The human body A beginner's text-book of anatomy, physiology and hygiene .. . nges. The knee is a hinge-joint: it can only be bent andstraightened; or, as physiologists say, flexedd^nd, the phalanges of the fingers there are otherhinge-joints. 6. Pivot-Joints.—In pivot-joints one bone rolls roundanother. A good example is the joint which permits us to turnthe head from side to side. The uppermost vertebra (Fig. 14), which carries the 4. What is a ball-and-socket joint ? 5. Describe a hinge-joint. Examples. 6. What are pivot-joints ? Describe the atlas. What is the odon- 38 PIV
The human body A beginner's text-book of anatomy, physiology and hygiene .. . nges. The knee is a hinge-joint: it can only be bent andstraightened; or, as physiologists say, flexedd^nd, the phalanges of the fingers there are otherhinge-joints. 6. Pivot-Joints.—In pivot-joints one bone rolls roundanother. A good example is the joint which permits us to turnthe head from side to side. The uppermost vertebra (Fig. 14), which carries the 4. What is a ball-and-socket joint ? 5. Describe a hinge-joint. Examples. 6. What are pivot-joints ? Describe the atlas. What is the odon- 38 PIVOT-JOINTS. skull, has been fancifully named the atlas vertebra^ afterthe fabled giant of antiquity who was believed to bearthe heavens on his shoulders. It is ringlike in form andthe space which it surrounds is separated by a ligament,Z, into a smaller front and larger back division. In thelarger division the spinal cord lies. Into the smaller pro-jects a bony peg (Z>, Figs. 14 and 15), called from itsshape the toothlike or odontoid process^ which springs from .Aa Fas. Fig. 14. Fig. Fig. 14.—The atlas vertebra sf ei from above. Fig. 15.—The axis vertebra,L^ the ligament which divides the space surrounded by the atlas into a backportion, containing the spinal cord; and a front portion, containing the odontoidprocess, Z>, of the axis, round which the atlas rolls when we turn the head to eitherside. the second or axis vertebra. Knobs on the under side ofthe skull fit into the hollows {^Fas^ Fig. 14) on the atlas:when we turn the face to right or left the atlas, carryingthe skull with it, rolls around the odontoid process. Another kind of pivot-joint is found in the the hand and forearm flat on a table, palm moving the shoulder-joint at all, it will be easy told process ? What happens at the joint between atlas and axisv^hen we turn the face to one side ? Where is there another kind ofpivot joint ? What is the position of radius and ulna v^rh
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Keywords: ., bookcentury1800, bookdecade1, booksubjectphysiology, bookyear1884
