The Spiral Line (SPL) (Fig. 6.1) loops around the body in a double helix, joining each side of the skull across the upper back to the opposite shoulder, and then around the ribs to cross in the front at the level of the navel to the same hip. From the hip, the Spiral Line passes like a ‘jump rope’ along the anterolateral thigh and shin to the medial longitudinal arch, passing under the foot and running up the back and outside of the leg to the ischium and into the erector myofascia to end very close to where it started on the skull.
The SPL functions posturally to wrap the body in a double spiral that helps to maintain balance across all planes (Fig. 6.2A-C/Table 6.1). The SPL connects the foot arches with the pelvic angle, and helps to determine efficient knee-tracking in walking. In imbalance, the SPL participates in creating, compensating for, and main- taining twists, rotations, and lateral shifts in the body. Depending on the posture and movement pattern, espe- cially relative to the weighted and unweighted leg, forces from the legs can travel up the same side or cross to the opposite side of the body at the sacrum. Much of the myofascia in the SPL also participates in the other cardinal meridians (SBL, SFL, LL) as well as the Deep Back Arm Line (see Ch. 7). This insures the involvement of the SPL in a multiplicity of functions, and that dys- function in the Spiral Line will affect the easy function- ing of these other lines.
The overall movement function of the SPL is to create and mediate spirals and rotations in the body, and, in an eccentric and isometric contraction, to steady the
trunk and leg to keep it from folding into rotational collapse.
