LECTURE III. 

 FRONT LIMB. 



This limb is composed of 20 bones and includes the shoulder, 

 arm, fore arm and foot. 



The shoulder contains but one bone, the scapula or shoulder 

 blade. It is triangular and situated at the front and lower por- 

 tion of the chest wall. Its direction is downward and forward 

 and it articulates below with the head of the humerus or arm 

 bone. The inner surface is somewhat concave. The external 

 surface is divided into two portions by a long ridge which ex- 

 tends lengthwise of the bone. The upper portion is flat and 

 thin. 



The arm contains a single bone, the humerus. The humerus 

 is a long bone. Tts upper end articulates with the scapula, and 

 the lower end with the ulna and radius. It offers for descrip- 

 tion a shaft, and upper and lower extremities. A peculiar fea- 

 ture of the shaft is a sort of furrow, which twists around the 

 bone and is known in anatomy as the furrow of torsion. The su- 

 perior extremity shows a rounded head which is fitted for articu- 

 lation with a corresponding cavity of the scapula. 



The fore arm contains the radius and ulua, which in the horse 

 and cow are firmly united. The radius belongs to the group 

 classified as long bones and articulates with the humerus above 

 and the carpal bones below. The anterior surface of this bone is 

 convex and smooth ; the posterior surface concave. The ulna is 

 also a long bone, located just back of the radius. The shaft is 

 triangular. The upper extremity shows a marked enlargement 

 which is useful for attachment of muscles and gives leverage. 

 It also contains a deep notch for articulation with the humerus. 

 The inferior portion of this bone is slender and more or less 

 pointed, containing at its extremity a small knob. 



The foot includes seven carpals, three metacarpals, two sesa- 

 moids, three phalanges, and one navicular. 



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