Saturday, October 22, 2005


Templates for cases are complete with history, gross, microscopic and diagnosis. The following are examples of some gross only cases with an explanation of the goals in examination:

Rectus Muscle for ID only
Rectus muscles receive a gross description after viewing under the dissecting microscope. The high magnification under the dissecting microscope is of the same order of magnitude (usually greater) than the low magnification at the compound microscope. During the gross examination the resident should try to identify tendon which is white and usually quite abundant with striations that run parallel to the apparent short axis (arrow 1 in the figure). Muscle appears tan and is usually most abundant at one edge (arrowhead 2 in the figure. The length of the muscle removed needs to be documented accurately. Since the extraocular muscle is quite wide in vivo (about 9 mm) but the length resected quite small (usually 2-4 mm), the axis of the apparent width of the gross specimen corresponds to that of the length in the orbit. This is especially evident when one sees the striations running in the short axis of the specimen. In the figure striations are obvious both in muscle and tendon (arrows 1 and 2) and therefore the muscle length is actually the distance between the arrowheads marked 3. In the body the long axis of the muscle is oriented parallel to arrow 3.

Gross description:
Specimen 1, in formalin, labeled "right lateral rectus muscle" consists of one rectangular red and white fragment measuring 9 x 2 x 2mm in greatest dimensions. Under the dissecting microscope the external surface has fibrous white strands which are parallel and longitudinally oriented, adipose tissue, and blood vessels.
Dx: Muscle and fibrous tissue, "right lateral rectus muscle" (resection) - muscle and tendon

For more detail see this link.

Intraocular Lenses
An accurate diagram of the IOL should be drawn out. Note the type of lens if you know it; otherwise make your description accurate enough that one could draw a picture from your words. Note any tissue adherent to the lens and process tissue for appropriate histologic sections. Describe the shape, size, and color of optic and note any defects. The flexibility of the lens gives a clue whether it is made of polymethylmethacrylate (PMMA is hard) or silcone (soft). This should be indicated. Note the color, shape, size, and position of haptics (L-shaped, closed loop, etc. for anterior chamber lenses; C-shaped, J-shaped for posterior lenses). Note evidence of broken / amputated haptic or transected optic (often done to get the lens out of the eye). Note positioning holes, their size and position. Intraocular lenses are stored for 6-9 months! Restor Lenses should be saved for possible return to the patient for rebate.

Gross Description:
Specimen 1, in formalin, labeled "IOL, OS" consists of a clear synthetic hard device measuring 13 mm in overall length with a round clear optic that measures 6 x 5 x 1 mm. There is a positioning hole in the periphery. The lens is a 3 piece style; two blue J-shaped haptics extend from the periphery of the optic 180 degrees apart. The optic shows some pitting on the posterior surface.

Diagnosis: Synthetic device, "IOL, OS" (removal) - synthetic intraocular lens, posterior chamber style

Lenses (native)
Cataractous lenses are carefully examined with a stereomicroscope. It is important to note the color (yellow, yellow-white, or brunescent), the degree of opacification, and the diameter of the lens. You can calibrate the degree of opacification by trying to read newsprint through the lens. The lenses are then shelved for temporary storage (3 months), then discarded. No histologic sections need to be taken unless specifically requested or if there is an interesting finding such as a congenital anomaly, infection (like rubella, fungus, or bacteria) or tissue attached to the lens that would be important to document.


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