Cranial cavity

“ Nor should we be justified in regarding the cranial conformation as perhaps representing the most savage primitive type of the human race, since crania exist among living savages, which, though not exhibiting, such a remarkable conformation of the forehead, which gives the skull somewhat the aspect of that of the large apes, still in other respects, as for instance in the greater depth of the temporal fossae, the crest-like, prominent temporal ridges, and a generally less capacious cranial cavity, exhibit an equally low stage of development. ”

“ This development of air cells is accompanied by the obliteration of the sutures between the various bones. The most noticeable point with regard to the cranial cavity is the comparatively large size of the olfactory fossa. The supra-occipital (figs. 96 and 97, 9) is large—exceedingly large in the adult skull; the parietals (figs. 96 and 97, 2) are also very large. The frontals send out small postorbital processes, but these do not meet processes from the small jugal, which [475] forms only the middle part of the slender zygomatic arch, the anterior part being formed by the maxillae. ”

“ In addition to forming the organs, the tissues are also grouped in such a manner as to provide supports for organs and to form cavities in which organs are placed. The various cavities of the body are of particular interest and importance. The three largest ones are the cranial cavity, containing the brain; the thoracic cavity, containing the heart and the lungs; and the abdominal cavity, containing the stomach, the liver, the intestines, and other important organs (Fig. 2) . Smaller cavities serving different purposes are also found.
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“ The absence of any sign of gross bleeding into the anterior chamber is opposed to the existence of a perforating lesion of the globe in this case.
(78) Entry (Mauser) , from cranial cavity, just within the centre of the roof of the right orbit; exit, from the orbit by a notch in the lower orbital margin internal to the infra-orbital foramen; track thence beneath the soft parts of the face to emerge from the margin of the upper lip near the left angle of the mouth. Collapse of globe, proptosis, subconjunctival hæmorrhage, œdema and ecchymosis of lids. ”

“ The first or mandibular arch consists on each side of an upper portion, the palato-pterygo-quadrate or palato-quadrate cartilage, which passes forwards in the side-wall of the oral cavity, along the upper margin of the mouth, its anterior or palatine part curving inwards to a ligamentous connexion with its fellow beneath the cranial floor. Each cartilage has an upwardly directed process (ethmo-palatine process) which is connected by a suspensory ethmo-palatine ligament with the lateral wall of the cranium behind the lateral ethmoid process. ”

“ The sac is completely closed, so that no communication exists between the serous cavity and the parts in its neighborhood. The various serous membranes are the pleura which envelops the lungs; the pericardium which surrounds the heart; the peritoneum which invests the viscera of the abdomen, and the arachnoid in the spinal canal and cranial cavity. In health the serous membranes secrete only sufficient fluid to lubricate and keep soft and smooth the opposing surfaces. ”

“ If we pursue our researches into the interior of this animal, we find within the framework of the skeleton a great cavity, or rather, I should say, two great cavities,—one cavity beginning in the skull and running through the neck-bones, along the spine, and ending in the tail, containing the brain and the spinal marrow, which are extremely important organs. The second great cavity, commencing with the mouth, contains the gullet, the stomach, the long intestine, and all the rest of those internal apparatus which are essential for digestion ”

“ If death was not too soon the consequence of the puncture of the head of hydrocephalic patients, I am persuaded that we should see the bones gradually contract, and restore the cavity of the cranium to its natural dimensions. When we remove the dead piece from a long bone in necrosis, the new bone, formed on the exterior by means of the periosteum contracts in an evident manner. In paralysis of the optic nerve, its foramen becomes narrower. The orbit contracts when a cancerous eye has been extirpated. ”

“ In the chronic stage there is usually an old necrotic shaft perforated by sinuses, and often freely movable, inclosed by a shell of dense periosteal bone. The sequestrum must be removed, but the bony defect fails to heal, and for months persists as a filthy, discharging cavity, with the constant danger of secondary infection and phlegmon, or erysipelatous inflammation. The healing of this cavity is very difficult and requires a very long time. ”

“ Soft mucous polypus may exist for many years, without depressing the palate, or projecting into the fauces. The anterior nasal cavity is its most frequent seat, and it widens and fills up the fissure between the anterior and posterior cavities: frequently it projects backwards, but is not visible, though it may be felt with the finger behind the soft palate. Its growth is slow. ”

“ In young teeth, he says, the dental cavity is very large, in proportion to the size of the tooth. According to some anatomists, the central cavity of a tooth is coated by a very soft and thin membrane, formed by a tissue of very small vessels and nerves; and besides, this cavity is filled with marrow, like hollow bones. The observations of the author, however, do not agree with these statements. The dental cavity does not contain any fatty substance analogous to the marrow of bones. As to the above-mentioned membrane, Eustachius doubts its existence. ”

“ Previous to successful evacuation, the brain immediately surrounding the abscess cavity is compressed and anæmic. As soon as drainage is supplied, it swells out like a sponge, more or less obliterating the cavity. The closure of a cavity by means of the formation of granulation tissue probably never occurs, and, if the falling together of the surrounding brain is insufficient to obliterate the cavity, final closure is completed by the in-dragging of the overlying tissues—scalp, membranes, and brain becoming intimately fused together. ”

“ He describes accurately (p. 226 and table xvi.) the cavity in the superior maxillary bone, to which his attention was drawn by a lady patient, in whom an abscess of this cavity, ever since known as the antrum of Highmore, was drained by the extraction of the left canine tooth. He became a magistrate for Dorsetshire, and attained considerable practice as a physician. ”

“ It is generally sessile and solitary, and may grow into the interior of the skull, into the frontal sinus, into the cavity of the orbit or nose, or may fill up the external auditory meatus, causing most unsightly deformity and interference with sight, breathing, and hearing. ”

“ Highmore calls attention to the fact that the inferior wall of the antrum often presents small projections, which correspond with the tops of the alveoli, and that the osseous lamina which interposes between these latter and the maxillary sinus is often extremely thin; for which reason, it may easily happen that, in extracting one of the teeth below the cavity, one may bring away together with the tooth the small osseous plate that forms the bottom of the alveolus, thus leaving the maxillary sinus open at its inferior part. ”

“ The upper jaw bone is the most complex of all the bones of the face. Looking at its central part or body we are first of all struck with the cavity in it—the antrum of Highmore. Now, if you take a hundred bones, you will not be able to find two antra exactly alike, but they will differ in size, in shape, in depth, in width, and in size of their angles and inclination of each of their walls. And all these peculiarities influence the countenance, and must, therefore, be studied before you can hope to be successful in replacing the lost dental organs. ”

“ The alveolar border swells slightly where it forms the dental base; the outer side of the tooth is sculptured like the rest of the bone, but in a less or finer degree (see the magnified view, fig. 5, a) . At rather less than a line in advance of this tooth is a minute one like the fourth ; in advance of this is the base of a larger denticle (ib. b) , the fracture of which shows a cavity filled by pyritic matrix; and at a line in advance of this is the fractured hollow base of a smaller denticle: these hollows might at first sight be mistaken for sockets. ”

“ Its hemostatic power is also observed in bone cavities. Care should be taken never to use it unless there is a free [Pg 25] exit, as it increases rapidly in volume after coming in contact with dead tissue or pus, and serious accidents have happened from its improper use; for instance, if it is injected into an abdominal sinus where free escape is not provided for, the distention will result in ruptures of the sinus and infiltration of the surrounding tissues; possibly of the peritoneal cavity. ”

“ A pair of cœlomic cavities appears in every segment except the segments of the 2nd, 3rd, and 4th appendages, in which cœlomic cavities do not appear at all. At least eleven pairs of these cavities are produced. The eleventh pair belongs to the seventh abdominal segment.
The first pair of cœlomic cavities is common to the cephalic lobe and the segment of the first appendage (i.e. the cheliceræ) .
The second cœlomic cavity belongs to the segment of the fifth appendage. It is well developed. ”

“ After removal of the bone, the deep vessels, branches of the internal maxillary, are secured either by ligature, or by firm pressure with charpie or dossils of lint. The facial flap is replaced, brought together over the charpie by which the cavity is filled, and united by interrupted or convoluted suture. Cures by such proceedings, in such cases, are reported; the patients do not always die immediately after the operation ”

“ These two sections of the body cavity, which in Amphibia and Sauropsida remain in free communication with the undivided peritoneal cavity behind, may, from the fact of their containing the lungs, be called the pleural cavities.
In Mammalia a further change takes place, in that, by the formation of a vertical partition across the body cavity, known as the diaphragm, the pleural cavities, containing the lungs, [Pg 632] become isolated from the remainder of the body or peritoneal cavity. ”

“ In shipping a body, cavity embalming must always be resorted to and consists of introducing a trocar into the abdominal and thoracic cavities and injecting sufficient fluid over the contents of these cavities to thoroughly preserve them. ”

“ Gray is right, they must admit the violation of a physiological law: that the organs within the pelvis have outgrown the capacity of the cavity containing them; that there exist adult organs in an infantile pelvis. Such a state of things in a healthy animal is impossible, if we accept the evidence of universal experience. The cavities of the cranium, the thorax, and the pelvis, have a steady and relatively equal development. ”

“ The cavity itself was lined with a thick vascular membrane, united to the papilla at its base. Within the space lying between this membrane and the pulp, there was deposited from the wall of the former a soft, granular, non-vascular substance, known as the enamel organ. The cells on the inner surface of this substance then took the form of long, sub-parallel prisms, set in close array, perpendicular to the surface of the tooth. Earthy matter was progressively deposited in them, by which they became the exceedingly dense and hard enamel of the crown. ”

“ This regularity is found too only in the human skeleton. The animals are irregular men. (Vide Oken's Zahlengesetz in den Wirbeln. Isis, 1829, S. 306.)
Cavities of the Trunk.
2115. The osseous system forms the trunk or body, because it follows the vascular system; the two other galvanic systems, the dermal and intestinal systems, form the large portions of the trunk or its cavities; to them is added the sexual cavity or pelvis.
2116. There are thus three truncal cavities, a pulmonary, an intestinal, and a sexual cavity, or thoracic, abdominal, and pelvic cavity. ”

“ It is formed by the projection of the external plate of the skull, leaving a separation or cavity between it and the inner plate, which cavity is called the frontal sinus, and is sometimes half an inch wide. As there is no positive method of determining its dimensions in the living head, there must ever be some doubt concerning the development of the perceptive organs which it covers. The superciliary ridge at the external angle of the brow extends really as much as three-quarters of an inch from the brain. ”

“ The mouth is at the hinder end of a depression called the buccal cavity, and is surrounded by an annular tumid lip, raised into papilliform ridges and bearing a few spines (Fig. 3) . Within the buccal cavity are the two jaws. They are short, stump-like, muscular structures, armed at their free extremities by a pair of cutting blades or claws, and are placed one on each side of the mouth. In the median line of the buccal cavity in front is placed a thick muscular protuberance, which may be called the tongue, though attached to the dorsal instead of to the ventral wall of the mouth (Fig. 3) . ”

“ The depth of the glenoid cavity is increased by a transverse production of bone both before and behind it: the posterior process (g, Pl. II.) descends the lowest, and affords the requisite defence against backward dislocation of the lower jaw; the pressure of the condyle against this process is denoted by a well defined, transversely-ovate, flattened and smooth surface, as if the bone had been planed down at that 25part: the anterior transverse boundary is convex and smooth, and probably formed part of the articulation for the lower jaw. ”