Perineum

Question 1

Anatomical borders of the perineum

Answer 1

• Anterior – Pubic symphysis.
• Posterior- The tip of the coccyx.
• Laterally – Inferior pubic rami and inferior ischial rami, and the sacrotuberous ligament.
• Roof – The pelvic floor.
• Base – Skin and fascia.

Question 2

Surface borders of the perineum

Answer 2

Anteriorly: Mons pubis in females, base of the penis in males.

Laterally: Medial surfaces of the thighs.

Posteriorly: Superior end of the intergluteal cleft.

Question 3

Anal triangle

Answer 3

The posterior half of the perineum - bounded by the coccyx, sacrotuberous ligaments and an imaginary line between the ischial tuberosities.

Question 4

Contents of anal triangle

Answer 4

Anal aperture – the opening of the anus.

External anal sphincter muscle – voluntary muscle responsible for opening and closing the anus

Two ischioanal fossae - spaces located laterally to the anus.

(The anal aperture is located centrally in the triangle with the ischioanal fossae either side. These fossae contain fat and connective tissue, which aid expansion of the anal canal during defecation. They extend from the skin of the anal region inferiorly to the pelvic diaphragm superiorly)

Question 5

Urogenital triangle

Answer 5

The anterior half of the perineum - bounded by the pubic symphysis, ischiopubic rami, and an imaginary line between the two ischial tuberosities.

The triangle is associated with the structures of the urogenital system – the external genitalia and urethra.

Question 6

Contents of the urogenital triangle (deep to superficial)

Answer 6

Deep perineal pouch

Perineal membrane

Superficial perineal pouch

Deep perineal fascia

Superficial perineal fascia

Question 7

Attachments to the perineal body

Answer 7

Levator ani (part of the pelvic floor).
Bulbospongiosus muscle.
Superficial and deep transverse perineal muscles.
External anal sphincter muscle.
External urethral sphincter muscle fibres.