Anal Triangle Flashcards
What makes up the walls of the ischioanal fossa?
- Ischial tuberosity
- Rectum/anal canal
What makes up the roof of the ischioanal fossa?
Levator ani
What makes up the floor of the ischioanal canal?
Skin
What are the contents of the ischioanal canal?
- Branches of pudendal nerve
- Branches of pudendal artery/vein
- Adipose tissue
Identify the features of the anal canal.
What part of the anal canal is smooth muscle?
Internal anal sphincter
What part of the anal canal is skeletal muscle
External anal sphincter
At what point does the rectum become the anal canal?
When it pierces the pelvic floor
What do the anal columns contain?
- Terminal radicle of the superior rectal vessels
- Anal sinus related
What type of muscle is present at the external anal sphincter?
Skeletal muscle
Where is the external anal sphincter located?
From perineal body to anococcygeal ligament.
What is the function of the external anal sphincter?
Closes the anus
What aids rectal control along side the external anal sphincter?
Puborectalis muscle
What innervates the external anal canal?
Inferior rectal branch of the pudendal nerve (S2-4)
What happens at the pectinate line?
End of the visceral internal part of the digestive tract
What happens at the anocutaneous line?
Transition to true skin
Describe the arterial supply of the anal canal.
- Superior rectal artery
- Middle rectal artery
- Internal pudendal artery
- Inferior rectal artery
What artery gives branches to supply the anal canal above the pectinate line?
Inferior mesenteric artery
What vein does blood drain to above the pectinate line?
Portal venous system
What artery gives branches to supply the anal canal below the pectinate line?
Internal iliac artery
What vein does blood drain to below the pectinate line?
Caval venous system
Where does lymph drain above the pectinate line?
Internal iliac nodes
Where does lymph drain to below the pectinate line?
Superficial inguinal nodes
Describe the innervation above the pectinate line.
- Visceral motor
- Mixed sympathetic and parasympathetic
- Sensory innervation
Describe the innervation below the pectinate line.
- Somatic motor
- Sensory innervation
