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Cervical Spine Muscle-Tendon Unit Length Differences Between Neutral and Forward Head Postures: Biomechanical Study
Saeed Khayatzadeh1, Olivia A Kalmanson2, Dale Schuit3
1Musculoskeletal Biomechanics Laboratory, Edward Hines Jr VA Hospital, Hines, Illinois.
Physical Therapy
|April 27, 2017
Summary
Forward head posture (FHP) alters cervical spine alignment, causing specific muscle length changes. This study quantifies these changes in cadavers, revealing shortened extensors and lengthened flexors.
Area of Science:
- Biomechanics
- Anatomy
- Human cadaveric studies
Background:
- Forward head posture (FHP) is linked to neck pain and reduced quality of life.
- Previous research qualitatively described muscle length changes in FHP.
- Quantifying these changes is crucial for understanding FHP's impact.
Purpose of the Study:
- To quantitatively assess muscle-tendon unit length alterations in human cadavers with simulated FHP.
- To establish a method for quantifying postural alignment and associated muscle length changes.
Main Methods:
- Utilized 13 fresh-frozen human cadaveric cervical spine specimens (Occiput-T1).
- Simulated increasing FHP severity while maintaining horizontal gaze.
- Created specimen-specific anatomic models using CT data and muscle attachment points to estimate length changes.
Main Results:
- FHP involved mid-lower cervical spine flexion and upper cervical spine extension.
- Cervical flexors and occipital extensors shortened; cervical extensors and occipital flexors lengthened.
- Rectus capitis posterior muscles showed greatest shortening; posterior muscles at C4-C6 showed greatest lengthening.
Conclusions:
- This study provides a novel quantitative method for assessing FHP-related muscle length changes.
- Findings align with existing qualitative descriptions of FHP's effects.
- Active muscle biomechanics were not included in this cadaveric model.
