BONY PELVIS anatomy and pathophysiology with management

the anatomy of the pelvis and pelvic wall with the features and pathophysiology

1. PELVIS

2. THE PELVIS region of the trunk lying below the abdomen area of transition between trunk and lower limbs. the two regions are described separately, even though their cavities (abdominal and pelvic) are continuous

3. FUNCTIONS OF THE PELVIS Weight transmission Contain, Support, Protect pelvic viscera Provide muscles attachment (trunk and lower limb). Passage way - birth canal.

4. The bony pelvis provides a strong, stable connection between the trunk and the lower extremities.

5. PELVIS COMPOSITION Two hip bones, forming lateral and anterior walls, Sacrum and Coccyx, part of the vertebral column and form posterior wall. The hip bones articulate anteriorly at the symphysis pubis and posteriorly with sacrum at the sacroiliac joints. The bony pelvis contains the lower parts of the intestinal and urinary tracts and the internal organs of reproduction.

6. Iliac crest Iliac fossa Anterior superior iliac spine Anterior inferior iliac spine Ilium Pubis Ischium Hip bone Subpubic angle Pubic arch A. Anterior View Ala of sacrum Sacro-iliac joint Sacral promontory Sacrum Sacrococcygeal joint Coccyx Acetabulum Ischial spine Pubic tubercle Obturator foramen Pubic symphysis

7. PELVIC BONE

8. The sacrum consists of five rudimentary vertebrae fused together to form a single wedge-shaped bone with a forward concavity. The upper border or base of the bone articulates with the fifth lumbar vertebra. The narrow inferior border articulates with the coccyx .

9. The vertebral foramina together form the sacral canal. The laminae of the fifth sacral vertebra, and sometimes those of the fourth, fail to meet in the midline, forming the sacral hiatus.

10. The coccyx consists of four vertebrae fused together to form a small triangular bone, which articulates at its base with the lower end of the sacrum.

11. The pelvis is divided into two parts by the pelvic brim. false pelvis a bove the brim , which forms part of the abdominal cavity. true pelvis below the brim

12. The pelvic brim formed by: Sacral promontory, posteriorly (anterior and upper margin of the first sacral vertebra) behind, Ileopectineal lines, laterally (a line that runs downward and forward around the inner surface of the ileum), and Symphysis pubis, anteriorly (joint between bodies of pubic bones).

13. Embryology cartilaginous ossification mesoderm-cartilage-calcified cartilage-bone 3 primary ossification centres in pelvic bone ilium, ischium and pubis appear at second, third and fourth months of inter-uterine life respectively

14. secondary ossification centres for ilium, ischium and pubis occur at puberty occur at the iliac crest, pubic symphysis, ischial tuberosity , ASIS cartilage ossifies at puberty and unites at about 20 years of age

15. Pelvic Tilt Pelvis is normally tilted in anatomical position. Thus: ASIS and the pubic tubercles are in the same vertical plane . Coccyx is in same horizontal plane as the upper margin of the pubic symphysis . Axis of the pelvic cavity running through the central point of the inlet and the outlet almost parallels the curvature of the sacrum.

16. Comparison of male and female pelvis Bony pelvis Male Female General structure Thicker and heavier Thinner and lighter Greater pelvis(pelvis major) deeper shallower Lesser pelvis(pelvis minor) Narrower deeper, tapering Wider shallower, cylindrical Pelvic inlet(superior pelvic aperture) Heart shaped, narrower More oval rounded, wider

17. Comparisons cont….. Bony pelvis Male Female Sacrum/coccyx More curved Less curved Pelvic outlet(inferior pelvic aperture) Comparatively small Comparatively large Pubic arch and sub-pubic angle narrower wider Obturator foramen round oval Acetabulum Large small

18. Figure 6-1 Anterior view of the male pelvis (A) and female pelvis (B).

19. Symphysis Pubis is a fibrocatilaginous joint. surrounded by superior and inferior ligaments extending from one pubic bone to the other. Movements Almost no movement is possible at this joint.

20. Sacro-coccygeal Joint cartilaginous joint between body of the last sacral vertebra and first coccygeal vertebra. sacrum and coccyx are joined by anterior, posterior and lateral sacro-coccygeal ligaments . Movements Extensive flexion and extension are possible at this joint.

21. Sacroiliac Joints Synovial joints formed between sacrum and the iliac bones. sacrum suspended between the two iliac bones by strong posterior and interosseous sacroiliac ligaments Movements small but limited amount of movement is possible at these joints. Nerve Supply The nerve supply is from branches of the sacral spinal nerves.

22. The Female Pelvis Deformities of the pelvis may be responsible for dystocia (difficult labor). Gynaecoid type present in about 41% of women Android type present in about 33% of white females and 16% of black females is the male or funnel-shaped pelvis with a contracted outlet. Anthropoid type present in about 24% of white females and 41% of black females is long, narrow, and oval shaped.

23. Platypelloid type present in only about 2% of women is a wide pelvis flattened at the brim, with the promontory of the sacrum pushed forward.

24. Applied anatomy Pelvic fracture e.g. obturator foramen Pelvic fractures may also disrupt the contents of the pelvis, leading to urethral disruption, potential bowel rupture and nerve damage Iliac crest for bone marrow biopsy e.g. in leukaemia Sacroiliac joint in rheumatoid arthritis

25. Reference Books 1. Standring , Susan and Standring (2015).Gray's anatomy. 41st International edition, Elsevier Health Sciences. ISBN 9780702052309. 2. Keith L. Moore, Arthur F. Dalley , Anne M. R. Agur (2017). Moore's Clinically Oriented Anatomy, 8th edition, Walter Kluwer . ISBN 9781496347213. 3. Alan J. Detton (2020). Grant’s Dissector. 17th edition, Lippincott Williams & Wilkins. ISBN 9781975134600. 4. Adrian Kendal Dixon, David J. Bowden, Bari M. Logan and Harold Ellis (2017). Human Sectional Anatomy - Pocket atlas of body sections, CT and MRI images, 4th edition, CRC Press. ISBN 9781498708548.

26. The End Thank you