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Bones: Lumbo-Pelvic Hip Complex.

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Anatomy & Physiology: Bones—Lumbo-Pelvic Hip Complex (Pelvic Girdle).

 

Structure.

  • The lumbo-pelvic hip complex (LPHC) is a keystone structure in the human body as it transmits forces up through the lower kinetic chain to the upper kinetic chain.
  • The LPHC consists of: 2 coxal (hip) bones joined anteriorly at the pubic symphasis; the sacrum; and the coccyx.
  • Sacroiliac joint: where the auricular surface of the ilium articulate with the auricular surface of the sacrum.
  • Coxal bone (hip bone): consists of 3 bones (initially separated by cartilage but fuses together around age 23 yrs): ilium, pubis; ischium (“Your hip is I.P.I. or ippy”).
  • Ilium: superior and largest of the hip bones.
    • Ala (“wing”).
    • Acetabulum: forms part of the hip socket.
    •  
    • Iliac crest: superior border, extending anteriorly to form the anterior superior iliac spine. Palpateable.
    • Anterior superior iliac spine (ASIS): palpateable landmark.
    • Anterior inferior iliac spine (AIIS): palateable landmark.
    • Posterior superior iliac spine (PSIS): palpateable landmark.
    • Posterior inferior iliac spine (PIIS): palpateable landmark.
    • Greater sciatic notch: inferior to the PIIS, through which the sciatic nerve passes (sciatic nerve is longest nerve in human body).
    • Iliac fossa.
    • Auricular surface: roughened area and articulates with the auricular surface of the sacrum to form the SI joint.
    • Arcuate line.
    • Posterior gluteal line (lateral surface).
    • Anterior gluteal line (lateral surface).
    • Inferior gluteal line (lateral surface).
  • Ischium: inferior and posterior portion of the coxal bone.
    •  
    • Ramus: fuses with the pubis.
    • Ischial spine.
    • Lesser sciatic notch.
    • Ischial tuberosity: rough and thickened area.
    • Obturator foramen: formed from the ischium and pubis. Largest foramen in the skeleton. Almost totally closed off by fibrous obturator membrane.
  • Pubis: inferior and anterior portion of the coxal bone.
    • Superior ramus.
    • Inferior ramus: the inferior rami of the two coxal bones, form the pubic arch.
    •  
    • Pubic tubercle.
    • Pubic crest.
    • Pubic symphasis: joint between two hip bones with fibrocartilage inbetween. In pregnant women, relaxin (hormone) increases the flexibility of the pubic symphasis.
    • Obturator foramen.
  • Acetabulum: hip socket of hip joint formed by ilium, ischium, and pubis.
  • False vs. True Pelvis.
    • Pelvic brim: defines the superior and inferior pelvis. Higher posteriorly than anteriorly due to tilt.
    • False pelvis: the portion of the pelvis superior to the pelvic brim.
    • True pelvis: the portion of the pelvis inferior to the pelvic brim.
    • Pelvic inlet: superior opening of the true pelvis.
    • Pelvic outlet: inferior opening of the true pelvis.
    • Pelvic axis.
  • Male pelvis: tend to be larger, heavier, with more surface markings.
  • Female pelvis: tend to be shallower and wider, more spacious true pelvis.

Function.

Clinical Significance.

 

References

Biel, A. (2015). Trail guide to the body: A hands-on guide to locating muscles, bones and more.

Cedars-Sinai. (2018). Vertebrae of the spine. Retrieved from https://www.cedars-sinai.org/health-library/diseases-and-conditions/v/vertebrae-of-the-spine.html

Jenkins, G., & Tortora, G. J. (2012). Anatomy and Physiology: From Science to Life, 3rd Edition International Stu. John Wiley & Sons.

Muscolino, J. E. (2017). The muscular system manual: The skeletal muscles of the human body.