Week 1 - A - Anatomy 1 - Bony Pelvis Anatomy - Pelvic Fracture and Childbirth Flashcards
What bones does the bony pelvis consist of?
2 Hip bones
Sacrum and coccyx
What is the other name for the hip bones? What are the components of the hip bones?
Hip bones are also known as innominate bones (and are known as ossae coxae)
Hip bone - ilium, ischium and pubis
What are the main functions of the bony pelvis?
Transference of weight from the vertebral column (one column) to the femurs (right and left column)
Supports and protects the pelvic organs and the pelvic vessels
Passage for childbirths
Also support for when sitting and standing
What is the difference in the bones of the pelvic girdle and the bony pelvis?
Bony pelvis - 2 hip bones (ilium, ischium and pubis), sacrum and coccyx
Pelvic girdle - 2 hip bones (ilium, ischium and pubis), sacrum
Coccyx is not part of the pelvic girdle
Each hip bone is a fusion of the ilium, ischium and pubis Where do these three bones fuse to form and at what age?
The three bones fuse at to form the acetabulum (where the femur head inserts)
The fusion of three bones begins at puberty and should be completed by the age of 20 in males and females
Hyaline cartilage sits between the three bones forming the hip bone WHat is this cartilage sometimes known as?
This is known as the triradiate cartilage important when looking at an xray of a pediatric that there may be sutures on xray as the bone hasnt fused yet (not a fracture)
Where does the iliac crest run from? On the image state what the coloured arrows are pointing to
The iliac crest runs from the anterior superior iliac spine (ASIS) to posterior superior iliac spine (PSIS)
Green arrow - iliac crests
Dark red - PSIS
Bright red - Anterior inferior iliac spine
Black - ASIS
What is the notch lying slightly above the ischial spine in the ilium known as? What is the notch in the ischium lying just below the ischial spine known as?
Greater sciatic notch is a notch in the ilium lying just above the ischial spine
Lesser sciatic notch is a notch in the ischium lying just below the ischial spine
It is only when the bony pelvis is on it own with no ligaments that greater and lesser sciatic notch are under these names WHen ligaments lie over the notches, what are they known as? What are the ligamanets?
Sacrospinous and sacrotuberous ligaments
The sacrospinous ligament changes the greater scoatic notch into an opening, the greater sciatic foramen.
The sacrospinous and sacrotuberous ligaments change the lesser sciatic notch into an opening, the lesser sciatic foramen
What are the attachment points of the sacrotuberous and sacrospinous ligaments?
Sacrospinous - ischial spine to sacrum
Sacrotuberous - ischial tuberosity to sacrum
Which structures form the ischiopubic ramus?
Formed by the inferior pubic ramus and the ischial ramus
What nerve runs very close to the ischial spine? Where does and leave and re-enter the pelvic cavity? What does it innervate? Does it carry parasympatehtic or sympathetic fibres?
- The pudendal nerve runs very close to the ischial spine (Pudendal - S2,3,4)
- It leaves the pelvic cavity via lower part of the greater sciatic foramen to, passes over sacrospinous liigament very close to the ischial spine and re-enters via the lesser sciatic foramen
- Sympathetic fibres
What is the prominence on the ischium that can be felt when sitting down? What ligament attaches here?
This is the ischial tuberosity
The sacrotuberous ligament attaches here
What attaches between the ASIS and pubic tubercle? What connects the left and right pubic bones?
The inguinal ligament attaches between the ASIS and pubic tubercle
The pubic symphysis connects the left and right pubic bones
The pubic arch is formed by the convergence of the inferior rami of the ischium and pubis on either side What lies at the apex of the pubic arch?
The subpubic angle is the angle at which the ischiopubic rami on either side converge
The subpubic angle helps determine the sex of a skeleton How is this so?
In males the angle is typically less than 70 degress
In females the angle is typically more than 80-90 degrees
What bones do the bony pelvis consists of again? What forms the roof and lower boundary of the pelvic cavity?
Bony pelvis consists of the 2 hip bones, sacrum and coccyx
Roof of pelvic cavity - formed by the pelvic inlet
Lower boundary of pelvic cavity - formed by the pelvic floor
The pelvic inlet is more of a circle shape whereas the pevlic outlet is more oval shaped What course does the pelvic inlet run? What is another name for the pelvic inlet?
Runs from the sacral promontory, along the medial aspect of the ilium, along the superior pubic ramus and to the pubic symphysis where the course goes to the other side
The pelvic inlet is sometimes referred to as the pelvic brim
The pelvic outlet has the slightly more oval shape Describe the course of the pelvic outlet?
Runs from pubic arch, along the inferior pubic ramus inferiorly to the ischial tuberosity posteriorly and along the sacrotuberous ligaments to the coccyx (then continues back down sacrotuberous ligaments etc)
What is the largest muscle of the pelvic floor and what is its nerve supply?
The levator ani muscle - supplied by the pudendal nerve (S2,3,4)
What are the palpable surface landmarks of the bony pelvis? Which are felt on deeper palpation?
ASIS, most if not all of iliac crest, PSIS and ischial tuberosity should be palpable
Deeper palpation can feel coccyx, pubic tubercle and pubic symphysis