The left and also right hip bones (innominate bones, pelvic bones) space two irregularly shame bones that type part of the pelvic girdle – the bony framework that attaches the axial skeleton come the reduced limbs.

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The i know good bones have actually three key articulations:

Sacroiliac joint – articulation v the sacrum.Pubic symphysis – articulation in between the left and also right i know good bones.Hip joint – articulation v the head the femur.

In this article, we shall look at the anatomy the the hip skeletal – their composition, bony landmarks, and also clinical relevance.


Fig 1 – synopsis of the anatomical place of the i know good bones.

Composition that the i know well Bone

The i know well bone is consisted of of the 3 parts; the ilium, pubis and also ischium. Prior come puberty, the triradiate cartilage separates these parts – and blend only starts at the age of 15-17.

Together, the ilium, pubis and ischium type a cup-shaped socket recognized as the acetabulum (literal an interpretation in Latin is ‘vinegar cup‘). The head that the femur articulates v the acetabulum to kind the hip joint.

We shall now look in ~ the individual components of the i know well bone, and also their particular bony landmarks.


Fig 2 – The i know good bone of a 5 year old, through triradiate cartilage tho present.

The Ilium

The ilium is the widest and also largest that the three components of the i know good bone, and is situated superiorly. The body of the ilium creates the superior component of the acetabulum (acetabular roof). Immediately over the acetabulum, the ilium increases to form the wing (or ala).

The soup of the ilium has two surfaces:

Inner surface – has actually a concave shape, i m sorry produces the iliac fossa (site of origin of the iliacus muscle).External surface (gluteal surface) – has a convex shape and provides attachments to the gluteal muscles.

The exceptional margin that the wing is thickened, developing the iliac crest. It extends indigenous the anterior premium iliac spine (ASIS) to the posterior remarkable iliac spine (PSIS).

On the posterior facet of the ilium over there is one indentation known as the greater sciatic notch.


Fig 3 – The bony landmarks the the ilium.

Clinical Relevance: Anterior remarkable Iliac Spine

The anterior exceptional iliac spine (ASIS) is an important anatomical landmark:

Mid-inguinal point – halfway in between the ASIS and also the centre of the pubic symphysis. The femoral artery deserve to be palpated here.Mid-point that the inguinal ligament – halfway in between the ASIS and also the pubic tubercle.

In clinical practice, a patient’s “true” leg length is measured native the ASIS to the medial malleolus in ~ the fishing eye joint. This is distinctive from “apparent” foot length, i beg your pardon is measured from the umbilicus to the medial malleolus.

True leg size discrepancy is a feature of assorted hip disorders, and being a potential complication that hip share replacement (arthroplasty).

The Pubis

The pubis is the many anterior section of the hip bone. It is composed of a body, premium ramus and also inferior ramus (ramus = branch).

Pubic body – located medially, it articulates through the opposite pubic body at the pubic symphysis. That is superior aspect is significant by a rounded thickening (the pubic crest), which extends laterally as the pubic tubercle.Superior pubic ramus – extends laterally native the human body to type part of the acetabulum.Inferior pubic ramus – tasks towards the ischium.

Together, the superior and inferior rami enclose component of the obturator foramen – through which the obturator nerve, artery and vein pass through to reach the reduced limb.


Fig 4 – Bony landmarks the the pubis.


Fig 5 – The orientation that the hip bones in ~ the pelvis.

Clinical relevance – Pubic Rami Fractures

Pubic rami fractures can sometimes be observed on x-rays in elderly patient who space investigated after simple low power falls indigenous standing height. In this paper definition and listed they room the just injury a patient has sustained, these fractures space usually treated there is no surgery.

Healing have the right to be supposed within 6-8 weeks and patients are motivated to totally weight be afflicted with straightaway.

The Ischium

The ischium creates the posteroinferior component of the i know well bone. Much like the pubis, that is written of a body, an inferior ramus and superior ramus.

The inferior ischial ramus combines with the worse pubic ramus developing the ischiopubic ramus, i beg your pardon encloses part of the obturator foramen. The posterorinferior facet of the ischium creates the ischial tuberosities and also when sitting, it is these tuberosities on which our body load falls.

Near the junction the the superior ramus and body is a posteromedial estimate of bone; the ischial spine.

Two important ligaments connect to the ischium:

Sacrospinous ligament – runs from the ischial spine to the sacrum, thus producing the greater sciatic foramen through which lower limb neurovasculature (including the sciatic nerve) transcends.Sacrotuberous ligament – operation from the sacrum come the ischial tuberosity, developing the lesser sciatic foramen.

Clinical Relevance: Pelvic Fractures

There are two large groups that pelvic fractures:

Low energy injuries:For example, a basic fall native standing elevation in an osteoporotic patient causing pubic rami fracture.These space usually ‘stable’ injuries, no requiring surgery.High power injuries with straight ortransfer trauma:For example, after a high speed roadway traffic accident. These result in more extensive fractures i beg your pardon may incorporate the acetabulum and also sacroiliac joint.These deserve to be ‘unstable’ injuries and also may call for urgent surgery.Higher energy injuries deserve to be associated with soft tissue and also vascular injury. In particular, the bladder and also urethra space at high danger of damage. Vascular injury can an outcome in life threatening haemorrhage.

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In the context of a high energy major trauma patient, the pelvis deserve to be a significant source that bleeding because of fracture. As a result, significant trauma patients are assumed to have actually a pelvic fracture until proven otherwise and a ‘pelvic binder’ is supplied to stabilise the pelvis and also minimise additional bleeding. Circumferential push is used by the binder in ~ the level that the greater trochanters – an important anatomical landmark.