perinaeal

The middle of the incision is over the left lobe of the prostate gland and neck of the bladder, which parts, together with the membranous portion of the urethra, are still concealed by the deep perinaeal fascia, the structures between its layers, and the anterior fibres of K, the levator ani muscle.

Surgical Anatomy Joseph Maclise

Fig. 1, Plate 54, represents the normal relations of the more important parts concerned in lithotomy as performed at the perinaeal region.

Surgical Anatomy Joseph Maclise

While the anus remains connected with the deep perinaeal fascia in front, the fibres of the levator ani muscle of the left side may be divided; and by now inserting the finger between them and the rectum, the left lobe of the prostate can be felt in apposition with the forepart of the bowel, an inch or two above the anus.

Surgical Anatomy Joseph Maclise

By dividing the levator ani muscle on both sides of the rectum, F, Fig. 2, Plate 53, and detaching and depressing this from the perinaeal centre, the prostate, C C, and base of the bladder, P, are brought into view.

Surgical Anatomy Joseph Maclise

Thus it is that the force originated in the muscular parietes of the thorax and abdomen is, while opposed by the counterforce of the perinaeal muscles, brought so to bear upon the pelvic organs as to become the principal means whereby the contents of these are evacuated.

Surgical Anatomy Joseph Maclise

On the contrary, if the staff happen to have surmounted the prostate, the incision, in order to divide the whole vertical thickness of this body, will require to be made very deeply from the perinaeal surface, and this circumstance occasions what is termed a "deep perinaeum."

Surgical Anatomy Joseph Maclise

These several parts are situated at different depths from the perinaeal surface.

Surgical Anatomy Joseph Maclise

In this manner the pelvic fascia serves to insulate the perinaeal space from the pelvic cavity.

Surgical Anatomy Joseph Maclise

Along the surface of this interval, the superficial perinaeal artery and nerve are seen to pass forwards; and deep in it, beneath these, may also be observed, L, the artery of the bulb, arising from the pudic, and crossing inwards, under cover of the anterior layer of the membrane named the deep perinaeal fascia.

Surgical Anatomy Joseph Maclise

The muscles occupying the anterior perinaeal space require to be removed, Fig. 1, Plate 53, in order to expose the urethra, B M, the crus penis, D, and the deep perinaeal fascia.

Surgical Anatomy Joseph Maclise