176 THE MUSCLES. 



we may determine their extent and direction, and even their relations and 

 uses. 



By the term attachment, fixed insertion, or origin, is meant the point of 

 the muscle which most usually remains fixed while that organ contracts ; 

 the attachment, movable insertion, or termination is the name given to that 

 portion which corresponds to the lever displaced by the muscular contraction. 

 Muscles are frequently met with whose two insertions are alternately fixed 

 or movable ; and in such cases care is taken not. to give these insertions one 

 or other of the designations. 



The fixed insertion is often confounded with that of other muscles ; the 

 movable insertion is generally free and independent. 



The muscles are sometimes directly attached to the bones by the ex- 

 tremities of their fleshy fibres ; but most frequently they are fixed to these 

 inert levers through the medium of a tendon or an aponeurosis, whose 

 volume is less considerable than that of the fibres. Without this latter 

 disposition, the surface of the skeleton would not have been sufficiently 

 extensive to give insertion to all the external muscles. 



The attachment of the muscles to the bony levers is effected by a 

 kind of fusion between the fleshy or tendinous fibres, and the periosteum. 



F. RELATIONS. The indication of the relations of the muscles completes 

 the idea of their situation, and is of great importance in a surgical point 

 of view. They should, therefore, be studied with all the precision 

 possible. 



The muscles entertain relations either with the skin, the bones, other 

 muscles, or with vessels and nerves. 



a. It is only, properly speaking, the subcutaneous muscles, such as the 

 panniculus carnosus and the muscles of the face, which are really in im- 

 mediate contact with the skin. The others are separated from it by the 

 aponeurotic fascia which will be described as the appendices of the muscular 



6. The superficial muscles are only related to the bones by their ex- 

 tremities. Those which are deeply 'situated are immediately applied by 

 their bodies against the bones of the skeleton. 



c. The muscles are related to each other in a more or less intimate 

 manner. Sometimes they adhere closely to one another ; and at other times 

 they are separated by interstices filled with fat or cellular tissue, and 

 generally traversed by vessels and nerves. 



d. The connections of the muscles with the latter organs sometimes 

 assume a remarkable character ; this is when one of them accompanies, 

 like a satellite, the vascular and nervous trunks concealed beneath its deep 

 face. There is in this circumstance an important fact with regard to 

 surgical anatomy. 



G. NOMENCLATURE. Before the time of Sylvius, the muscles had not 

 received particular names. Since the days of Galen they had been dis- 

 tinguished by the numerical epithets of first, second, third, etc., to indicate 

 their place and their order of superposition in the regions to which they 

 belonged. It is in this fashion that they are designated in the Italian work 

 on the Anatomy of the Horse by Ruini. 



Sylvius was the first to give the muscles real names ; and his example 

 being followed by succeeding anthropotomists, the nomenclature of these 

 organs was soon completed. But no general view, no methodic spirit guided 

 Sylvius and his successors ; it was sometimes their form, and sometimes their 

 direction, position, uses, etc. to which the muscles owed their names. 



