Week 3: Osteology of Pelvic Girdle Flashcards
What is the pelvis?
An osseoligamentous ring - bones and ligaments
What is the function of the pelvic inlet?
Entrance to the pelvic cavity
What is the function of the pelvic outlet?
Inferior exit of the pelvic cavity
What is the function of the greater or false pelvis?
Portion of the wall of the abdominal cavity
What is the function of the lesser or true pelvis?
Portion of the wall of the pelvic cavity
What sexual differences are evident between the pelvic cavity, and why?
- Pelvic cavity in females is short and round compared to males (longer and more conical).
- Differences more pronounced at pelvic outlet –adapted for childbirth
What are the 3 principal functions of the bony pelvis?
- Transmit body weight from the trunk to the lower limbs
- Absorb stresses of muscular activity
- Contribute to the walls of the abdominopelvic cavity (support and protection of viscera)
What is the sacrofemoral arch?
The lines of force transmission from the body through the sacrum to the pelvis and onto the femurs
What is the hip bone composed of?
- Ilium
- Ischium
- Pubis
What differences are evident in the morphology of an adult compared to a juveniles hip bone? And why do these morphological differences exist?
- The bones are present as three separate bones in a juvenile, being widely separated by cartilage in the infant or child
- The 3 bones are fused in the adult
- Allow growth - fusion of bones varies with sex and age but is usually complete by about 20 years of age
Which bones contribute to the formation of the acetabulum?
- Ischium
- Ilium
- Pubis
At what age do the secondary centres of ossification of the ilium, ischium and pubis fuse at the acetabulum?
15-18 years
Describe the morphology of the obturator foramen:
Large oval foramen, bounded by the pubis and ischium, lying below the acetabulum
What neurovascular structures pass through the obturator membrane, and what do they supply?
Obturator nerve, artery and vein – supply the medial compartment of thigh
What name might you give to a muscle that arises from the iliac fossa?
Iliacus
2 muscles of the lower limb attach to the anterior superior iliac spine (ASIS). What are they?
- Tensor fascia lata (hip abductor)
- Sartorius (medial compartment thigh)
Name three muscles that attach to the gluteal surface, in decreasing order of size:
- Gluteus maximus
- Gluteus medius
- Gluteus minimus
With what bone does the auricular surface of the ilium articulate?
Sacrum (to form the anterior part of the sacroiliac joint)
The greater sciatic notch lies between which bony features?
Posterior inferior iliac spine and ischial spine
The lesser sciatic notch lies between which bony features?
Ischial spine and ischial tuberosity
With what bone does the ramus of the ischium fuse?
Fuses with the pubis (inferior pubic ramus)
What muscle group attaches to the ischial tuberosity?
Hamstrings
What portion of the pelvic cavity is formed by the pubic body?
Anterior wall
With which bones does the superior pubic ramus fuse, and where?
With the ischium and ilium, at the acetabulum
With what bone does the inferior pubic ramus fuse?
With the ramus of the ischium
When in situ, to what joint does the symphyseal surface contribute?
Pubic symphysis
What attaches to the pectineal line?
Pectineus muscle
