this invention can be used to locate abnormalities in various organs . as an example we have selected bladder and urinary passage . fig1 shows the diagram of a male urinary bladder and urinary passage . the bladder 1 , temporarily stores urine and periodically expells it when the bladder neck 2 , opens as the bladder 1 , contracts . urine passes through the prostatic urethra 3 , which is completely surrounded by the prostate 4 . the distal limit of the prostate is marked by a small projection called the verumontanum 5 . this is a most important landmark because just distal to the verumontanum 5 , is the external urethral sphincter 6 , which relaxes soon after the urination process begins . beyond this is the urethra 7 , affording a free passage of urine to the outside beyond the external urethral meatus 8 . one way to accomplish the objectives of this invention is by using the apparatus displayed in fig2 . a ring 9 , is attached to the patient &# 39 ; s body , not shown , to provide a fixed reference point . two arms 10 , and 11 , one ends of each 12 and 13 , are attached to the ring 9 . between the distal ends 14 and 18 is attached a transducer 15 and its rotating shaft 16 which goes through a grooved wheel 17 . the circumference of the wheel 17 , is at least 1 / 10th of the length of the passage being examined because the transducer 15 , used here is a potentiometer with 10 turns . this is obtainable from any electronic component store . another grooved wheel 19 , is just above wheel 17 , and is held in place by shaft 20 , which is fixed to distal ends 14 and 18 , of arms 11 and 10 , respectively . the space between wheels 17 , and 19 is for the passage of an endoscope , a catheter 21 , or a probe . rubber rings 22 and 23 ( not visible ), are to keep the wheels 17 and 19 , tightly in contact with the catheter 21 , so that as the catheter 21 , moves in and out of the patient &# 39 ; s body the wheels 17 and 19 , will turn without slipping . the proximal end 24 , of catheter 21 , is attached to a pressure transducer 25 , obtainable from omega engineering , inc ., one omega drive , p . o . box 4047 , stamford , ct 06907 . electrical connections are made from three pins 26 , 27 , and 28 , of transducer 15 , and three pins 29 , 30 and 31 of pressure transducer 25 . pins 26 and 29 , are connected to + 12 volts supply which is derived from the microcomputer , not shown . microcomputer used here is an apple , model iie ( enhanced ), obtainable from apple computer , 20525 mariani avenue , cupertino , california 95014 . pins 27 and 30 , are connected to ground of the said microcomputer . pin 28 is output of transducer 15 , and pin 31 , gives output from pressure transducer 25 . these two outputs 28 and 31 , are connected to an analog to digital converter card , not shown , that is plugged into a slot , not shown , inside the microcomputer . calibration of the transducer 15 , is done by passing a catheter 21 , between wheels 17 and 19 , a known distance . similarly the pressure transducer 25 , is calibrated by applying a known pressure and taking computer readings . the first thing to do after calibration is to establish the landmarks and fix it in the microcomputer memory . in this case the landmarks are the bladder neck 2 , and the verumontanum 5 . the transducer 15 , is set to its highest reading by turning the wheel 17 , counterclockwise . then a cystoscope , preferably a flexible cystoscope is passed between wheels 17 and 19 , and then through the external urethral meatus 8 , into the bladder 1 . the cystoscope is then withdrawn . when the bladder neck 2 is reached the ` open apple ` key of the microcomputer is pressed . the reading from transducer 15 , will then be stored in memory as being the location of the bladder neck . as the cystoscope is withdrawn and when the verumontanum 5 , is reached , the ` open apple ` key is again depressed . the reading of transducer 15 , is taken and stored in memory as being the location of the verumontanum 5 . upon further withdrawal of the cystoscope the external urethral meatus 8 will finally be reached . in a similar fashion this is also marked in memory by pressing the ` open apple ` key . fixing of landmarks can also be performed in many ways . for example ultrasound display of prostate will enable localization of upper and lower limits of prostate which is bladder neck 2 and level of the verumontanum 5 respectively . xray display means will also accomplish the same . the next step is to draw the bladder and urethra on the computer display screen . the distance between bladder neck 2 , and verumontanum 5 , is computer . the prostate 4 , and prostatic urethra 3 , are drawn according to measurement taken and stored in memory . next the bladder 1 , is drawn . since size of the bladder 1 , is variable and not important , it is drawn 2 . 5 times the size of the prostate 4 . the rest of the urethra 7 , is then drawn up to the external urethral meatus 8 . the length of the urethra 7 , being exactly according to measurement taken intitially . transducer 15 , is again set to its maximum reading by turning wheel 17 , counter clockwise . a catheter 21 , is then passed into the bladder . moving this catheter 21 in and out will vary computer readings from transducer 15 . since anatomical positions were marked and stored in memory , position of the tip of the catheter 21 , will be known and will be displayed . graphic display of the pressure at corresponding points along the urinary tract is shown below the figure of the bladder and urethra just drawn on the computer screen . a vertical line 32 , representing ` y ` axis is drawn below the end of the bladder . below this is a horizontal line 33 , representing ` x ` axis is drawn . as the catheter 21 is moved , a dot is drawn . its position in the ` y ` axis is dependent on the pressure recorded from transducer 25 . ` x ` axis of the dot depends on the reading obtained from transducer 15 , and displays exact location along the urinary passage . as the catheter 21 is withdrawn pressure along its passage is graphically displayed 34 . in one mode of this test according to present art water is injected into the catheter at a fixed rate and pressure is simultaneously recorded . interpretation can easily be programmed . the computer stores and prints the display . the first time ` open apple ` key is depressed , a reading of the transducer 15 is taken and assigned to variable bn , which represents bladder neck 2 . next when the ` open apple ` is depressed value is similarly assigned to variable uv , which represents verumontanum 5 . the third time ` open apple ` is pressed the external urethral meatus 8 , is marked as em . the computer is switched to high resolution graphics page . a circle is drawn , in the upper half of the screen , to represent the prostate 4 with radius being pr =( vm - bn )/ 2 . then the bladder 1 is drawn with radius br = 2 . 5 * pr . the urethra 7 is drawn from vm to em . y axis 32 and x axis 33 lines are drawn in the lower half of the screen . memory locations of transducers 15 and 25 are peeked and these form the x and y axis for the dot to be plotted . after plotting is completed then this is saved in the computer disc in the patient &# 39 ; s file . for printing a screen dump program is used . what is described is one method of accomplishing the objects of the invention . other methods are possible once the principles are understood . this invention is not limited by the illustration presented but is within the scope of the following claims .