Download Anorectal anatomy and physiology

Anorectal anatomy and physiology
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Surgical anal canal ≈ 5 cm up to the
Anorectal ring
Anatomic anal canal ≈ 3 cm up to the dentate
line
The rectum
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1/3 division
Peritoneal coverage
Valves of Houston
Anorectal angle
Fascial attachments; lateral ligament,
Denonvillier fascia, rectosacral fascia
Anorectal anatomy and physiology
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Dentate line (pectinate)
Anoderm
Transitional area
Columns of Morgagni
Internal hemmorrhoidal plexus
Anorectal anatomy and physiology
Anatomy of the anal canal
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Anal glands
Anal sphincters
Levator ani
Anococcygeal raphi
Perianal spaces
External sphincter
Levator ani
Anorectal angle
Perianal & perirectal spaces
Blood supply of the anorectum
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Portal circulation; inferior mesenteric artery
→ superior rectal artery
Systemic circulation; middle rectal artery,
inferior rectal artery, middle sacral artery
Blood supply
Venous drainage
Lymphatic drainage of anus& rectum
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Perirectal nodes
Inferior mesenteric nodes
Internal iliac nodes
Superficial inguinal nodes
Lymphatic drainage of rectum
Lymphatic drainage of anus
Nerve supply of the rectum
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Sympathetic L1-3
Parasympathetic S2-4 (nervi ergentes)
The hypogastric plexus
Pelvic plexus
Nerve supply of the anus
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Pudendal nerve (S2-4)
Sensory; internal pudendal
Motor
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Internal sphincter; sympathetic & parasympathetic
External sphincter; inferior rectal branch of internal
pudendal n, perineal branch of S4
Nerve supply
Physiology of defecation
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Reflex
Sensation; receptive relaxation of the rectum,
anal sampling, rectoanal reflex
Center; S2-4, cortical
Effectors; sphincters, rectal contraction,
abdominal muscles, levator
Physiology of defecation
Continence mechanism
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Sensory function; proprioception, touch
Rectal reservoir function
Internal sphincter; involuntary, resting tone
External sphincter; voluntary, squeeze
pressure
Levator ani
Anorectal angle
Anal cushions
Anal incontinence
types
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Major; solid feces
Minor; gas, liquid stools, night soiling
Anal incontinence
Causes
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Structural damage;
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Rectal disease
Sphincter injury; birth trauma , surgery ….
Neurologic ;
Idiopathic
Anal incontinence
diagnosis
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History
Rectal examination; tone, squeeze pressure ,
soilage, ….
Endoscopy
Endoanal U/S
Manometry
Nerve studies
Endoanal Ultrasonography
Anal incontinence
Treatment
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Diet and drugs
Biofeedback
Sphincteroplasty
Gracilis flap ± electrical stimulator
Sacral nerve stimulation= neuromodulation
Artificial anal sphincter
colostomy
Sphincteroplasty
Artificial anal sphincter