LIGAMENTS. CARTILAGE. JOINTS 39 



therefore, do not move on each other, but all motion is due to the 

 flexibility of the layer of cartilage between them. The vertebra 

 with the intervertebral cartilages form such joints. 



SUMMARY. 



1. Ligaments bind bones together. 



2. Tendons connect muscles with bones. 



3. Cartilage is tough, flexible, and elastic. When boiled it yields chon- 

 drine, which resembles gelatine. Chondrine is insoluble in cold water, but 

 dissolves in hot water, forming a jelly on cooling. 



5. Kinds of Cartilage : 



{a) Temporary becomes converted into bone in adults. 

 (b) Permanent not converted into bone. 



6. Uses of Cartilage : 



(a) Forms strong yet flexible frameworks. 



(b) Acts as buffers in deadening shocks and blows. 



(c) Deepens the sockets of joints ; example the hip-joint. 



(d) Covers the articulating surfaces of bones, thus reducing the 



friction. 



IIK-UUH. 



Immovable Sutures skull. 



/ Glidinn- ioints 



7. JOINTS -\ 



/Perfect . 



Movable 



Gliding joints ankle and 



nrvtcif 



wrist. 



Wllbl. 



Ball-and-socket joints 



shoulder and hip. 

 Hinge joints elbow and 



1.- n f* A 



knee. 



K11CC. 



Pivot joints joint of atlas 



and axis. 



ouu axis. 



VImperfect . . Vertebral joints. 



QUESTIONS ON LESSON V. 



1. What are ligaments ? Where are they to be found ? 



2. What is the difference between ligament and tendon ? 



3. What is cartilage ? Describe its chief characteristics. 



4. Describe the chief uses of cartilage. Illustrate^ your description by 



reference to various parts of the body. 



5. Describe briefly the various kinds of joints, giving examples of each kind. 



6. Describe the manner in which the bones of the skull are united to each 



other. 



7. By what means are the bones enabled to move smoothly over each other ? 



8. Describe the ankle and wrist joints. 



9. Give a full description of the shoulder-joint. Illustrate your answer by a 



sketch. 



10. Draw a sketch and give a description of the hip-joint. Show how the 



bones forming this joint are held together. 



11. Give an example and explain the action of a pivot joint. 



12. Describe the manner in which the bones of the vertebral column are con- 



nected together. 



13. Write out, in tabular form, a list of all the various kinds of joints, giving 



examples of each kind. 



14. Why in old age is the back generally stiff? 



