GENERAL ANATOMY. 23T 



Eectus abdominis, Obliquus capitis, Transversalis ; 3, from their uses, as Flexors, 

 Extensors, Abductors, etc. ; 4, from their shape, as the Deltoid, Trapezius, Rhom- 

 boideus ; 5, from the number of their divisions, as the Biceps from having two 

 heads, the Triceps from having three heads ; 6, from their points of attachment, 

 as the Sterno-cleido-mastoid, Sterno-hyoid, Sterno-thyroid. 



In the description of a muscle, the term origin is meant to imply its more fixed 

 or central attachment; and the term insertion, the movable point upon which the 

 force of the muscle is directed : this holds true, however, for only a very small 

 number of muscles, such as those of the face, which are attached by one extremity 

 to the bone, and by the other to the movable integument ; in the greater number, 

 the muscle can be made to act from either extremity. 



In the dissection of the muscles, the student should pay especial attention to 

 the exact origin, insertion, and actions of each, and its more important relations 

 with surrounding parts. An accurate knowledge of the points of attachment of 

 the muscles is of great importance in the determination of their action. By a 

 knowledge of the action of the muscles, the surgeon is able at once to explain the 

 causes of displacement in the various forms of fracture, or the causes which produce 

 distortion in various forms of deformities, and, consequently, to adopt appropriate 

 treatment in each case. The relations, also, of some of the muscles, especially 

 those in immediate apposition with the larger bloodvessels, and the surface- 

 markings they produce, should be especially remembered, as they form most useful 

 guides to the surgeon in the application of a ligature to these vessels. 



Tendons are white, glistening, fibrous cords, varying in length and thickness, 

 sometimes round, sometimes flattened, of considerable strength, and only slightly 

 elastic. They consist almost entirely of white fibrous tissue, the fibrils of which 

 have an undulating course parallel with each other, and firmly united together. 

 They are very sparingly supplied with bloodvessels, the smaller tendons pre- 

 senting in their interior not a trace of them. Nerves also are not present in the 

 smaller tendons ; but the larger ones, as the tendo A chillis, receive nerves which 

 accompany the nutrient vessels. The tendons consist principally of a substance 

 which yields gelatine. 



Aponeuros'es are fibrous membranes, of a pearly- white color, iridescent, glisten- 

 ing, and similar in structure to the tendons. They are destitute of nerves, and 

 the thicker ones are only sparingly supplied with bloodvessels. 



The tendons and aponeuroses are connected, on the one hand, with the muscles ; 

 and, on the other hand, with the movable structures, as the bones, cartilages, 

 ligaments, fibrous membranes (the sclerotic, for instance), and the synovial mem- 

 branes, the subcrureus and subanconeus for example. Where the muscular 

 fibres are continuous in a direct line, with those of the tendon or aponeurosis, the 

 two are directly continuous, the muscular fibre being distinguishable from that 

 of the tendon only by its striation. But where the muscular fibre joins the tendon 

 or aponeurosis at an oblique angle, the former terminates, according to Kolliker, 

 in rounded extremities, which are received into corresponding depressions on the 

 surface of the latter, the connective tissue between the fibres being continuous 

 with that of the tendon. The latter mode of attachment occurs in all the penni- 

 form and semi-penniform muscles, and in those muscles the tendons of which 

 commence in a membranous form, as the Gastrocnemius and Soleus. 



The Fascia? (fascia, a bandage) are fibro-areolar or aponeurotic laminae, of 

 variable thickness and strength, found in all regions of the body, investing the 

 softer and more delicate organs. The fasciae have been subdivided, from the 

 structure which they present, into two groups, fibro-areolar or superficial fasciae, 

 and aponeurotic or deep fasciae. 



The fibro-areolar fascia is found immediately beneath the integument over 

 almost the entire surface of the body, and is generally known as the superficial 

 fascia. It connects the skin with the deep or aponeurotic fascia, and consists of 

 fibro-areolar tissue, containing in its meshes pellicles of fat in varying quantity. 

 In the eyelids and scrotum, where adipose tissue is rarely deposited, this tissue is 



