ANATOMY OF THE CAT. 
THE SKELETON OF THE CAT. 
THE skeleton of the cat consists of 230 to 247 bones ex- 
clusive of the sesamoid bones (44) and the chevron bones (8). 
These are divided as follows: head 35-40, vertebral column 
52-53, ribs 26, sternum 1-8, pelvis 2-8, upper extremities 62, 
lower extremities 54-56. The number of bones varies with 
the age of the individual, being fewer in the old than in the 
young animal, owing to the fact that in an old animal some 
bones that were originally separate have united. 
I. THE VERTEBRAL COLUMN. COLUMNA VERTEBRALIS. 
The vertebral column, spinal column, or back-bone, consists 
of a varying number of separate bones, the vertebre. At its 
cranial end are seven vertebrz (cervical, Fig. 1, c) which are 
without ribs and support the head; caudad of these are thirteen 
rib- bearing vertebrz (thoracic, Fig. 1, 7); caudad of these are 
seven that are again without ribs (lumbar, Fig. 1, 0); these 
are followed by three vertebre (sacral, Fig. 1, +) which are 
united into a single bone, the sacrum, which supports the 
pelvic arch. Following the sacral vertebre are twenty-two 
or twenty-three small ribless vertebra which support the tail 
(caudal, Fig. 1, y). 
Thoracic Vertebre. Vertebre thoracales (Fig. 4).—The 
thoracic vertebra are most typical, and the fourth one of these 
may therefore be first described (Figs. 2 and 3). It forms an 
oval ring which has numerous processes and surrounds an 
opening which is the vertebral foramen (a). The ventral one- 
