1. Anatomy of the Pelvis in Computed Tomography
Michael C. Ficorelli, RT

2. Lesson Description
To explain the various exams pertaining to the pelvis using computed tomography, incorporating cross sectional anatomy from images

3. Lesson Description
To be able to identify anatomy within the pelvis. Understand the clinical indications for exams. To understand the methods of patient scanning, positioning, and protocols. To understand indications for contrast.

4. CT of the Pelvis

5. Pelvis
Provides structural support for the body and contains both the male and female reproductive organs
Bony Pelvis – contains the sacrum, coccyx and two innominate bones

6. Bony Pelvis

7. Bony Pelvis
Sacrum – Triangular shaped bone formed by 5 fused vertebrae
S-1 contains prominent ridge on anterior surface referred to as sacral promontory – separates abdomen from pelvis
Transverse process of the 5 are fused to form the lateral mass (ala)
Sacral foramina – located within the lateral mass for transmission of the sacral nerves
Coccyx – 3 to 5 fused small bony segments

8. Bony Pelvis

9. Bony Plevis Innominate bone – Made of 3 bones
Ilium – largest and superior portion
Body and ala
Superior rim – Iliac crest
Slopes downwards to ASIS (Anterior Superior Iliac Spine) and PSIS
Body is uppermost portion of acetabulum
Ischium – inferior portion
Body and 2 rami
Superior ischial ramus extends posteriorly and inferiorly to ischial tuberosity (you sit on it)
Body is lowermost portion of acetabulum
Greater and Lesser sciatic notches extend from ischial spine and allows transmission of nerves and vessels
Obrturator Foramen – opening enclosing the union of pubic and ischial rami
Pubis – lower anterior portion of acetabulum
Body and 2 rami (superior and inferior)
Bodies of both sides meet at midline – Symphysis Pubis

10. Bony Pelvis

11. Pelvic Muscles
Rectus Abdominus – anterior surface of abdomen and pelvis
Psoas Muscle – Lateral to the lumbar vertebrae and medial to the ilium
Gleuteus Muscles
Maximus - outermost
Medius
Minimus – innermost (lateral to pelvic bone)

12. Pelvic Muscles

13. Perineum Posterior to pubic arches; anterior to coccyx 2 divisions
Anal Triangle – contains inferior 1/3 of anal canal and sphincter muscles
Urogenital diaphragm – openings of the urethra and vagina in females; urethra and root structures of penis in males

14. Pelvic Organs
Bladder – lies on the pelvis floor immediately posterior to symphysis pubis and is responsible for the storage of urine
Pyramid shaped
Storage capacity 750 cc Max
Urethra – muscular tube which drains urine from the bladder
Rectum – Terminal colon extending from L-3
Anus – Exit
Anal Sphincter – ring of muscle fibers under voluntary control
Prostate Gland – largest accessory gland in the male reproductive system
Inferior to the bladder and surrounds the urethra

15. Bladder and Prostate

16. Pelvic Vasculature
Abdominal Aorta descends into the pelvic cavity and bisects at the level of L-4 into the Right and Left Iliac arteries
Right and Left Iliac bifurcate again at the level of the SI Joints into Internal and External Iliac arteries
Internal and External Iliac Veins run similar courses as the arteries and meet at the level of the SI joints to form the Right and Left Iliac Veins
Meet at L-4 to form the IVC

17. Pelvic Vasculature

18. Pelvis Standard 2 1 1 – Ascending Colon 2 – Ileum 3 – Descending Colon
4 – Iliac Artery 3 4

19. Pelvis Standard 1
1 - Cecum

20. Pelvis Standard 1 2
1 – Uterus
2 – Ovary
3 - Rectum 3

21. Pelvis Standard 2 1 – Bladder 2 – Uterus 3 – Ovarian Cyst 4 - Rectum 1

22. Pelvis Standard 1
1 - Bladder

23. Pelvis Standard
1 - Anus 1

24. Pelvis Bone 1 2
1 – L – 5
2 – Iliac Crest

25. Pelvis Bone 1
1 – Sacral Promontory
2 – SI Joint 2

26. Pelvis Bone 1
1 – Ilium
2 - Sacrum 2

27. Pelvis Bone
1 – Ilium (top of acetabulum) 1

28. Pelvis Bone 1
1 – Pubic Bone
2 – Acetabulum
3 - Iscium 3 2

29. Pelvis Bone 1 2
1 – Pubic Rami
2 – Femoral Head
3 – Iscium 3

30. Pelvis Bone 1 2 1 – Symphysis Pubis 2 – Femoral Neck
3 – Iscial Tuberosity 3

31. Pelvis Bone
1 – Pubic and Iscial Ramus 1