46 ANTHROPOLOGY. 



or through loops, or else .bj the intervention of pulleys {trochlece), in or 

 over which they glide. 



For the sake of facilitating the play of tendons, and to prevent friction, 

 they are surrounded by loose cellular membranes {vagince tendinum mucosce\ 

 which permit them to glide freely one on the other ; in other places they 

 glide over synovial sacs of a similar character {bursce mucosce), especially 

 about the joints 



2. Anatomy of the Fascia. 



The muscles are intimately connected with certain membranous expan- 

 sions {fasciae) found in various regions of the body, and forming coverings 

 to particular parts. These expansions are composed either of cellular 

 tissue more or less condensed, or of fibrous tissue ; the former are called 

 cellular fasciae,^ the latter the aponeuroses or aponeurotic fasciae. They 

 include and embrace not only single muscles but entire systems, maintain- 

 ing them securely in their place and relative position. The most extensively 

 distributed cellular fascia is that layer of cellular membrane immediately 

 adjacent to the subcutaneous cellular tissue all over the body, and in most 

 cases so intimately connected with it as to be inseparable. This is usually 

 known as the superficial fascia. Although this is universal, there are 

 nevertheless certain regions where it is of more importance than in others, 

 as in the neck and abdomen ; here it constitutes a distinct membraniform 

 expansion. The cervical fasciae bind down the muscles, and support the 

 vessels and glands in this region ; at the lower part of the neck they serve 

 to protect the trachea and the upper part of the thorax from the pressure 

 of the atmosphere during respiration. 



PI. 129, fig. 1, cervical fascia, the platysma myoides supposed to be 

 removed : ', superficial layer ; *, temporal aponeurosis ; ', portion over the 

 parotid gland; ", clavicular portion ; ^ continuation over the pectoralis major; 

 °, external jugular vein showing through the superficial layer. 



PI. 129, fig. 2 \ middle layer of the cervical fascia; ^, cut edge of the 

 superficial layer ; ", continuation of the middle layer beneath the sterno- 

 cleido-mastoid muscle ; ", sheath for the cervical vessels ; °, section of the 

 sterno-cleido-mastoid ; ", portion of the fascia attached to the lower jaw, 

 separating the parotid gland, ', from the submaxillary, ^ 



PL 129, fig. 3, deep-seated layer : *, section of the superficial layer ; 

 ", do. of the sterno-cleido-mastoid ; ', middle layer ; *, deep-seated layer 

 extending into the thoracic cavity, and passing above along the lower edge 

 of the thyroid gland, \ 



PI. 129, fig. 4 ', layer descending anterior to the vertebral column ; 

 *, scalenus anticus forming a swelling beneath it ; ', clavicle removed ; 

 *, section of sterno-cleido-mastoid. 



The eye is protected in a measure by the ocular fascia^ which, although 

 not very thick or strong, is tough, flocculent, and difficult to remove. It 

 covers the recti muscles as far back as their origin, and is continued ante- 

 752 



