The function of the erectores spinae muscles in certain movements and postures in man*

Abstract

The erectores spinae muscles are described by topographical anatomists as extensors of the trunk. Borelli (1710), Duchenne (1867) and Beevor (1904) asserted that they contract when the trunk is flexed from the upright position and so act as antagonists to gravity. Weddell, Feinstein & Pattle (1944) stated that the lumbar and thoracic sacro-spinalis muscles are easily relaxed with ' satisfactory positioning', but gave no details of postures in which this occurs. Akerblom (1948) reported briefly that the electromyogram of the lumbar sacro-spinalis muscle, in eight out of twelve subjects sitting in the sunken position (i.e. with full flexion of the trunk), showed practically no difference from the resting electromyogram. Allen (1948) stated that the erector spinae is quiescent when full trunk flexion has been reached from the orthograde position. Kelton & Wright (1949) found in two subjects that the erectores spinae muscles were electrically silent for long periods of time in the 'easy standing position '. Floyd & Silver (1950 described the action of the erectores spinae during 'straining' and in flexion and extension of the trunk.The present paper describes the functions of the erectores spinae muscles in certain postures and movements and during weight-lifting, as studied in 150 human subjects by electromyographic, photographic and radiographic methods. A preliminary account of this work has been given in brief communications to the Anatomical and Physiological Societies during 1949-52. METHODSIn most experiments surface electrodes were placed directly over the muscles in the lumbar region. Concentric needle electrodes were also used in order to record the activity of the deeper parts of the muscles. The action potentials were amplified and recorded with either a 4-or 6-channel Ediswan electroencephalograph.

Chapter 4 European guidelines for the management of chronic nonspecific low back pain

“…The role of the paraspinal muscles for the stabilisation and movement of the spine was assessed in some of the earliest kinesiology studies using surface and wire electromyography (EMG) (Floyd and Silver 1955). The absence of "flexion-relaxation" (electrical silence in the paraspinal muscles when in full trunk flexion) was introduced as a characteristic particularly associated with the presence of CLBP.…”

A comparative investigation of flexion relaxation phenomenon in healthy and chronic neck pain subjects

“…Movements in the spine are supported by a complex neuromuscular system involving active (muscle), passive (vertebrae, intervertebral discs, ligaments, tendons and fascia) and neural components [31]. During full flexion, this supporting role transfers from the superficial extensor musculature to other stabilisation systems [7,[9][10][11][12]. The relationship between pain and altered muscle activation patterns is also complex, and researchers use experimental pain models to explain how pain can change the motor control and load transfer between tissues [7,32].…”

“…The FRP was first defined by Floyd and Silver [9] and refers to a reduced or sudden onset of myoelectric silence in erector spinae muscles during full trunk flexion. Three mechanisms have been proposed for this phenomenon: (a) transfer of the moment force of weight to passive structures of the spine [7,9,10], (b) transfer of the extension moment force from the superficial muscles to deeper muscles [11,12] and finally, (c) reflexive mechanisms involving tension mechanoreceptors which are in ligaments and other viscoelastic structures which may trigger the FRP [13], although the last suggested mechanism is questionable for it could only explain the FRP [14].…”

Validation of a computer analysis to determine 3-D rotations and translations of the rib cage in upright posture from three 2-D digital images

“…These postures are also associated with asymmetrical muscle efforts and abnormal disc loads. Numerous EMG studies over the past four decades support this idea [2,4,5,11,17,28,29,30,31,34,38].…”