201. Strong ligaments maintain in their proper position the bones that form the ankle-joint (fig. XCVII.), connect the bones of the tarsus and metatarsus with one another (fig. XCVIII. 1), and articulate the several phalanges of the toes (fig. XCVIII. 2).
General view of the posterior ligaments of the ankle-joint.
1. Lower end of the tibia; 2. lower end of the
fibula; 3. astragalus; 4. os calcis; 5. ligament between
the tibia and fibula; 6. ligament passing from the fibula
to the astragalus; 7. ligament passing from the fibula to
the os calcis; 8. ligament passing from the tibia to the
astragalus.
General view of the ligaments of the sole of the foot.
1. Ligaments connecting the bones of the tarsus; 2. ligaments
connecting the bones of the toes.
202. The joint of the hip, like that of the shoulder, is capable of flexion, extension, and rotation; but its rotatory motions are to a much less extent, on account of the greater depth of the acetabulum and the stronger and shorter fibrous capsule. When the femur is flexed, the thigh is bent upon the pelvis, and its inferior extremity is carried forwards. When it is extended, the thigh is carried backwards. The two thighs may be separated from each other laterally (abduction), or brought near to each other (adduction), or the one may be made to cross the other, and they may be rotated outwards or inwards.
203. The apparatus of muscles that produces these varied motions is seated partly on the trunk and partly on the pelvis. Thus, the powerful muscle that flexes the thigh, or that carries it forwards, termed the psoas (fig. XCIX. 1), arises from the last vertebra of the back, and successively from each vertebra of the loins (fig. XCIX. 1), and is inserted into the lesser trochanter of the femur (fig. XCIX. 3). Its action is assisted first by a large and strong muscle named the iliacus (fig. XCIX. 2), which occupies the whole concavity of the ilium (fig. XCIX. 2), and which, like the psoas, is inserted into the lesser trochanter of the femur (fig. XCIX. 3).
