OSTEOLOGY 43 



sides of the sternum are thus provided with an external and an in- 

 ternal process forming an external and an internal notch. These 

 notches are bridged over by a broad ligament, to which the muscles 

 are attached. In poor flyers, as the domestic fowl, these notches 

 are large. The posterior end of the sternum is called the xiphoid 

 process or processus xiphoideus. Anteriorly the sternum is provided 

 ■with lateral external processes, the cotsal processes. The lateral 

 borders of the sternum are pitted by four depressions into which 

 ■the sternal segments of the ribs are received. The dorsal, or inner 

 surface of the bone is pierced by openings by which the air-sacs 

 communicate with the interior. 



THE Appendicular Skeleton 



The appendicular skeleton consists of the shoulder girdle, the fore 

 limb, the pelvic girdle, or hip bone, and the hind limb. The shoulder 

 girdle consists of the scapula, the coracoid, and the clavicle. The fore 

 limb consists of the arm, forearm,, and the hand. The arm consists 

 of the humerus, the forearm of the radius and the ulna; and the hand 

 consists of the carpus, the metacarpus, and the phalanges. The 

 pelvic girdle consists of the ilium, the ischium, and the pubis. The 

 hind limb consists of the thigh, the leg, and the foot. The thigh 

 consists of the femur, and the leg consists of the tibia and the fibula. 

 The foot consists of the metatarsus and the phalanges. 



THE SHOULDER GIRDLE 



The shoulder girdle consists of the scapula, the clavicle and the 

 coracoid. 



The Scapula. Location. — The scapula (Fig. 1 1 , ^ , B) lies on the 

 outer and superior rib surface, extending parallel with the dorsal 

 vertebrae. 



Description. — The scapula is a thin, sword-like bone, becoming 

 thicker as it approaches the shoulder-joint. The scapula expands 

 and becomes thin near the free end, which reaches nearly to the 

 antero-lateral portion of the ilium (Fig. 4, No. 24). The scapula 

 articulates with the coracoid. A pneumatic foramen is located at 

 the base of the acromion process. The anterior part of the scapula 

 is provided with an articular head and is provided with an inner 

 process, called the processus furcularis, which lies near the furcula 

 and coracoid. An outer stronger processus humeralis forms the 



