According to his investigations the haemorrhages are usually situ ated under the arachnoid and in the tissues of the pia: less frequently subdural hemorrhages are found along with these. Occasionally intra meningeal hemorrhages occur over the cerebellum and rarely into the lateral ventricles. As a rule there are no hemorrhages in the substance of the brain itself. According to Kundrat, these lifemorrhages regu larly occur in the same manner: during the passage of the foetus there is compression of the head, over-riding of the cranial bones, tension on and tearing of the vessels or occlusion of the falci form sinus, stasis in the veins emptying into this sinus and tearing of these veins.
The hemorrhages into the lateral ventricles are probably due to tearing of the vena Inagua Galeni.
Hemorrhages in other organs, such as the muscles, the lungs and the ehorioid membrane (Sidler-Huquenin) have been often reported as consequences of birth traumata.
Fractures of the long bones and the clavicle are most frequent amongst the injuries to the bones. They are, moreover, not uncommon in unassisted labor. Separation of the epiphysis of the humerus has been found at times.
Dislocations are less common; that of the shoulder occasionally, and rarely of the hip-joint.
Fractures and dislocations of the inferior maxilla and of the clavicle are among the rarest of birth injuries.
The changes that occur in the cranial bones are especially impor tant. The commonest result of birth trauma is overlapping of the cra nial bones. The parietal bones lap over the occipital or the frontal and possibly one parietal bone over the other. This overlapping usually disappears within a few days after birth. It is brought about. by the disproportion between the cranial and pelvic diameters; the various fcetal positions show constantly recurring types of cranial overlapping.
Changes in the shape of the cranium, either as a flattening or a bulg ing, occur in many cases (according to Litzmann, in 45 per cent.). The sacral promontory especially exerts pressure on the contiguous cranial bones and thus flattens them out with this comes an increased bend ing of the bone opposite, against the symphysis.
Depressions of the skull are serious occurrences. One recognizes grooved and spoon (or funnel) shaped depressions; they are usually produced by pressure of the promontory, seldom by the symphysis or by an exostosis.
The flat pelvis rather than the generally contracted pelvis produces these indentations; they may be caused by the pressure of forceps or, it is said by a prolapsed arm or leg. The deeper depressions are, as a rule, combined with very' slight fractures of the external table of the skull.
Cephala'niatomata commonly occur at the site of spoon-shaped impressions. Spoon-shaped impressions offer a more unfavorable prog nosis than the gutter-shaped ones, often leading to death and occasion ally to cerebral complications, as for example convulsions.
The attempt to relieve these depressions by operation has been made time and again. Trephining and also elevation by means of a suction apparatus have been recommended. Munro Kerr suggests the possibility of forcing out the depression by compression antero posteriorly.
Fractures of the cranial hones, lacerations of the sutures and tear ing off of the eondyloid processes of the occipital bone from its tabular portion are rare happenings due to the injudicious pulling in cases of contracted pelvis.
In the following sections the most important birth injuries are taken up in detail.