33 2 



PRACTICAL ANATOMY. 



osus in the nude. Pull the penis upward and from side to side gently, and this 

 will bring the crura and their investing muscles into view. (Fig. 239.) 



6. Tlie external spliinctcr ani you will see reaching from the tip and sides of 

 the coccyx, surrounding the anus, to the central perineal point. The outer 

 margins of this muscle seem to become lost in a quantity of fatty and connective 

 tissue. 



7. Another muscle, the superficial transvcrsus pcriiuci, lies between the 

 sphincter ani and the erector penis, extending in an oblique direction from the 

 tuberosity of the ischium to the central perineal point. 



8. The central perineal point, or tendinous centre of the perineum, is in the 

 mid-line from side to side and about one inch in front of the anus. As you will 



Superficial perinrtal vessels 



Accelerator urinae 



Colles's fascia, turned back 



Erector penis 



Transverse perin&al ivw/.? 

 Cut edge of triangular 



ligament 



SUPERFICIAL PERIN^AL 

 NERVE GIVING OFF 

 TRA NS I 'ERSE BRA NCH 

 Ptidic vessels 



Inferior hcemorrhoidal vessels 

 and nerves 



Qluteus maximus, 

 hooked back 



Crus penis 



Dorsal artery of penis 

 A rtery of crus 



BULB 



.-1 rtery of bulb 

 COWPER'S GLAND 

 /''/'/j'o artery 



Great sciatic ligament 

 Levator ani 

 External sphincter 



Gluteus maximus 



Fi<;. 230. THE ARTERIES OF THE PERINEUM. 



On the right side Colics' fascia has been turned back to show the superficial vessels. On the left side the 

 superficial vessels have been cut away with the anterior layer of the triangular ligament to show the 

 deep vessels. 



demonstrate in your dissection, and as you may see in figure 229, this point is 

 where the following muscles meet: (i) The sphincter ani ; (2) the superficial 

 transversus perinaei ; (3) the accelerator urinae or bulbo-cavernosus. 



9. The levator ani shows well in botli figures, but at this stage of the dissec- 

 tion is obscured by (i) the sphincter ani and (2) the large mass of fat in the 

 ischio-rectal fossa. The muscle is seen in figure 230 on each side of the anus. 



10. The space on each side of the anus is the ischio-rectal fossa. It is now 

 full of fat. Figure 230 shows this fat removed and the levator ani muscle 

 divested of the anal fascia. 



1 1. The greater sacra-sciatic ligament must now be located. In the figures it 

 is shown cut on one side to expose the internal pudic structures. 



1 2. Notice the lueinorrhoidal brandies, and the perineal branches of the internal 



