MUSCLES AND FASCIA OF THE CRANIUM AND FACE. 297 



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 very liable to serous infiltration. The superficial fascia 

 varies in thickness in different parts of the body: in the groin it is so thick as to 

 be capable of being subdivided in several laminae. Beneath the fatty layer of 

 the superficial fascia, which is immediately subcutaneous, there is generally another 

 layer of* the same structure, comparatively devoid of adipose tissue, in which the 

 trunks of the subcutaneous vessels and nerves are found, as the superficial epigas- 

 tric vessels in the abdominal region, the radial and ulnar veins in the forearm, 

 the saphenous veins in the leg and thigh, and the superficial lymphatic glands; 

 certain cutaneous muscles also are situated in the superficial fascia, as the 

 Platysma myoides in the neck, and the Orbicularis palpebrarum around the eye- 

 lids. This fascia is most distinct at the lower part of the .abdomen, the scrotum, 

 peririaeum, and extremities ; is very thin in those regions where muscular fibres 

 are inserted into the integument, as on the side of the neck, the face, and around 

 the margin of the anus. It is very dense in the scalp, in the palms of the hands 

 and soles of the feet, forming a fibro-fatty layer which binds the integument 

 firmly to the subjacent structure. 



The superficial fascia connects the skin to the subjacent parts, facilitates the 

 movement of the skin, serves as a soft medium for the passage of vessels and nerves 

 to the integumen", and retains the warmth of the body, since the fat contained in 

 its areolae is a bad conductor of heat. 



The deep fascia is a dense, inelastic, unyielding fibrous membrane, forming 

 sheaths for the muscles and affording them broad surfaces for attachment. It 

 consists of shining tendinous fibres, placed parallel with one another, and connected 

 together by other fibres disposed in a rectilinear manner. It is usually exposed on 

 the removal of the superficial fascia, forming a strong investment, which not only 

 binds down collectively the muscles in each region, but gives a separate sheath to 

 each, as well as to the vessels and nerves. The fasciae are thick in unprotected 

 situations, as on the outer side of a limb, and thinner on the inner side. The deep 

 fasciae assist the muscles in their action by the degree of tension and pressure they 

 make upon their surface ; and in certain situations this is increased and regulated 

 by muscular action ; as, for instance, by the Tensor fascige femoris and Gluteus 

 maximus in the thigh, by 'the Biceps in the upper and lower extremities, and 

 Palmaris longus in the hand. In the limbs the fasciae not only invest the entire 

 limb, but give off septa which separate the various muscles, and are attached 

 beneath to the periosteum : these prolongations of fasciae are usually spoken of as 

 intermuscular septa. 



The Muscles and Fasciae may be arranged; according to the general division 

 of the body, into those of the cranium, face, and neck ; those of the trunk ; those of 

 the upper extremity ; and those of the lower extremity. 



MUSCLES AND FASCIAE OF THE CRANIUM AND FACE. 



The muscles of the Cranium and Face consist of ten groups, arranged according 

 to the region in which they are situated : 



1. Cranial Region. 6. Maxillary Region. 



2. Auricular Region. 7. Mandibular Region. 



3. Palpebral Region. 8. Intermaxillary Region. 



4. Orbital Region. 9. Temporo-mandibular Region. 



5. Nasal Region. 10. Ptervgo-mandibular Region. 



The muscles contained in each of these groups are the following: 

 1. Cranial Region. 2. Auricular Region. 



Occipito-frontalis. Attrahens auriculam. 



Attollens auriculam. 

 Retrahens auriculam. 



