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Prevention and Repair Of perineal Trauma Episiotomy through Coordinated Training

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Welcome to the PROTECT test system. You will be taken through 6 modules with multiple choice questions. After each completed module you may take a break and come back at any time. To continue with your test click in the top link where it says "Continue with previous test session here".
If you have any questions or concerns, please contact Amanda Grabloski at amanda@iuga.org

ANATOMY OF THE PERINEUM AND THE ANAL SPHINCTER

1. The following are superficial muscles of the perineum

The superficial transverse perineal, the bulbospongiosus and ischiocavernosus muscles constitute the superficial muscles of the perineum. The superficial transverse perineal muscle is a narrow slip of a muscle which arises from the inner and forepart of the ischial tuberosity and is inserted into the central tendinous part of the perineal body on either side.
The bulbospongiosus muscle runs on either side of the vaginal orifice, covering the lateral aspects of the vestibular bulb anteriorly and the Bartholin’s gland posteriorly. The ischiocavernosus muscle is elongated, broader at the middle than at either end and is situated on the side of the lateral boundary of the perineum. It arises by tendinous and fleshy fibres from the inner surface of the ischial tuberosity, behind the crus clitoridis, from the surface of the crus and from the adjacent portions of the ischial ramus.

a Superficial transverse perineal True | False
b Bulbospongiosus True | False
c Pubococcygeus True | False
d Puborectalis True | False
e Ischiocavernosus True | False


2. Which of the following muscles are contributors to the perineal body?

The perineal body is the central point between the urogenital and the anal triangles of the perineum. Its three-dimensional form has been likened to that of the cone of the red pine, with each “petal” representing an interlocking structure, such as an insertion site of fascia or a muscle of the perineum. Within the perineal body there are interlacing muscle fiber from multiple sources but mainly the bulbospongiosus and the superficial transverse perineal muscles. Above this level, there is a contribution from the conjoint longitudinal coat and the medial fibers of the puborectalis muscle. Therefore, the support of the pelvic structures, and to some extent the urogenital hiatus between the levator ani muscles, depends upon the integrity of the perineal body.

a Bulbospongiosus True | False
b Superficial transverse perineal True | False
c Ischiocavernosus True | False
d internal anal sphincter True | False
e Conjoint longitudinal muscle True | False


3. The following statements apply to the anal canal

The rectum terminates in the anal canal. Definitions of the anal canal vary among surgeons and anatomists. The surgical anal canal is approximately 4 cm long and extends from the anal verge to the anorectal ring, which is defined as the proximal level of the levator-external anal sphincter (EAS) complex. This clinical description correlates with a digital or sonographic examination but does not correspond to the histological architecture.

The anus is surrounded laterally and posteriorly by loose adipose tissue within the ischioanal fossae, which is a potential pathway for spread of perianal sepsis from one side to the other. The anal canal is surrounded by an inner epithelial lining, a vascular subepithelium, internal anal sphincter (IAS), EAS and fibromuscular supporting tissue. The lining of the anal canal varies along its length due to its embryologic derivation. The proximal anal canal is lined with rectal mucosa (columnar epithelium) and is arranged in vertical mucosal folds called the columns of Morgagni. Each column contains a terminal radical of the superior rectal artery and vein. The vessels are largest in the left-lateral, right-posterior, and right-anterior quadrants of the wall of the anal canal where the subepithelial tissues expand into three anal cushions. These cushions seal the anal canal and help maintain continence of flatus and liquid stools. The columns are joined together at their inferior margin by crescentic folds called anal valves. About 2 cm from the anal verge, the anal valves create a demarcation called the dentate line. The anoderm covers the last 1-1.5 cm of the distal canal below the dentate line and consists of modified squamous epithelium that lack skin adnexal tissues such as hair follicles and glands, but contains numerous somatic nerve endings. Since the epithelium in the lower canal is well supplied with sensory nerve endings, acute distension or invasive treatment of hemorrhoids in this area causes profuse discomfort, whereas treatment can be carried out with relatively few symptoms in the upper canal lined by insensate columnar epithelium. As a result of tonic circumferential contraction of the sphincter, the skin is arranged in radiating folds around the anus creating the corrugator cutis ani. These folds appear to be flat or ironed out when there is underlying sphincter damage (dovetail sign).

Anal fissures are a tear in the anal mucosa and can be very painful. They are associated with spasm of the internal sphincter but it is unclear as to what occurs first.

Hemorrhoidectomy can be associated with anal incontinence because the anal cushions contribute about 15% of the resting tone and inadvertent damage to the internal and external anal sphincter muscles can cause anal incontinence.

a It is 7 centimeters in length True | False
b It is lined completely by columnar epithelium True | False
c The lining in the lower canal (below the dentate line) is sensitive to pain, touch and temperature True | False
d A fissure is a split in the anal mucosa and can be painless True | False
e Hemorrhoidectomy can be a cause of fecal incontinence True | False


4. The anal sphincter consists of the following:

The anal sphincter complex consists of the striated muscle of the EAS and smooth muscle of the IAS, separated by the conjoint longitudinal coat. Although they form a single unit, they are distinct in structure and function. Structurally, the EAS is subdivided into three parts: the subcutaneous, superficial, and deep. However, these subdivisions are not easily demonstrable during anatomical dissection or surgery, but may be of relevance during imaging. In contrast to the EAS, the IAS has a pale appearance. The longitudinal layer is situated between the EAS and IAS and consists of a fibromuscular layer, the conjoint longitudinal coat and the intersphincteric space with its connective tissue components. The longitudinal layer has a muscular and fibroelastic component. The muscular component is formed by the fusion of the striated muscle fibers from the puboanalis, the innermost part of the puborectalis with smooth muscle from the longitudinal muscle of the rectum. Traced downwards, it separates opposite the lower border of the IAS and the fibrous septae fan out to pass through the EAS and ultimately attach to the skin of the lower anal canal and perianal region.

a Internal anal sphincter True | False
b Conjoint longitudinal coat True | False
c Superficial transverse perineal muscles True | False
d External anal sphincter True | False
e Bulbospongiosus True | False


5. Which nerve innervates the external anal sphincter?

The inferior rectal branch of the pudendal nerve innervates the EAS. In contrast to the other striated muscles, the EAS contributes up to 30% of the unconscious resting tone through a reflex arc at the cauda equina level. The IAS is innervated by autonomic nerves, namely the sympathetic (L5) and parasympathetic nerves (S2-S4). It remains in a state of tonic contraction and accounts for 50-85% of the resting tone. The conjoint longitudinal coat is innervated by autonomic fibers from the same origin.

a Sciatic nerve True | False
b Inferior rectal nerve True | False
c Pudendal nerve True | False
d Obturator nerve True | False
e Parasympathetic nerve True | False


6. The internal anal sphincter

The IAS is a thickened continuation of the circular smooth muscle of the large bowel and terminates with a well-defined rounded edge 6-8 mm above the anal margin at the junction of the superficial and subcutaneous part of the EAS. In contrast to the EAS, the IAS is pale in appearance and is adherent to the anal mucosa.

a Is a continuation of the circular muscle of the rectum True | False
b Lies outside the longitudinal smooth muscle True | False
c Is the same length as the external sphincter True | False
d Comprised of striated muscle True | False
e Is adherent to the anal mucosa True | False


7. Which of the following statements about the anatomy of the external anal sphincter are correct?

The EAS is composed of skeletal muscle fibers and structurally, is subdivided into three parts: the subcutaneous, superficial, and deep. However, these subdivisions are not easily demonstrable during anatomical dissection or surgery, but may be of relevance during imaging. In females, the EAS is shorter anteriorly. The deep EAS is intimately related to the puborectalis muscle but does not have posterior attachment. The superficial EAS is attached posteriorly to the anococcygeal ligament which is attached to the tip of the coccyx. The subcutaneous part is circular but may have attachments to the perineal body anteriorly and the anococcygeal ligament posteriorly.

a It is comprised of striated muscle True | False
b It is a continuation of the longitudinal muscle True | False
c The subcutaneous portion extends beyond the caudal aspect of the internal anal sphincter True | False
d The deep external anal sphincter is contiguous posteriorly with the puborectalis muscle True | False
e There is no difference in male and female anatomy True | False


8. The levator ani muscle is broadly subdivided into

The levator ani is a broad muscular sheet of variable thickness attached to the internal surface of the true pelvis and is subdivided into parts according to their attachments and pelvic viscera to which they are related, namely Iliococcygeus and Pubococcygeus. Although referred to as separate muscles, the boundaries between the different parts cannot be easily distinguished.

a Iliococcygeus True | False
b Bulbospongiosus True | False
c Coccygeus True | False
d Puborectalis True | False
e Ischiocavernosus True | False


9. The pudendal nerve

The pudendal nerve, which has both motor and sensory function, is derived from the ventral branches of the second, third, and fourth sacral nerves and leaves the pelvis through the lower part of the greater sciatic foramen. It then crosses the ischial spine and re-enters the pelvis through the lesser sciatic foramen. It accompanies the internal pudendal vessels upward and forward along the lateral wall of the ischioanal fossa, contained in a sheath of the obturator fascia termed Alcock’s canal. It is hypothesized that during a prolonged second stage of labor, the pudendal nerve is vulnerable to stretch injury due to its relative immobility at this site. The pudendal nerve gives off the inferior rectal nerve, and divides into two terminal branches, the perineal nerve and the dorsal nerve of the clitoris.

a Is derived from the dorsal branches of the second, third and fourth sacral nerves True | False
b Is only a motor nerve True | False
c Leaves the pelvis through the greater sciatic foramen True | False
d Traverses Alcock’s canal True | False
e Terminates as the inferior rectal nerve True | False


10. With regard to the anal sphincter

The IAS is a circular smooth muscle that appears pale (similar to raw fish) compared to the red striated muscle of the EAS (similar to red meat). The superficial transverse perineal muscle is also striated and can be easily mistaken for the torn EAS muscle. As the EAS is normally under tonic contraction, it tends to retract when it is torn. In this situation the ischioanal fat is an important land mark to identify the EAS as it lies lateral to the EAS. The IAS (2 to 4 mm) is thinner than the EAS (4 to 8 mm). The anorectum receives its major blood supply from the superior (terminal branch of the inferior mesenteric artery) and inferior hemorrhoidal (branch of the pudendal artery) arteries, and to a lesser degree, from the middle hemorrhoidal artery (branch of the internal iliac) forming a wide intramural network of collaterals.

a The IAS appears red in color True | False
b The EAS is similar in color to the superficial transverse perineal muscle True | False
c The IAS is thicker than the EAS True | False
d The ischioanal fat is an important land mark to identify the EAS True | False
e The anorectum receives it’s blood supply from the hemorrhoidal arteries True | False


References:

  1.  Thakar R, Fenner DE. Anatomy of the perineum and the anal sphincter. In: Sultan AH, Thakar R, Fenner DE, eds. Perineal and anal sphincter Trauma. London: Springer-Verlag; 2007. 1-12.
  2.  True Pelvis, pelvic floor and perineum. In: Standring S, eds. Gray’s Anatomy. 39th Edition. London: Elsevier Churchill Livingston: 2005. p.1357-1371.