PELVIS
1. Bony Pelvis formed by 4 bones united by 4 joints
2 hip bones anteriorly by pubic symphysis (2ry cartilaginous joint)
Sacrum & coccyx by sacrococcygeal joint
Sacrum & 2 hip bones each side by 2 sacroiliac joints
2. Bony pelvis is divided into true pelvis & false pelvis by,
Pelvic brim (pubic crest, pectinate line of pubis, arcuate line of ilium, ala & promontory of sacrum)
3. The plane of the pelvic brim is oblique, lying at 600 with the horizontal plane (the vagina lies in the same plane)
4. Pelvic floor slopes downwards and faces forwards (so that the anterior superior iliac spine (ASIS) and the upper
border of the pubic symphysis lies in the same coronal plane)
True pelvis
Superior ASIS
aperture
Pelvis False pelvis Head of Ischial spine
the femur
Inferior Perineum
aperture
Upper border of
pubic symphysis Apex of Tip of the
greater coccyx
Boundaries of true pelvis trochanter
1. Upper border of pubic symphysis
2. Pubic crest
3. Pubic tubercle
Pelvic
4. Pectineal line
inlet
5. Arcuate line
6. Sacroiliac joint
7. Sacral promontory
1. Lower border of pubic symphysis
Pelvic 2. Ischio-pubic rami
outlet 3. Ischial tuberosity
4. Sacrotuberous ligament
5. Coccyx
1
, Stability
Joint Bony factors Ligamentous factors
1.Lumbosacral Widely spaced inferior Strong iliolumbar ligament (prevents forward
Articular disc is very thick; articular processes of L5 movement of sacroiliac joint)
thickest anteriorly From – transverses process of L5 to iliac crest
Lumbosacral ligament
From – transverse process of L5 to ala
2. Sacroiliac joint Interlocking articular Thick & strong interosseous ligament
Anterior, interosseous, surfaces Vertebro pelvic ligaments (Iliolumbar, sacrotuberous,
posterior sacroiliac ligaments sacrospinous ligaments)
Sex differences
Due to easier passage of fetal head in labor
female bones are more slender than male bones
Identify the sex from a X –ray by the shadow of the penis
2
1. Bony Pelvis formed by 4 bones united by 4 joints
2 hip bones anteriorly by pubic symphysis (2ry cartilaginous joint)
Sacrum & coccyx by sacrococcygeal joint
Sacrum & 2 hip bones each side by 2 sacroiliac joints
2. Bony pelvis is divided into true pelvis & false pelvis by,
Pelvic brim (pubic crest, pectinate line of pubis, arcuate line of ilium, ala & promontory of sacrum)
3. The plane of the pelvic brim is oblique, lying at 600 with the horizontal plane (the vagina lies in the same plane)
4. Pelvic floor slopes downwards and faces forwards (so that the anterior superior iliac spine (ASIS) and the upper
border of the pubic symphysis lies in the same coronal plane)
True pelvis
Superior ASIS
aperture
Pelvis False pelvis Head of Ischial spine
the femur
Inferior Perineum
aperture
Upper border of
pubic symphysis Apex of Tip of the
greater coccyx
Boundaries of true pelvis trochanter
1. Upper border of pubic symphysis
2. Pubic crest
3. Pubic tubercle
Pelvic
4. Pectineal line
inlet
5. Arcuate line
6. Sacroiliac joint
7. Sacral promontory
1. Lower border of pubic symphysis
Pelvic 2. Ischio-pubic rami
outlet 3. Ischial tuberosity
4. Sacrotuberous ligament
5. Coccyx
1
, Stability
Joint Bony factors Ligamentous factors
1.Lumbosacral Widely spaced inferior Strong iliolumbar ligament (prevents forward
Articular disc is very thick; articular processes of L5 movement of sacroiliac joint)
thickest anteriorly From – transverses process of L5 to iliac crest
Lumbosacral ligament
From – transverse process of L5 to ala
2. Sacroiliac joint Interlocking articular Thick & strong interosseous ligament
Anterior, interosseous, surfaces Vertebro pelvic ligaments (Iliolumbar, sacrotuberous,
posterior sacroiliac ligaments sacrospinous ligaments)
Sex differences
Due to easier passage of fetal head in labor
female bones are more slender than male bones
Identify the sex from a X –ray by the shadow of the penis
2
