Unit 3- Perineum- Anal Triangle Flashcards
Perineum
Diamond shaped area inferior to the pelvic floor between thighs
Bony landparts of the perineum
Anterior: Symphysis pubis
Lateral: Ischial tuberosity
Post: Coccyx
Subdivisions of the perineum
Urogenital triangle
Anal triangle
Boundaries of the anal triangle
Ant: Imaginary line connecting the Ischial tuberosities
Post: Tip of the coccyx
Lateral: Sacrotuberous ligament overlapped by the gluteus maximus
Contents of the anal triangle
Anal canal
Isciorectal fossa
Location of the anal canal
From the rectal ampulla to the anal aperture (anus)
-Starts at anorectal junction marked by puborectal sling
Upper half of the anal canal epithelium
Columnar - insensitive to cutting
Epithelium of lower half of the anal canal
Stratified squamous epithelium
Which half of the anal canal has anal columns and valves present?
Upper half
Anal valves connect:
They are located:
Lower portion of columns together
Inf border of sinuses
Separation of hindgut structures from proctodeum
Pectinate line
Nerve supply to upper half of anal canal
Pelvic autonomic plexus (stretch)
Nerve supply to lower half of the anal canal
Inf rectal nerve (pain, temp, touch, and pressure)
The inferior rectal nerve is a branch of what nerve?
Pudendal
Arterial supply of the upper half of the anal canal
Superior rectal art (from the inf mesenteric art)
Anterior supply to the lower half of the anal canal
Inf rectral art
From internal pudendal art which is a branch from the internal iliac art
Venous drainage for upper half of the anal canal
Superior rectal vein (to the inf mesenteric vein)
Venous drainage for the lower half of the anal canal
Inf rectal vein (to the internal pudendal , then to the internal iliac vein)
Lymphatic drainage for upper half of the anal canal
Internal iliac nodes
Some to pararectal nodes (to the inf mesenteric nodes)
Lymph drainage for the lower half of the anal canal
Superficial inguinal lymph nodes
Anal sphincters
Internal and external
Puborectalis part of levator ani
Internal sphincter is:
(VOLUNTARY/INVOLUNTARY)
Innervated by:
Located:
Involuntary
Pelvic plexus
At the upper end of the anal canal
External Sphincter is:
(VOLUNARY/INVOLUNTARY)
Innervated by:
Parts:
Voluntary
Inf rectal nerve
Subcutaneous, superficial, deep
Wedge shaped space on each side of the anal canal
Ischiorectal/Ischioanal fossa
Borders of the ischiorectal fossa
Base: Skin
Medial wall:
Levator ani
Anal canal
Lateral wall:
Obturator internus
Covered with pelvic fascia
Location of the pudendal canal
On the lateral wall of the ischiorectal fossa
The pudendal canal is formed by:
The fascia over obturator internus
Contents of the pudendal canal
Pudendal nerve
Internal pudendal vessels
Pudendal canal, AKA:
Alcock’s canal
