Foramen ovale

“ Such, for instance, is the preservation in the adult of the foramen ovale between the auricles of the heart, or of the open ductus arteriosus by which blood of the pulmonary and body circulation may mingle. In case of the veins also an arrangement of vessels is often found in the adult which is due to the persistence of a truly embryonic condition. ”

“ The lower wall of the infra-orbital canal is cut away by a chisel, the posterior wall of the antrum by a smaller trephine, the nerve thus isolated is traced up to and past Meckel's ganglion, which is removed close to the foramen rotundum by cutting the nerve by curved blunt-pointed scissors.
2. Pancoast's Operation.—Expose the coronoid process by a free incision, divide it at its root and throw it up, then expose and tie internal maxillary artery, after which the upper portion of the external pterygoid is to be detached from the sphenoid, thus exposing the nerve leaving foramen ovale ”

“ Another minute foramen penetrates the sphenoid between the wing and the body of the bone, just laterad of the tuberculum sellæ. This foramen is continuous craniad with a groove on the dorsal surface of the pterygoid process; the groove and foramen constitute the pterygoid canal. It transmits a nerve.
The external surface shows the orbital fissure, the foramen rotundum and the foramen ovale, bounded ventrally by a sharp ridge, which is continued onto the pterygoid process. Between this ridge and the body the surface is longitudinally grooved for the tuba auditiva or Eustachian tube. ”

“ The open or closed condition of the foramen does not seem to depend on the degree of stenosis of the pulmonary artery itself. It depends, probably, more on the freedom of escape for the blood from both the ventricles through the aorta—probably also on the condition of the ductus arteriosus Botalli. The foramen ovale and ductus art. Bot. have been found closed much more frequently in stenosis than in atresia of the pulmonary artery, and the ductus is deficient or absent oftener in stenosis than in atresia. ”

“ The Foramen Ovale and Septum of the Auricles.—In markedly deformed hearts the entire septum may be in greater or less degree wanting, as seen in cases of the bilocular or trilocular organ. This defect is comparatively rare, and the foetus has but a short extra-uterine life. In other cases the septum is complete, but the foramen may be unusually large, and remain unclosed wholly or in part ”

“ Weight, 3.6 grams; basilar length, 43.5; zygomatic breadth less than distance between condylar foramen and M1 and more or less than (in the single specimen, equal to) that between anterior palatine foramen and anterior margin of tympanic bulla; least width of palate more or less than (about equal to) outside length of P4; tympanic bulla as far posterior to foramen ovale as width of 4 or 5 upper incisors; height of tympanic bulla less than distance from its anterior margin to foramen ovale.
The skull of the female is 48 per cent lighter than that of the male. ”

“ All the blood that the trunk of the inferior vena cava receives, either from the capillary system of the inferior extremities, or from that of the abdomen, or from the placenta by the umbilical vein, instead of stopping in the right auricle, as in the adult, passes entire into the left through the foramen ovale, the superior edge of which is so arranged, that nothing can mix with the blood of the superior vena cava ”

“ The cranial part is in contact with the inner table of the skull, and is adherent along the lines of the sutures and to the margins of the foramina, which transmit the nerves, more especially to the foramen magnum. It forms, therefore, for these bones an internal periosteum, and the meningeal arteries which ramify in it are the nutrient arteries of the inner table. As the growth of bone is more active in infancy and youth than in the adult, the adhesion between the dura mater and the cranial bones is greater in early life than at maturity. ”

“ 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. ”

“ It consists of two layers, an outer fibrous and an inner cellular layer; the cells, which are called osteoblasts, are continuous with those lining the Haversian canals and the medullary cavity.
The arrangement of the blood vessels determines to some extent the incidence of disease in bone. The nutrient artery, after entering the medullary canal through a special foramen in the cortex, bifurcates, and one main division runs towards each of the extremities, and terminates at the ossifying junction in a series of capillary loops projected against the epiphysial cartilage. ”

“ About two-thirds of the way back the sagittal suture becomes less serrated and on each side of it the small parietal foramen may be seen. This only transmits a small emissary vein (see Veins) in the adult, but, as will be seen later, is of considerable morphological interest. As middle life is reached the cranial sutures tend to become obliterated and the bones can no longer be separated; this fusion begins at the places, where the sutures are least deeply serrated, and as a rule the sagittal suture disappears between the two parietal foramina between thirty and forty years of age. ”

“ The sculpturing of the internal surface of the cranial cavity bespeaks the high vascularity of the soft parts which it contained, and there are evident indications that the upper and lateral surfaces of the brain had been disposed in a few simple parallel longitudinal convolutions. The two anterior condyloid foramina (m) have the same relative position as the single corresponding foramen in the Glossothere, Orycterope, and Armadillos, and the inner surface of the skull slopes outwards from these foramina to the inner margin of the occipital condyle. ”

“ The anterior region, as is the laminal surface, is covered with foraminæ; in this case more minute. In the recent state it is covered by the sensitive sole. The posterior region, lying immediately behind the semilunar crest, shows on each side of a median process a large foramen, the Plantar Foramen. From this foramen runs the Plantar Groove, a channel, bounded above by the superior edge, and below by the semilunar crest of the bone, which conducts the plantar arteries into the Semilunar Sinus, a well-marked cavity in the interior of the bone. ”

“ The borders of the foramen are hardly as smooth as they would be had they transmitted some erratic tendon or artery, and outside of its borders there is no trace of any groove such as a large artery or a tendon would produce. As to tumor, there is very little if any excavation or absorption of the walls in the opening, and no thickening of the bone.
The formation must have taken place very early in the life of the individual, as the form of the entire head of the ulna is affected. In all probability the anomaly of the foramen is due to congenital causes. ”

“ The artery, in company with the nerve and vein, re-enters the pelvis by the small sciatic foramen, and gets under cover of a dense fibrous membrane (obturator fascia) , between which and the obturator muscle, it courses obliquely downwards and forwards to the forepart of the perinaeum. At the place where the vessel re-enters the pelvis, it lies removed at an interval of an inch and a half from the perinaeum, but becomes more superficial as it approaches the subpubic space, N. The levator ani muscle separates the pudic vessels and nerves from the sides of the rectum and bladder. ”

“ Its occlusion may be effected by means of a sterilized wooden match or bone peg, by a small piece of bone derived from those osseous fragments which have been removed during the operation, or with [147] the aid of a piece of catgut; in each case the occluding medium should be well driven into the foramen. ”

“ Even when, as is sometimes the case, this branch of the human occipital artery passes right through the mastoid foramen, and actually reaches the dura mater, yet a comparison of the diameter of the artery as it enters, with that of the artery as it makes its exit through the foramen, will show a very striking difference in size; the artery, as it makes its appearance at the inner side of the mastoid foramen, not having half the diameter that it possessed on its entrance into the foramen, and, even in these cases, it sends a very considerable off-shoot to the diplöe. ”

“ It passes craniad and dorsad at the side of the thoracic portion of the longus colli muscle, and enters the foramen transversarium of the sixth cervical vertebra. It passes thence craniad through the foramina transversaria (which together form the vertebrarterial canal) and gives off at the intervertebral foramina branches to the muscles of the neck and branches which pass across the ventral surface of the spinal cord to join A. spinalis anterior. Craniad of the foramen transversarium of the atlas the vertebral artery turns dorsad in the groove on the lateral surface of the atlas. ”

“ In the sketch here given, showing extensive fracture of the occipital and sphenoid bones into the foramen magnum, the patient, a brick-layer, fell from a ladder on the vertex. He lay comatose for some days before death: there was found extensive extravasation over the middle lobes and cerebellum. Concussion has resulted from falls when the person has alighted on his nates or feet; but the symptoms attendant on fracture of the base are more generally those of compression of the brain. In this accident the bones are seldom displaced to any great extent ”

“ General thinning of intervertebral substance through a condition of disturbed metabolism itself produced through the agency of some one serious subluxation, may narrow all the foramina and increase impingement of nerves at any point where a slight subluxation previously existed. An irritated nerve may become swollen and the nerve impinged at the foramen. ”

“ Also diagnosed by a unique combination of the following features: five maxillary foramina consisting of four scattered small ones anteroposteriorly arranged in a row and a large one close to the ventral extremity of the jugal articular surface of the maxilla; markedly convex dorsally maxillary and dentary occlusal surfaces; elevated maxillary body that is approximately 150% longer than tall; laterally exposed, large anterior foramen limited to the anterior half of the anterodorsal surface of the maxilla and located just lateral to the premaxillary articular surface of the bone ”

“ Six per cent. exhibit an anomaly which is extremely rare among normal individuals—the olecranon foramen, a perforation in the head of the humerus where it articulates with the ulna. This is normal in the ape and dog and is frequently found in the bones of prehistoric man and in some of the existing inferior races of mankind. ”

“ Rami musculares.—Muscular branches are given off near the supracondyloid foramen to the biceps (4) , epitrochlearis (6) , and brachialis muscles. A nutrient artery leaves [297] the brachial proximad of the supracondyloid foramen, either separately or in common with the muscular branches, and passes into the nutrient foramen at the junction of the middle and distal thirds of the shaft of the humerus, supplying the bone. ”

“ To reach the foramen rotundum (second division) —a rather more difficult procedure—it is necessary to find the posterior border of the orbital process of the malar bone, prolonging this line downwards to the lower border of the zygoma and inserting the needle 1⁄2 cm. posterior to this point. The needle is pushed horizontally inwards and the point directed slightly upwards, the foramen being reached in the pterygo-maxillary fossa at a depth of about 3 cm. from the zygoma. ”

“ It may be that the crack has extended across a bony groove in which an artery is running, and, the artery being torn, haemorrhage may take place within the skull and the symptoms of compression of the brain may supervene. Experiments upon the lower animals have taught the surgeon how to recognize the exact spot at which the compression is situated. One set of muscles after another being thrown out of work in regular order, he knows exactly where the bleeding is going on, so, having made a hole in the skull by trephining, he turns out the clot and secures the leaking vessel. ”