AN48.1-8 | Pelvic wall and viscera — Glossary

Muscular floor of the pelvis formed by levator ani and coccygeus, supporting pelvic viscera and maintaining continence

Chief muscle of the pelvic floor comprising pubococcygeus, puborectalis, and iliococcygeus; innervated by S3-S4

U-shaped sling of levator ani that maintains the anorectal angle at 90 degrees, essential for faecal continence

Branch of common iliac artery that supplies pelvic walls, viscera, perineum, and gluteal region via anterior and posterior divisions

Abnormal obturator artery replacing or anastomosing with the inferior epigastric artery, crossing behind the superior pubic ramus; at risk during hernia repair

Nerve plexus formed by L4-S4 ventral rami on the anterior surface of piriformis, giving rise to the sciatic and pudendal nerves

S2-S4 nerve supplying the perineum, external genitalia, and sphincters; travels through Alcock's canal in the lateral wall of the ischiorectal fossa

Rectouterine pouch — the most dependent part of the female peritoneal cavity, between the uterus and rectum; site of fluid collection

Mackenrodt's ligament extending from the cervix to the lateral pelvic wall; the main support of the uterus

Normal uterine position where the long axis of the uterus tilts forward relative to the vaginal axis

Normal uterine position where the body of the uterus bends forward on the cervix

Lobe of the prostate between the urethra and ejaculatory ducts; enlargement causes urinary obstruction in BPH

Reflex bladder from suprasacral cord lesion; intact sacral arc allows reflex emptying without voluntary control

Atonic/flaccid bladder from lesion at or below S2-S4; loss of reflex arc causes overflow incontinence

Smooth muscle of the bladder wall that contracts during micturition under parasympathetic (S2-S4) control

Emergency drainage of the bladder via a trocar inserted 2 cm above the pubic symphysis when urethral catheterisation fails

Parasympathetic nerves from S2-S4 supplying the hindgut derivatives and pelvic viscera

Branch of anterior division of internal iliac artery that crosses above the ureter at the lateral fornix of the cervix ('water under the bridge')

Dilated veins of the anal canal; internal (above dentate line, portal drainage) and external (below dentate line, systemic drainage)

Pectinate line — mucocutaneous junction of the anal canal marking the boundary between internal and external haemorrhoids

90-degree angle at the anorectal junction maintained by the puborectalis sling, essential for faecal continence

Largest branch of the posterior division of the internal iliac artery; exits above piriformis through the greater sciatic foramen

Key pelvic muscle originating from the anterior sacrum (S2-S4), exiting through the greater sciatic foramen; divides the foramen into superior and inferior compartments

Largest nerve in the body (L4-S3); exits below piriformis through the greater sciatic foramen to supply the posterior thigh and entire leg