34 



INTRODUCTION 





of the viscera may be grouped according to their functions: (a) the respiratory 

 apparatus; (6) the digestive apparatus; and (c) the urogenital apparatus. Strictly 

 speaking, the third subgroup should include only such components of the 

 urogenital apparatus as are included within the abdomino-pelvic cavity, but it 

 15 convenient to study under this heading certain parts which lie in relation to 

 the surface of the body, e. g., the testes and the external organs of generation. 



For descriptive purposes. the body is supposed to be in the erect posture, with 

 the arms hanging by the sides and the palms of the hands directed forward. The 

 median plane is a vertical antero-posterior plane, passing through the center of the 

 trunk. This plane will pass approximately through the sagittal suture of the skull, 

 and hence any plane parallel to it is termed a sagittal plane. A vertical plane at 

 right angles to the median plane passes, roughly speaking, through the central 

 part of the coronal suture or through a line parallel to it; such a plane is known as 

 a frontal plane or sometimes as a coronal plane. A plane at right angles to both 

 the median and frontal planes is termed a transverse plane. 



The terms anterior or ventral, and posterior or dorsal, are employed to indicate 

 the relation of parts to the front or back of the body or limbs, and the terms 

 superior or cephalic, and inferior or caudal, to indicate the relative levels of different 

 structures; structures nearer to or farther from the median plane are referred to as 

 medial or lateral respectively. 



The terms superficial and deep are strictly confined to descriptions of the 

 relative depth from the surface of the various structures; external and internal 

 are reserved almost entirely for describing the walls of cavities or of hollow 

 viscera. In the case of the limbs the w-ords proximal and distal refer to the 

 relative distance from the attached end of the limb. 



