Quick Answer
When you rest your hands on your hips just below your waist, you are resting them on your pelvic bones, specifically the iliac crest of your pelvis. The iliac crest is the upper curved edge of the ilium, which is the largest bone in the pelvis. Your hands naturally rest on this part of your pelvic girdle when placing them on your hips.
Anatomy of the Pelvis
The pelvis is made up of two hip bones, each containing 3 fused bones: the ilium, the ischium, and the pubis.
The ilium is the upper flared portion of the hip bone. It contains a raised ridge called the iliac crest along the top outer edge. This is the part you feel when you place your hands on your hips.
Ilium
The ilium forms the upper portion of the hip bone and contains the iliac crest along its upper border. Key features of the ilium include:
– Iliac crest – The curved superior edge of the ilium. This is where the hands rest when placed on the hips.
– Iliac fossa – The concave portion of the inner ilium. Important muscles like the iliacus originate here.
– Anterior superior iliac spine – A bony prominence on the anterior portion of the iliac crest. Often used as a landmark for injections or assessments.
– Anterior inferior iliac spine – Another bony landmark on the anterior ilium, below the anterior superior iliac spine.
– Posterior superior iliac spine – A projection on the posterior ilium, often used clinically as a landmark.
Ischium
The ischium forms the lower and back portion of the hip bone. Key features include:
– Ischial tuberosity – Roughened portion of the ischium that bears weight in sitting. Often referred to as the “sit bones.”
– Ischial spine – A sharp projection on the posterior ischium. Forms part of the lesser sciatic notch.
Pubis
The pubis forms the anterior portion of the hip bone. Key features are:
– Pubic crest – Ridge along the superior edge of the pubis.
– Pubic tubercle – Small bump on the anterior surface of the pubis.
– Pubic symphysis – Joint between the left and right pubic bones, made of fibrocartilage.
Muscles Attaching to the Iliac Crest
Several important muscles originate along the iliac crest that you are resting your hands on when you place them on your hips. These include:
Iliacus
The iliacus muscle lies within the iliac fossa of the inner ilium. It joins with the psoas major muscle to form the iliopsoas muscle group. The iliacus flexes the thigh at the hip joint.
Tensor Fasciae Latae
The tensor fasciae latae originates at the anterior superior iliac spine and helps stabilize the hip joint. It also helps abduct, medially rotate, and flex the thigh.
Gluteus Medius
The gluteus medius originates along the outer surface of the ilium between the iliac crest and posterior gluteal line. It abducts and medially rotates the hip.
Gluteus Minimus
The gluteus minimus lies underneath and forward of the gluteus medius, originating between the anterior and inferior gluteal lines on the outer ilium. It also abducts and medially rotates the thigh.
Hip Anatomy and Biomechanics
The pelvis and hip joint provide a stable connection between the lower limbs and axial skeleton while allowing a wide range of motion.
Bony Anatomy
– Acetabulum – The cup-shaped socket on the outer surface of the hip bone that articulates with the femoral head.
– Femoral head – Rounded end of the femur that fits into the acetabulum to form the hip joint. Covered in articular cartilage.
Joint Capsule and Ligaments
– Iliofemoral ligament – Strong ligament on the front of the hip joint that prevents overextension.
– Pubofemoral ligament – Inferior ligament that resists abduction.
– Ischiofemoral ligament – Posterior ligament that limits internal rotation.
Hip Biomechanics
The hip allows flexion, extension, abduction, adduction, medial and lateral rotation. Key actions include:
– Flexion – Bending the thigh upwards towards the torso. Performs by iliopsoas.
– Extension – Straightening the hip joint. Performed by gluteus maximus.
– Abduction – Lifting the thigh out to the side. Performed by gluteus medius/minimus.
– Adduction – Bringing the thigh back towards or across midline. Performed by adductor muscles.
– Medial rotation – Turning the thigh inward. Performed by gluteus medius/minimus.
– Lateral rotation – Turning the thigh outward. Performed by obturator internus.
Conclusion
In summary, when you place your hands on your hips, you are resting them on the iliac crest of your pelvic bones. This is the upper curved ridge of the ilium, which makes up the largest portion of the hip bones. Key muscles like the iliacus, tensor fasciae latae, and gluteals originate from the iliac crest and span across the hip joint, allowing you to flex, extend, abduct, adduct, and rotate your thigh through a wide range of motion. So next time your hands are on your hips, you can appreciate the complex anatomy you are actually touching!