MSK Bones of the pelvis Flashcards
What are the 3 bones making up the hip bone?
What separates these 3 bones during development?
Ilium ischium pubis
Up to 15-17yrs the bones are separated by triradiate cartilage
What are the articulations of the hip bone?
Sacroiliac joint - articulates with sacrum
Pubic symphysis - articulates with other hip bone
Hip joint - articulates with head of femur
What are the bony landmarks of the ilium?
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)
What is the difference between true and apparent leg length?
True leg length - ASIS to medial malleolus
Apparent leg length - umbilicus to medial malleolus
What are the bony landmarks of the pubis?
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
What are the bony landmarks of the ischium?
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
What are the ligaments that attach to the ischium?
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
What is the pelvic girdle?
Consists of the 2 hip bones, sacrum and coccyx
What are the articulations within the pelvic girdle?
Pubic symphysis
Sacroiliac joints (2) between ilium and sacrum
Sacrococcygeal symphysis between sacrum and coccyx
What is the base, apex and 4 surfaces of the sacrum?
Base articulates with L5
Apex touches coccyx
Auricular surfaces are either side and articulate with the ilium
Anterior and posterior surfaces
what is the sacrum formed by?
fusion of the five sacral vertebrae
What are the bony landmarks on the dorsal surface of the sacrum?
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
What are the bony landmarks on the pelvic surface of the sacrum?
4 transverse lines - remnants of fused intervertebral discs
Superiorly there is an anterior bony projection called the sacral promontory
What is the coccyx made up of?
4 fused vertebra
What is the embryonic development of the coccyx?
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
What are the bony landmarks of the coccyx?
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
What are the articulations of the coccyx?
Articulates with sacrum at fibrocartilaginous joint called the sacrococcygeal symphysis
What muscles attach to the coccyx?
Gluteal maximus
What are the ligaments that support the sacrococcygeal symphysis?
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
What are the muscular attachments to the sacrum?
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
What are the major artieries/veins of the pelvis?
External iliac artery + vein
Internal iliac artery + vein
Common iliac artery + vein
At what locataion does the femoral vein become the external iliac vein?
As it crosses underneath the inguinal ligament
What is the relation between the external+internal iliac veins and the common iliac vein?
The external and internal iliac vein join together to form the common iliac vein
What veins does the internal iliac vein receive blood from?
Superior + inferior gluteal veins
Obturator vein
At what location do the internal and external veins join to form the common iliac vein?
What does the common iliac vein form?
The upper margin of the pubic symphysis
The left and right common iliac veins combine at L5 to become the inferior vena cava
