appears deceptively simple at how complex on closer study these guards are vibrating about three hundred times a second too fast for our eyes or for the ordinary motion picture camera to distinguish the development of all dry speed photography has given us a new picture of these rapid and complex movement photographed at approximately five thousand frames are pictures per second these vocal cards show the original function in exaggerated slow motion this technique presents a new medium for the original research and diagnosis the casual observer sees little of the vigorous activity at the site of voice note the position of the vocal chords deep in the larynx here is the airway leading from the lungs to the larynx and sends via the firing mouth and no to the outside the vocal cords are protected by a firm shell of cartilage and connecting ligament muscles result of these complex movements can be visualized with the aid of a mirror placed in the fair the image of the larynx is reflected by the mirror to an observer or to a camera we have chosen this in direct method of observation for our cinematic graphic studies because it permits visualization of the larynx under normal functional conditions for the same reason no local anesthetic as been used order to provide a simultaneous record of lauryn hill function and voice production it was necessary to exclude extraneous noise as by sound treating our camera this is a standard motion picture camera after the patient has moved into position a number of simultaneous photographs and recordings are obtained this shows a female larynx producing normal sound action and sound will be by contrast here is a male larynx again the voice was recorded while the larynx was photograph down this hurried image by ultra high speed photography note the additional detail which now becomes apparent the basic tenets of indirect learned gasket they hold for all forms of the original photography ultra high speed requires special equipment a light source must be of sufficient intensity to permit an exposure of one ten thousandth of a second the cooling system reduces the intense heat generated by the land and prevents injury of the delicate tissues under observation a diagonal mirror reflects the light on to the laryngeal mirror and thus illuminates the interior of the larynx the lower energy of the image in turn is reflected by the mirror to the high speed camera transformers regulate the light intensity and the speed of the camera to permit exposure at speeds from two thousand to five thousand frames are pictures  the same phenomenon at ultra high speed as our special camera records it the time element of the motion is magnified two hundred times this technique has enabled us to record several new observations on a normal range all physiology you will see a new and different sequence of events when the cards abduct  during normal phone nation and the complex motion of the loose mucous membrane during sound production similarly newer concepts average annoyed motion and the relation of length and mass to pitch are confirmed by high speed photography at such speed it becomes impossible to correlate the sound with the slow motion picture however the recorded sound will be reproduced during each sequence the noise of the camera may be heard in the background while it exposes one hundred feet of film in one second we have chosen this sound because it demonstrates a firm closure of the larynx with an abrupt release in one continuous rapid motion while you may not recognize it in isolation all of us produce this type of sound frequently to initiate evolved singers have turned it could have blocked note the motion of the vocal chords on their release it is this motion which produces the first so while our patients repeated the sound several times at the beginning of the sequence for identification you realize of course that the entire complex scene for trey's just one sound by now the ides have separated and the exaggerated motion of the cards produces little or no sound note the mark relaxation of the card and their flabby appearance while this film does not reproduce as well as the standard color film these pictures represent a new development in slow motion photography of the larry color photography our next sound is a slow glide from a low film where the pitch is low note the massive chords and the wide amplitude of each movement this is characteristic of low pitch the large blobby all of milkers appears to have no effect on the quality of the sound this view represents a slightly higher pitch from the latter part of the same filmstrip the vocal chords have lengthened somewhat while the amplitude of the vibration has decrease this is a characteristic of the higher pitched ra the study of additional details of vocal chord behavior at alter of slow motion requires the use of black and white film our first sequence shows laryngeal function at low pitch again we observe the thickness of the vocal chords and the amplitude of the vibration which are typical of the low tone reigns in addition we discover that the free margin of each vocal chord is not the thin linear structure we visualize before but rather a thick shelf with upper and lower lip the intricate motion of these lips suggests some basic changes from the traditional concept of the original function the next two series will present a brief glimpse of isolated medium and high pitch sounds you have just heard an octave glide within that brief time many major rangel adjustments occur in the lower ranges the chords are shortened massive and relaxed the vibrations are relatively slow observe here that the chords are along getting rapidly as the pitch rises they become tense and narrow this lengthening of the vocal chords with a rise in it seems a paradox since  physical law maintains that the length of a vibrator is directly proportional to the frequency of vibration while it is true that the larger male larynx produces lower tones than the smaller the male larynx lengthening of the cards in the same individual increases their elasticity and decreases their cross sectional mass this combination increases the frequency of vibration which is associated with higher pitch with the ris pitch the vocal chord movements of the patient have become slightly asynchronous this is not uncommon and causes no apparent change in voice maximum lengthening of the chords for the octave dry it has now occurred the vocal chords are vibrating twice as fast as they did earlier in the scene you will now be in a position to observe the complex laryngeal adjustments in reverse order as the pitch is lowered the normal vibratory cycle consists of three separate faces the opening the closure and the complete approximation in the breathy voice pictured here the last phase is eliminated on the other hand folds is simply a byproduct of the vocal effort the blood vessels on the surface of the cards mark the progression of the vibratory movement the small collection of mucus at the post area commissar indicates the nature of the movements in that area as the pitch decreases more and more we again note the thick double layer gone to our of the free borders of the vocal chords this finding confirms the traditional concept of massive approximation in the lower pitch range it is equally interesting to observe the sequence of events as the chords separate in abduction contrary to traditional teaching the vocal chords separate first to be followed by the vocal processes of the original it cartilage is the abduction is then completed by lateral movement of these cartilage and this is a view of the larynx during inhalation and at the beginning of the multiple muscular adjustments which produce a clue to blo ides approach each other observe the smooth movement without rotation the tremendous energy with which the earth now its crash together in this type of phone nation is revealed clearly in the this constriction is even more sudden and dynamic than the closure the lateral and and carrier parts of the larynx returned to their customary open positions but the original i'd remain approximated to adjust for four nation the overhanging epiglottis and the sting teri garr action of the super the logic structures prevent complete visibility of the first few vibrations during the release of a clue to gloat it is evident however that the vocal chords are squeezed tightly together during several vibratory cycles the kuta got resembles a cough with one important variation when a cough is released the original is abduct instantly we have seen that the entire larynx participates in the production of sound not only the vocal chords this short strip reveals the motion of the original ads and interest annoyed areas during  is this experience that for it was reserved not for its sound effect but for the protection and self preservation of the individual the human larry was a range of sound what variety of how simple in appearance how complex in its action how