Articulations
Synarthrosis, or immoveable
Amphiarthrosis, or mixed
Diarthrosis, or moveable
Kinds of movement
Articulations of the trunk
The vertebral column
The atlas with the axis
The atlas with the occiptal bone
The axis with the occiptal bone
Tempoko-maxillart articulation
The ribs with the vertebras
The cartilages of the ribs with the sternum
Ligaments of the sternum
The pelvis with the spine
The pelvis
Articulations of the upper extremity
Sterno-clavicular articulation
Scapulo-clavicular articulation
Proper ligaments of the scapula
Shoulder joint
Elbow joint
Radio-ulnar articulations
Whist joint
Articulations of the carpus
Capro metacapral articulations
Metacarpo-phalangeal articulations
Articulations of the phalanges
Articulations of the lower extremity
Hip joint
The knee joint
Articulations between the tibia and fibula
Ankle joint
Articulations of the tarsus
Tarso-metatarsal articulations
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The Ligaments connecting the bones of the pelvis with each other may be divided into four groups:
1. Those connecting the sacrum and ilium. 2. Those passing between the sacrum and ischium. 3. Those connecting the sacrum and coccyx. 4. Those between the two pubic bones. The sacro-iliac articulation is an amphiarthrodinl joint, formed between the lateral surfaces of the sacrum and ilium. The anterior or auricular portion of the articular surfaces is covered with a thin plate of cartilage, thicker on the sacrum than on the ilium. The surfaces of these cartilages in the adult are rough and irregular, and separated from one another by a soft yellow pulpy substance. At an early period of life, occasionally in the adult, and in the female during pregnancy, they are smooth and lined by a delicate synovial membrane-. The ligaments connecting these surfaces are the anterior and posterior sacro-iliac. The Anterior Sacro'iliac Ligament consists of numerous thin ligamentous bands, which connect the anterior surfaces of the sacrum and ilium. The Posterior Sacro-iliac (fig. in) is a strong interosseous ligament, situated in the deep depression between the sacrum and ilium behind, and forming the 
chief bond of connexion between these bones. It consists of numerous strong fasciculi, which pass between the bones in various directions. Three of these are of large size; the two superior, nearly horizontal in direction, arise from the first and second transverse tubercles on the posterior surface of the sacrum, and are inserted into the rough uneven surface at the posterior part of the inner surface of the ilium. The third fasciculus, oblique in direction, is attached by one extremity to the third or fourth transverse tubercle on the posterior surface of the sacrum, and by the other to the posterior superior spine of the ilium; it is sometimes called the oblique sacro-iliac ligament.
The Great Sacro-Sciatic (Posterior). The Lesser Sacro-Sciatic (Anterior). The Great or Posterior Sacro-Sciatic Ligament is situated at the posterior and inferior part of the pelvis. It is thin, flat, and triangular in form; narrower in the middle than at the extremities; attached by its broad base to the posterior inferior spine of the ilium, to the third and fourth transverse tubercles on the sacrum, and to the lower part of the lateral margin of that bone and the coccyx; passing obliquely downwards, outwards, and forwards, it becomes narrow and thick; and at its insertion into the inner margin of the tuberosity, it increases in breadth, and is prolonged forwards along the inner margin of the ramus forming the falciform ligament. The free concave edge of this ligament has attached to it the obturator fascia, with which it forms a kind of groove, protecting the internal pudic vessels and nerve. One of its surfaces is turned towards the perineum, the other towards the Obturator internus muscle. The posterior surface of this ligament gives origin, by its whole extent, to fibres of the Gluteus maximus. Its anterior surface is united to the lesser sacro-sciatic ligament. Its superior border forms the lower boundary of the lesser sacro-sciatic foramen. Its lower border forms part of the boundary of the peri-naeum. This ligament is pierced by the coccygeal branch of the sciatic artery. The Lesser or Anterior Sacro-Sciatic Ligament, much shorter and smaller than the preceding, is thin, triangular in form, attached by its apex to the spine of the ischium, and internally, by its broad base, to the lateral margins of the sacrum and coccyx, anterior to the attachment of the great sacro-sciatic ligament, with which its fibres are intermingled. It is in relation, anteriorly, with the Coccygeus muscle; posteriorly, it is covered by the posterior ligament, and crossed by the pudic vessels and nerves. Its superior border forms the lower boundary of the great sacro-sciatic foramen. Its inferior border, part of the lesser sacro-sciatic foramen. These two ligaments convert the sacro-sciatic notches into foramina. The superior or larger sacro-sciatic foramen is bounded, in front and above, by the posterior border of the os innominatum; behind, by the great sacro-sciatic ligament; and below, by the lesser ligament. It is partially filled up, in the recent state, by the Pyriformis muscle. Above this muscle, the gluteal vessels and nerve emerge from the pelvis; and below it, the ischiatic vessels and nerves, the internal pudic vessels and nerve, and the nerve to the Obturator internus. The inferior or smaller sacro-sciatic foramen is bounded, in front, by the tuber ischii; above, by the spine and lesser ligament; behind, by the greater ligament. It transmits the tendon of the Obturator internus muscle, its nerve, and the pudic vessels and nerve. This articulation is an amphiarthrodial joint, formed between the oval surface on the summit of the sacrum, and the base of the coccyx. It is analogous to the joints between the bodies of the vertebra, and is connected by similar ligaments. They are the Anterior Sacro-Coccygeal. Posterior Sacro-Coccygeal. Inter-articular Fibro-Cartilage. The Anterior Sacro-Coccygeal Ligament consists of a few irregular fibres, which descend from the anterior surface of the sacrum to the front of the coccyx, becoming blended with the periosteum. The Posterior Sacro-Coccygeal Ligament is a flat band of ligamentous fibres, of a pearly tint, which arises from the margin of the lower orifice of the sacral canal, and descends to be inserted into the posterior surface of the coccyx. This ligament completes the lower and back part of the sacral canal. Its superficial fibres are much longer than the deep-seated; the latter extend from the apex of the sacrum to the upper cornua of the coccyx. Anteriorly, it is in relation with the arachnoid membrane of the sacral canal, a portion of the sacrum, and almost the whole of the posterior surface of the coccyx; posteriorly, with some aponeurotic fibres from the Gluteus maximus. An Inter-articular Fibro-Cartilage is interposed between the contiguous surfaces of the sacrum and coccyx; it differs from that interposed between the bodies of the vertebras, in being thinner, and its central part more firm in texture. It is somewhat thicker in front and behind, than at the sides. Occasionally a synovial membrane is found where the coccyx is freely movable, which is more especially the case during pregnancy. The different segments of the coccyx are connected together by an extension downwards of the anterior and posterior sacro-coccygeal ligaments, a thin annular disc of fibro-cartilage being interposed between each of the bones. In the adult male, all the pieces become ossified; but in the female, this does not commonly occur until a later period of life. The separate segments of the coccyx are first united, and at a more advanced age the joint between the sacrum and the coccyx. Actions. The movements which take place between the sacrum and coccyx, and between the different pieces of the latter bone, are slightly forwards and backwards; they are very limited. Their mobility increases during pregnancy. The articulation between the ossa pubis is an amphiarthrodial joint, formed by the junction of the two oval surfaces which have received the name of the sym-physis. The ligaments of this articulation are the Anterior Pubic. Posterior Pubic. Superior Pubic. Sub-Pubic. Inter-a ticul ar Fibro-Cartilage. The Anterior Pubic Ligament consists of several superimposed layers, which pass across the anterior surface of the articulation. The superficial fibres pass obliquely from one bone to the other, decussating and forming an interlacement with the fibres of the aponeurosis of the External oblique muscle. The deep fibres pass transversely across the symphysis, and are blended with the inter-articular fibro-cartilage. The Posterior Pubic Ligament consists of a few thin, scattered fibres, which unite the two pubic bones posteriorly. The Superior Pubic Ligament is a band of fibres, which connects together the two pubic bones superiorly. The Sub-Pubic Ligament is a thick, triangular arch of ligamentous fibres, connecting together the two pubic bones below, and forming the upper boundary of the pubic arch. Above, it is blended with the inter-articular fibro-cartilage; laterally, with the rami of the pubes. Its fibres are of a yellowish colour, closely connected, and have an arched direction. The Inter-articular Fibro- Cartilage consists of two oval-shaped plates, one covering the surface of each symphysis pubis. They vary in thickness in different subjects, and project somewhat beyond the level of the bones, especially behind. The outer surface of each is firmly connected to the bone by a series of nipple-like processes, which accurately fit within corresponding depressions on the osseous surface. Their opposed surfaces are connected, in the greater part of their extent, by an intermediate fibrous elastic-tissue; and by their circumference ,to the various ligaments surrounding the joint. An interspace is left between the two plates at the upper and back part of the articulation, where tho 
fibrous-tissue is deficient, and the surface of the fibro-cartilage lined by epithelium. This space is found at all periods of life, both in the male and female; but it in larger in the latter, especially during pregnancy, and after parturition. It is most frequently limited to the upper and back part of the joint; but it occasionally reaches to the front, and may extend the entire length of the cartilages. This structure may be easily demonstrated, by making a vertical section of the sympliysis pubis near its posterior surface.
The Obturator Ligament is a dense membranous layer, consisting of fibres which interlace in various directions. It is attached to the circumference of the obturator foramen, which it closes completely, except at its upper and outer part, where a small oval canal is left for the passage of the obturator vessels mid nerve. It is in relation, in front, with the Obturator cxternus; behind, with the Obturator internus; both of which muscles are in part attached to it. |