MYOLOGY. 



PRELIMINARY REMARKS ON THE MUSCLES. 



To the naked eye, the muscles appear to 

 be composed of fasciculi, or bundles of 

 fibres, which are arranged side by side in 

 the direction in wliich the muscle is to act, 

 and which are united by areolar tissue. 

 These fasciculi when separated appear like 

 simple fibres, but when examined under a 

 microscope are found to be themselves fas- 

 ciculi, composed of minuter fibres, bound 

 together by delicate filaments of areolar tis- 

 sue. By carefully separating these, we may 

 obtain the ultimate muscular fibre. This 

 fibre exists under two forms, the striated 

 and non-striated. The former is chiefly 

 distinguished by the transversely-striated 

 appearance which it presents. The non- 

 striated consist of a series of filaments 

 which do not present transverse markings. 

 At an early stage of the development of 

 muscular fibre, however, there is no differ- 

 ence in the forms of either striated or non- 

 striated. Both are simple tubes, containing 

 a granular matter in which no definite 

 arrangement can be traced, yet presenting 

 enlargements occasioned by the presence of 

 nuclei. But, whilst the striated fibre goes 

 on in its development, until the cells of the 

 fibrillsB are fully produced, the non-striated 



j fibre retains throughout life its original 

 embryonic condition ; the contents of the 

 tube remaining granular. The non-striated 

 muscular fibre is the kind of structure proper 

 to the muscular coat of the alimentary 

 canal, bladder, uterus, trachea, bronchial 

 tubes, etc. They seem to be arranged in a 

 parallel manner into bands or fasciculi, 

 without any very definite points of attach- 

 ment. On the other hand, striated muscular 

 fibre has attachments to its extremities of 

 fibrous tissue, through the medium of which 

 it exerts its contractile power on the part 

 it is destined to move. 



At the truncated extremity of the striated 

 muscles we find tendons. To the ordinary 

 observer, tendons appear to unite abruptly 

 with muscular fibre ; but this is not the case, 

 for tendinous fibres are distributed over the 

 whole muscle, crossing it diagonally in both 

 directions, so as to form a double-spirally 

 extensible sheath ; the tendinous fibre finally 

 collects at the extremity of a muscle, and 

 forms the tendon. 



Each muscle is surrounded by cellular 

 membrane, which dips into its substance, 

 and, by means of the fat which its cells con- 

 tain, lubricates the parts, and thus guards 

 against friction. 



A TABLE OF THE NAMES AND NUMBER OE MUSCLES, DIVIDED INTO REGIONS. 



SUBCUTANEOUS REGION (BENEATH THE SKIN). 



1. Panniculus carnosus. 



AURICULAR REGION (MUSCLES OF THE EAR). 



2. AttoUentes maximus. 



3. AttoUentes anterior. 



4. AttoUentes posterior. 

 0. Anterior conchse. 



6. Posterior conchae. 



7. Retrahentes extemus. 



8 



8. Retrehentes internus. 



9. Abducens vel deprimens aurem. 



PALPEBRAL REGION (MUSCLES OF THE EYELIDS). 



10. Levator palpebrce superioris. 



11. Orbicularis palpebrarum. 



OCULAR REGION (MUSCLES OF THE EYE). 



12. Levator palpebrae superiorus internus. 



13. Levator oculi. 



(57) 



