Squamosal Suture Research Articles

Relationship of squamosal suture to asterion in pongids (Pan): relevance to early hominid brain evolution.

Based on 244 measurements of the relationship of the squamosal suture to the landmark asterion in 49 chimpanzee skulls, it is shown that in the normal lateral view the squamosal suture is very rarely inferior to asterion. In hominid crania, the squamosal suture is always well superior to asterion. Even in Pan, that part of the squamosal suture most homologous with the remnant found on the Hadar AL 162-28 Australopithecus afarensis hominid cranial fragment is very rarely inferior to asterion. Such variability suggests that Falk's (Nature 313:45-47, 1985) orientation of the Hadar specimen is incorrect; she places asterion superior to the position of the squamosal suture if projected endocranially. The implication for the brain endocast is that, however the fragment is oriented, the posterior aspect of the intraparietal (IP) sulcus is in a very posterior position relative to any chimpanzee brain. The distance from the posterior aspect of IP to occipital pole is twice as great in chimpanzee brain casts than on the Hadar AL 162-28 endocast, even though the chimpanzee brain casts are smaller in overall size. This suggests that brain reorganization, at least as exemplified as a reduction in primary visual striate cortex (area 17 of Brodmann), occurred early in hominid evolution, prior to any major brain expansion.

On the squamosal suture of KNM‐WT 17000

The extensive overlap of the temporal squama on the parietal in KNM-WT 17000 is restricted to a narrow segment of the arc of the squamosal suture. It appears as a long, narrow, posterosuperior extension onto the calvarial wall. The long axis of this extended strip is aligned with what appears to be the most hypertrophied section of the temporalis muscle fan. The substantial differences between the squamosal suture and associated masticatory elements of KNM-WT 17000 and those of Australopithecus boisei provide an opportunity to evaluate the various forces molding the anatomy of the squamosal suture of A. boisei. It is suggested that the extreme flare of the zygomatic arches in the latter accounts for these differences.

Circum-mortem damage to some ancient African hominid crania: a taphonomic and evolutionary essay

Close examination of three early hominid crania from Africa yields taphonomic information long after they were excavated, and can contribute information relevant to their dating and taxonomic status. The condition of the bone and breaks and markings are reviewed in the Florisbad, Saldanha and Broken Hill (Kabwe) crania, indicating animal biting while the bone was still fresh in the first and last of these specimens. However, the damage to the base of the Kabwe cranium indicates that there may also have been breakage by hominids, including scorings near the margin of the squamous suture. No tooth marks are observed on the Saldanha cranium, but a depressed fracture and other lesions indicate hominid damage to fresh bone. Postmortem weathering indicates cranial thickness even greater than the original measurements, which implies a more primitive evolutionary status for Saldanha than for Kabwe. This view is supported by other morphological evidence, and suggests a considerably earlier date for Saldanha and a classification asHomo erectus.

New perspectives in the treatment of craniosynostosis

The history of ideas on the pathogenesis and treatment of craniosynostosis syndromes is discussed, with special reference to the emerging role of cranio-facial units. Emphasis has changed from correction of established deformities, to early surgery to prevent such deformities, as well as relief of existing pathology such as exorbitism and raised intracranial pressure. These early operations, best performed in the first three months of life, essentially involve unilateral or bilateral fronto-orbital advancements. The coronal suture is released with a craniectomy, extended to the squamosal suture, and a wide temporal decompression performed. The frontal bone and superior orbital margin are mobilized and moved to their new position, and wired in place. Intermediate and late stage operations are also discussed, together with complications.

Palatal growth studied on human autopsy material: A histologic microradiographic study

The postnatal development of the hard palate was studied by conventional histologic and microradiographic means on autopsy material from thirty-three boys and twenty-seven girls aged 0 to 18 years. The findings indicated that growth in length of the hard palate until the age of 13 to 15 was due to growth in the transverse suture and to apposition on the posterior margin of the palate. After this age the sutural growth was found to cease, whereas the apposition seemed to continue for some years. During the postnatal development the morphology of the transverse suture changed. At birth the suture was broad and slightly sinuous; later it developed into a typical squamous suture, the palatine part covering the maxillary part. During puberty the course of the suture was again slightly sinuous. The importance of this change for the vertical growth of the hard palate was discussed. It was pointed out that the lowering of the posterior part of the palate was possibly caused by remodeling rather than by lowering of the anterior part of the palate.

Mechanical properties of the cat soleus muscle in situ.

Mechanical properties of the cat soleus muscle in situ.

Extraoral high-pull forces with rapid palatal expansion in the Macaca mulatta

On the basis of the cephalometric and histologic findings, the following conclusions were made: Over-all evaluation of this study indicates that orthopedic forces brought about changes in sutural, endochondral, and appositional growth systems of the dentofacial complex. None of the changes produced was pathologic. Combining orthopedic forces and appliances in the form used in this study produces increased cellular activity in sutures while still maintaining cellular and sutural integrity. These forces decrease endochondral activity and apposition while maintaining cellular integrity. Squamous sutures are not as responsive to orthopedic forces as serrated sutures. Root resorption was a result of lateral and distal orthopedic movement. Discontinuation of orthopedic therapy allows resorption lacunae to return to normal by filling with cementum. The changes observed are a combination of slight tooth movement and much sutural adaptation. Observation of the procion dye indicates that the headgear traction decreases lateral apposition in facial bones. Occipital headgear traction force as applied in this study can alter the position of the maxilla. With proper management, the combination of the rapid palatal expansion appliances and the occipital-pull headgear may have implications in Class II, Division 1 and open-bite therapy. The exact mechanism of sutural movement found in this study is not understood. Superimposition of the zygomaticomaxillary implants indicates that sutural area and geometry of the face may be factors in determining changes resulting from orthopedic force. Orthopedic changes, like orthodontic changes, require retention. Specific attention to technique in fabrication of headgear for monkeys would aid in the study of orthopedic forces in animals. Future combination of orthopedic forces should be studied to determine the amount, duration, and application necessary to bring about desired skeletal changes.

Cloverleaf Skull: Kleeblattschädel-Deformity Syndrome

KLEEBLATTSCHADEL syndrome, translated to cloverleaf skull by Comings, 1 is the evocative name given by Holtermuller and Wiedemann 2 to the grotesque, trilobed skull resulting from congenital hydrocephalus associated with intra-uterine synostosis of the coronal and lambdoidal sutures. The increased intracranial pressure is manifested as bulging in the areas of the sagittal suture and squamosal sutures with a downward displacement of the ears, severe proptosis or exophthalmos, and facial deformities similar to those of craniofacial dysostosis. Deformities of the long bones resembling achondroplasia have been described in 11 of the 17 reported cases. 1-4 The purpose of this communication is to report two additional cases of cloverleaf skull: one with all of the severe bony deformities previously described, the other, manifesting only the cranial abnormalities. Report of Cases Case1.—This white female infant was born Sept 17, 1965, the product of the first pregnancy of a 29-year-old mother after eight

A Mimicry of the Turricephalic Skull in Children Treated on a Bradford frame

THE importance of abnormal pressure and traction in the production of skull deformities has been recognized for many years. In 1834, Stern (7) called attention to peculiarities in skull contour which seemed related to scoliosis. Certain trades (blacksmith, porter) have also been known to modify the shape of the head by asymmetrical tension of the muscles of the neck upon their attachments in the skull (4). In such instances, one usually finds the normal contour of the head on the side of less muscular strength, while the calvarium becomes less prominent on the side of greater muscular development. Brachycephaly and dolichocephaly have been produced by laying infants in one position or another (2) and by using hard and soft pillows (5). In addition, unilateral temporomandibular joint dysfunction, developing in childhood, may produce peculiar asymmetrical changes as the result of unequal tension of the muscles of mastication upon the skull (3). Probably the most bizarre deformities of the skull are the deformities arbitrarily produced because of barbaric or tribal custom (6). The purpose of this report is to record skull changes in children treated for tuberculosis of the spine by hyperextension. Spinal immobilization by fixation in the hyperextended position (Fig. 1) for Pott's disease has been a recognized therapeutic procedure for years. The knowledge that this position in time may modify the shape of the skull has been unknown to us and we were unable to find any reference to such skull changes in the literature. Our attention was accidentally directed to the association of Pott's disease and skull changes by roentgen evidence suggesting turricephaly with increased intracranial pressure in a child with spinal caries. The child (Fig. 1), almost five years of age, had been on a Bradford frame since admission to the hospital, two years and three months prior to the present study. Because of tuberculous changes in several bones other than the spine, it was decided to study the entire skeleton in an effort to identify early unrecognized foci in other parts of the skeletal system. It was this roentgen survey that directed our attention to the changes in the head (Fig. 2), which were described as follows: “The bones of the calvarium are thin. The lambdoidal and squamosal sutures are wide, suggesting increased intracranial pressure. While the general configuration of the skull suggests turricephaly, the absence of roentgen evidence of premature synostosis militates against such a diagnosis.” Clinically, there was no evidence of craniostenosis or increased intracranial pressure. The diet and vitamin intake were normal. Knowing that the child had been on a Bradford frame for many months, it occurred to us that the skull changes were postural in origin. Roentgenograms of two other children treated by hyperextension were obtained and similar turricephalic changes observed.

The Later Developmental Features in the Skull of Sus barbatus barbatus

Abstract.Skull growth after eruption of the third permanent molar in Sus barbatus presents the following features:–Extension of maxilla accompanies eruption of the canine tooth. Following this additional growth takes place in the region of maxillary tuberosity.Meantime bodily size of the animal increases and there is a vertical expansion of upper or respiratory area of face. Fronto‐parietal forward growth overbalances maxillary extension, and face buckles down and back on cranium, as in the sheep, with sliding of zygomatic processes of malar and temporal on each other. This facial buckling terminates on closure of the coronal suture.Between the dates of closure of coronal and squamous sutures the swing of the face changes. There being no more growth above, that in the maxillary area causes the fronto‐nasal contour to increaae its forward concavity by adjustments in the hafting zone which runs from nasion to palato‐pterygoid plate. There is further sliding of malar and temporal zygomatic processes on each other, but it occurs in the reverse direction.Increase of the muscular scaffolding now occurs, more particularly for cranio‐vertebral musculature than for masticatory muscles. Zygomata move laterally. The lambdoid crests but not the sagittal enlarge.Some elongation of face follows by additions along the hafting line, mainly on the orbital side. Fronto‐nasal contour is not changed.The last skull modification is produced by great masticatory muscle development. Elevation of the sagittal crest exaggerates the already existing fronto‐nasal concavity, while extension and lateral movement of the zygomata indicate the increased size of the masticatory musculature.So‐called individual differences can thus be resolved into simple orderly growth changes,

Societies and Academies

LONDON. Royal Society, March 30.—Sir J. J. Thomson, president, in the chair.—Prof. W. J. Sollas: Skull of Ichthyosaurus, studied in serial sections. The anatomy of the palate, including the form and disposition of the vomer, is described; there is no transverse bone. The parietal is split into two wings, an inner, which contributes to the roof of the cranial cavity, and an outer, which unites with the post-frontal and pre-frontal to form a part of the orbital arch. This feature and the separate opisthotic recall the Chelonia. The columella cranii is an important bone which rises from the surface of the pterygoid to meet the descending limb of the parietal. A rather large pre-articular or goniale is present in the lower jaw. The hyobranchial apparatus proves more complicated than had been supposed, and is more akin to the Amphibia than the Reptiles. The relations of the bones in general are also more complicated. The prevalent squamous sutures are remarkable for their excessive overlap, an adaptive character met with also in the Cetacea. Ichthyosaurus, though a true reptile, possesses many characters in common with the stegocephalous Amphibia, so that a close comparison of the roof of the skull and the palate may be made with Loxomma, so well described by Dr. Watson. But it shares these characters with the Cotylosaurian reptiles also, and from this group it is probably descended. The nature of the material which enters into the composition of the Ichthyosaur bones, when these are of a black or deep brown colour, has been investigated, and is found to consist largely of coal. This had already been proved in the case of Coccosteus. As the bones of the Palæozoic Coccosteus have become converted into “stone” coal of the same nature as that furnished by Palæozoic plants, so the bones of the Mesozoic Ichthyosaurus have been converted into “brown” coal of the same nature as that furnished by Mesozoic plants.—Dorothy J. Lloyd: The relation of excised muscle to acids, salts, and bases, (i) Acids and alkalis both cause swelling in excised muscle. The degree of swelling is not directly proportional to the concentration of acid on alkali in the surrounding fluid, but has a maximum at 0-005 normal for hydrochloric acid and for caustic soda. Alkalis first coagulate and then re-dissolve the muscle substance. (2) The chlorides of the alkali and alkaline earth metals all ultimately coagulate the protoplasm of an excised muscle in isotonic solutions. The bivalent kations show this effect much more rapidly than the monovalent. (3) The iso-electric point for muscle is between PH =5 and Pa =7. (4) It is suggested that the swelling and shrinking of muscles, both in the body and out, is an osmotic phenomenon, and that the state of aggregation of the colloids of the muscle substance is the chief determining factor which fixes the degree of swelling. Lillie's demonstration that acids and alkalis raise the osmotic pressure of gelatin, while the neutral salts lower it, is in harmony with this view. (5) The osmotic phenomena of muscle can be fully explained without assuming the presence of a semi-permeable membrane round the muscle fibres.—J. C. Willis: The endemic flora of Ceylon, with reference to geographical distribution and evolution in general.