IS 



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which the ribs an drawn down by those muscles in strong expirations. 

 The extremities of this rim, and the anterior and posterior edges of 

 the ilium, into which it is continued, have at either end two strong 

 projections for the attachment of muscles of the thigh, which arc 

 named Spinous Processes. In Jig. 6, 3 is the anterior superior, and 4 

 the anterior inferior spinous process; 6 is the posterior superior 

 pinous process, and 6 the posterior inferior. At the posterior part 

 of the inner aspect of the Ilium is a rough oval surface, which is 

 fixed behind that at the back of the sacrum, with which its fore part 

 forms the sacro-iliac symphvsis. (Kg. 2.) From .the upper part of 

 this symphysis a line, continuous with that of the top of the sacrum 

 and the promontory of the pelvis, passes in a curve across the lower 

 part of the ilium to the upper and inner edge of the pubcs, along 

 which it is continued to the middle line at the symphysis pubia. 

 This line, by which the pelvis it divided into nn upper and a lower 

 cavity, is called (be Brim, and the space it incloses is named the Upper 

 Strait of the Pelvis. (Fig. 2.) At and just below the brim is the 

 thickest part of the ilium ; its inner surface, which is opposite the 

 acetabulum, is smooth, and gives attachment to muscles of the pelvis 

 and thigh. The outer and back surface of the Ilium (which is repre- 

 sented in fg. 6, 13) forms the Haunch, that is, that expansion of bone 

 which is felt above the hip-joint. It is marked by curved lines for 

 the attachment of the strong glutei muscles of the buttock, and of 

 the ligaments connecting it with the sacrum and last lumbar vertebra. 

 At its lowest and. narrowest part it swells outwards, and is then sud- 

 denly and deeply hollowed, to form the upper part of the wall of the 

 acetabulum. In this cavity it is united with the pubes before, and 

 the ischium behind, by flat surfaces, which in the adult bones are 

 indicated only by slightly elevated Hues tending to the deepest part 

 of the cavity. 



The Ischium is the bone on whose lowest part, or tuberosity, the 

 body rests in sitting. It is described as composed of two principal 

 portions : a body (7), consisting of the tuberosity and the thick strong 

 part above it; and a ramus (3), which passes from the tuberosity 

 obliquely upwards, forwards, and inwards. The upper port of the 

 body is united to the lower part of the ilium, and its outer and 

 anterior surface is deeply hollowed to form the lower and back part 

 of the acetabulum. At its posterior and inner bonier there is a strong 

 pointed process, the spine of the Ischium (9), to which one of the main 

 ligaments of the pelvis, the lesser sacro-sciatic, is attached. Above the 

 pine, the body of this bone and the adjacent posterior border of the 

 ilium, as far as its posterior inferior spinous process, are cut out in a 

 crescentic form ; they thus form the ischiatic notch, and, with the 

 ligament just mentioned and the outer border of the sacrum, inclose 

 an oval aperture, the (.Teat ischiatic foramen, through which there pass 

 from the pelvis to the thigh the pyriform muscle, and the gluteal, 

 ischiatic, and pudic blood-vessels and nerve*. Below the spine, another 

 foramen, the lesser ischiatic, is inclosed between the same and another 

 stronger ligament, the great facro-sciatic, and the lower part of the 

 body of the ischium ; through this, together with some vessels and 

 nerves, pastes the internal obturator muscle, which, on its way to the 

 femur, winds round a smooth oval surface on the back of the i-c-lnum 

 directly below its spine. The posterior thick surface of the l.o..ly i. 

 rough, for the attachment of tmircles, especially those of the ham- 

 strings, which form the greater part of the back of the thigh. From 

 the lowest part of the tuberosity, and forming an acute angle with it, 

 ascends the ramus, which at its anterior extremity (10) unites with 

 the descending rauius of the pubcs. 



The I'ubes forms the anterior part of each os innomtnatum, and ix 

 composed of a body (11), and a descending ramus (12). The body in 

 th upper, anterior, and larger part. At its outer extremity it arti- 

 culates with the ilium just below the anterior and inferior spine, from 

 which it descends in an even gentle curve, over which the iliac and 

 pnoas muscles, the thief vessel*, and one of the princip.il nerves of the 

 thinh. pass beneath the crural arch. Its outer end is hollowed 

 part of the acetabulum. The horizontal part of the body has a some- 

 what pyramidal form with three sides. Along its posterior and upper 



border is the line which forms part of the brim of the pelvis. V-.ir 

 the termination of this line is an elevation, the spine of the pubes, for 

 the attachment of one end of the crural arch, the strong ligament 

 already mentioned, whose other end is fixed to the anterior superior 

 spine of the ilium. The inner ends of the bodies of the two pubic 

 bones are opposed by flat oval surfaces, which, with ligaments and a 

 strong intermediate cartilage, form the symphysis pubis. From below 

 and on the side of this, the ramus descends outwards and backwards to 

 meet the ascending ramus of the ischium, with which it forms one flat 

 and thin beam. Between these rnmi below, the body of the pubes 

 above and on the inner side, and the meeting of the pubes and ischium 

 at the acetabulum on the outer side, is an oval aperture, the foramen 

 ovale or obturatorium (13), which in the recent body is nearly closed 

 by the obturator ligament, and of which the borders, as well as the 

 surfaces of the ligament, give attachment to the two obturator muscles, 

 which thence proceed to the back of the thigh-bone, which it is their 

 office to rotate outwards. The space included between the rami of 

 the pubes and ischia on either side and in front, and the great sacro- 

 sciatic ligaments, passing from both borders of the sacrum and coccyx 

 to the tuberosities of the ischia, behind, is named the Lesser Aperture, 

 or Strait of the Pelvis. The meeting of the two rami in the middle 

 line makes the angle of the pubes. 



The general purposes served by the pelvis are to support the 

 abdominal viscera, to inclose and guard those in its own cavity, to give 

 insertion to muscles of the abdomen, back, and thighs, and to be such 

 an intermedium between the rest of the trunk and the lower limb* 

 that the latter may move freely and yet firmly support the body. In 

 all its dimensions it is larger in women than in men. 



The last main division of the trunk is the Chest, or Thorax, com- 

 posed of the dorsal vertebra behind, the sternum in front, and the 

 twelve ribs and their cartilages on either side. (Pig. 7.) All the 

 Kibs articulate with the Spine, but only the seven uppermost on each 

 side have distinct connections with the sternum ; these are therefore 

 called True Ribs, and the five lower on each side False Hibs. Of these, 

 last the three upper have their cartilages united before they reach the 

 sternum; and the two lower, which are sometimes nailed Floating 

 Kiln, have short cartilages, which a-e not attached to the ( 

 at all. 



In each of the greater number of the Kibs there arc a head, a nock, 

 a tuberosity, an angle, a body or shaft, and a cartilage. Tim In -ad U 

 that part which articulates with the vertebral column. It is lai /.IT 

 than the neck, and its articulating surface has a somewhat oval out- 

 line, and is divided into two parts by a transverse elevation, 

 elevated lino corresponds to the intervertebral cartilage, to which it is 

 affixed by ligament. The motion permitted at the joint between the 

 bead of the rib and the border of each of the vertebra- next above and 

 below it is not extensive ; but it is sufficient to give the body of each 

 rib, which has the relation of a long lever to the joint as a fulcrum, a 

 wide sweep outwards and upwards in the actof deep inspiration. Pro- 

 ceeding onwards from the head, and passing over the neck, which is 

 ! the smallest and roundest part of the rib, the next object is the 

 I tubercle, an elevation on the posterior surface, by which the ri!> n 

 | articulated with the end of the transverse process of the vertebra 

 next below it. Farther outward is the angle, an oblique projecting 

 line at which each rib turns somewhat more upwards and becomes 

 flatter. The remainder of the rib is its shaft This is thin and flat ; 

 its surfaces are both nearly smooth, the outer being slightly convex, 

 the inner as slightly concave ; the upper edge is rounded; the lower 

 (which is also directed somewhat outwards) is sharp, and, from the 

 ; angle inwards, is grooved on its inner aspect, where the intercostal 

 | vessels and nerves lie. The end of the osseous part of each ril> h;n 

 a rough surface, to which is adapted one end of the costal cartilage, 

 of which the other end (except in the instances already meiit 

 in attached to the sternum. The costal cartilages have, each the same 

 ! form and direction as tho part of the rib to which they are 



