THE PENIS. 



1967 



somewhat expanded crura attached to the inner border of the pubic arch, the cavern- 

 ous bodies are at first separated by an interval occupied by the bulb of the corpus 



FIG. 1674. 



D 



ddv sdv sk da 



FIG. 1675. 



Cross-sections of formalin-hardened penis at different levels. A, through glans, near tip; B, about 

 middle of glans; C, through corona; >, body, distal part; E, body, proximal part, cc, corpus caver- 

 nosum ; cs, corpus spongiosum ; da, dorsal artery ; ddv, deep dorsal vein ; e, fibrous envelope ; eg, erectile 

 tissue of glans ; /, frenum ; ft, fibrous tissue ; s, fibrous septum ; sdv , superficial dorsal vein ; sf, super- 

 ficial fascia ; sk, skin ; ta, tunica albuginea ; u, urethra. 



spongiosum. Farther forward, in the vicinity of the penile angle, the corpora caver- 



nosa press against each other with their median surfaces, the opposed flattened cap- 



sules blending to form a median partition (septum penis). Lower the latter becomes 



imperfect and replaced by a series of vertical bands, and hence is often designated the 



pectiniform septum, the intervening 



slit-like apertures permitting commu- 



nication between the blood-spaces of 



the two cavernous bodies, as well as 



the passage of anastomotic branches 



of their arteries. In certain mammals, 



especially the carnivora and some 



marsupials, a bone (os penis) is de- 



veloped within the fibrous septum. 



On approaching the corona, the cor- 



pora cavernosa again become discrete 



and rapidly taper to blunt-pointed 



ends that are separated externally by a 



slight furrow and capped by the over- 



lying glans. The dorsal and under 



surfaces common to the closely ap- 



plied cavernous bodies are marked by 



longitudinal grooves ; that along the 



former surface lodges the dorsal ves- 



sels of the penis, while the under fur- 



row is filled by the spongy body. 



The corpus spongiosum (cor- 

 pus cavernosum urethrae), the third and 

 much smaller, although longer (about 



Dorsal vein, 

 now double 



Pubic bon< 



Crusr 



Deep artery in' 



corpus cavernosum 



Urethra 1 



Ischio-cavernosus 1 

 muscle 



Bulb 



Bulbo-cavernosus 

 muscle 

 Colles's fascia- 



Frontal section through pubic arch and root of penis. 



17 cm. or 6^ 

 surface of the 



in.), cylinder of erectile tissue, occupies the groove along the under 

 cavernous bodies. The two ends of this cylinder are enlarged, the 



