A critical evaluation of the current status of myofascial chains

Introduction

From a morphological point of view, most anatomy textbooks have described the skeletal muscles of the human body as being discrete actuators with clear origins and insertions ( ). Recent analyses of published anatomical cadaveric studies have challenged this assumption, revealing that the active components of the locomotor system are directly linked by fibrous connective tissue ( ) ( Fig. 1.6.1 ). The bridging structures include: ligaments (hamstrings – sacrotuberous ligament – erector spinae muscle) ( , ); fasciae ¹

1 In this Commentary, the term fascia refers to the connective tissue investing the skeletal muscles, sometimes also called ‘deep fascia’.

(gastrocnemius muscle – hamstrings) ( ); aponeuroses (gluteus maximus/tensor fasciae latae – iliotibial tract – calf muscles) ( ); tendons (gastrocnemius muscle – Achilles tendon – plantar aponeurosis – toe abductors) ( , ).

A common feature of the listed elements is their considerable tensile strength, conferred by a large quantity of collagen type I fibres. Moreover, comparisons between samples of the fascia lata and different tendons located around the knee joint revealed that these structures share similar biomechanical, biochemical and histological properties ( , ). Therefore, in addition to the classical distinctive terminology, it has been suggested that the entirety of soft collagenous connective tissues should be grouped under the umbrella terms ‘fascial tissues/fascial system’ when describing the body from a holistic and functional point of view ( ).

Myofascial Chains

Concepts of myofascial chains assume that the connectivity of muscles and stretch-resistant soft tissue creates systemic lines of pull with the potential to transmit mechanical force to distant body regions. The selection of the components of a myofascial chain is based on the criterion of continuity between their longitudinal axes ( Fig. 1.6.2 ): it is assumed that this construction maximizes the amount of transmittable force. Another relevant factor is the common fibre orientation of neighbouring myofascial chain components. In tendons, the collagen fibrils are oriented parallel to each other, almost directly following the muscle’s line of pull. A similar architecture with mostly parallel fibres running in a longitudinal direction can be found in ligaments. Although the investing fasciae often display a bidirectional, lattice-like fibre arrangement, biomechanical studies reveal a markedly higher longitudinal stiffness ( ), which might indicate a more pronounced strain transmission capacity in this direction.

Based on these thoughts, a variety of concepts have suggested body maps with hypothesized myofascial chains ( Fig. 1.6.3 ) (for an overview, see ). Only three continuous lines, the posterior longitudinal chain, the posterior diagonal chain and the anterior diagonal chain, have been systematically verified so far ( Fig. 1.6.4A , Table 1.6.1 ) ( ). Two other possible chains, the lateral longitudinal chain and the spiral chain, still exhibit some unresolved inconsistencies but are at least partially backed by scientific evidence ( Fig. 1.6.4B , Table 1.6.2 ).