. P. of the Fetus, 

 the relation of the presenting part to the cardinal points 

 of Capuron. For the vertex, the face and the breech, 

 there are each four positions : a right anterior, a right 

 posterior, a left anterior and a left posterior. For each of 

 the shoulders there is an anterior and & posterior position. 

 In order to shorten and memorize these positions, the 

 initials of the chief words are made use of as follows : 

 For vertex presentations the word occiput is indicated 

 by the letter O., and preceded by the letter R. or L., 

 for right or left, and followed by A. or P., accord- 

 ing as the presenting part is anterior or posterior. 

 We thus have the initials L. O. A. , left-occipito ante- 

 rior, to indicate that the presenting occiput is upon the 

 anterior left side. In the same way are derived the 

 terms, L. O. P., P. O. A., R. O. P. For facial pre- 

 sentations we have in the same way, L. F. A. (left 

 fronto-anterior), L. F. P., R. F. A., R. F. P. For 

 breech or sacral presentations, L. S. A., L. S. P., 

 R. S. A., R. S. P., and for shoulder {dorsal) pre- 

 sentations, L. D. A., L. D. P., R. D. A., R. D. P. 

 See Table of Fetal Positions, under Fetus. P., Primary 

 {of the eyes), that position in which the eyes can move 

 laterally and vertically without rotating the vertical axis. 

 P., Roser {of the head), the head dependent over the 

 end of a table. P., Secondary {of the eyes), that posi- 

 tion in which the vertical meridian is rotated away from 

 its vertical position. P., Shoe-and-Stocking, a posi- 

 tion so named by Allis, in which the limb of one side 

 is crossed upon the other, as in putting on the shoe 

 and stocking, with the external malleolus of one side 

 upon the patella of the opposite side. Inability to do 

 this is diagnostic of disease in the hip-joint on that 

 side. P.-test, a test for the function of coordination. 

 If a normal individual be placed in a strictly erect 

 position, with the heels and toes of the two feet closely 

 approximated, a certain amount of swaying of the body 

 occurs, especially if the eyes be shut. If, however, 

 there be loss of coordinating power, this swaying is 

 greatly augmented. See Romberg's Symptom in Signs 

 and Symptoms, Table of. 



POSITION AND DIRECTION— TABLE OF INTRINSIC TERMS 



EMPLOYED IN HUMAN AND COMPARATIVE ANATOMY AND ZOOLOGY. THE TERMS ARE IN 



PAIRS, AND THE ADVERBIAL FORM FOLLOWS THE LATIN AND ENGLISH 



ADJECTIVE FORMS. 



Latin Adjective English Adjective 

 Form. and Adverbial Form. 



Definitions. 



Extrinsic Equivalents. 



In Human Anat- In Comparative 

 omy. Anatomy. 



\fferens. 

 Efferens. 



Afferent. 

 Efferent. 



Conveying or conducting toward. 

 Conveying or conducting from. 



Same as the in- 

 trinsic. 



Same as the in- 

 trinsic. 



laudalis. 

 -ephalicus. 



Caudal, caudad. 

 Cephalic, cephalad. 



At or in the direction of the tail end or as- 

 pect of the body or part. 



At or in the direction of the head end or 

 aspect of the body or part. 



Lower; inferior. 

 Upper ; superior. 



Back ; backward ; 



posterior. 

 Front ; forward ; 



anterior. 



Centralis, 

 'eripheralis. 



Central, centrad. 

 Peripheral, peripherad. 



At or in the direction of a center. 



At or in the direction of the periphery- 



Same as the in- 

 trinsic. 



Same as the in- 

 trinsic. 



3extralis, dexter, 

 iinistralis, sinister. 



Dextral, dextrad. 

 Sinistral, sinistrad. 



At or in the direction of the right side or 



aspect of the body. 

 At or in the direction of the left side or 



aspect of the body. 



Same as the in- 

 trinsic. 



Same as the in- 

 trinsic. 



\ iistalis. 



i 'roximalis, proxi- 

 mus. 



Distal, distad. 

 Proximal, proximad. 



At or in the direction of the extremity of 

 an appendage ; peripheral (q. v.). 



At or in the direction of the attached or 

 more important end of an appendage ; 

 central {q. v.). 



Same as the in- 

 trinsic. 



Same as the in- 

 trinsic. 



