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Pennation Angle
Muscle architecture is the physical arrangement of muscle fibers at the macroscopic level that determines a muscle’s mechanical function. There are several different muscle architecture types including: parallel, pennate and hydrostats. Force production and gearing vary depending on the different muscle parameters such as muscle length, fiber length, pennation angle, and the physiological cross-sectional area (PCSA). Architecture types Parallel and pennate (also known as pinnate) are two main types of muscle architecture. A third subcategory, muscular hydrostats, can also be considered. Architecture type is determined by the direction in which the muscle fibers are oriented relative to the force-generating axis. The force produced by a given muscle is proportional to the cross-sectional area, or the number of parallel sarcomeres present. Parallel The parallel muscle architecture is found in muscles where the fibers are parallel to the force-generating axis. These muscles are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skeletal Muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscle tissue, and are often known as muscle fibers. The muscle tissue of a skeletal muscle is striated – having a striped appearance due to the arrangement of the sarcomeres. Skeletal muscles are voluntary muscles under the control of the somatic nervous system. The other types of muscle are cardiac muscle which is also striated and smooth muscle which is non-striated; both of these types of muscle tissue are classified as involuntary, or, under the control of the autonomic nervous system. A skeletal muscle contains multiple muscle fascicle, fascicles – bundles of muscle fibers. Each individual fiber, and each muscle is surrounded by a type of connective tissue layer of fascia. Muscle fibers are formed from the cell fusion, fusion of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biceps
The biceps or biceps brachii ( la, musculus biceps brachii, "two-headed muscle of the arm") is a large muscle that lies on the front of the upper arm between the shoulder and the elbow. Both heads of the muscle arise on the scapula and join to form a single muscle belly which is attached to the upper forearm. While the biceps crosses both the shoulder and elbow joints, its main function is at the elbow where it flexes the forearm and supinates the forearm. Both these movements are used when opening a bottle with a corkscrew: first biceps screws in the cork (supination), then it pulls the cork out (flexion). Structure The biceps is one of three muscles in the anterior compartment of the upper arm, along with the brachialis muscle and the coracobrachialis muscle, with which the biceps shares a nerve supply. The biceps muscle has two heads, the short head and the long head, distinguished according to their origin at the coracoid process and supraglenoid tubercle of the sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deltoid Muscle
The deltoid muscle is the muscle forming the rounded contour of the human shoulder. It is also known as the 'common shoulder muscle', particularly in other animals such as the domestic cat. Anatomically, the deltoid muscle appears to be made up of three distinct sets of muscle fibers, namely the # anterior or clavicular part (pars clavicularis) # posterior or scapular part (pars scapularis) # intermediate or acromial part (pars acromialis) However, electromyography suggests that it consists of at least seven groups that can be independently coordinated by the nervous system. It was previously called the deltoideus (plural ''deltoidei'') and the name is still used by some anatomists. It is called so because it is in the shape of the Greek capital letter delta (Δ). Deltoid is also further shortened in slang as "delt". A study of 30 shoulders revealed an average mass of in humans, ranging from to . Structure Previous studies showed that the insertions of the tendons of the delto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rectus Femoris
The rectus femoris muscle is one of the four quadriceps muscles of the human body. The others are the vastus medialis, the vastus intermedius (deep to the rectus femoris), and the vastus lateralis. All four parts of the quadriceps muscle attach to the patella (knee cap) by the quadriceps tendon. The rectus femoris is situated in the middle of the front of the thigh; it is fusiform in shape, and its superficial fibers are arranged in a bipenniform manner, the deep fibers running straight ( la, rectus) down to the deep aponeurosis. Its functions are to flex the thigh at the hip joint and to extend the leg at the knee joint. Structure It arises by two tendons: one, the anterior or straight, from the anterior inferior iliac spine; the other, the posterior or reflected, from a groove above the rim of the acetabulum. The two unite at an acute angle and spread into an aponeurosis that is prolonged downward on the anterior surface of the muscle, and from this the muscular fibers arise. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
