Dissection of muscles of male perineum and pelvic diaphragm

Muscles of superficial space of perineum

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Image #174-1
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Dissection of muscles of male perineum and pelvic diaphragm
Muscles of superficial space of perineum
In this dissection of a young male subject the blood vessels and nerves have been sacrificed in order to demonstrate the arrangement of muscles related to the pelvic outlet. The muscles that lie within the superficial perineal space have been exposed. The ischiorectal fossae have been dissected to demonstrate muscles of the pelvic diaphragm. Several muscles on the left side of this specimen are considerably larger than the corresponding muscles on the right. These are the bulbospongiosus (1), superficial transverse perineal muscle (15) and subcutaneous part of the sphincter ani externus muscle (18). Also it should be noted that the puborectalis muscle (6) on each side extends into the subcutaneous connective tissue of the ischiorectal fossa alongside the anus.
1 . Bulbospongiosus muscle
2 . Body of pubic bone
3 . Central tendon of perineum
4 . Upper pointer: Crus of penis Lower pointer: Ischiocavernosus muscle
5 . Inferior fascia of urogenital diaphragm
6 . Fibers of puborectalis muscle that extend into subcutaneous connective tissue of ischiorectal fossa
7 . Obturator internus muscle
8 . Obturator fascia
9 . Sacrotuberous ligament
10 . Levator ani muscle
11 . Inferior pubic ramus
12 . Obturator canal
13 . Obturator membrane
14 . Joint capsule of coccyx
15 . Upper pointer: Inferior fascia of urogenital diaphragm Lower pointer: Superficial transverse perineal muscle (note asymmetry on two sides)
16 . Ramus of ischium
17 . Ischial tuberosity
18 . External anal sphincter muscle (subcutaneous part) Note asymmetry ot this muscle on the two sides
19 . Anus
20 . Anococcygeal ligament
21 . Coccyx