Deep Layers Of Intrinsic Back Muscles
Deep Layers Of Intrinsic Back Muscles

A. The transversospinalis muscle group (major deep layer— purple ) is deep to the erector spinae. The short lumbar rib is articulating with the transverse process of L1 vertebra. This common variation does not usually cause a problem; however, those unfamiliar with its possible presence may think it is a fractured transverse process. B. Deeper […]

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Deep Layer Of Intrinsic Back Muscles (transversospinalis Muscles)
Deep Layer Of Intrinsic Back Muscles (transversospinalis Muscles)

A. Multifidus, levator costarum, intertransversarii, and thoracolumbar fascia. B. Rotatores and levatores costarum. DEEP LAYER Deep to the erector spinae is an obliquely disposed group of much shorter muscles, the transversospinalis muscle group consisting of the semispinalis, multifidus, and rotatores. These muscles originate from transverse processes of vertebrae and pass to spinous processes of more […]

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Types Of Muscle (muscle Tissue)
Types Of Muscle (muscle Tissue)

Types of Muscle (Muscle Tissue) Muscle cells, often called muscle fibers because they are long and narrow when relaxed, are specialized contractile cells. They are organized into tissues that move body parts or temporarily alter the shape (reduce the circumference of all or part) of internal organs. Associated connective tissue conveys nerve fibers and capillaries to the […]

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Architecture And Shape Of Skeletal Muscles
Architecture And Shape Of Skeletal Muscles

The architecture and shape of a skeletal muscle depend on the arrangement of its fibers. Skeletal Muscles FORM, FEATURES, AND NAMING OF MUSCLES All skeletal muscles, commonly referred to simply as “muscles,” have fleshy, reddish, contractile portions (one or more heads or bellies) composed of skeletal striated muscle. Some muscles are fleshy throughout, but most […]

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Superficial Skeletal Muscles
Superficial Skeletal Muscles

Most of the muscles shown move the skeleton for locomotion, but some muscles—especially those of the head—move other structures (e.g., the eyeballs, scalp, eyelids, skin of face, and tongue). The sheath of the left rectus abdominis, formed by aponeuroses of the flat abdominal muscles, has been removed to reveal the muscle. Retinacula are deep fascial […]

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Isometric And Isotonic Contractions
Isometric And Isotonic Contractions

Isometric contraction (A) sustains the position of a joint without producing movement. Concentric (B) and eccentric (C) contractions are isotonic contractions in which the muscle changes length: concentric contractions by shortening and eccentric contractions by actively controlled lengthening (relaxation). CONTRACTION OF MUSCLES Skeletal muscles function by contracting; they pull and never push. However, certain phenomena—such […]

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Structure Of Skeletal Muscle And Motor Units
Structure Of Skeletal Muscle And Motor Units

A. A motor unit consists of a single motor neuron and the muscle fibers innervated by it. B. Epimysium is the same as investing fascia. Actin (thin) and myosin (thick) filaments are contractile elements in the muscle fibers. Whereas the structural unit of a muscle is a skeletal striated muscle fiber, the functional unit of a muscle is a motor […]

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