Variation of Neck Muscle Strength Along the Human Cervical Spine

Moment arms of the human neck muscles in flexion, bending and rotation

“…Our results also compare favourably with the moment arms computed by Vasavada et al (1998) using a musculoskeletal model of the neck (e.g., moment arms of splenius and semispinalis during axial rotation), although a number of their muscle moment arms are larger than those indicated by our measurements (e.g., the flexor moment arm of semispinalis and levator scapulae). We note here that some discrepancies may arise with models when broad muscles are represented as straight lines between the attachment sites (Deng and Goldsmith, 1987;Oi et al, 2004;Snijders et al, 1991). Muscle-wrapping models have been shown to lead to significantly different moment arms compared to straight-line models (Kruidhof and Pandy, 2006).…”

“…Neck muscle moment arms have been estimated by combining musculoskeletal computer modeling with data obtained from cadaver dissections and medical imaging techniques, such as magnetic resonance imaging (MRI) (Oi et al, 2004;Kruidhof and Pandy, 2006;Dugailly et al, 2005;Anderson et al, 2005;Vasavada et al, 1998). In modeling the neck musculature, however, broad muscles with extensive attachment sites are frequently represented by single lines of action.…”

Influence of pre-collision occupant parameters on injury outcome in a frontal collision

“…Additionally, to improve the biofidelity of the head-neck dynamics of the braced occupant model, the inter-vertebral joint stiffness functions defined in the model were adapted to account for muscular contractions in the cervical spine region. The bending moment stiffness due to maximum contraction expressed as a function of the flexion, extension and lateral bending angle for the C1 vertebraeoccipital condylar (C1-OC) joint and the C7-T1 vertebral joint were determined from the results reported by Oi et al (2004). Using the values of neck muscle load sharing as a function of muscle tension (Chancey, 2003), the ordinates of the bending moment-angle stiffness curves representative of maximum contraction were scaled to represent moment-angle stiffness characteristics for a relaxed (unaware) and braced (aware) occupant.…”

Effect of muscle wrapping on model estimates of neck muscle strength

“…Chancey et al (2003) used Van Ee's model to determine the neck muscle forces needed to hold the head upright against the downward pull of gravity with the muscles in a relaxed and tensed state. Oi et al (2004) developed a 9-segment, 23 degree-offreedom (dof) model from anthropometric data reported by Camacho et al (1997) and morphometric data published by Chancey et al (2003). The model was used to simulate maximum isometric contractions of the neck muscles during flexion, extension and lateral bending.…”

“…Three computer models built upon anthropometric data have been recently developed (Vasavada et al 1998, Van Ee et al 2000, Oi et al 2004. Vasavada et al (1998) developed a detailed 3D model of the cervical spine that included all of the intervertebral joints from the head down to the first thoracic vertebra.…”