Part 4
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
Transcriber’s Notes
Page 127, cutting window in: either in the wrong place alphabetically, or it is an error for window, cutting in.
The (unusual) spellings zonuloe and zonulœ have been retained.
Changes:
Footnotes have been moved to the end of the chapter in which they are referenced. Illustrations have been moved out of text paragraphs.
Some obvious minor typographical and punctuation errors have been corrected silently.
In some illustrations the reference letters have been accentuated.
Page 11, 12: Illustration numbers added.
Page 127, Gland, racemose construction: page number 114 added.
Page 130: the entries iris and lens have been moved to their proper place; the entry Retinæ, pars ciliaris has been moved to a separate line.
End of Project Gutenberg's Technique of Eye Dissections, by Frederic A. Woll