4 DISEASES OF DOMESTICATED BIRDS 
shaped and extends in a posterior direction obliquely ventrad from 
scapular to sternum. The coracoid at its ventral extremity presents 
an opening for the passage of air to the internal air space. The 
clavicle is attached to the coracoid at its superior end. It extends 
ventrad and caudad and curves in to the median line at the point 
of the sternum where the two clavicles unite in a flattened plate and 
become attached to the episternal process by a ligament. The united 
clavicles form a V or U shaped bone termed the fork or furculum. 
This bone represents an elastic spring and serves to prevent the 
wings from approaching’ each other during contraction of the de- 
pressor muscles. 
The humerus is long in palmipeds and the galline, and short in 
the pigeon. It is stout, slightly curved and presents a pneumatic 
foramen near its articular head. 
The ulna is much larger than the radius and is separated from it 
except at the extremities, where the two are united by ligamentous 
bands. The olecranon process of the ulna is only slightly developed. 
The two carpal bones represent fusions in embryonic life, of the 
four bones of the proximal row. The distal carpal row of three 
bones fuse with the metacarpal bones. 
Bones of the leg. These are the pelvie or hip bone; the femur 
or thigh bone; the patella, tibio-tarsus and fibula in the lower leg 
region ; a tarso-metatarsal bone, and four digits. 
The pelvic bone is made up of three bones as in mammals, the 
ilium, ischium and pubis. It differs from the mammalian bone in 
that the pelvic girdle is not complete on the ventral floor, the two 
pubic bones failing to meet in the center to form the pubic sym- 
physis. ‘This arrangement facilitates the passing of the egg through 
the cavity. The ilium is the largest segment and extends along the 
vertebral column in the lumbar and sacral regions. It is consoli- 
dated with the last two thoracic vertebree and the lumbar and sacral 
vertebre, this extensive fusion giving the pelvis a rigidity which 
compensates for the lack of a pubic union. The ischium partly 
forms the side of the pelvic cavity. The pubis is mainly attached 
to the ischium along the lower border and bends inward to form the 
incomplete floor of the pelvic cavity. The ilium, ischium and pubis 
are united at the acetabulum or articular cavity for the reception 
of the head of the femur. 
The femur articulates at its distal extremity with the patella, tibia 
and fibula. The latter bone is united to the tibia, but does not ex- 
tend to its distal articulation. The tibia is comparatively long. 
