perineum anatomy

The Perineum

What is the perineum?

MALE PERINEUM SUP ..

SUPERFICIAL PERINEUM IN FEMALE
1)vulva. 2)mons pubis. 3)clitoris . 4)hood of clitoris. 5)labia majora . 6)labia minora.

Bony Pelvis

Moore et al; Fig. 3.3

Netter 334

Anorectal hiatus

Urethral hiatus
Tendinous arch
Piriformis m.
(Ischio)coccygeus m.
Iliococcygeus m.
Puborectalis m.
Pubococcygeus m.
Obturator internus m.
Plate 340

Plate 341

Gluteus maximus m.
(Ischio)coccygeus m.
Iliococcygeus m.
Pubococcygeus m.
Puborectalis m.
Urethra

Plate 338

Urethra
Vagina
Rectum
Piriformis m.
Tendinous arch
Pubococcygeus m.
Iliococcygeus m.
(Ischio)coccygeus m.

Urethra

Vagina
Plate 339
Sacrotuberous ligament
Obturator internus m.
Pubococcygeus m.
Puborectalis m.
Iliococcygeus m.
(Ischio)coccygeus m.

Plate 338

Rectum
Vagina
Urethra
Piriformis m.
Obturator internus m.
Tendinous arch
(Ischio)coccygues m.
Iliococcygues m.
Pubococcygeus m.

Levator Ani

Consists of three parts – the pubococcygeus, the puborectalis and the iliococcygeus.Origin :- from the body of the pubis, the tendinous arch of the obturator fascia and the ischial spine.Insertion:- the perineal body, the coccyx, the anococcygeal ligament, the walls of the prostate or vagina, the rectum and the anal canal.Innervated by the nerve to levator ani from S4 and the inferior rectal nerve ( S2-S4) and the coccygeal plexusFunction:-1)support the pelvic viscera2) they raise the pelvic floor 3)assist the abdominal muscles in forced expiration activities

Urogenital Diaphragm The outlet of the pelvis is spanned by two muscular sheets - a deeper "pelvic diaphragm" and a more superficial "urogenital diaphragm." The pelvic diaphragm forms the floor of the pelvic cavity, and the urogenital diaphragm fills the space within the pubic arch. The muscles of the male and female urogenital diaphragm include the following: (1) "superficial transversus perinei," a small bundle of muscle fibers that pass along the back border of the urogenital diaphragm and assists other muscles in supporting the pelvic tissues;

Urogenital Diaphragm (2) the "bulbospongiosus" muscles, which are united and surround the base of the penis; (3) the "ischiocavernosus muscle," a tendinous structure that extends down to the margin of the pubic arch and assists the function of #2; and (4) the "sphincter urethrae" are muscles that arch around the urethra and unite with those on the other side. Together they act as a sphincter that closes the urethra by compression and opens it by relaxation to control the flow of urine.

Perineum

Two Triangles Anal triangle (posterior) contains the anus Urogenital triangle (anterior) contains the root of the scrotum and penis in males or the external genitalia in females The perineal membrane stretches between the two sides of the pubic arch and covers the anterior part of the outlet The perineal body is an irregular fibromuscular mass located between the anal canal and the perineal membrane

Muscles Inferior to the Pelvic Floor:The Urogenital Diaphragm

Muscles inferior to the pelvic floor Stretches between two sides of the pubic arch in the anterior half of the perineum Contains Deep transverse perineal muscle External urethral sphincter muscle The ischiocavernosus and bulbospongiosus assist in erection of the penis and clitoris; lie superficial to the urogenital diaphragm

Muscles of the Pelvic Floor

Figure 10.12b

Female Urethra

Female Urethra

Triangles

Perineal Body



Perineal Membrane

Perineum-Female

Perineum - Male

Perineum

MusclesBulbospongiosus – F O: central tendon of perineum, M O: central tendon of perineum and bulb of penis; F I: dorsum of clitoris, urogenital diaphragm, M I: root of penis; A: compress vagina orifice or compress urethra, N: perineal nerve, pudenal nerveIschiocavernosus – O: ramus of ischium, I: near pubic symphysis, maintains erection of penis or clitoris

Muscles - Female

Muscles - Female


Sup.perineal pouch :- 1)crura of penis . 2)bulb of penis. 3)bulbs of vestibule. 4)ischiocavernosus. 5)bulbospongiosus. 6)perineal branch of pudendal nerve. 7)perineal body. 8)superficial transversus perinie muscle. 9)greater vestibular glands(Bartholin)



Deep perineal pouch:-
1)membranuous part of urethra. 2)deep transversus perinie muscle. 3)int.pudendal artery. 4)Bulbourethral glands. 5)dorsal nerve of penis. 6)sphinecter urethrae muscle.

Muscles – Male

Muscles - Male

Superficial Transverse Perineal

O: Ischial tuberosity I: Perineal body A: Support perineal body N: Pudenal nerve

External Urethral Sphincter

O: Ischial tuberosity I: surround urethra A: compress urethra to maintain urine continence N: Pudenal (S2-S4)

Superficial Transverse Perineal F

Superficial Transverse Perineal F

Superficial Transverse Perineal M

Deep Transverse Perineal
O: Medial Aspect of Ischial Ramus I: Pineal Body A: Stabilizes position of the perineal body N: Pudenal N (S2-S4)

Deep Transverse Perineal - F

Deep Transverse Perineal -M

Deep Transverse Perineal - M

Deep Transverse Perineal M

Superficial Perineum Female

Superficial Perineum Male

Female Peritoneum

Male Peritoneum

Male Urethra

Male Urethra

Perineal Body


At perineal body, the following muscles converge and are attached: External anal sphincter Bulbospongiosus Superficial transverse perineal muscle Anterior fibers of the levator ani fibers from external urinary sphincter Deep transverse perineal muscle

Plate 393

Inferior rectal nn.
Perineal n.
Dorsal n. of clitoris
Pudendal nerve

Plate 384

Inferior rectal a.
Internal pudendal a.
Perineal a.

Plate 391

Fascia of obturator internus m. forming pudendal canal
Inferior rectal nn.
Perineal n.
Posterior scrotal n
Inferior rectal a
Pudendal n.

Plate 385

Inferior rectal a.
Inferior rectal v.
Perineal a. and v.
Pudendal canal