Anatomy of a Pose: Janu Sirsasana

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By Ray Long, MD, FRCSC • May 9th, 2011 • 27753 Views

Anatomy of a Pose: Janu Sirsasana

The main story in Janu Sirsasana is an asymmetrical stretch of the posterior kinetic chain, including the muscles at the back of the straight leg and the back itself. Two subplots contribute to the main stretch. One is the action of the bent leg and the other is the action of the arms. In the bent leg, the femur flexes, abducts, and externally rotates, drawing that side of the pelvis away from the straight leg.

Although the main focus is on the extended leg, periodically bring your attention to the flexed knee. Look at the muscles that produce the positions of the hip and knee on this side. Engage these muscles to make the pose more active. Grasp the foot with the hands to link the shoulder and pelvic girdles, transmitting a stretch from the back into the leg. Connect the action of the bent leg with the same-side arm. For example, as the bent knee draws back, flex the same-side elbow more. This creates two counterbalancing forces with simultaneous movements in different directions.

We saw this concept in the warrior postures, with the back foot constrained as the front of the body lunges forward. Observe the effect of flexing the trunk while moving the bent knee back. Note that when the trunk flexes, the muscles and ligaments of the back pull on the pelvis, tilting it forward. Similarly, as the femur flexes, the pelvis tilts forward. In this way, both the trunk and hip work together to affect the hamstring muscles of the straight leg. Conversely, the hamstring muscles, which pull on the ischial tuberosities, affect the orientation of the pelvis. As these muscles gain length, the lumbar spine flexes less and the pelvis tilts forward more.

Note how the bent-leg side of the trunk is longer than the straight-leg side. To balance this, flex the elbow on the bent-leg side to lengthen the trunk on the straight-leg side.

Basic Joint Positions

• The straight-leg hip flexes.

• The knee extends.

• The ankle plantar flexes.

• The foot everts.

• The bent-leg hip flexes, abducts, and externally rotates.

• The trunk flexes.

• The shoulders flex, abduct, and externally rotate.

• The elbows flex.

• The forearms pronate.

• The wrists extend.

Janu Sirsasana Preparation

The posterior kinetic chain links the muscles, tendons, and ligaments at the back of the body. Tightness in one muscle affects the position of the joints in other muscles; for example, tightness in the lower back can make it...

Ray Long, MD, FRCSC

Location:  Baldwinsville, US

Ray Long, MD, FRCSC, began his study of human anatomy and science at a young age under the guidance of his father, David Michael Long Jr., MD, PhD, a cardiovascular surgeon and research scientist. He went...