Pelvic Girdle

• Pelvic Girdle's Components

  Pelvic girdle = formed by the sacrum and a pair of hip bones (coxal bones)

  Each hip bone unites w it's partner anteriorly + w the sacrum posteriorly
• Pelvic Girdle - Function

  Pelvic girdle attaches the lower limbs to the axial skeleton

  Transmits the full weight of the upper body to the lower limbs

  Supports the visceral organs of the pelvis
• Pelvic Girdle- Stucture

  Secured to the axial skeleton by some of the strongest ligaments in the body

  The corresponding sockets of the girdle r deep + cup like + firmly secure the head of the femur in place

  Lacks the mobility of the pectoral girdle but is far more stable
• Bones of the Pelvic Girdle

  Ilium

  Ischium

  Pubis

  In adults these bones r firmly fused + their boundaries r indistinguishable
• Acetabulum

  At the point of fusion of the ilium, ischium and pubis, is a deep hemispherical socket = acetabulum on the lateral surface of the pelvis

  The acetabulum receives the head of femur at this hip joint
• Ilium

  Ilium = a large flaring bone that forms the superior region of the coxal bone

  It consists of a body and a superior wing-like portion = ala
• Iliac Crests

  Thickened superior margins of the alae to which many muscles attach to

  Each iliac crest ends anteriorly in the blunt anterior superior iliac spine and posteriorly in the sharp superior iliac spine
• Iliac Spines

  located below the anterior superior + posterior superior iliac spines r the less prominent anterior + posterior inferior iliac spines

  all of these spines r attachment points for the muscles of the trunk, hip + thigh

  
• Ilium - Greater Sciatic Notch

  just inferior to the posterior inferior iliac spine, the ilium indents deeply to form the greater sciatic notch, thru which the thick cordlike sciatic nerve passes to enter the thigh

  
• Ilium's Gluteal Lines

  the broad posterolateral surface is crossed by 3 ridges, the posterior, the anterior + inferior gluteal lines, to which the gluteal msucles attach to

  
• Ischium

  the ischium forms the posteroinferior part of the hip bone

  roughly arc-shaped, it has a thicker, superior body adjoining the ilium + a thinner inferior ramus

  ramus = a bar of bone which joins the pubis anteriorly

  
• Ishium - Ischial Spine

  its ischial spine projects medially into the pelvic cavity + serves as a point of attachment of the sacro-spinous ligament running from the sacrum

  
• Ischium - Lesser Sciatic Notch

  just inferior ro the ischial spine is the lesser sciatic notch

  a no of nerves + blood vessels pass thru this notch to supply the anogenital area

  
• Ischium - Ishicial Tuberosity

  the inferior surface of the ischial body is rough + grossly thickened as the ischial tuberosity

  when we sit, our weight is borne by the ischial tuberosities, which r the strongest parts of the hip bones

  
• Ischium - Sacrotuberous Ligament

  a massive ligament runs from the sacrum to each ischial tuberosity

  this sacrotuberous ligament helps hold the pelvis together

  the ischial tuberosity is a site of attachment of the large hamstring muscles of the posterior thigh

  
• Pubis

  the pubis forms the anterior portion of the hip bone

  in the anatomical position, it lies nearly horizontally = the urinary bladder rests upon it

  
• Pubic Ramis

  the pubis is v-shaped w superior + inferior pubic rami issuing from its flattened medial body

  
• Pubic Crest & Tubercle

  the anterior border of the pubis is thickened to from the pubic crest

  at the lateral end of the pubic crest is the pubic tubercle, one of the attachments for the inguinal ligament

  
• Pubis - Obturator Foramen

  as the 2 rami of the pubis run laterally to join w the body + ramus of the ischium, they define a large opening in the hip bone, the obturator foramen

  = thru which a few blood vessels + nerves pass