-,'.'11 



SK01TSY 



SKULL 



back again in Asia ; and it was lie who commanded 

 At tin- storming <>f tin' Turkoman stronghold Geok 

 Tepe (24th .lanuary 1881). Skobeleff was one of 

 the recognised leaders of the aggressive and mili- 

 tant wing of the Panslavist agitators ; but he died 

 suddenly on 7th July 1882, at Moscow, before he 

 could put his ambitious schemes into execution. 



See Pcrtonal Rcminucentet of General Stobek/, by 

 Nfiiiinivitcli-Dantchvnko ( Eiig. trans. 1884), and the 

 Life in German by Osaipovitcli ( Hanover, 1887). 



Skoplsj. See RUSSIA, Vol. IX. p. 36. 



SkowlieglUK a town of Maine, capital of 

 Somerset county, on the Kennel>ec (which here 

 has a fall of 28 feet), 37 miles by rail NNE. of 

 Augusta. It manufactures Hour, oil-cloth, axes, 

 paper, woollens, leather, &c. Pop. 5068. 



Skua, or SKUA GULL. See GULL. 



Skull. The skull is divided into two parts, the 

 cranium and the face. In human anatomy it is 

 customary to describe the former as consisting of 

 eight anil the latter of fourteen bones ; the eight 

 cranial bones, which constitute the brain -case, 

 lieing the occipital, two parietal, frontal, two tem- 

 poral, sphenoid, and ethmoid : while the fourteen 

 facial bones, which surround the cavities of the 

 mouth and nose and complete the orbits or cavities 

 for the eyes, are the two nasal, two superior maxil- 

 lary, two lachrymal, two malar, two palate, two 

 inferior tnrbinated, vomer, and inferior maxillary. 

 The bones of the ear, the teeth, and the Wormian 

 hone* are not included in this enumeration. The 

 lower jaw articulates with the temporal bones by 

 means of a diarthrodial Joint (q.v.), but all the 

 others are joined by sutures. On the base of the 

 cranium the occipital and sphenoid bon.es articulate 

 by means of a plate of cartilage (synchondrosis) in 

 young subjects ; in adults this becomes bony 

 union. Sutures are named from the bones between 

 which they are found, but to those around the 

 parietal Ixnies special names are given e.g. inter- 

 parietal or sagittal ; occipito-parietal or lamMoid ; 

 fronto-parietal or coronal; parieto-temporal or 

 sqiiamoits. During adult life many of the sutures 

 close by bony union and disappear, but l>oth the 

 age at which this occurs and the order of its occur- 

 rence are subject to variation. Wormian tones 

 are irregular ossifications found in relation to the 

 sutures of cranial bones, but seldom Keen in rela- 

 tion to the bones of the face. They are most 

 frequent in relation to the lambdoid suture, and 

 -"Mum one inch in diameter. The closure of a 

 suture stops tin' growth of the skull along that 

 Jine, and in order to compensate for this defect an 

 increase of growth may occur at right angles to the 

 closet! suture and thus irregularities of form may 

 result : for example, closure of the sagittal suture 

 stops transverse growth, but the skull continues to 

 grow in the longitudinal and vertical directions, 

 with the result that a boat-shaped cranium is pro- 

 diiced sciiplioccplialy. Irregular forms may be 

 produced artificially by pressure applied early in 

 life. This is liest seen among certain American 

 trilx* who compress their children's heads by 

 means of lioardx and bandages. The Imnes of the 

 skull are pierced by holes (fnriimiiin), and similar 

 holes are found in relation to the adjacent margins 

 of l>oiies. Mci-t of these foramina are situated 

 in the base or floor of the skull, and are for the 

 ingress of arteries and the exit of veins and 

 cranial nerves. The largest of these foramina 

 the foramen magnum -is found in the occipital 

 bone. It is situated immediately almve the 

 ring of the atlas vertebra, and through it the 

 continuity between the brain and spinal cord is 

 established, and further, it transmits the vertebral 

 arteries which supply blood to the brain. Com- 

 Vared with the skulls of animals, the form of the 



human skull is modified ( 1 ) by the proportionately 

 large size of the brain and the consequent expan- 

 sion of the bones which surround it; (2) by the 

 smaller size of the face, esjiecially of the jaws, so 

 that the face of man, instead of projecting in 

 front of, is under the forepart of the cranium ; (3) 

 by the rrert uttittide, which places the base of the 

 skull at a considerable angle with the vertebral 

 column, and, in consequence of a development 

 backwards from its point of articulation with the 

 vertebra 1 , the skull is nearly balanced on the 

 summit of the vertebral column. Hence the orbits 

 look forwards and the nostrils look downwards. 

 The development of the skull is a subject of great 

 interest, not only in itself, but as throwing light 

 on many points which the study of the adult skull 



Fig. 1. Side View of Human Sknll : 

 a, frontal bone ; 6, parietal bone ; r, occipital bone ; d, tem- 



bone; a, nanal bone; A, superior maxillary or upper Jaw 

 bone; t, inferior maxillary or lower Jaw bone. 

 BD, height of cranium ; GO, length of cranium ; BN, baainaMl 

 length : HA, basialveolar length. (These meamirraiicnts are 

 supposed to be made in a straight line from point to point.) 



would fail to explain. At a very early period of 

 foetal existence the cerebrum is enclosed in a mem- 

 branous capsule external to the dura mater, and in 

 close contact with it. This is the first rudiment of 

 the skull, the ceiebral portion of which is conse- 

 quently formed before there is any indication of a 

 facial part. Soon, however, four or live processes 

 jut from it on either side of the mesial line, which 

 grow downwards, incline towards each other, and 

 unite to form a series of inverted arches, from 

 which the face is ultimately developed. Imperfect 

 development or ossification of these rudimentary 

 parts of the face gives rise to ' hare-lip ' and ' cleft 

 palate,' or in very extreme cases to the monstrosity 

 termed 'Cyclopean,' in which, from absence of the 

 frontal processes, the two orbits form a single 

 cavity, and the eyes are more or le-- Mended in 

 the mesial line. 



The cartilage, formed at the base of the menv 

 branous capsule, is speedily followed by the deposi- 

 tion of ossilic matter at various points of the cap 

 sule, which soon becomes converted into flakes of 

 Ivone ; while the intervening portions, which remain 

 membranous, permit the skull to expand as its con- 

 tents enlarge. Then follows the appearance of 

 osseous nuclei in the cartilage at the base, corre- 

 s|Minding to the future occipital and sphenoid bones. 

 Lastly, the various liones, some originating in 

 membrane, and some in cartilage (sec OSSIKICA- 

 TION), approach one another by gradual enlarge- 

 ment, and become united in various ways, so as to 

 form a continuous, and ultimately an unyielding 



