Perineum 1 Flashcards
What is the anterior border of the perineum as a whole? Including both the UG and Anal triangles.
Pubic symphysis
What are the anterolateral boundaries of the perineum?
Ischiopubic rami
What form the lateral borders of the perineum?
Ischial Tuberosity
What forms the posterolateral borders of the perineum?
Sacrotuberous ligament and gluteus maximus
What is the posterior border of the perineum?
Coccyx
What forms the floor of the perineum?
Skin and Fascia
What forms the roof of the perineum?
The Levator Ani muscle of the Pelvic Diaphragm.
What is contained within the anal triangle?
Anal canal, Pudendal nerve, Internal Pudendal Artery and Vein
The Urogenital Diaphragm (UG diaphragm) attaches laterally to which two structure?
The right and left ischiopubic rami.
In females, what pierces the UG diphragm?
The urethra and vagina.
To what does the external genitalia attach?
The UG diaphragm (both males and females)
Which part of the body communicates with the superficial space of the perineum?
The anterior pelvis (due to a small space between the UG diphragm and the pubic symphysis)
The INFERIOR fascia of the UG diphragm is more commonly known as….?
Perineal Membrane
True/False: The UG diphragm extends into the Anal Triangle.
False
Name the lateral border of the ischioanal fossa.
Obturator internus muscle
Superomedial border of the ischioanal fossa
Levator Ani muscle of the pelvic diphragm
Inferior border of the Ischioanal Fossa.
Skin/Fascia
Posterior boundary of the Ischioanal Fossa
Sacrotuberous ligament and gluteus maximus with overlying skin and fascia
Anterior boundary of the Ischioanal Fossa
Anterior Recess- runs in between the UG diaphragm and the muscular pelvic diphragm
What are the 3 sides of the Anterior Recess?
Floor: UG Diaphragm (superior surface)
Superiomedial: Levator Ani Muscle of the pelvic diaphragm
Lateral: Obturator Internus Muscle
What is contained in the Anterior Recess?
Fat- clinically important for collection of fluids.
Name the 3 parts of the External Anal Sphincter Muscle.
Subcutaneous, Superficial, and Deep.
What is the purpose of the External Anal Sphincter?
Constant tone keeps walls of the anal canal opposed to one another till voluntarily relaxed.
What type of muscle is the EAS? How about the internal anal sphincter?
External Anal Sphincter is striated skeletal muscle and under voluntary control.
Internal Anal sphincter is involuntary and under autonomic control.
What nerve innervates the External Anal Sphincter muscle? What are its spinal nerve contributions?
Somatic innervation by the inferior rectal nerve (S2-S4), which branch from the Pudendal nerve.
The External Anal Sphincter is anchored anteriorly and posteriorly by what two specializations of the perineal region?
Anteriorly anchored to the Perineal body (fibrous extension of the UG diaphragm) and posteriorly to the Anococcygeal body
The Anococcygeal body connects what two structures?
The anal canal and the coccyx.
The specialization of obturator internus fascia is more commonly called…?
The Pudendal Canal/ Alcock’s Canal
What fascial portions of the obturator internus muscle contribute to the pudendal canal?
The deep fascia of the obturator internus splits to from a medial and a lateral lamina to encompass the canal.
The internal pudendal artery is a branch of the….
Internal Iliac Artery and Vein
What are the contents of the Pudendal Canal?
Pudendal Nerve and its 3 branches, Internal Pudendal Artery and Vein
What is the path of the Pudendal Nerve?
Branches from the Sacral Plexus in ther Pelvis. Exits the pelvis via the greater sciatic foramen, crosses over the sacrospinous ligament into the lesser sciatic foramen. Travels through the ischioanal fossa within the pudendal canal, then terminates into 3 branches.
Name the 3 branches of the Pudendal Nerve from most medial to lateral.
Inferior Rectal, Pudendal, Dorsal Nerve of the Penis/Clitoris
What are the spinal contributions to the Pudendal Nerve?
S2-S4
What is the clinical significance of the Pudendal Nerve?
It is the sole motor supply and primary sensory supply to the perineum/skin of perineum. During birth it frequently requires local anesthetic.
Which branch of the pudendal nerve passes superiorly to the UG diaphragm?
The Perineal Nerve enters the superficial perineal space.
What does the Perineal Nerve innervate?
The 5 muscles of the superficial and deep perineal spaces, sensory innervation to the bulb of penis/urethra, LABIA
Which branch of the Pudendal nerve is sensory only?
Dorsal Nerve of the Penis/Clitoris
Which layer of fascia continues on to form the mons pubis and labia in females?
Camper’s Fascia (Fatty)
In the female, scarpa’s fascia turns into….
Colles fascia
Colles fascia in both sexes attaches posteriorly to….
The free posterior margin of the UG diaphragm, and is also continuous with the fascia lata of the thigh.
What are the superior and inferior boundaries of the superficial pouch?
Superior Boundary = Perineal Membrane
Inferior Boundary = Colles fascia (or its derivatives) and associated tissues
What is the posterior boundary of the superficial pouch?
The fusion of Colles fascia with the the posterior margin of the UG diaphragm.
What are the lateral boundaries of the superficial space?
Fusion of Colles fascia with the pubic arch
Is the superficial space more extensive in males or females? Why
Males- cocks and balls
Can the superficial compartment communicate with any other surrounding spaces?
Yes- the abdomen, through the free space between the anterior border of the UG diaphragm and the pubic symphysis.
Which compartments are isolated from the superficial space?
Anal triangle and Deep Space
The pelvic girdle consists of what two bones?
The OsCoxae and the Sacrum
The Os Coxae is the fusion of what 3 bones?
Ileum, Ischium, Pubis
What are the Joints of the Pelvic girdle?
Pubic Symphysis (Connecting Os Coxae) and the Sacroiliac Joints (Sacrum and Os Coxae)
What two muscles contribute to the Pelvic Diaphragm?
The Levator Ani and the Coccygeus.
What innervates the Levator Ani muscle?
Direct Branches from S4 and Inferior Rectal Nerve
What innervates the Coccygeus Muscle?
Direct branches from S3-S4
What are the two functions of the pelvic diaphragm?
1 - Support of pelvic viscera
2 - Keeping the vagina and rectum closed.
(pelvic diaphragm… the anti-slut muscle)
What structure passes through the anterior gap in the perineal membrane (UG diaphragm)?
Dorsal Vein of the PENIS
