Article

The dynamic rotation of Langer's lines on facial expression

Faculty of Life Sciences, The University of Manchester, Manchester, England, United Kingdom
Journal of Plastic Reconstructive & Aesthetic Surgery (Impact Factor: 1.42). 04/2007; 60(4):393-9. DOI: 10.1016/j.bjps.2006.06.008
Source: PubMed

ABSTRACT

Karl Langer investigated directional variations in the mechanical and physical properties of skin [Gibson T. Editorial. Karl Langer (1819–1887) and his lines. Br J Plast Surg 1978;31:1–2]. He produced a series of diagrams depicting lines of cleavage in the skin [Langer K. On the anatomy and physiology of the skin I. The cleavability of the cutis. Br J Plast Surg 1978;31:3–8] and showed that the orientation of these lines coincided with the dominant axis of mechanical tension in the skin [Langer K. On the anatomy and physiology of the skin II. Skin tension. Br J Plast Surg 1978;31:93–106]. Previously these lines have been considered as a static feature. We set out to determine whether Langer's lines have a dynamic element and to define any rotation of the orientation of Langer's lines on the face with facial movement.

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    • "Several types of the main lines were distinguished. The static lines were described by Langer and correspond to the lines of maximum tension [42]. The dynamic lines were described by Kraissl and Borges [43]. "
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    ABSTRACT: The skin fulfills one of its most important functions, that is protection from mechanical injuries, due to the mechanism of reversible deformation of the structure. Human skin is a complex living material but in biomechanical tests it reveals its homogeneous nature. Biomechanical skin parameters change with time. Results of thickness measurements, where the skin was subjected to pressure, revealed that the Young's modulus increased linearly with age. The process of ageing is the reason why the skin becomes thinner, stiffer, less tense and less flexible. Skin tension measured during in vivo uniaxial load and the elasticity modulus are higher in children than in elderly adults. Furthermore, mean ultimate skin deformation before bursting is 75% for newborns and 60% for the elderly. Several types of the main lines were distinguished on the skin. The static lines, described by Langer, correspond to the lines of maximum tension, the Kraissl's lines correspond to the movements of the skin during muscle work, whereas the Borges lines are the relaxed skin tension lines. Biomechanical tests of the human skin help to quantify the effectiveness of dermatological products, detect skin diseases, schedule and plan surgical and dermatological interventions and treatments.
    Full-text · Article · Oct 2013 · Postepy Dermatologii I Alergologii
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    • "The rotation of the tension field during a facial expression may affect the appearance of a healed facial wound and should be taken into account when planning an incision (Bush et al. 2007). For this reason, the inclusion of the in vivo tension in the face model is an important and significant development and an improvement over previously proposed models, which do not include it. "
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    ABSTRACT: Computer models of the human face have the potential to be used as powerful tools in surgery simulation and animation development applications. While existing models accurately represent various anatomical features of the face, the representation of the skin and soft tissues is very simplified. A computer model of the face is proposed in which the skin is represented by an orthotropic hyperelastic constitutive model. The in vivo tension inherent in skin is also represented in the model. The model was tested by simulating several facial expressions by activating appropriate orofacial and jaw muscles. Previous experiments calculated the change in orientation of the long axis of elliptical wounds on patients' faces for wide opening of the mouth and an open-mouth smile (both 30(o)). These results were compared with the average change of maximum principal stress direction in the skin calculated in the face model for wide opening of the mouth (18(o)) and an open-mouth smile (25(o)). The displacements of landmarks on the face for four facial expressions were compared with experimental measurements in the literature. The corner of the mouth in the model experienced the largest displacement for each facial expression (∼11-14 mm). The simulated landmark displacements were within a standard deviation of the measured displacements. Increasing the skin stiffness and skin tension generally resulted in a reduction in landmark displacements upon facial expression.
    Full-text · Article · Aug 2013 · Computer Methods in Biomechanics and Biomedical Engineering
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    • "In the case of non-extension examination, Cox demonstrated that collagen fibers, a major dermal structural protein, run along Langer’s lines [5]. Recently, however, some papers demonstrated that the relationship between the direction of collagen fibers and that of Langer’s lines varies depending on the body site and motion [6,7]. Pierad et al. found thin elastic-like fibers, along the relaxed skin tension lines between collagen fibers [8]. "
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    ABSTRACT: We performed an in vivo three-dimensional analysis of anisotropic changes in the dermal birefringence of mechanically deformed human skin using polarization-sensitive optical coherence tomography (PS-OCT). The papillary-dermal birefringence of the forehead increased significantly when the skin was shrunk parallel to the body axis, and decreased significantly when the skin was shrunk perpendicular to the body axis. En-face images of the papillary-dermal birefringence revealed variations among individual subjects, and that both shrinking parallel to and stretching in perpendicular to the body axis promoted the formation of macro rope-like birefringent domains. We found that PS-OCT is useful for understanding anisotropic properties of collagen structure in the skin.
    Full-text · Article · Sep 2011 · Biomedical Optics Express
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