32 MAMMALIAN AXATOMY 



An angle is formed by the meeting of surfaces or borders, and 

 may be right, acute, or obtuse. Example : angle of a rib, anyulus 

 costce. 



In some cases the term angle includes also the prominent region of 

 bone around the actual angle. Example : angle of the lower jaw, 

 angulus man dibu Ice . 



Surfaces are marked (1) by elevations, ("2} by depressions, and 

 (3) by openings. 



(1) Elevations assist in articulations and afford greater surface for 

 the attachment of muscles. 



In addition to those elevations which were considered of sufficient 

 size to be classified as parts of bones, the names of the following are 

 to be noted : 



Process is a general term for a projection. If the process bear a 

 smooth articular surface, it is called an articular process. Example : 

 articular process of a vertebra, processes articulari* vertebrae. 



Articular eminence (tuber articulare] is sometimes used for an 

 articular process. 



Apoph'ysis (Greek apo, from, and phuo, to grow) is sometimes used 

 in place of the term process. 



A pair of rounded articular processes in the same plane are termed 

 condyles (knuckles). Example: condyles of the femur. 



The meaning of the term condyle has been in several instances 

 extended to include an elevation near an articular swelling. Ex- 

 ample : the processes found on each side of the lower extremity of 

 the humerus, or of the femur, known as the internal and external 

 condyles. As they are not true articular swellings, the term epi- 

 condyle (Greek epi, upon) should be used. 



A spool-shaped articular swelling is sometimes termed a trochlea 

 (a pulley). Example: trochlea of the humerus, trochlea humcrl. 



A tuberosity (tuber, tuberositas) is a rough, obtuse, non-articular 

 swelling. It may be clearly denned or may pass down gradually on 

 all sides continuous with the surrounding surface. Example : tuber- 

 osity of the calcaneum, tuber calcaneum. 



Tubercle is a term applied to a non-articular swelling smaller and 

 usually sharper than a tuberosity. Example : tubercle of the rib, 

 tuberculum costa*. 



