178 Anatomy of the Rabbit. 



II. THE ABDOMINAL WALL. 



1. Place the animal in the supine position. Make a median in- 

 cision of the skin of the ventral surface extending from the pubic 

 symphysis to the tip of the mandible, being careful not to^rt 

 through more than the skin itself. Make three transverse in- 

 cisions on the left side, the first on the medial sur^ce of the arm 

 and extending to the elbow, the second, midway between the anterior 

 and posterior limbs, the third on the medial surface of the thigh and 

 extending to the knee. Work the flaps loose from the surface, 

 using the handle of the scalpel, until the side of the trunk is well 

 exposed. On the right side of the body it is sufficient to clear the 

 middle line. Identify the structures as follows: 

 On the skin : 



(a) The thick compact connective tissue^brming the corium. 



(b) The imbedded hair-follicles. 



(c) The loose subcutaneous tissue (tela subcutanea) by which 

 Jthe skin is attached. 



(d) In the female: the mammary glands (mammae), forming 

 a layer on the inner surface, and more or less closely aggre- 

 gated about the mammary nipples. 



On the exposed, surface : 



(e) The linea afba, a white aponeurotic line extending from the 

 pubic symphysis to the xiphoid, process of the sternum. 



(f) The cutaneus maximus muscle, a thin sheet of muscle 

 * fibres covering the entire lateral surface of the thorax and 



abdomen. Origin: The linea alba, the ventral surface of the 

 sternum in its posterior portion, and the deltoid tuberosity. 

 The last-named portion appears on the medial surface of the 

 humerus. Insertion: The skin of the dorsolateral surface 

 of the trunk. The fibres are directed, upward and. backward. 

 The muscle is continuous across the back with its fellow of 

 the opposite side, and is extended backward to the dorsum 

 of the tail. It is used in shaking the skin. 



The artery passing forward for a short distance in the inguinal region, 

 and lying in the subcutaneous tissue, is the superficial epigastric, a 

 branch of the femoral (p. 224). Passing into the ventral portion of the 

 cutaneus maximus muscle, it anastomoses forward with the external 



