pack Flashcards
(27 cards)
What are the anterior and posterior relations of the anal canal?
Anterior: Perineal body
Posterior: anococcgeal body
What is the pectinate (dentate) line?
The line that is formed by the lower border of the anal columns
What is the signifgance of the pectinate (dentanate) line?
It seperates the upper half of the anal canal from the lower half
What is the embryological origin of the mucosa of the upper half of the anal canal?
Hind gut (Endoderm)
What is the nerve supply of the upper half of the anal canal?
The nerve supply of the upper half of the anal canal comes from the hypogastric plexuses.
What type of sensation is the upper half of the anal canal sensitive to?
The upper half of the anal canal is sensitive to stretch.
What artery supplies the upper half of the anal canal?
The upper half of the anal canal is supplied by the superior rectal artery.
Which vein drains the upper half of the anal canal, and where does it drain?
The upper half of the anal canal is drained by the superior rectal vein, which flows into the portal circulation.
Where does lymph from the upper half of the anal canal drain?
Lymph from the upper half of the anal canal drains into the pararectal and inferior mesenteric lymph nodes.
What is the embryological origin of the mucous membrane of the lower half of the anal canal?
The mucous membrane of the lower half of the anal canal is derived from ectoderm.
What type of epithelium lines the lower half of the anal canal?
The lower half of the anal canal is lined by stratified squamous epithelium.
What nerve supplies the lower half of the anal canal, and what sensations is it sensitive to?
The somatic inferior rectal nerve supplies the lower half of the anal canal, making it sensitive to pain, touch, pressure, and temperature.
What is the arterial supply to the lower half of the anal canal?
The arterial supply to the lower half of the anal canal is the inferior rectal artery, a branch of the internal pudendal artery.
How is the lower half of the anal canal drained venously, and where does it ultimately drain?
The lower half of the anal canal is drained by the inferior rectal vein, a tributary of the internal pudendal vein, which drains into the internal iliac vein (caval system).
Where does lymph from the lower half of the anal canal drain?
Lymph from the lower half of the anal canal drains to the medial group of the superficial inguinal lymph nodes.
What is the intersphinteric white line of hilton?
It is the line that marks the transtion of the epithelium from non-keratinized to keratinized
From where does the internal anal spintcher extend?
It occupies the upper two thirds of the anal canal up until the white line of hilton
What are is the innervation of the internal anal spintcher?
From the hypogastric plexus
What are the three parts of the external anal sphincter, and where are they located?
A. Subcutaneous part: Encircles the lower end of the anal canal, has no bony attachments, and is separated from the skin by the corrugator cutis ani muscle.
B. Superficial part: Attached to the coccyx behind and the perineal body in front.
C. Deep part: Encircles the upper part of the anal canal, has no bony attachment, and fuses with fibers of the puborectalis muscles.
What nerves supply the external anal sphincter?
The external anal sphincter is supplied by the inferior rectal nerve, a branch of the pudendal nerve, and the perineal branch of S4.
What is the longitudinal muscle of the anal canal, and where is it located?
The longitudinal muscle of the anal canal is continuous with that of the rectum. It forms a continuous coat around the anal canal and descends between the internal and external anal sphincters.
How is the anorectal ring formed?
By the union of the internal spintcher, deep external sphinchter, and pubo rectalis muscle at the anorectal junction
Label
What are the 5 things that anal continence is dependent on?
- External anal spinchter
- Internal anal sphinchter
- Anal colums of morgani
- Transverse folds (Vavles of houston)
- Puborectalis sling (90 angle)
