V. THE HUMAN SKELETON 
Materials. —Mounted and disarticulated human skeletons; 
also a variety of skeletons of other mammals, for comparison. 
Note that in the following study, features of bones may usually 
be identified by considering the meaning of the name which they 
bear. Reference books should be used as a help only as a last 
resort. 
A. THE VERTEBRAL COLUMN, RIBS AND STERNUM. 
A general preliminary view of these bones and their relation¬ 
ships should be obtained by arranging upon the table top the 
entire series of vertebrae in their correct order, the thoracic ones 
sufficiently separated from each other to allow the pair of ribs 
corresponding to each to be placed in position beside it, careful 
attention being given to the distinction of rights and lefts. As a 
criterion for the arrangement of the bones, refer to a correctly 
mounted skeleton and apply also the test of fitting together adja¬ 
cent bones by their corresponding articular surfaces. Note the 
gradual transition from each group of vertebrae to the adjacent 
group. 
i. A Typical Thoracic Segment. 
Avoiding the more modified anterior and posterior ends of the 
thoracic region, each student should select for study one of the 
more typical thoracic vertebrae (2nd to 9th inclusive) and its 
corresponding pair of ribs. To understand correctly the relation¬ 
ships of these, the vertebra next anterior to the segment selected 
should be included in the set of bones selected. Record the serial 
number of the segment. 
(a) A Thoracic Vertebra. 
Orientation. —Distinguish dorsal, ventral, anterior, posterior, 
right and left lateral aspects. 
Parts. —Body or centrum; and vertebral arch which encloses, 
dorsal to the body, the vertebral foramen. The arch bears a 
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