L6. GA - The Perineum

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Questions and Answers

What is the structure that defines the superior boundary of the perineum?

Perineal body

Superior perineal fascia (correct)

Perineal membrane

Deep perineal fascia

Which of the following structures is NOT a component of the deep pouch in females?

Bulbourethral glands (correct)

Compressor urethrae

External urethral sphincter

Sphincter urethrovaginalis

Which muscle is associated with the deep pouch in both males and females?

Ischiocavenosus

Sphincter urethrae

Bulbospongiosus

Deep transverse perineal muscle (correct)

What is the role of the perineal membrane in the urogenital triangle?

Separates the deep and superficial pouches Signup and view all the answers

Which structure is specifically associated with the male reproductive system?

Bulbourethral glands Signup and view all the answers

Which erectile tissue is common to both males and females?

Corpus cavernosum Signup and view all the answers

What layer of fascia is derived from the deep investing fascia of the anterior abdominal muscles?

Deep perineal fascia Signup and view all the answers

Which of the following structures is included in the superficial pouch of the perineum for both genders?

Erectile tissues Signup and view all the answers

What structure do the dorsal nerves travel along in both males and females?

The dorsal surface of the erectile tissues Signup and view all the answers

Which fascia invests the dorsal nerves in the male?

Buck's fascia Signup and view all the answers

Which type of nerve provides motor and sensory innervation to the perineum?

Pudendal nerve Signup and view all the answers

Where do the pelvic splanchnic nerves derive their preganglionic parasympathetic fibers from?

S2, S3, and S4 Signup and view all the answers

Which structure provides sympathetic innervation to the erectile tissues?

Sacral splanchnic nerves Signup and view all the answers

The deep clitoral fascia in females corresponds to which fascia in males?

Deep penile fascia Signup and view all the answers

What type of nerves contribute to the autonomic input to erectile tissues?

Pelvic splanchnic and sacral splanchnic nerves Signup and view all the answers

What is the role of the inferior hypogastric plexus in the genital innervation?

It relays autonomic input to the genital structures. Signup and view all the answers

What is the primary muscular structure that constitutes the deep pouch of the urogenital triangle?

Urogenital diaphragm Signup and view all the answers

What structure anchors the posterior border of the urogenital diaphragm?

Perineal body Signup and view all the answers

Which of the following structures is located inferior to the deep transverse perineal muscle?

Perineal membrane Signup and view all the answers

Which anatomical feature acts as the anterior boundary of the deep pouch of the urogenital diaphragm?

Body of the pubis Signup and view all the answers

What is the function of the perineal membrane in relation to the urogenital diaphragm?

Maintains the integrity of the UG diaphragm Signup and view all the answers

What describes the urogenital triangle in relation to the anal triangle?

Anterior to the anal triangle Signup and view all the answers

What forms the deep compartment of the urogenital triangle?

Urogenital diaphragm and perineal membrane Signup and view all the answers

Which ligament connects the anal canal to the coccyx?

Anal coccygeal ligament Signup and view all the answers

What is another name for the deep penile fascia?

Buck's fascia Signup and view all the answers

Which fascia is found in the male perineum and lacks adipose tissue?

Colle's fascia Signup and view all the answers

How do the superficial and deep perineal fascia relate in terms of infections or fluid accumulation?

They create a potential space for fluid collection. Signup and view all the answers

What structure attaches the superficial perineal fascia to the inferior margins of the ischiopubic rami?

Scarpa's fascia Signup and view all the answers

What is the primary composition of Dartos fascia?

Smooth muscle fibers Signup and view all the answers

What happens if there is a laceration of the anterior abdominal wall?

Fluid can accumulate in the perineum. Signup and view all the answers

What distinct feature do Colle's and Dartos fascia have in regards to their attachment?

Bound posteriorly to the free border of the UG diaphragm. Signup and view all the answers

Which fascia is responsible for investing the erectile tissues of the clitoris?

Deep clitoral fascia Signup and view all the answers

What is the primary function of the cavernous nerves?

To innervate the erectile tissues Signup and view all the answers

Which arteries supply the deep structures of the perineum?

Internal pudendal arteries Signup and view all the answers

What branch does the internal pudendal artery give off in the ischioanal fossa?

Inferior rectal branch Signup and view all the answers

Where does the deep artery of the penis/clitoris supply blood?

To the corpus cavernosum Signup and view all the answers

What is the relationship between the names of branches of the internal pudendal veins and the corresponding arteries?

They mirror each other Signup and view all the answers

Which of the following nerves pierces the pelvic diaphragm?

Cavernous nerve Signup and view all the answers

How do the right and left internal pudendal arteries function after piercing the UG diaphragm?

They branch off to form the dorsal artery of the penis/clitoris Signup and view all the answers

What is the exception in venous return from the erectile tissues?

It is carried by the deep dorsal vein of the penis/clitoris Signup and view all the answers

What is the primary artery supplying blood to the clitoris?

Internal pudendal artery Signup and view all the answers

Which structures are located in the anal triangle?

Ischioanal fossa and external anal sphincter Signup and view all the answers

What forms the roof of the ischioanal fossa?

Levator ani Signup and view all the answers

In which direction does the deep dorsal vein of the clitoris travel after passing through the hiatus?

Anteriorly to the bladder Signup and view all the answers

What is the function of the ischioanal fat pad within the anal triangle?

Maintains the shape of the region surrounding the anal canal Signup and view all the answers

Which nerve is responsible for innervating the structures associated with the perineum?

Pudendal nerve (S2-4) Signup and view all the answers

How do the branches of the nerves supplying the clitoris terminate?

On the glans of the clitoris Signup and view all the answers

Which of the following best describes the location of the anal triangle?

Posterior to the transverse line between the ischial tuberosities Signup and view all the answers

Study Notes

Perineum Course Learning Objectives

Describe normal anatomy of the male and female perineum
Describe the bones forming the skeleton
Recall the muscles and coverings of the perineum
Describe the nerves innervating structures
Describe arterial supply and venous drainage
Describe skin, joints, and tissues
Detail compartments, spaces, and transition areas
Describe glands and organs
Outline anatomical relationships of all structures

Relating Anatomy to Function

Relate bone anatomy to structural attachments and functions
Describe muscle anatomy in terms of actions on structures
Relate nerve anatomy to innervation of structures
Correlate vessel anatomy to structures supplied or drained
Relate connective tissue anatomy to attachment functions
Explain compartment, space, and transition area functions related to connective tissue
Describe gland and organ anatomy related to visceral functions

Applying Anatomical Knowledge to Problems

Apply anatomy to evaluating deficits of nerve lesions
Apply anatomy to evaluating effects of tissue damage/pathology
Apply anatomy to evaluating clinical approaches and procedures
Apply anatomy to evaluating radiological images

Perineum Session Outline

Describe the boundaries and subdivisions of the perineum (urogenital and anal triangles)
Compartmentalization of the urogenital triangle (deep and superficial compartments)
Describe male external genitalia (scrotum and penis) including function, innervation, blood supply and venous return
Describe female external genitalia (components of the pudendum) including innervation, blood supply and venous return
Review the anal triangle, its boundaries, and contents (ischioanal fossa)
Clinical relevance (pudendal nerve block, episiotomy, damage to male urethra)

The Perineum: Deep and Superficial Pouches/Compartments

Deep pouch/compartment comprises the urogenital diaphragm
This structure is attached laterally along the ischiopubic rami, bridges the urogenital triangle
Contains the deep transverse perineal muscle and associated fibers contributing to the urethra in both male and female
Perineal membrane is located inferior to the deep transverse perineal muscle
It is a tough sheet maintaining the integrity of the urogenital diaphragm

Male and Female External Genitalia

Identify male components and their functions (scrotum, penis, corpora cavernosa, corpus spongiosum)
Identify female components and their functions (mons pubis, labia majora, labia minora, clitoris, vestibular bulbs, greater vestibular glands)
Describe the innervation, blood supply, and venous return

The Anal Triangle

Outline the boundaries of the anal triangle
Detail the contents of the ischioanal fossa (pudendal canal, nerves, blood vessels, ischioanal fat pad)

Clinical Relevance

Briefly describe pudendal nerve blocks, episiotomies, and damage to male urethra (anterior and posterior urethral injuries)
Mention intercourse-related traumas (to the corpora cavernosa and distal penile urethra).

Fascia Layers Defining the Perineum

Deep perineal fascia (Gallaudet's fascia)
- Invests the erectile muscle tissues, attaching to posterior perineal membrane and ischiopubic rami
Superficial perineal fascia (Colle's fascia)
- Overlies scrotum (with Dartos fascia inside), anteriorly joins Scarpa's fascia

Blood Supply

Internal pudendal artery branches provide blood to deep perineal structures
Inferior rectal artery and branches supply structures within the anal triangle
Dorsal arteries of the penis/clitoris supply erectile tissues
Describe venous return paths, largely following the arterial routes and eventually draining into the pelvic plexus.

Venous Return

Deep dorsal vein (male/female)
External and internal pudendal veins empty into systemic venous system

Female External Genitalia

Identify component parts (and briefly describe their roles) of the pudendum:
Mons pubis, labia majora, labia minora, clitoris, vestibule, and bulbs of the vestibule
Greater vestibular glands

The Anal Triangle (and Ischioanal Fossa)

Describe the ischioanal fossa
Its boundaries and contents (ischioanal fat pad): how this tissue maintains the structure of the anal canal

Clinical Relevance (cont'd)

Mention intercourse-related traumas to the corpora cavernosa and distal penile urethra, and the potential for hematoma formation. Also reference trauma damage to the bulbar/penile urethra, including "Straddle injuries"

Innervation of the Perineum

Note the pudendal nerve is mostly responsible for the perineum's innervation
It arises from the sacral plexus (S2-S4) and travels via the greater/lesser sciatic foramina, emerging into the perineum
Identify the pudendal canal's role
Understand the distal branches of the Pudendal nerve; the perineal nerve, deep perineal nerve, and dorsal nerves of the penis/clitoris
Note the sensory and motor functions of the different branches (e.g., sensory to skin, and/or motor to muscles).

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