Lateral moraine

“ Each lateral mass bears at its cranial end on its medial surface a concave, pear-shaped facet, cranial (or superior) articular facet, (Fig. 12, e) for articulation with the condyles of the skull. These facets look craniomediad. Dorsad of each is a foramen, the atlantal foramen (Fig. 10, i; Fig. 12, g) , which pierces the dorsal arch at its junction with the lateral mass. Caudal to the facet, on the medial face of each lateral mass, within the vertebral canal, is a tubercle. ”

“ Female (based on three adults, Hayward, Palo Alto, and Morro) : See measurements and plates 34-36; weight (no. 43574, from Morro) 2.7 grams; basilar length, 41.2 (40.2-42.2) ; zygomatic breadth more or less than distance between condylar foramen and M1 and more or less than distance between anterior palatine foramen and anterior margin of tympanic bulla; postorbital breadth less than length of upper premolars and less than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; least width of palate less than lateral length of P4 ”

“ Here, except, of course, at the junction of the spinal and cranial regions, each segmental nerve arises from two roots only, dorsal and ventral, and these roots are separately sensory and motor, and not mixed in function as was the lateral root of each cranial segment. Now, these lateral roots were originally the nerves supplying the prosomatic and mesosomatic appendages with motor as well as sensory fibres. The absence, therefore, of lateral roots in the spinal region implies that in the vertebrate none of the musculature belonging to the metasomatic appendages has remained. ”

“ 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 ”

“ All the precaudal vertebræ have large cavities in the centrum, communicating exteriorly with the surface by means of large lateral foramina. This cavernous structure of the vertebræ gradually decreases posteriorly, until in the anterior caudal vertebræ it is confined to a small pocket above the transverse process. ”

“ The postfrontal forms the antero-lateral boundary of the supratemporal fossa.
Articulating posteriorly and laterally with the parietal and the postfrontals, and forming the highest point of the skull, is the single frontal bone (24) , which, like the parietal, is paired in the embryo. It is a heavy bone whose dorsal surface is flattened posteriorly, deeply concave in the middle region, and drawn out into a long projection anteriorly. It forms part of the roof of the cranial cavity and articulates ventro-laterally with the alisphenoid and anteriorly with the prefrontals and nasals. ”

“ Maxillary characteristics (Figs. 4 and 5)
Maxillary teeth anterior to fangs 10-14 (mean, 12.1; N = 20) ; tooth-socket number 6.5-8.5 (mean, 7.2; N = 20) directly opposite distal tip of suborbital process; lateral anterior foramina 1-3 (mean, 1.8; N = 20) ; tooth number 6-9 (mean, 6.9; N = 12) directly below center of posterior foramen (if only two foramina present) . Three specimens lack a diastema and 17 specimens have a diastema. The anterior and posterior edges of the suborbital process are parallel in two specimens and not parallel in 14; the process is broken in four specimens. ”

“ The dorsal portion of the hemispheres has been dissected away and the corpus callosum removed. a, fornix; b, columns or pillars of the fornix; c, crura of the fornix; d, hippocampus; e, choroid plexus of the lateral ventricles overlying the fimbria (the choroid plexus shows an artery) ; f, corpus striatum; g, corpora quadrigemina; h, position of the interventricular foramen (foramen of Monroe) .
The fornix (Fig. 148, a; Fig. 143, u, v; Figs. 150-152, b) consists of an arched tract of longitudinal fibres near the medial border of each hemisphere, ventrad of the corpus callosum. ”

“ It is connected with the lateral reticular processes, and in its cephalo-caudal course becomes gradually attenuated, giving off its fibres to these processes, thus to be exhausted in the lower part of the lumbar enlargement of the cord, where it approaches, if it does not actually reach, the surface. The fibres controlling the voluntary motions of the lower limbs, and which have a longer course to run before they reach the brain than those which mediate the voluntary control of the arms, are situated nearest the lateral boundary of the cord. ”

“ In the region of the internal nares, the nasal forms the lateral wall of the cavum principale (Fig. 12) .
Fig. 13. Transverse section through sphenethmoid region at level of orbitonasal foramen. Abbreviations: ant. max. proc., anterior maxillary process; max., maxillary; orbnas. f., orbitonasal foramen; pasph., parasphenoid; spheth., sphenethmoid.
Sphenethmoid Region
Posterior to the transition zone between the planum antorbitale and solum nasi, the sphenethmoid (spheth., Fig. 1) is fully ossified medially, the lateral parts of the bone at this level are only ossified perichondrally. ”

“ In this depression is « 55 » an oval pneumatic foramen; on the right of the median ridge of the other side, but placed more distally, is another pneumatic foramen. The median ridge has sometimes a slight furrow on each side. It terminates proximally in strong muscular insertions, which extend round the right side of the bone; and distally, becoming more elevated and rounded, it curves obliquely to the rights and forming one of the sides of the pulley, passes round the base as three quarters of a spiral, the termination extending laterally beyond the shaft. ”

“ The dorsal plane surface of the centrum is marked by a median longitudinal ridge on either side of which is an opening (nutrient foramen) for a blood-vessel. The ends are nearly plane, the caudal being slightly concave; they are harder and smoother than the other surfaces. They may be easily separated in a young specimen as thin plates of bone known as epiphyses.
Fig. 2.—Fourth Thoracic Vertebra, Cranial End.
Fig. 3.—Fourth Thoracic Vertebra, Side View.
a, vertebral foramen; b, centrum; c, caudal, and d, cranial, costal demifacets; e, radix or pedicle; f, lamina; g, transverse process ”

“ Through openings in the bony axis—foramina—the central nerve organs give off or receive the nerve bundles which bring them into communication with every other structure of the body. And the body has been so arranged that every single part of it is partly or wholly under control of nerves emerging through224 these foramina. Even the brain and spinal cord themselves respond to changes in the blood-vessels which are controlled by nerve impulses which have emerged through the intervertebral or cranial foramina and returned by other routes to supply the muscular coats of the vessels. ”

“ XVI. fig. 3) is broader than it is high; the occipital foramen (ib. m) partakes of the same proportion; the transverse diameter also exceeds in the condyle (ib. 1) , of which hemisphere the upper part is truncate. The upper border of the foramen, through the posterior swelling of the cerebellum, slightly overhangs the condyle. The cerebellar protuberance (ib. 3) seems to have had a vertical median ridge, as it shows the broken or worn base of such a prominence. On each side of the cerebellar protuberance the occipital surface is smooth and moderately concave across ”

“ 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. ”

“ It will be seen that the conformation of the upper surface of the beak is quite different from that of bidens or any other species.
The maxillary foramina are large and directed forward, and have a distinct broad channel in front of them. In the Oregon skull the right foramen is single, but the left divided into two. The premaxillary foramina are a little behind the maxillary foramina. The distance between the maxillary foramina is less than that from the median line to the anteorbital notch. In bidens it is much greater. ”

“ 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. ”

“ Meningeal tubercles are very common and often hard to recognize. They are usually best seen over the basal meninges. Often they can be demonstrated by stripping off the meninges and floating the membrane in mercuric chloride or formalin fixing-fluids. After a few minutes’ fixation the tubercles appear as minute grayish or opaque points, the membrane often appearing as if sprinkled with fine sand or powder. The Pacchionian bodies of the arachnoid must not be mistaken for tubercles. They are grayish in color, and most abundant along the longitudinal sinus. ”

“ The neural arch is strong, compressed from back to front, and placed as usual on the anterior part of the centrum. In outline it is sub-rhomboid with the sides concave. There is a strong process on each side above the neural canal for a rib, and apparently a neural spine, but all are broken. The transverse processes for the ribs are directed outward, and a little forward, flattened in front and behind, the surfaces being sub-parallel, so that in front the neural arch is concave from side to side. ”

“ Bone diseases such as rachitis osteomalacia, etc., and especially Potts’ Disease, or spinal caries, make marked changes in the shape of vertebrae. Also a subluxated vertebra may gradually assume a shape suited to the abnormal position it occupies, the commonest change being the assumption of a wedge shape by the centrum. This is a great obstacle to adjustment, as the abnormal shape of the vertebra makes it tend to settle after each movement into the old abnormal position.
There are few spines without some more or less misshapen vertebrae. ”

“ 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. ”

“ The second primary constriction separating the mid-brain from the hind-brain is still more interesting, for it is coincident with the position of the trochlear or fourth cranial nerve. In all vertebrates without exception this nerve takes an extraordinary course; all other nerves, whether cranial or spinal, pass ventralwards to reach their destination. This nerve passes dorsalwards, crosses its fellow mid-dorsally in the valve of Vieussens, where the roof of the brain is thin, and then passes out to supply the superior oblique muscle of the eye of the opposite side. ”

“ The hindbrain (hb) is wider than, but not so deep as, the forebrain; its walls are very thick laterally, but [285] are thin on the dorsal and ventral sides. The dorsal wall is reduced to a mere membrane, which, with the overlying ectoderm, has been pushed into the brain cavity, as is generally the case with such embryos. Close to the ventral wall of the hindbrain the notochord (nt) is seen. The character of the notochord has already begun to change; the cells are becoming rounded and vacuolated, with but few visible nuclei except around the periphery of the notochord. ”

“ The bones of the cranium will sometimes be widely separated by it, and the head be made so large that it cannot possibly be born till made less. The causes which produce this disease before birth are unknown.
In cases of hydrocephalus the head does not descend into the straits, owing to its size, and is felt to be full and firm, during a pain, but soft and yielding during the intervals, especially at the fontanelles and sutures, which are also very large. The bones are usually very wide asunder, or even totally separated, as if floating in the fluid. ”