INTRODUCTION 35 



surface of the earth, is spoken of as being horizontal (horizon- 

 tails) ; if it merely run across the body or one of its parts at 

 right angles to the axis of the body, it is said to be transversal 

 (transver salts). The term transverse (transversus) means 

 across the long axis of the organ concerned. Lines or planes 

 which run parallel to the median plane are called sagittal (sagit- 

 talis) ; those parallel to the surface of the forehead, frontal 

 (front alls}. 



The terms inner (internus) and outer (externus) have been 

 very loosely used in English text-books, often being employed 

 in the sense of medial and lateral, as well as indicating the direc- 

 tion in relation to the interior of organs, cavities of the body, or 

 regions of the body; in the nomenclature used in this book the 

 terms are restricted exclusively to the latter meaning. In de- 

 scribing the dimensions of organs length or longitudinal direc- 

 tion (longitudinalis) , breadth or transverse direction (trans- 

 versus), and thickness are the terms employed to indicate the 

 largest, middle, and smallest dimensions. Particular attention 

 is called to the distinction between transversus and transver sails, 

 the latter being reserved for a direction transverse to that of 

 the median plane. 



The terms upper (superior] and lower (inferior] refer to 

 the directions towards the vertex and towards the sole of the 

 foot respectively, while the terms superficial (superficialis) and 

 deep (profundus) indicate a position of less or greater separa- 

 tion from the external surface of a part or organ. The term 

 middle (medius) is used to indicate a position between superior 

 and inferior or between externus and internus, but, since medius 

 is easily confused by the beginning student with medialis, espe- 

 cially when abbreviated, the term intermediate (intermedium) is 

 employed to indicate a position midway between lateralis and 

 medialis. 



In order to have terms, independent of the position of the 

 body in space, for the directions towards the head-end or the 

 tail-end of the body, the designations cranial (cranialis) and 

 caudal (caudalis) have been introduced. In the head itself the 

 continuance of the cranial direction can no longer very satis- 

 factorily be designated as cranial ; accordingly, this direction as 

 far as the mouth or the nose is spoken of as rostral (rostmlis). 

 When the body is in the upright position, the direction towards 

 the front is spoken of as anterior, that towards the back as 

 posterior; the same directions in the body thought of as inde- 

 pendent of its position in space, are spoken of as ventral (ven- 



