Pelvic floor anatomy and Radiology

1. MRI- ANATOMY OF PELVIC FLOOR
DR.RAMALAKSHMI V
JUNIOR RESIDENT
DEPARTMENT OF RADIODIAGNOSIS

3. Female pelvic floor

4. Female pelvic floor – Indications :
Pelvic floor anatomy is complex and better understanding is now possible with MR imaging
 Dynamic MR imaging of pelvic floor is an excellent tool for assessing functional disorders of
pelvic floor – pelvic organ prolapse, outlet obstruction, incontinence.
 Underestimation/ misdiagnosis of the condition occurs when there is sole rely on the clinical
examination only.
 Also MRI imaging provides both anatomical and functional details about the compartments
involved- Accurate and reliable especially when multiple compartments are involved -pre
operative planning and thereby reducing the incidence of recurrence by proper assessment.

5. Anatomy – COMPARTMENTS:

6. PELVIC SUPPORT:
Active and passive pelvic support
Active – the pelvic diaphragm containing the levator ani and ischiococcygeus muscle
Passive supports – the fascia and ligaments
From superior to inferior we have
 Endopelvic fascia
 Pelvic diaphragm
 Urogenital diaphargm

8. Endopelvic fascia
Enveloping connective tissue network- suspending, supporting and fusing the pelvic organs to
arcus tendinous fascia pelvis – which inserts into pelvic side walls and pubic bones
 Three levels of support
Level 1 – suspends the upper portion of vagina and uterine cervix
Level 2 – supports the middle portion of vagina and posterior bladder Wall
Level 3 – lower portion of vagina to the perineal membrane ; urethral ligaments

12. As such the endopelvic fascia cannot be seen on imaging.
Damage to fascia can be inferred by the presence of various signs.
 CHEVRON SIGN – posterior drooping of posterolateral wall of upper third of vagina
 Middle third of vagina normally has a H or W shape on axial imaging
 Loss of paravaginal ligaments lead to loss of support to posterolateral aspect of bladder –
saddle bag bladder sign
 Damage to level 3 fascia and periurethral ligaments – posterior drooping of lateral corners of
retropubic fat – drooping moustache sign

19. Pelvic diaphragm
Levator ani - predominant supporter of pelvic floor
Muscle Origin Insertion
Pubococcygeus Posterior surface of body
of pubis
Coccyx – midline
Puboprostaticus
Pubovaginalis
puboanalis
Puborectalis Posterior surface of body
of pubis
Forms a sling around the
anorectal junction
Iliococcygeus Originates from the fascia
covering the obturator
internus muscle
Joins in midline to form a
raphe extending from anal
aperture to coccyx.

26. Coccygeus

28. Urogenital diaphragm

32. MALE PELVIC FLOOR

33. INDICATIONS:
 PELVIC ORGAN PROLAPSE
 DEFECATORY DYSFUNCTION
 URINARY INCONTINENCE
 SEXUAL DYSFUNCTION

34. DIFFERENCES BETWEEN MALE AND FEMALE PELVIC FLOOR:
 HAS ONLY TWO COMPARTMENTS
UROGENITAL DIAPHARGM IS TRAVERSED BY URETHRA AND DEEP DORSAL VEIN OF PENIS
LONGER URETHRA
LAYERS :
PELVIC DIAPHARGM
UROGENITAL DIAPHARGM
SUPERFICIAL PERINEAL POUCH

36. SUPERFICIAL PERINEAL POUCH:

38. PELVIC FLOOR FASCIA:
ENDOPELVIC FASCIA
VISCERAL PELVIC FASCIA
DENONVILLIER FASCIA/RECTOVESICAL SEPTUM – IMPORTANT IN PREVENTING THE SPREAD OF
DISEASE.

42. MR defecography procedure:
Patient co operation decides the success of study – clear explanation of procedure to the patient.
Emptying the bladder may comfort the patient
Patient is placed in supine position with knees slightly flexed and legs slightly parted.
Ultrasound coupling gel (120-150 ml ) is instilled in the distal rectum and around 50 ml in vagina for better
visualization of anatomical landmarks
The patient during the dynamic study is asked to strain first – during which the competency of internal and
external anal sphincters can be analysed
Squeeze – kegel maneuver – provides information about pelvic muscle floor strength.
Then defecate
When there is a lateral prolapse, coronal and axial dynamic sequences are added to the protocol. At the level of
pelvic hiatus in axial plane and anal canal in coronal plane.
Axial plane demonstrate the puborectalis and ischiorectal fossa defects , coronal plane shows the iliococcygeus
and lateral prolapses.

43. LINES

47. Anorectal angle
Angle between the posterior border of distal part of rectum and central axis of anal canal.

49. Reference values in male:

50. Puboprostatic angle

51. Thank you