بایگانی برچسب برای: Biomechanics

Hand.and.Wrist.Anatomy.and.Biomechanics.[taliem.ir]

Hand and Wrist Anatomy and Biomechanics

In their biological taxonomy and status as “higher-level mammal—homo sapiens,” humans owe their distinction from primates to the miraculous structure of the hand. With its 19 degrees of freedom and its opposing thumb, the hand is a highly developed and complex grasping organ. This enables a wide range of movement combinations while simultaneously allowing adaptation of force, speed, and facileness. Moreover, the hand also features a highly specific sensory and tactile organ that human beings use to perceive and assess themselves and their surroundings. Owing to its capacity for making gestures, the hand plays an important role in interpersonal communication. In writing, music, and the visual arts, the hand acts as a means of expression for the human mind.229 These gross and fine motor skills, along with sensory capacities, enable humans to take care of and nourish their bodies, as well as communicate and shape their environment. With all these possibilities, the hand also plays a major role in self-expression and in developing the human mind, and significantly contributes to modifying human motor capacities.202 The mobilizing of this functionality requires exceptional interaction between the central control system and anatomical structures such as bones and joints, muscles and tendons, nerves and blood vessels, making the hand an extremely complex organ. The distal area of the lower arm consists of the distal radioulnar joint, the thumb and finger carpometacarpal (CMC) joints, the palm, and the fingers. In total, there are 27 bones with 36 articulations and 39 active muscles. In order for the hand to translate its wide range of fine and gross motor capabilities into its complex range of motion, these structures must all be coordinated.
Cardiovascular.Biomechanics.2017.Peter.[taliem.ir]

Cardiovascular Biomechanics

An understanding of the functioning of the cardiovascular system draws heavily on principles of fluid flow and of the elastic behaviour of tissues. Indeed, much of the cardiovascular system consists of a fluid (blood), flowing in elastic tubes (arteries and veins). This chapter will introduce basic principles of fluid flow and of solid mechanics. This area has developed over many centuries and Appendix 1 provides details of key scientists and their contribution. The concept of a fluid and a solid is familiar from everyday experience. However, from a physics point of view, the question arises as to what distinguishes a fluid from a solid? For a cubic volume element there are two types of forces which the volume element experiences (Fig. 1.1); a force perpendicular to a face and a force in the plane of a face. The forces perpendicular to the face cause compression of the material and this is the case whether the material is liquid or solid. The force parallel to the face is called a shear force. In a solid, the shear force is transmitted through the solid and the solid is deformed or sheared. The shear force is resisted by internal stresses within the solid and, provided the force is not too great, the solid reaches an equilibrium position. At the nano level the atoms and molecules in the solid retain contact with their neighbours. In the case of a fluid, a shear force results in continuous movement of the material. At the nano level the atoms and molecules in the fluid are not permanently connected to their neighbours and they are free to move. The key distinction between a fluid and a solid is that a solid can sustain a shear force whereas a fluid at rest does not.
Biomechanics.of.the.Human.Stomach.[taliem.ir]

Biomechanics of the Human Stomach

The human stomach is the organ of the gastrointestinal tract located in the left upper quadrant of the abdomen. Its prime role is to accommodate and digest food. The shape of the stomach is greatly modified by changes within itself and in the surrounding viscera such that no one form can be described as typical. The existing classification of anatomical variants of the human stomach is based on radiological data. Four main types are proposed: J-shaped, hourglass (fish-hook), steer-horn and cascade (Fig. 1.1). The chief configurations under normal physiological conditions are determined by the amount of the contents, the stage of the digestive process, the degree of development of the gastric musculature, the condition of the adjacent organs, the loops of the small and large intestines, body habitus, sex and age .The human stomach is more or less concave on its right side and convex on its left. The concave border is called the lesser curvature; the convex border, the greater curvature. The region that connects the lower esophagus with the upper part of the organ is called the cardia. The uppermost adjacent part to it is the fundus. The fundus adapts to the varying volume of ingested food and frequently contains a gas bubble, especially after a meal. The largest part of the stomach is known simply as the body (corpus). The antrum, the lowermost part, is usually funnel-shaped, with its narrow end connecting with the pyloric region. The latter empties into the duodenum, the upper division of the small intestine. The pyloric portion tends to curve to the right, slightly upward and backward.
Anatomy, Neuroanatomy, and Biomechanics of the Pelvis[taliem.ir]

Anatomy, Neuroanatomy, and Biomechanics of the Pelvis

The pelvis, both in the female and male forms, proves to be one of the most complex anatomic and physiologic regions within the human body. Nowhere else in the body can one fnd the multitude of muscles, tendons, nerves, ligaments, blood vessels, organs and physiological functions tightly knit into such a compact structure (Fig. 1.1). The pelvis is responsible for biped ambulation and support of the spinal column, sexuality, reproduction, storage and elimination of urinary and fecal waste, and indeed represents the human body’s foundation for both form and function. A thorough and proper understanding of all of these structures and functions and how they integrate into one seamless anatomic box is of paramount importance for the surgeon operating within the pelvis. In order to be successful, the surgeon who operates within the pelvis must be disciplined and prepared, as along with its complexity, comes a great deal of risk. Often times it is resourcefulness and creativity that allows successful surgical operations here, and this can only be made possible with an appropriate fund of knowledge. Perhaps one of the most fascinating aspects of the pelvis is its remarkable dynamic nature. From its embryological origins, through its fetal and adolescent development and into its adult maturation and fnally senescent changes in older age, it truly embodies the point that the only thing that is constant is change. In addition to its evolution along the broader span of one’s life span, it has only recently been truly recognized for its dynamic nature in daily activities.
Bone Toxicology[taliem.ir]

Bone Toxicology

This chapter is intended to provide the researcher with information to facilitate in the design, execution, and interpretation of studies with bone endpoints. The ability to use our knowledge of bone biology to ensure study conditions are optimal to detect an effect will be presented. This includes study design considerations and the utility of other models to explore the impact new compounds may have on the skeleton in the development of safe and effective drugs.