Yoga Anatomy

Notes

Gravity is pulling the torso into the back bend, which is checked by the arm action and the
eccentric action of the spinal flexors.
In the cervical spine, the anterior neck muscles are eccentrically active, but the ster-
nocleidomastoid should not be active to avoid the base of the skull being pulled into the
atlas and axis.
Internal rotation of the legs will help stabilize the SI joint by encouraging the front of
this joint to align.
It can be very challenging to find a healthy extension of the spine at the base of the
neck or the top of the thoracic spine. It helps to focus on releasing the sternocleidomastoid
using the eccentric strength of the deeper anterior neck muscles to stabilize the weight
of the head. Ustrasana can be an intense mobilization for the digestive system, especially
the esophagus.

Breathing

In ustrasana, the thoracic structures are maintained in an inhalation position, and the
abdominal wall is lengthened. This results in a decreased ability of the body to breathe
“normally.” The trick is to find support from the deeper musculature so that the more
superficial efforts can quiet down. Then it’s possible to notice an interesting relationship
between the deepest layer of superficial neck muscles (scalenes) and the breath movement
in the apex of the lungs, which are suspended from the inner scalene muscles.

Muscular joint actions

Spine

Concentric contraction Eccentric contraction Passively lengthening

To extend spine (though most

of action of extension is

caused by gravity):

Spinal extensors

To prevent overmobilization of

lumbar spine:

Psoas minor, abdominal muscles

To resist hyperextension in

cervical spine as head extends:

Anterior neck muscles

Psoas major

Upper limbs

Concentric contraction Passively lengthening

To adduct, elevate, and down-

wardly rotate scapula:

Rhomboids, levator scapulae

To stabilize shoulder joint and

prevent protraction of head

of humerus:

Rotator cuff

To extend and adduct shoulder

joint:

Triceps brachii (long head), teres

major, posterior deltoid

To extend elbow:

Triceps brachii

Pectoralis major and

minor, biceps brachii,

coracobrachialis

Lower limbs

Concentric contraction Eccentric contraction

To extend, adduct, and internally rotate hip:

Hamstrings, adductor magnus, gluteus

maximus

To resist hip extension and knee flexion:

Rectus femoris

To resist knee flexion:

Articularis genu, vastii