BONES, MUSCLES, EXERCISE, AND REST. 259 



wrist (Fig. XLVIII.) and the ankle are supplied with a great 

 variety of ligaraentous bands, that hold their small bones in 



FIG. XLVII. Knee and Internal Ligaments. 



a, Thigh-bone. 



b, c, Bones of the leg. 



d, e, f, Ligaments connecting these bones 

 together. 



their several places, and yet allow them due freedom of mo- 

 tion. The hip joint has a round ligament, which is attached 

 to the bottom of the socket and to the middle of the head of 

 the thigh bone, (Fig. XLV. e.) 



613. These capsules and ligaments are strong and inelastic. 

 They are so distributed and arranged as to allow all the 

 requisite movements, and yet to retain the bones in their re- 

 spective situations. When they are exposed to great or 

 sudden violence, they are sometimes strained, and some of 

 their minute fibres are broken. Then the joint is said to be 

 sprained, and requires a long healing process for restoration. 

 This happens most frequently to the foot and ankle from any 

 misstep or fall, causing a greater strain upon the ligaments 

 than they can safely bear. 



614. A bone is dislocated or thrown out of joint when it is 

 exposed to still greater strains or violence. The shoulder is 

 more liable to this -injury than any other joint. The cavity 

 is so shallow, that when the arm is stretched forward or back- 

 ward, and any pressure or blow comes upon it in front or be- 

 hind, it has little power of resistance, and the head is thrown 

 out of its socket. Persons falling forward, as when thrown 



