Case 14- anatomy Flashcards
Pelvic girdle
The bony pelvis. Made from the Sacrum, Coccyx and left and right pelvic bones
Pelvic bone
Made up of the ileum, ischium and pubis which are separate before puberty but fuse as adults. When they fuse they are connected by cartilage in the area of the Acetabulum.
Function of pelvic girdle
- Weight bearing
- Muscle attachment
- Attachment point for the erectile bodies and external genitalia
- Protect pelvic viscera and inferior abdominal viscera
- Support abdominopelvic viscera and gravid uterus
How is the pelvic girdle divided
Between the abdominal and pelvic cavity.
1) The superior region of pelvis is the false pelvis (greater pelvis) and is part of the abdomen.
2) The true pelvis (lesser pelvis) is related to the inferior parts of the pelvic bones, sacrum, and coccyx, and has an inlet and an outlet.
The pelvic cavity
The pelvic cavity is enclosed by the true pelvis and consists of the pelvis inlet, walls and floor. Continuous with abdominal cavity and contains parts of the urinary, gastrointestinal and reproductive system.
Sacrum
- Fusion of 5 sacral vertebrae
- Articulates with L5 vertebra – via superior articular facet
- Articulates with the Ilium – via articular facet on lateral surface
- The Sacral cornua on the sacrum articulates with the Coccygeal cornua on the Coccyx
Sacral ala
The expanded transverse process
Sacral canal
Continuation of the vertebral canal, nerves pass through it
Sacral promontory
Sticks out from the sacrum and projects anteriorly
Nerves associated with the sacrum
The posterior and anterior rami of spinal nerves S1 to S4 emerge from the sacrum through separate foramina. 4 pairs of nerves on each side
The Ileums articulate line
The Ileum articulates with the Sacrum. The articulate line separates the upper and lower parts of the ileum, it forms part of the pelvic brim. The upper part is the greater/false pelvis, the lower part is the lesser/true pelvis.
Iliac fossa
Where the cecum and appendix are located.
Iliac crest
Superior arch of the pelvis
Landmarks in the Ileum
Anterior to the Iliac crest is the Anterior superior iliac spine (ASIS). Inferior to this is the Anterior inferior iliac spine (AIIS). Posterior to the Iliac crest is the Posterior superior iliac spine. Inferior to this is the Posterior inferior iliac spine. The Iliac tuberosity is a large outgrowth on the posterior region of the pelvis.
The greater sciatic notch
A notch in the Ileum, it is below the posterior inferior iliac spine.
Pectineal line
The pelvic inlet. In the pubis
Ramus of ischium
In the pubis. Continuation of the inferior ramus
Pubis structures
Both pubic bones come to together and articulate at the Pubic symphysis. The joining of the two pubic bones is the pubic arch. There is a bump on the pubic bones called the pubic tubercle. The superior pubic ramus and inferior pubic ramus make up the shape of the pubic bone. Together they form the body of the pubis at the front. The articulate line continues at the Pectineal line on the pubic bone.
Obturator foramen
In the Ischium. Covered by the Obturator membrane, some things do pass through it i.e. the obturator nerve
Structures in the Ischium
The ischial ramus is a continuation of the inferior pubic ramus. Together they are the Ischiopubic ramus. The Obturator foramen is a gap in the pelvic bone. The ischial tuberosity are the bones you sit on. The ischial spine are superior and point out. The lesser sciatic notch is inferior to the greater sciatic notch.
Ligaments in the Sacroiliac joint
Between the sacrum and Ilium. The strongest ligament is the Interosseous ligament, on the posterior aspect of the joint. The posterior Sacroiliac ligament runs over the top of the Interosseous ligament. The anterior Sacroiliac ligament is along the top of the joint.
1) Interosseous
2) Posterior Sacroiliac
3) Anterior Sacroiliac
Ligaments between the pubic symphysis
The anterior and superior pubic ligament
The Sacrotuberous and Sacrospinous ligament
Form part of the pelvic wall. The Sacrospinous and Sacrotuberous ligament splits the greater and lesser sciatic notches into foramen. Foramen are enclosed spaces.
Pelvic inlet
Bordered by the Sacrum posteriorly and the pubic symphysis anteriorly, the pelvic brim is made of the arcuate and pectineal lines. Sacrum promontory is part of it.
Pelvic outlet
Bordered by the coccyx posteriorly, the lateral tuberosities laterally and the pubic arch anteriorly. Pubic symphysis is superior, the sacrotuberous ligament also forms the lateral border
Male adaptions of the pelvis
False pelvis- deep
True pelvis- narrow and deep
Angle of pubic arch- narrow <70
Pelvic outlet- small
Female adaptions of the pelvis
False pelvis- narrow
True pelvis- wide and shallow
Angle of pubic arch- wide >80
Pelvic outlet- relatively large