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The Carpal, Metacarpal, and Phalangeal joints are formed by the union of the bones entering into the formation of the skeleton of the hand.

The function of these joints is to endow the hand with all varieties and combinations of movements, enabling it to perform a large number of delicate and complicated actions.

The Pelvic Girdle presents anteriorly the inter-pubic joint and poste. riorly the sacro-iliac joints.

The function of these joints, which are amphiarthrodial in character, is not so much to permit of movement, which is slight, as to prevent the forward and downward displacement of the sacrum and to enable it to transmit the weight of the body through the pelvic girdle to the lower extremities.

The Hip Joint is formed by the acetabulum on the outer surface of the os innominatum and the globular head of the femur, both structures being accurately adapted to each other. To retain the femur in position the acetabu. lum is deepened by a rim of cartilage ; to render the joint more stable and to limit the extent of motion it is provided with strong ligaments and strengthened by overlying muscles.

The function of the hip joint is to permit all those movements of the trunk on the femur, or the reverse, which are involved in walking, running, rowing, and allied muscular acts. Being a typical enarthrodial joint, movements can take place in all directions within certain limits, and may be grouped as follows: 1. A pendulum-like movement in any plane. 2. Rotation around the long axis of the limb. 3. Circumduction, in which the limb describes a cone, the apex of which is in the joint, the sides being formed by the limb itself.

The Knee Joint is formed by the apposition of the articular surfaces of the femur, tibia, and patella. It is partially subdivided by the interposition of two fibro-cartilages. From the mechanical construction of this articulation displacement of the bones would readily take place were it not provided, as it is, with a large number of ligaments, tendons, and synovial membranes, which are so arranged as to make it the most complicated joint in the body.

The function of the knee joint, being ginglymus in structure, is to permit movements of Alexion and extension, which cover an angle of about 145o. These simple movements, however, are complicated by a gliding of the condyles upon the tibial facets so that the points of contact are constantly shifting. Owing to the shape of the condyles, extension is accompanied by outward rotation and flexion by inward rotation.

The Ankle Joint unites the skeleton of the foot to the lower extremity of the leg, and is formed by the apposition of the convex surface of the astragalus and the concavity of the tibia, and embraced on either side by the external and internal malleoli.

The function of the ankle joint is to permit of Mexion and extension around an axis passing through the body of the astragalus, but at such an angle that the movements do not take place in a direct antero-posterior plane, but in a plane directed outward and forward. It serves to transmit the weight of the body to the foot.

The Tarsal, Metatarsal, and Phalangeal joints unite the bones of the foot. They are very numerous and abundantly supplied with ligaments and synovial membranes.

The function of these joints is to endow the arches of the foot with considerable elasticity, to diminish the effects of jars or shocks that are transmitted to the vertebral column, and to adapt the foot to changes of form necessitated by the acts of walking, jumping, etc.

PHYSIOLOGY OF THE TISSUES. The study of the Structure of the body reveals that it is composed of a number of dissimilar pa such as the brain, heart, lungs, muscles, etc., to which the name organ has been given. The organs upon a closer examination can be resolved into elementary structures, to which the name tissue has been given. The study of the physical and physiological properties of the tissues bas given rise to that department of anatomy known as histology, or, as it is largely prosecuted with the microscope, microscopical anatomy. Notwithstanding the complexity of the body, the number of constituent tissues is not great. They can be classified as follows :

1. Epithelial.

2. Connective, comprising the areolar, adipose, fibrous, elastic, cartilage and bone.

3. Muscular. 4. Nervous.

The majority of the tissues, however, are not simple structures, but complexly organized masses, whose physiological properties are dependent upon

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