THE PELVIS AXD LOWER LIMB. 93 



Ulna continued. 



The epiphysis of the carpal extremity appears in the 4th or 5th year. 

 The epiphysis of the olecranon appears in the 10th year. 

 The superior epiphysis and shaft unite about the 17th year. 

 The inferior epiphysis and shaft unite about the 20th year. 



VI. Carpus. 



The nucleus of the os magnum appears in the 1st year. 



The nucleus of the unciform bone appears in the 1st or 2nd year. 



The nucleus of the cuneiform bone appears in the 3rd year. 



The nuclei of the trapezium and semilunar bones appear in the 5th year. 



The nucleus of the scaphoid bone appears in the 6th or 7th year. 



The nucleus of the trapezoid bone appears in the 7th or 8th year. 



The nucleus of the pisiform bone appears in the 12th year. 



VII. Metacarpus. 



The nuclei of the shafts appear in the 8th and 9th week. 



The nuclei of the epiphyses appear from the 3rd to the 5th year. 



The epiphyses and shafts unite about the 20th year. 



VIII. Phalanges. 



The nuclei of the shafts appear in the 8th, 9th, and 10th weeks. 



The nuclei of the epiphyses appear from the 3rd or 4th to the 5th or 6th years. 



The epiphyses and shafts unite before the 20th year. 



NOTE. From what is stated above it appears that in the bones of the arm and 

 forearm the epiphyses which meet at the elbow-joint begin to ossify later and unite 

 with their shafts earlier than those at the opposite ends of the bones, while in the 

 bones of the thigh and leg the epiphyses distant from the knee-joint are the latest 

 to ossify (excepting the fibula) and the first to unite with their shafts. In the bones 

 of the arm and forearm the nutrient foramina are directed towards the elbow ; in 

 those of the thigh and leg they are directed away from the knee. Thus in each 

 bone the epiphysis of the extremity towards which the nutrient foramen is directed 

 is the first to be united to the shaft. 



V. THE PELVIS AND LOWER LIMB. 



The divisions of the lower limb are the haunch or hip, thigh, leg, and foot. 

 In the haunch is the innominate bone, which, as entering into the formation 

 of the pelvis, likewise constitutes part of the skeleton of the trunk ; in the 

 thigh is the femur ; in the leg the tibia and fibula ; and at the knee 

 a large sesamoid bone, the patella. The foot is composed of three parts ; 

 the tarsus, metatarsus, and phalanges. 



THE INNOMINATE BONE. 



The innominate bone, os coxce, or pelvic bone, with its neighbour of the 

 opposite side and the addition of the sacrum and coccyx, forms the pelvis ; 

 it transmits the weight of the body to the lower limb. In form it is con- 

 stricted in the middle and expanded above and below, and is so curved 

 upon itself that while tha superior expansion is directed inwards posteriorly 

 and outwards anteriorly, the inferior part is curved inwards so as to reach 

 the middle line in front. On the external aspect of the constricted portion 

 is the acetabulum, a cavity which articulates with the femur, and per- 

 forating the inferior expansion is a large opening, the obturator foramen. 

 The superior wider part of the bone forms part of the abdominal wall : the 

 inferior enters into the formation of the true pelvis. The innominate bone 

 articulates with its fellow of the opposite side, with the sacrum and with the 

 femur. 



In the description of this bone it is convenient to recognise as distinct 

 the three parts of it which are separate in early life, viz., the ilium, os 



