4. Inner Meninges. Normally gray, transparent, delicate. Note intrameningeal pressure, contents of subarachnoid space, color, thickness and translucency of arachnoid and pia, blood-vessels, presence of blood, pus, fibrinous exudates, localized thickenings, calcification, etc. Most common pathologic conditions are acute and chronic leptomeningitis, results of trauma, hemorrhage, syphilis, tuberculosis, cerebrospinal meningitis, leprous meningitis, etc. Bony plates (osteomata) are found in the arachnoid of the majority of people over forty-five years of age. In small number and size they have no pathologic significance; they are often large and very numerous in old cases of syphilitic leptomeningitis, sometimes encasing the cord. Primary tumors (fibroma, myxoma and sarcoma) are rare. Teratoid tumors (lipoma, myolipoma, neuroma) are occasionally found in the lumbosacral region, often associated with spina bifida. Secondary carcinoma and sarcoma, and metastases of the so-called glioma of the eye are also rarely found.

5. Cord. Size and form. Average length about 45 cms.; weight, 30 grms.; weight of cord to that of brain, 1:48.

Anteroposterior diameter of cervical cord0.9 cm.
Anteroposterior diameter of dorsal cord0.8 cm.
Anteroposterior diameter of lumbar cord0.9 cm.
Transverse diameter of cervical cord1.4 cm.
Transverse diameter of dorsal cord1.0 cm.
Transverse diameter of lumbar cord1.2 cm.

Adhesions to inner meninges, consistence (should be uniform; changes in form and consistence are often the results of postmortem changes), color (gray-white, as seen through the pia), translucency (sclerotic areas in the white matter are firmer, depressed and gray or brownish-gray in color, and more translucent when present in the gray matter), moisture, color and blood-content of cut surface, relation of white and gray matter, symmetry of parts, size of central canal, presence of cavities, areas of softening (soft, yellowish-white, loss of structure), hemorrhages, congestion, anæmia, œdema, gumma, tubercle, tumors, parasites, etc. The normal consistence of the lower portion of the cord is usually somewhat firmer than that of the upper part. The “butterfly-figure” should stand out distinctly on the freshly-cut surface; the outlines between the white and gray matters should be sharp, and the gray matter should be grayish-red in color. Normally the white matter tends to rise above the gray. Inasmuch as the cord is often injured accidentally during its removal it is important to distinguish such artefacts from pathologic softenings. This can be easily done by taking a small portion of the doubtful area and examining in the fresh state under the microscope. In true softening numbers of “fat-granule” cells and also capillary walls showing fat-degeneration are seen.

The pathologic lesions of the cord easily recognized by the naked-eye are areas of sclerosis or gray degeneration, yellow degeneration, hemorrhage, anæmia, œdema, congestion, tabes dorsalis, amyotrophic lateral sclerosis, acute poliomyelitis, syringomyelia, ascending and descending degenerations, glioma, gumma, tubercle, certain malformations, neoplasms and parasites. Other important pathologic conditions are: Malformations (myelocele, hydrorrhachis interna, diastematomyelia, etc.), atrophy, myelitis, sclerosis, effects of trauma, syphilis and intoxications, infections, tuberculosis, etc. Primary tumors are: Glioma, gliosarcoma, gliomyxoma, sarcoma (spindle-cell, myxo-, angiosarcoma, etc.), neuroepithelioma, neuroma, diffuse gliosis, etc. All are rare with the exception of the gliomata. Metastatic carcinoma and sarcoma are relatively rare. Cysticercus and echinococcus are rare.

The thickness, color, consistence and translucence of the spinal ganglia should be noted. Atrophic nerves are smaller, more gray and more translucent.

6. Inner Surface of Vertebrae. The remains of the epidural tissue and the inner surface of the spinal canal should also be carefully examined, noting the consistence of the vertebræ, the character of the ligaments, fascia, periosteum, etc. The anterior wall of the canal should be smooth, the color of the vertebræ grayish-red, that of the intervertebral disks grayish-white. Caries, tuberculosis and syphilis lead to roughening of the bony wall of the canal.

CHAPTER VI.
THE EXAMINATION OF THE HEAD.

I. METHODS OF EXAMINATION.

1. Removal of Skull-Cap. For the section of the head the cadaver is placed upon its back with its head near the end of the table. The head may be elevated by a block placed beneath the neck, or it may be elevated and at the same time firmly held in position by the use of a special head-rest, different varieties of which are offered by instrument-makers. It is better to use the simple block of wood and to control the position of the head with the hands during the operation. The prosector takes his position behind the head of the table. The hair of the cadaver is then arranged in such a manner as to be out of the way, and protected by towels so that it will not become matted with blood and bone-dust. When the hair is short it is parted in a line extending from just behind the ears across the vertex. The shape of the head and the degree of baldness will determine the exact position of the primary incision through the scalp; sometimes it must be made farther back than the line connecting the ears in order that the incision may be concealed. In the great majority of cases it will be made as follows: The head is steadied with the operator’s left hand, and turned as far to the right as possible. The point of the cartilage-knife is then inserted into the scalp, just within the hair-line, behind the left ear, and with the belly of the knife the scalp is cut through to the periosteum, in the line of the hair-part, over the vertex, and as the head is turned to the left, down to the hair-line behind the right ear, the knife, as it approaches the end of the incision being raised so as to make the point finish the cut. This scalp-incision should be made with a strong and quick drawing movement, but the knife should not be pressed so firmly against the bone as to cut through the periosteum, else hemorrhages, collections of pus. etc., may escape before they are seen.