194 THE LOWER EXTREMITIES. 



will be all right. Dislocation of the knee is rare, though 

 it may occur in any direction. Often the bursae of the 

 joint are irritated, as by kneeling to scrub floors, and 

 bursitis or housemaid's knee results. Fracture of the 

 patella may be caused by muscular traction or by direct 

 violence, and is generally repaired by making an incision 

 and sewing the parts of the bone together. Tumor albus 

 or white swelling is tuberculosis of the knee and is fairly 

 common in children. Specific knee means syphilis of the 

 knee and generally occurs in both knees. 



The Tibia. The tibia or shin bone is next longest 

 to the femur and is on the inner side of the leg, corre- 

 sponding to the ulna in the arm. The shaft is prismoid 

 and is more slender for the lower quarter, where fracture 

 is consequently most frequent. The anterior border 

 forms the crest or shin and can be felt for its upper two- 

 thirds. The lower extremity, which is smaller than 

 the upper, articulates with the astragalus bone of the 

 ankle and with the fibula. Its head or upper extremity 

 is expanded into two lateral tuberositis for articulation 

 with the femur and for muscular attachment, both of 

 which can easily be felt just below the bend of the knee. 

 Their upper surfaces are smooth and concave, with a 

 vertical bifid spine in the middle and a prominent 

 tubercle for the attachment of the scmilunar cartilages 

 on either side. On the anterior surface of the head, 

 below, is a rough eminence or tubercle, which also can be 

 felt. The lower part of this is for the attachment of the 

 ligamentum patellae, while the upper part, which is 

 smoother, is for the bursa that is placed under the tendon 

 to prevent friction. On the back of the outer tuberosity 

 is a facet for the head of the fibula. At the lower end 

 there projects downward on the inner side, overhanging 

 the arch of the foot, the internal malleolus, the prominent 

 part of the ankle. It is on a higher level and somewhat 

 farther forward than the external malleolus. 



The Fibula. The fibula is the most slender of all the 

 bones in proportion to its length and is on the outer side 



