Technique of Eye Dissections

Be supplied with two knitting-needles. Take one, lubricate its full length with a little vaseline, lard, oil, or any other lubricant. Insert the needle into the punctum of the lower lid, and push it downward and forward, aiming to come out in the nose a short distance from its end. At first it may be a little difficult to get the needle started; if so, just wiggle the needle, pushing it at the same time as directed, until the nasal duct is found. Do not remove the needle. To insert the other needle into the punctum of the upper lid is rather difficult; for that reason the punctum of the lower lid was chosen, first. Grease the needle, as was done to the first one, and, with a little patience and careful manipulation, the canal opening and its course will soon be found. The needle may then be pushed through until it meets the first one. (Fig. 45.) From the puncta lacrimalia to the place of meeting of the two needles, marks the course of the two canaliculi and their junction before they merge and form the nasal duct. Leave the needles where they are, and begin cutting away the skin. The needles will then mark the course of each canal and the duct very plainly. With the small scissors the canals and the duct may be loosened from the surrounding tissues. Or, the scalpel may be used to lay open the canals, cutting along over the top of the needles. (Fig. 46.)

The cilia, palpebræ, palpebral conjunctiva, ocular conjunctiva, and other superficial ocular accessories may be examined without dissection.

MEIBOMIAN GLANDS AND DUCTS

An examination of the eyelids will show the openings of the ducts of the meibomian glands a short distance back of the cilia. Very fine pins or needles that have been greased may be easily inserted for a short distance into the ducts, and then a dissection made along the course of the duct as outlined by the presence of the inserted pins or needles. Another way to see the glands is to slice through the ducts, with the scalpel or safety-razor blade, the entire width of either eyelid. This will separate the glands into two parts and show their length, breadth and structure.

ENUCLEATION OF THE ORBITAL CONTENTS

The eyes one procures from a butcher or a slaughter house will always have the extrinsic tissues so badly cut and torn that identification of the various parts and their relations is impossible. Therefore, it is best to supply one’s self with the head of an animal, such as a sheep or a calf, and dissect an eye with all its extrinsic tissues intact. For this dissection, a hammer and a chisel are necessary in addition to the tools needed for doing the previous dissections.

Using the left orbit, begin the dissection by making an incision directly over the supra-orbital ridge, extending from over the inner to the outer canthus. At the middle of that line, make an incision, and cut at right angles upward to the top of the head. Next make a cut below the eye, extending from the outer to the inner canthus. (Fig. 47.) Loosen the skin from the bone with the scalpel, and lay bare the skull immediately over the orbit. Fold the flaps of the skin back and fasten them down to the skull with pins or tacks so they will not interfere with the work.

Using the hammer and the chisel, cut through the roof of the orbit at the middle of the supra-orbital ridge, and continue upward for about two and one-half inches. Do not strike hard blows, or the chisel may be driven through the underlying tissues. Listen for the peculiar sound that is heard when the bone has been completely penetrated; then remove the chisel. Continue until the full distance of two and one-half inches of bone has been separated. (Fig. 48.) Now, begin at the upper end, and cut through the bone downward to the right for about two inches toward the outer canthus. A similar line should be cut on the right of the centre line toward the inner canthus. This will mark out two irregular, triangular-shaped pieces of bone. (Fig. 49.) Remove the piece on the right-hand side by prying it off. (Fig. 50.) The left-hand piece should be pried loose and then carefully cut away with the scalpel, so that the pulley through which the superior oblique muscle runs its tendon, will not be injured. In removing the orbital contents, dissect close to the bone (Fig. 51), so that the periosteum will also be removed, and form a sort of sac or capsule in which will be contained the eye with all its extrinsic tissues. If difficulty is experienced in getting at the posterior parts of the orbit, it will be best to cut away as much more of the obstructing bone as is necessary. In this way the “capsule” containing the eye, its six muscles, the lacrimal gland, and both eyelids, all in situ, will be removed. (Fig. 54.) As the orbital entrance of the optic nerve is neared, care must be exercised not to cut into this “capsule,” or sever any of the muscles. (Fig. 52 shows the excavated orbit. Fig. 53 shows an anterior view of the enucleated eye. Fig. 54 is a side view of the enucleated eye.)

OPHTHALMOSCOPIC EXAMINATION

By practising on an enucleated eye, one may gain considerable ability in the use of the ophthalmoscope, and also learn to recognize the blood-vessels and other important parts of the retina. To do this, the eye to be examined must be very fresh, for only in this condition will the cornea and lens be sufficiently clear to permit rays of light to enter the inside of the eye.

However, since the pupil is oblong in shape, and often only a narrow slit—but several millimetres in diameter—the field presented for observation is a rather limited one. To increase the pupillary aperture, take a pin, and force the point through the cornea about three or four millimetres from the corneo-scleral junction, and at right angles to the direction of the parallel edges of the pupil. After the pin has been pushed through until it has reached to within a short distance (one millimetre) of the edge of the iris, carefully pick up the iris by raising the pin into a position perpendicular to the cornea, and force the pin further down into the eye. The pupil will have been enlarged on one side. Do the same thing on the opposite side, and at each extremity of the pupil. (Fig. 55.)

The pupil will now have been made square, and so large that no difficulty will be experienced in reflecting either light into the eye, or in examining the inside of the eye. Care must be taken not to lacerate the anterior surface of the lens when the iris is drawn back by the pins.

Putting the pins into the cornea, and using them as levers with the point of entrance in the cornea as a fulcrum, will pucker the cornea considerably, and a good clear fundus cannot be obtained. This is easily overcome. Simply gather up all the tissues surrounding the eye, force them backward, and hold them firmly with the fingers of the left hand. (Fig. 56.) The right hand is then free to handle the skiascope or ophthalmoscope, so that the interior of the eye may be thoroughly examined.

Another way to prepare an eye for ophthalmoscopic examination is as follows: Go to a slaughter house and procure a beef eye from an animal that has been killed but a few minutes previously. Placing the eye immediately into an 8 per cent. solution of cocaine and leaving it there for about an hour will dilate the pupil to such an extent that work with the ophthalmoscope will be made very easy. This, as indicated, can be done only with an eye that is very fresh.

Still another way to see the interior is to cut out a piece of the sclerotic about the size of a twenty-five-cent piece; then pinch up and tear out the choroid and the retina under the opening made in the sclerotic. (Fig. 57.) Hold the eye, the cornea forward, close to a bright light, and the image of the light will be seen upon the retina. The closer the light is to the eye, the greater the illumination will be in the interior of the eye. If the opening or “window” is close enough to the optic nerve, the optic papilla can be seen easily. And, if care has been taken to have the opening made midway between the two branches of the retinal artery, the entire course may be followed. The direction of the retinal artery can be determined by ophthalmoscopic examination.

THE LACRIMAL DUCTS

To find the lacrimal ducts, cut across the outer and inner canthi of the enucleated eye, pushing the eye forward and the lids backward. That will expose the conjunctiva of both eyelids and eye, and also show the conjunctival fornices. On the upper surface of the palpebral conjunctiva, and near the outer canthus, will be seen, upon close inspection, a number of minute openings, usually eight. These are the openings of the lacrimal ducts. Pins or straw that have been lubricated with vaseline, may be inserted and pushed into these openings for a considerable distance, and the course of the ducts then can be traced easily. (Fig. 58.)

THE LACRIMAL GLAND

The lacrimal gland is easily distinguished by its pink appearance. There are two parts, inferior and superior. The gland lies directly over the eye and near the outer angle of the orbit. In the enucleated eye, it will be found to lie near the outer canthus and over the eye. The gland may be easily dissected out of its position and then examined more closely. A hand lens will show the racemose construction of the gland. If the gland is cut in two, the racemose construction may be seen even better.

THE CAPSULE OF TENON

To dissect the capsule of Tenon, it is necessary to carefully remove the superficial fat and connective tissue. In text-books and illustrations, the capsule is usually shown as a definite sac-like membrane of considerable thickness, with all its parts well defined. The dissector will soon find that the capsule is not discerned so easily. It will be found to be the thin, semi-transparent, fibrous membrane that surrounds each muscle, as well as the “posterior two-thirds of the eye,” and is continuous anteriorly with the ocular conjunctiva. Portions may be pinched up and inflated through an inserted blow-pipe. This will help to merely demonstrate its location and parts. (Fig. 59.)

THE SUPERIOR OBLIQUE MUSCLE AND ITS PULLEY

After the lacrimal gland has been dissected away, a beginning will have been made for cutting away the fat and the connective tissue. The first thing to do then is to locate the superior oblique muscle. Try to keep track of which part of the eye is the inner side. Having located the inner side, feel along the top for a little hard eminence. That is the pulley. Begin to dissect around the pulley, not through it, and then follow the muscle along to its origin; do not separate the muscle from its origin. When the superior oblique is completely freed, the action of the muscle may be readily demonstrated by holding the “ring” or tendinous pulley with the fingers of one hand, while the muscle is pulled backward and forward with the other.

THE OTHER EXTRINSIC MUSCLES

With the dissection of Tenon’s capsule and the superior oblique muscle, the work of isolating the other extrinsic muscles will have begun. This work needs no directions except a warning to be careful not to injure the pulley of the superior oblique, and to be careful not to cut away the inferior oblique. The inferior oblique will be found to be near the “pulley.” If the dissection is not carried too close to the origin of the recti muscles, all the muscles may be kept in place.

If the eye has not been previously subjected to the hardening influence of formaldehyde, it may be put into a 5 per cent. solution, and at the end of ten or twelve hours the muscles will have become rigid. They can then be better studied, and may be kept indefinitely. (Fig. 60.)

THE THREE TUNICS OF THE EYE, THE HYALOID AND ITS ATTACHMENTS

This dissection is a rather difficult one to make, and requires patience.

Prepare an eye by placing it in a 5 per cent. solution of formaldehyde for about ten days to two weeks. Remove all the outside tissues. Cut away the cornea, as in the dissection for the choroid or the retina. Loosen, as far back as possible, the sclerotic from the choroid. Remove the sclerotic for about 10 mm. back of the equator of the eye. With the tweezers pick up the pupillary edge of the iris. Using the small pointed scissors, cut through the iris. (Fig. 61.) Lift either one of the cut edges of the iris, and, with the sharp edge of the scalpel, gently scrape the processus zonuloe free from the ciliary processes, cutting through the ciliary ring as the ciliary processes are detached from the hyaloid (processus zonuloe). (Fig. 62.)

Great care must be taken not to thrust the point of the scissors into the hyaloid, suspensory ligament, or vitreous, else the lens may become detached.

After the iris with the processes has been removed, pinch up with the tweezers a fold in the choroid. Make an incision with the fine-pointed scissors, and begin removing the choroid to within about 5 mm. of the cut end of the sclerotic. (Fig. 63.) Care must be taken not to penetrate the underlying retina while making this part of the dissection.

After part of the choroid has been removed, the specimen will show the three coats of the eye in layer-like arrangement, the hyaloid and lens. The lens may now be cut away, if the specimen is preferred without it. Removing the lens before this time is unwise, because it acts as a protection to the other tissues while the specimen is being handled during the dissection.

This specimen will show to the best advantage if it is suspended in a jar containing a 5 per cent. solution of formaldehyde. Figure 64 shows the specimen.

INDEX

• A
• Accessories, ocular, 95
• Alcohol as a preservative, 34
• Alcohols, method of running through, 58, 59
• Anterior chamber, 50, 51, 86, 90
• half of eye, 49
• half, removing vitreous from, 49
• surface of lens, 55
• Aperture, increasing pupillary, 106, 107, 109
• Aqueous humor, 51
• Arteria centralis retinæ, 43, 49
• Arteries, ciliary, 72
• course of retinal, 111
• Artery of retina, central, 43, 49
• hyaloid, 43
• B
• Beef eyes, 26, 27
• Beginning of dissection of orbital contents, 97
• Benzine, 59
• Blood-vessels of retina, 106
• Blowing through blowpipe, folding retina by, 81, 82
• Blowpipe, folding retina by blowing through, 81, 82
• glass, 35
• using it to force out vitreous, 78-81
• Body, hyaloid, 41
• Boiling crystalline lens, 55, 56
• Books, text, 23, 25, 46, 52
• C
• Canal, hyaloid, 43
• of Petit, 35-37
• Canaliculi, puncta, papilla, and nasal duct, locating, 92-95
• Capsule of lens, 33, 50, 54
• of lens, removing, 59
• Capsule of Tenon, 115
• of Tenon and conjunctiva, 116
• Cedar oil, 60
• Cells of processes, pigment, 49, 50
• Central artery of retina, 43, 49
• Chamber, anterior, 50, 51, 86, 90
• posterior, 50, 51, 86, 90
• Chemicals, 22, 23
• Chisel and hammer, use of, 99-101
• Choroid, 62
• and sclerotic, cutting them away for isolating retina, 83
• emptying, 69, 70
• for dissecting three tunics, removing, 122
• from sclerotic, for dissection of three tunics and hyaloid, loosening, 120
• iridescence of, 45
• loosening from corneo-scleral junction, 64, 65
• loosening sclerotic from, 64, 66, 67, 68
• or retina, removing cornea for isolating, 62, 63, 64
• picking up retina and, 30, 31
• preparing eye for isolating, 62
• preserving isolated, 72
• removing, 46
• removing lens from, 69, 70, 71
• scraping sclerotic from, 68
• separating sclerotic from, 27, 29
• Cilia and other superficial accessories, 95
• Ciliaris, corona, 49, 51
• orbicularis, 49, 51
• retinæ, pars, 49
• Ciliary arteries, 72
• nerves, 72
• processes, 27, 33, 49
• processes free from processus zonuloe, scraping, 121
• ring, 51
• ring, cutting ciliary, 121
• Ciliary, clarifying lens, 58, 59
• Coats, preparing eye for dissection to show, in situ, the three, 120
• Cocaine, 109
• Color of processes, 50
• Concentric layers of lens, 56, 57
• Conjunctiva and Capsule of Tenon, 116
• Conjunctival fornices, 113
• Cornea, epithelium of, 52
• removing it for isolating choroid or retina, 62, 63, 64
• Construction of lacrimal gland, racemose, 114
• Contents, beginning of dissection of orbital, 97-101
• dissecting orbital, 97-105
• emptying eyeball of, 32, 33
• enucleating orbital, 102-104
• material for enucleation of orbital, 97
• preserving of hyaloid, 32, 33, 34, 36
• Cornea, 52
• and sclerotic, 52
• layers of, 52
• smoothing it for ophthalmoscopic examination, 109
• Corneo-scleral junction, loosening choroid from, 64, 65
• Corona ciliaris, 49, 51
• Cortex of lens, 54, 59
• Course of retinal arteries, 111
• Cross section of optic nerve, 48
• Crystalline lens, 33, 49, 53
• lens boiling, 55
• Cutting away sclerotic and choroid for isolating retina, 83
• ciliary ring, 121
• cross section of optic nerve, 48
• eye for sagittal section, 87-89
• eye in half, 38, 39
• iris for dissection of three tunics, 120
• optic nerve longitudinally, 47, 48
• D
• Dehydrating lens, 58, 59
• Demonstration of hyaloid, etc., 34
• Disc, optic, 43
• Dishes, Stender, 21
• Dissected hyaloid, 33
• Dissecting lacrimal gland, 114
• nasal duct, papilla and puncta, 92
• orbital contents, 97-105
• of hyaloid membrane, 25, 33
• of hyaloid, method of preparing for, 26, 27
• of orbital contents, beginning of, 97-101
• three tunics, removing choroid, for, 122
• Dissection, preparing eye for interior, 38
• preparing eye to show the three tunics in situ, 120
• of three tunics and hyaloid, loosening choroid from sclerotic for, 120
• of three tunics, cutting iris, for, 120
• Duct, material for dissecting papilla, puncta, and nasal, 92
• papilla, puncta lacrimalia, and nasal, 92
• Ducts, meibomian gland and, 96
• lacrimal, 112, 113
• E
• Emptying choroid, 69, 70
• eyeball of contents, 32, 33
• Entrance of optic nerve, 43
• Enucleated eye, 104
• Enucleating orbital contents, 102-104
• Enucleation of orbital contents, 97-105
• of orbital contents, material for, 97
• Epithelium of cornea, 52
• Equipment, 17-24
• Examination, ophthalmoscopic, 106
• preparing eye for ophthalmoscopic, 106-110
• smoothing out cornea for ophthalmoscopic, 109
• Excavated posterior half, 46, 47
• sagittal, 90
• Extrinsic muscles, other, 118
• muscles, preserving, 119
• Eye, anterior half of the, 49
• contents, emptying, 32, 33
• cutting it for sagittal section, 87-89
• for dissection of hyaloid, etc., preparing, 26, 27
• in half, cutting, 38, 39
• interior of, 38
• posterior half of the, 40
• preparing for dissecting interior, 38
• preparing it for dissection, to show the three tunics, in situ, 120
• preparing for isolating choroid, 62
• preparing for isolating retina, 74, 75
• preparing for ophthalmoscopic examination of, 106-110
• preparing for sagittal section of, 86
• sagittal section of, 86
• seeing interior of, 110
• vertical section of, 86
• cutting window in, 110
• Eyelids, 95, 105
• Eyes, sheep and beef, 26, 27
• F
• Fibres of lens, 56, 57
• network of vitreous, 41, 42
• Fluid, perichoroidal, 40, 46
• Folding retina by blowing air through blowpipe, 81, 82
• Forcing out vitreous, using blowpipe in, 78-81
• Fornices, conjunctival, 113
• G
• Gland, dissecting lacrimal, 114
• lacrimal, 114
• racemose construction, 114
• Glands and ducts, meibomian, 96
• Glass blowpipe, 35
• Glassware, 21
• H
• Half, anterior, 49
• cutting eye in, 38, 39
• Half, excavated posterior, 46
• posterior, 40
• posterior, excavated, 46
• preparing eye for dissecting interior, 38
• removing vitreous from anterior, 49
• removing vitreous from posterior, 41
• Hammer and chisel, use of, 99-101
• Humor, aqueous, 51
• vitreous, 33
• Hyaloid and attachments, demonstration of, 34
• artery, 43
• body, 41
• canal, 43
• dissected, 33
• membrane, dissection of, 25-33
• membrane with contents and attachments intact, removal of, 25
• preserving contents of, 32, 33, 34, 36
• preserving three tunics and, 123
• I
• Image, retinal, 110
• Increasing pupillary aperture, 106, 107, 109
• Inferior oblique muscle, 119
• Instruments, 21
• Interior of the eye, 38
• of the eye, seeing, 110
• Interior section, preparing the eye for dissecting, 38
• Iridescence of choroid, 45
• Iridescent choroid, 40, 43
• Iris, 49, 51
• and lens, removing, 75, 77
• and processes, removing, 121
• for dissection of three tunics, cutting, 120
• relation between processes and, 51, 52
• Isolated choroid, preserving, 72
• Isolating choroid or retina, removing cornea for, 62-64
• choroid, preparing eye for, 62
• Isolated retina, preserving, 84, 85
• Isolating retina, cutting sclerotic and choroid away for, 83
• retina, preparing eye for, 74, 75
• J
• Junction, loosening choroid from corneo-scleral, 64, 65
• K
• Knitting-needles, use of, 92-95
• L
• Lacrimal ducts, 112, 113
• gland, 114
• gland, dissecting, 114
• gland, racemose construction of, 114
• Lacrimalia, nasal duct, papilla, and puncta, 92
• Laminated structure of lens, 55, 56
• Layers, concentric lens, 56, 57
• of cornea, 52
• separating outer lens, 54
• Lens and iris, removing, 75, 77
• anterior surface of, 55
• boiling of, 55, 56
• capsule, 33, 50, 54
• clarifying, 58, 59
• concentric layers of, 56, 57
• cortex of, 54, 59
• crystalline, 33, 49, 53
• dehydrating, 58, 59
• fibres, 56, 57
• laminated structure of, 55, 56
• nucleus of, 55, 59
• posterior surface of, 55
• preparing the, 53
• preserving the, 57, 58
• removing capsule of, 59
• removing it from choroid, 69-71
• removing the, 51, 53
• separating outer layers of, 54
• staining, 57
• Ligament, suspensory, 33, 37
• Lines, tri-radiate, 54-56
• Locating papilla, puncta, canaliculi, and nasal duct, 92-95
• Longitudinally, cutting optic nerve, 47, 48
• Loosening choroid from corneo-scleral junction, 64, 65
• choroid from sclerotic, 64, 66-68
• choroid from sclerotic, for dissection of the three tunics and hyaloid, 120
• Lucidum, tapetum, 45
• M
• Material, 19, 20, 21
• for dissecting nasal duct, papilla, and puncta, 92
• for enucleation of orbital contents, 97
• Meibomian glands and ducts, 96
• Membrane with contents and attachments intact, removal of, 25
• Method of preparing eye for dissection of hyaloid, 26, 27
• of running through the alcohols, 58, 59
• Muscle, superior oblique and its pulley, 117
• Muscles, other extrinsic, 118
• preserving extrinsic, 119
• N
• Nasal duct, canaliculi, puncta, and papilla, locating, 92-95
• canaliculi, puncta, and papilla, 92
• canaliculi, puncta, and papilla, material for dissecting, 92
• Needles and pins, use of, 96, 106, 107, 108, 109, 112, 113
• use of knitting, 92-95
• Nerve, cross section of optic, 48
• entrance of optic, 43
• optic, 47
• optic, cutting it longitudinally, 47, 48
• Nerves, ciliary, 72
• Network of fibres in vitreous, 41, 42
• Nucleus of lens, 55, 59
• O
• Oblique, inferior, 119
• pulley of superior, 117
• Ocular accessories, 95
• conjunctiva and Capsule of Tenon, 116
• conjunctiva and other superficial accessories, 95
• Oil, cedar, 60
• Ophthalmoscope, 109
• Ophthalmoscopic examination, 106
• examination, preparing eye for, 106-110
• examination, smoothing out cornea for, 109
• Optic disc, 43
• nerve, 47
• nerve, cross section of, 48
• nerve, cutting it longitudinally, 47, 48
• nerve, entrance of, 43
• papilla, 111
• Ora serrata, 49
• Orbicularis ciliaris, 49, 51
• Orbital contents, beginning dissection of, 97-101
• contents, dissecting, 97-105
• contents, enucleating, 102-104
• contents, enucleation of, 97
• contents, material for enucleation of, 97
• P
• Palpebræ and other superficial accessories, 95
• Palpebral conjunctiva and other superficial accessories, 95
• Papilla, nasal duct, and puncta lacrimalia, 92
• nasal duct, and puncta lacrimalia, material for dissecting, 92
• optic, 111
• puncta, canaliculi, and nasal, duct, locating, 92-95
• Pars ciliaris retinæ, 49
• Perichoroidal fluid, 40-46
• Petit’s canal, 35-37
• Picking up choroid and retina, 30, 31
• Pigment cells of processes, 49, 50
• of sclerotic, 46
• removal of, 34
• Pinching up sclerotic, 27, 28
• Pins and needles, use of, 96, 106-109, 112, 113
• Pipette, 35
• Posterior chamber, 50, 51, 86, 90
• half excavated, 47
• half of the eye, 40
• half, removing vitreous from, 41
• surface of the lens, 55
• Preparing eye for dissecting interior, 38
• eye for dissecting hyaloid, 26, 27
• eye for dissection to show the three tunics, in situ, 120
• eye for isolating choroid, 62
• eye for isolating retina, 74, 75
• eye for ophthalmoscopic examination, 106-110
• eye for sagittal section, 86
• the lens, 53
• Preservative, alcohol as a, 34
• Preserving extrinsic muscles, 119
• hyaloid, contents and attachments, etc., 32-34, 36
• isolated choroid, 72
• isolated retina, 84, 85
• lens, 57, 58
• sagittal sections, 89
• three tunics and hyaloid, 123
• Processes, ciliary, 27, 33, 49
• and iris, removing, 121
• color of, 50
• pigment cells of, 49, 50
• relation between iris and, 51, 52
• zonular, 27, 34
• Processus zonulœ, 34
• zonulœ free from ciliary processes, scraping, 121
• Pulley of superior oblique muscle, 117
• Puncta lacrimalia, nasal duct, and papilla, 92
• lacrimalia, papilla, canaliculi, and nasal duct, locating, 92, 95
• lacrimalia, papilla, canaliculi, and nasal duct, material for dissecting, 92
• Pupillary aperture increasing, 106, 107, 109
• R
• Racemose construction of lacrimal gland, 114
• References, 23, 25, 46, 52
• Relation between iris and processes, 51, 52
• Removal of hyaloid membrane with contents and attachments intact, 25
• of pigment from processus zonulœ, 34
• Removing capsule of lens, 59
• choroid, 46
• cornea for isolating choroid or retina, 62-64
• choroid for dissecting three tunics, 122
• iris and lens, 75, 77
• iris and processes, 121
• lens from choroid, 69-71
• lens from anterior half and other parts, 51, 53, 54
• sclerotic to show the three tunics, 120
• the retina from posterior half, 44
• vitreous from anterior half, 49
• vitreous from choroid, 70-72
• vitreous from posterior half, 41
• Retina, 40-74
• blood-vessels of, 106
• central artery of, 43, 49
• cutting away sclerotic and choroid for isolating, 83
• folding it by blowing air through blowpipe, 81, 82
• or choroid, removing cornea for isolating, 62-64
• picking up choroid and, 30, 31
• preparing eye for isolating, 74, 75
• preserving isolated, 84, 85
• removing, 44
• straightening, 42, 43
• Retinæ, pars ciliaris, 49
• Retinal artery, course of, 111
• image, 110
• vessels, 40, 49
• Ring, ciliary, 51
• cutting ciliary, 121
• of superior oblique muscle tendinous, 117
• Running through the alcohols, 58, 59
• S
• Sagittal section, cutting eye for, 87-89
• section, excavated, 90
• section of the eye, 86
• section, preparing eye for, 86
• sections, preserving, 89
• Sclerotic and choroid, cutting them away for isolating retina, 83
• and cornea, 52
• from choroid, for dissection of three tunics and hyaloid, loosening, 120
• loosening choroid from, 64, 66-68
• pigment of, 46
• pinching up, 27, 28
• scraping choroid from, 68
• separating choroid from, 27, 29
• to show the three tunics, removing, 120
• Scraping choroid from sclerotic, 68
• processus zonulœ free from ciliary processes, 121
• Section of optic nerve, cross, 48
• cutting eye for sagittal, 87-89
• preparing eye for sagittal, 86
• sagittal, 86
• vertical, 86
• Sections, preparing eye for dissecting interior, 38
• preserving sagittal, 89
• Seeing interior of eye, 110
• Separating choroid from sclerotic, 27, 29, 64-68
• outer layers of the lens, 54
• Serrata, ora, 49
• Sheep eyes, 26, 27
• Skiascope, 109
• Smoothing cornea for ophthalmoscopic examination, 109
• Superior oblique muscle and its pulley, 117
• Staining lens, 57
• Stender dishes, 21
• Straightening retina, 42, 43
• Structure of lens, laminated, 55, 56
• Superior oblique muscle, pulley of, 117
• Surface of anterior of lens, 55
• of posterior of lens, 55
• Suspensory ligament, 55
• T
• Tapetum lucidum, 45
• Tendinous ring of the superior oblique muscle, 117
• Tenon and ocular conjunctiva, Capsule of, 116
• Tenon’s Capsule, 115
• Text-books, 23, 25, 46, 52
• Three tunics, removing choroid, for dissecting, 122
• Tools, 21
• Tri-radiate lines, 54-56
• Tunics, in situ, preparing eye for dissection to show the three, 120
• preserving hyaloid and three, 123
• removing the sclerotic, to show the three, 120
• U
• Use of hammer and chisel, 99-101
• of knitting-needles, 92-95
• Using blowpipe in forcing out vitreous, 78-81
• V
• Vena vorticosa, 72
• Vertical section of the eye, 86
• Vessels of retina, blood-, 40, 49, 106
• Vitreous, 33
• network of fibres in, 41, 42
• removing from anterior half, 49
• removing from posterior half, 41
• using blowpipe to force out, 78-81
• Vorticosa, vena, 72
• W
• Window, in eye, cutting, 110
• X
• Xylol, 59
• Z
• Zone of Zinn, 36, 37
• Zonular processes, 27, 34
• Zonulii Zinii, 36, 37
• Zonulœ processus, 34