Anatomization Of The Upper Spiral Line: A Cadaveric Case Study Of Myofascial Continuity

Anatomists and physiologists often present skeletal muscles as individual entities (e.g. long head - biceps brachii, vastus lateralis) with their associated movement outcomes (e.g. flexion, extension). A limitation to this approach is the inability to visualize the muscles across anatomical regions as being linked by the various fasciae of the body. This structural interconnectedness yields body-wide myofascial continuities which engage in multiple and coordinated movement actions. PURPOSE: To explore the existence of a myofascial continuity (Upper Spiral Line (USL)) that spans [bilaterally] from the posterior side of the skull and neck to the posterior - lateral - anterior aspect of the torso. METHODS: One embalmed human male cadaver was dissected. The donor voluntarily and legally willed his body for educational and research purposes. Skin, superficial fascia and adipose tissue were removed. Skeletal muscles and fascia with attachments to the skull, neck, vertebra column, thorax, abdomen and pelvis were identified. We employed a dissection strategy to manage muscles which were in-line with one another, linked by fascia, and that followed a spiral tract around the upper body. RESULTS: Fifteen muscles forming opposing helices were linked by fascia and identified to make up the USL. These muscles were: splenius capitis, splenius cervicis, rhomboid major and minor, serratus anterior, external oblique, internal oblique, and rectus abdominis (7 paired, 1 unpaired). The USL was associated with 49 bony structures including the skull, vertebrae, scapulae, ribs, sternum, ilia and pubes. CONCLUSION: This study highlights that an upper spiral line consisting of multiple skeletal muscles linked by fascia can be successfully dissected for visualization. This myofascial continuity forms a jacket around the upper body and contributes to a number of general actions such as extension, flexion, and rotational movements associated with the head, neck, torso, and pelvis. Consideration and more detailed study of body-wide myofascial continuities, such as the USL, may have clinical implications for treatment and injury prevention strategies that may be of interest to athletes and those suffering from or susceptible to musculoskeletalfascial injury. Supported by Graduate Studies and Research, CWU