ANATOMY OF BIRDS 3 
at the end. It is known as the’ pygostyle. The coccygeal vertebre 
are movable upon each other. 
Ribs. These bones articulate dorsally with the thoracic vertebra, 
and ventrally with the sternum by means of the inferior ribs, except 
in the case of the first two which do not reach the sternum. The 
last rib is often united to the one adjoining and does not connect with 
the sternum. Some of the ribs have flat uncinate processes which 
extend from the posterior border and lie over the external face of the 
following rib near its middle. 
The sternum is highly developed in birds and forms the floor 
of the thoracic cavity and to some extent, of the abdominal cavity. 
It is concave on its dorsal or internal face and convex on its ventral 
or external face. In fowls and pigeons a deep ridge extends along 
the median line of the ventral face. ~This is known as the brisket or 
keel. It serves to increase the area of attachment for the powerful 
breast muscles. The sternum of the duck and goose does not present 
as large a keel as that of the fowl and pigeon, but owing to the greater 
breadth of the sternum and more solid construction the area for 
muscular attachment is as great. In the fowl two long slender 
lateral processes are formed on each side as a result of deep notches 
which extend anteriorly into the body of the sternum. The lateral 
external process is shorter than the lateral internal process and covers 
the last two ribs with a broadened terminal bony plate. The lateral 
borders of the body of the sternum support articular facets for the 
reception of the inferior ribs. The anterior border presents an 
eminence, the episternal process to which the furculum (wishbone) 
is attached by a ligament. The articular surfaces for the coracoids 
are located on each side of the episternal process on the anterior 
border. 
The internal surface of the sternum exhibits several openings 
through which air is passed to the interior of the bony structure. 
Bones of the wing. These comprise the scapula, coracoid, and 
clavicle in the shoulder region; the humerus in the arm; the radius 
and ulna in the forearm; two carpal bones, the radio-carpal bone and 
ulno-carpal bone; one carpo-metacarpal bone, and three digits the 
second of which has two phalanges. 
The scapula is long, narrow, thin and curved like a sabre. It 
extends caudad over the ribs to near the pelvis. Anteriorly it is 
united with the coracoid with which it forms an articular cavity for 
the reception of the head of the humerus. The coracoid also 
articulates with the sternum by its ventral extremity. It is rod 
