1. Perineum

2. Definition
Perineum is generally defined as the surface region in both males and females between the pubic symphysis and the coccyx. The perineum is the region of the body inferior to the pelvic diaphragm and between the legs.
But at times it is defined in females as the area extending from the fourchette (fusion of the labia minora posteriorly) to the anal canal.

4. It is fixed to the pelvic floor It forms part of the pelvic floor
A line joining the anterior parts of the ischial tuberosities divides the perineum into a large posterior anal triangle and a smaller anterior urogenital triangle.
The anal triangle contains the anal canal and the ischiorectal fossae with their contents.
Lying in front of the anal canal is a fibro-muscular mass of tissue called the perineal body
It is fixed to the pelvic floor
It forms part of the pelvic floor
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5. Boundaries
Its deep boundaries are as follows:
in front: the pubic arch and the arcuate ligament of the pubis
behind: the tip of the coccyx
on either side: the inferior rami of the pubis and Ischium, and the sacrotuberous ligament

6. Urogenital Triangle : Anal Triangle : Triangles
A line drawn transversely across in front of the ischial tuberosities divides the space into two triangles:
Urogenital Triangle :
contains the scrotum and penis in the male
Contains the clitoris urethra and vagina in the females
Anal Triangle :
Contains the anus and ischiorectal fossae in both the male and the female

7. The perineal fascia has two parts the superficial and deep parts,
The layers and contents are : from superficial to deep:
1) Skin
2) Superficial perineal pouch
It contains superficial perineal muscles
Transversus perinei superficialis
Bulbospongiosus,
Ischiocavernosus
Inferior fascia of urogenital diaphragm (perineal membrane)

8. 3) Deep perineal pouch It contains the deep perineal muscles:
transversus perinei profundus,
sphincter urethrae
4) fascia and muscles of pelvic floor (levator ani, coccygeus)

9. Areas of the perineum
The following areas are parts of the perineal region:
perineal pouches: superficial and deep (see above for details)
Ischiorectal fossa - a fat filled space at the lateral sides of anal canal..
Anal canal Pudendal canal - contains internal pudendal artery and the pude

12. Pelivic diaphragm – Female - Perineal muscle

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16. Perineum and Female Genitalia