University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

108

Pages:

7
Author:

Mariam A. A.

Pelvic cavity • Continuous with the abdominal cavity - Bounded superiorly by pelvic inlet -> connects it to the abdominal cavity - Bounded inferiorly by a group of muscles and the fascia surrounding them “Pelvic Floor” or “Pelvic Diaphragm” which is suspended above the pelvic outlet, with its central dipping below it True vs False Pelvis • False pelvis - Also known as the greater pelvis - Not enclosed by pelvic cavity - Superior to pelvis inlet - Bounded by the iliac alae posterolaterally and the antero-superior aspect of the S1 vertebra body - Occupied by abdominal cavity ✓ E.g., ileum and sigmoid colon • True pelvis - Also known as the lesser pelvis - Enclosed by pelvic cavity - Between the pelvic inlet and the pelvic outlet - Bounded by the pelvic surfaces of the hip bones, sacrum and coccyx - That includes the true pelvic cavity and the deep parts of the perineum (perineal compartment), specifically the ischio-anal fossae - That is major obstetrical and gynaecological importance Bones and boundaries of the pelvis • Two hip bones, innominate bones or pelvic bones • Sacrum – 5 • Coccyx – 4 Pelvic Bone • Innominate bone • At birth the ilium, pubis and ischium are connected by cartilage Sacrum and Coccyx • Promontory - Posterior margin of the pelvic inlet - Located directly superior to the centre of the pelvic outlet ✓ Site of the perineal body - Anterior surface: concave - Posterior surface: convex Pelvic Joints • Lumbosacral Joint - Between the superior auricular process of sacrum and inferior articular facets of L5 • Sacrococcygeal Joint - Between the apex of the sacrum and the base of the coccyx • Sacroiliac Joint - Between lateral sacral surface and iliac articulation surface - Limited by interlocking of the articulating bones and the sacroiliac ligaments to slight gliding and rotatory movements Differences between female and male pelvis • Female - Differences relate to child birth ✓ Broader pelvis ✓ Circular pelvic inlet ✓ More oval obturator foreman ✓ Shorter and wider - Sacrum ✓ distributed more obliquely backwards which increases the size of the pelvic cavity, making it more convenient for enduring pregnancy and offering more space for the developing foetus • Male - Differences relate to heavier build and larger musculature ✓ Smaller pelvic outlet ✓ Ischial tuberosities closer together ✓ More prominent muscle attachments ✓ Rounder obturator foreman ✓ Heart shaped pelvic inlet ✓ Less and flatter ala -> deeper greater pelvis Ligaments of the pelvis • Sacrospinous ligament - Ischial spine to sacrum ✓ Creates greater sciatic foramen through which lower limn neurovasculature (including sciatic nerve) transcends • Sacrotuberous ligament - Runs from sacrum to the ischial tuberosity ✓ Forms lesser sciatic foramen • - Triangular and superficial - Broad bone -> superior iliac spine of pelvis -> along dorsal aspect and lateral margin of sacrum -> dorsal lateral aspect of coccyx along margin of ischial tuberosity -> laterally apex of ligament medially attached These ligaments together - Give rise to greater and lesser sciatic foramens - Define apparatus between pelvic cavity and adjacent regions through which structures pass