MSK Bones of the pelvis

Question 1

What are the 3 bones making up the hip bone?

What separates these 3 bones during development?

Answer 1

Ilium ischium pubis

Up to 15-17yrs the bones are separated by triradiate cartilage

Question 2

What are the articulations of the hip bone?

Answer 2

Sacroiliac joint - articulates with sacrum
Pubic symphysis - articulates with other hip bone
Hip joint - articulates with head of femur

Question 3

What are the bony landmarks of the ilium?

Answer 3

The wing or ala
Iliac fossa - anterior surface of wing (iliacus muscle)
Gluteal surface - posterior surface (glut muscles)
Iliac crest - superior margin of wing thickened (extends from anterior superior iliac spine to posterior superior iliac spine)

Question 4

What is the difference between true and apparent leg length?

Answer 4

True leg length - ASIS to medial malleolus

Apparent leg length - umbilicus to medial malleolus

Question 5

What are the bony landmarks of the pubis?

Answer 5

Pubic body - makes pubic symphysis joint
Superior pubic rami
Inferior pubic rami - joins to the ischium

Two rami enclose part of the obturator foramen which the obturator nerve artery and vein pass through

Question 6

What are the bony landmarks of the ischium?

Answer 6

Ischial body - makes up the ‘corner’
Inferior ischial rami - joins with inferior pubic rami to form ischiopubic rami
Superior ischial rami
Ischial tuberosity - posterioinferior aspect
Greater and lesser sciatic notch
Ischial spine

Question 7

What are the ligaments that attach to the ischium?

Answer 7

Sacrospinous ligament - ischail spine to sacrum. Creates the greater sciatic foramen which sciatic nerve passes through

Sacrospinous and sacrotuberous ligament run from sacrum to ischial tuberosity to form lesser sciatic foramen

Question 8

What is the pelvic girdle?

Answer 8

Consists of the 2 hip bones, sacrum and coccyx

Question 9

What are the articulations within the pelvic girdle?

Answer 9

Pubic symphysis
Sacroiliac joints (2) between ilium and sacrum
Sacrococcygeal symphysis between sacrum and coccyx

Question 10

What is the base, apex and 4 surfaces of the sacrum?

Answer 10

Base articulates with L5
Apex touches coccyx
Auricular surfaces are either side and articulate with the ilium
Anterior and posterior surfaces

Question 11

what is the sacrum formed by?

Answer 11

fusion of the five sacral vertebrae

Question 12

What are the bony landmarks on the dorsal surface of the sacrum?

Answer 12

Median sacral crest - formed by fusion of spinous processes of first 3 vertebrae

Intermediate sacral crests either side of the median sacral crest -formed by the fusion of articular processes

Lateral sacral crests - formed by fusion of transverse processes

4 pairs of posterior sacral foramina for nerve fibres to enter and leave the canal

Question 13

What are the bony landmarks on the pelvic surface of the sacrum?

Answer 13

4 transverse lines - remnants of fused intervertebral discs

Superiorly there is an anterior bony projection called the sacral promontory

Question 14

What is the coccyx made up of?

Answer 14

4 fused vertebra

Question 15

What is the embryonic development of the coccyx?

Answer 15

The coccyx arises from the caudal eminence (present weeks 4-8). The eminence regresses and the coccyx remains.
Initially the 4 coccygeal vertebrae are separate but fuse together to form 1 bone

Question 16

What are the bony landmarks of the coccyx?

Answer 16

The base is superior and has a facet for articulation with the sacrum
The apex is inferior
The lateral surfaces have small transverse processes projecting from Co1
The coccygeal cornua of Co1 project upwards to articulate with the sacral cornua

Question 17

What are the articulations of the coccyx?

Answer 17

Articulates with sacrum at fibrocartilaginous joint called the sacrococcygeal symphysis

Question 18

What muscles attach to the coccyx?

Answer 18

Gluteal maximus

Question 19

What are the ligaments that support the sacrococcygeal symphysis?

Answer 19

Anterior sacrococcygeal ligament - connects anterior aspects of vertebral discs

Deep posterior sacrococcygeal ligament - connects posterior 5th sacral body to dorsal coccyx

Superficial posterior sacrococcygeal ligament - median sacral crest to dorsal coccyx

Lateral sacrococcygeal ligament - lateral sacrum to transverse process of Co1

Interarticular sacrococcygeal ligament - cornua of sacrum to cornua of coccyx

Question 20

What are the muscular attachments to the sacrum?

Answer 20

Anterior surface - piriformis originates from S2-4 and attaches to greater trochanter

Iliacus originates from ala and some fibres originate from sacrum and attach to lesser trochanter

Question 21

What are the major artieries/veins of the pelvis?

Answer 21

External iliac artery + vein
Internal iliac artery + vein
Common iliac artery + vein

Question 22

At what locataion does the femoral vein become the external iliac vein?

Answer 22

As it crosses underneath the inguinal ligament

Question 23

What is the relation between the external+internal iliac veins and the common iliac vein?

Answer 23

The external and internal iliac vein join together to form the common iliac vein

Question 24

What veins does the internal iliac vein receive blood from?

Answer 24

Superior + inferior gluteal veins

Obturator vein

Question 25

At what location do the internal and external veins join to form the common iliac vein?
What does the common iliac vein form?

Answer 25

The upper margin of the pubic symphysis

The left and right common iliac veins combine at L5 to become the inferior vena cava