ABDOMINAL FASCLB. 279 



FASCLE OF THE TRUNK. 



The thoracic fascia* is a dense layer of cellulo-fibrous membrane 

 stretched horizontally across the superior opening of the thorax. It 

 is firmly attached to the concave margin of the first rib, and to the 

 inner surface of the sternum. In front it leaves an opening for the 

 connection of the cervical with the thoracic portion of the thymus gland, 

 and behind it forms an arch across the vertebral column, to give pass- 

 age to the esophagus. 



At the point where the great vessels and trachea pass through the 

 thoracic fascia, it divides into an ascending and descending layer. The 

 ascending layer is attached to the trachea, and becomes continuous 

 with the sheath of the carotid vessels, and with the deep cervical 

 fascia ; the descending layer descends upon the trachea to its bifurca- 

 tion, surrounds the large vessels arising from the arch of the aorta, and 

 the upper part of the arch itself, and is continuous with the fibrous 

 layer of the pericardium. It is connected also with the venae innomi- 

 natae and superior cava, and is attached to the cellular capsule of the 

 thymus gland. 



" The thoracic fascia," writes Sir Astley Cooper, " performs three 

 important offices: 



" 1st. It forms the upper boundary of the chest, as the diaphragm 

 does the lower. 



" 2nd. It steadily preserves the relative situation of the parts which 

 enter and quit the thoracic opening. 



" 3rd. It attaches and supports the heart in its situation, through 

 the medium of its connection with the aorta and large vessels which 

 are placed at its curvature." 



ABDOMINAL FASCIJE. 



The lower part of the parietes of the abdomen, and the cavity of the 

 pelvis, are strengthened by a layer of fascia which lines their internal 

 surface, and at the bottom of the latter cavity is reflected inwards to 

 the sides of the bladder. This fascia is continuous throughout the 

 whole of the above-mentioned surface ; but for convenience of de- 

 scription is considered under the several names of transversalis fascia, 

 iliac fascia, and pelvic fascia ; the two former meet at the crest of the 

 ilium and Poupart's ligament, and the latter is confined to the cavity 

 of the true pelvis. 



The fascia transversalis (Fascia Cooperi)f is a cellulo-fibrous lamella 

 which lines the inner surface of the transversalis muscle. It is thick 

 and dense below, near the lower part of the abdomen ; but becomes 

 thinner as it ascends, and is gradually lost in the subserous cellular 



* For an excellent description of this fascia, see Sir Astley Cooper's work on 

 the "Anatomy of the Thymus Gland." 



t Sir Astley Cooper first described this fascia in its important relation to 

 inguinal hernia. 



