FASCIAE OF THE UPPER EXTREMITY. 255 



rior layer is nearly plane in its direction, and sends a sheath for- 

 wards around the anterior termination of the membranous urethra 

 to be attached to the posterior part of the bulb. The posterior layer 

 is oblique and sends a funnel-shaped process backwaitfs, which 

 invests the commencement of the membranous urethra and the pro- 

 state gland. The inferior segment of this funnel-shaped process is 

 continued backwards beneath the prostate gland and the vesiculse 

 seminales, and is continuous with the recto-vesical fascia of Tyrrell, 

 which is attached posteriorly to the recto-vesical fold of peritoneum, 

 and serves the important office of retaining that duplicature in its 

 proper situation. 



Between the two layers of the deep perineal fascia are situated, 

 therefore, the whole extent of the membranous portion of the urethra, 

 the compressor urethrse muscle, Cowper's glands, the internal pudic 

 and bulbous arteries, and a plexus of veins. Mr. Tyrrell considers 

 the anterior lamella alone as the deep perineal fascia, and the pos- 

 terior lamella as a distinct layer of fascia covering in a considerable 

 plexus of veins. 



FASCI-ffi OF THE UPPER EXTREMITY. 



The superficial fascia of the upper extremity contains between 

 its layers the superficial veins and lymphatics, arid the superficial 

 nerves. 



The deep fascia is thin over the deltoid and pectoralis major 

 muscles, and in the axillary space, but thick upon the dorsum of the 

 scapula, where it binds down the infra-spinatus muscle. It is at- 

 tached to the clavicle, acromion process, and spine of the scapula. 

 In the upper arm it is somewhat stronger, and is inserted into the 

 condyloid ridges, forming the intermuscular septa. In the fore-arm 

 it is very strong, and at the bend of the elbow its thickness is aug- 

 mented by a broad band, which is given off from the inner side of 

 the tendon of the biceps. It is firmly attached to the olecranon 

 process, to the ulna, and to the prominent points about the wrist. 

 Upon the front of the wrist it is continuous with the anterior annular 

 ligament, which is considered by some anatomists to be formed by 

 the deep fascia, but which I am more disposed to regard as a liga- 

 ment of the wrist. On the posterior aspect of this joint it forms a 

 strong transverse band, the posterior annular ligament, beneath which 

 the tendons of the extensor muscles pass, in distinct sheaths. 



The tendons as they pass beneath the annular ligaments are 

 surrounded by synovial bursse. The dorsum of the hand is invested 

 by a thin fascia, which is continuous with the posterior annular 

 ligament. 



The palmar fascia is divided into three portions. A central por- 

 tion, which occupies the middle of the palm, and two lateral por- 

 tions, which spread out over the sides of the hand, and are continuous 

 with the dorsal fascia. The central portion is strong and tendinous : 

 it is narrow at the wrist, where it is attached to the annular liga- 



