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Hypaxial
In adult vertebrates, trunk muscles can be broadly divided into hypaxial muscles, which lie ventral to the horizontal septum of the vertebrae and epaxial muscles, which lie dorsal to the septum. Hypaxial muscles include some vertebral muscles, the diaphragm, the abdominal muscles, and all limb muscles. The serratus posterior inferior and serratus posterior superior are innervated by the ventral primary ramus and are hypaxial muscles. Epaxial muscles include other (dorsal) muscles associated with the vertebrae, ribs, and base of the skull. In humans, the erector spinae, the transversospinales (including the multifidus, semispinalis and rotatores), the splenius and suboccipital muscles are the only epaxial muscles. Hypaxial and epaxial muscles develop directly from somitic cells. Differentiation of hypaxial and epaxial muscles is postulated to have evolved as a new trait in vertebrate animals. Location The hypaxial muscles are located on the ventral side of the body, oft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somite
The somites (outdated term: primitive segments) are a set of bilaterally paired blocks of paraxial mesoderm that form in the embryonic stage of somitogenesis, along the head-to-tail axis in segmented animals. In vertebrates, somites subdivide into the dermatomes, myotomes, sclerotomes and syndetomes that give rise to the vertebrae of the vertebral column, rib cage, part of the occipital bone, skeletal muscle, cartilage, tendons, and skin (of the back). The word ''somite'' is sometimes also used in place of the word '' metamere''. In this definition, the somite is a homologously-paired structure in an animal body plan, such as is visible in annelids and arthropods. Development The mesoderm forms at the same time as the other two germ layers, the ectoderm and endoderm. The mesoderm at either side of the neural tube is called paraxial mesoderm. It is distinct from the mesoderm underneath the neural tube which is called the chordamesoderm that becomes the notochord. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cross Section Of Standard Fish
A cross is a geometrical figure consisting of two intersecting lines or bars, usually perpendicular to each other. The lines usually run vertically and horizontally. A cross of oblique lines, in the shape of the Latin letter X, is termed a saltire in heraldic terminology. The cross has been widely recognized as a symbol of Christianity from an early period.''Christianity: an introduction'' by Alister E. McGrath 2006 pages 321-323 However, the use of the cross as a religious symbol predates Christianity; in the ancient times it was a pagan religious symbol throughout Europe and western Asia. The effigy of a man hanging on a cross was set up in the fields to protect the crops. It often appeared in conjunction with the female-genital circle or oval, to signify the sacred marriage, as in Egyptian amule ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transversospinales
The transversospinales are a group of muscles of the human back. Their combined action is rotation and extension of the vertebral column. These muscles are small and have a poor mechanical advantage for contributing to motion. They include: * the three semispinalis muscles, spanning 4-6 vertebral segments ** semispinalis thoracis ** semispinalis cervicis ** semispinalis capitis * multifidus, spanning 2-4 vertebral segments * rotatores The rotatores muscles (rotatores spinae muscles) lie beneath the multifidus and are present in all spinal regions but are most prominent in the thoracic region; they are eleven in number on either side. Each muscle is small and somewhat quadrila ..., spanning 1-2 vertebral segments ** rotatores cervicis ** rotatores thoracis ** rotatores lumborum External links * Musculoskeletal Interventions: Techniques for Therapeutic exercise. Authors: Michael L. Voight, Barabara J. Hoogenboom, William E. Prentice. Muscles of the torso {{muscle-stu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventral Ramus
The ventral ramus (pl. ''rami'') (Latin for ''branch'') is the anterior division of a spinal nerve. The ventral rami supply the antero-lateral parts of the trunk and the limbs. They are mainly larger than the dorsal rami. Shortly after a spinal nerve exits the intervertebral foramen, it branches into the dorsal ramus, the ventral ramus, and the ramus communicans. Each of these three structures carries both sensory and motor information. Each spinal nerve carries both sensory and motor information, via efferent and afferent nerve fibers - ultimately via the motor cortex in the frontal lobe and to somatosensory cortex in the parietal lobe - but also through the phenomenon of reflex. Spinal nerves are referred to as "mixed nerves". In the thoracic region they remain distinct from each other and each innervates a narrow strip of muscle and skin along the sides, chest, ribs, and abdominal wall. These rami are called the intercostal nerves. In regions other than the thoracic, vent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Innervated
A nerve is an enclosed, cable-like bundle of nerve fibers (called axons) in the peripheral nervous system. A nerve transmits electrical impulses. It is the basic unit of the peripheral nervous system. A nerve provides a common pathway for the electrochemical nerve impulses called action potentials that are transmitted along each of the axons to peripheral organs or, in the case of sensory nerves, from the periphery back to the central nervous system. Each axon, within the nerve, is an extension of an individual neuron, along with other supportive cells such as some Schwann cells that coat the axons in myelin. Within a nerve, each axon is surrounded by a layer of connective tissue called the endoneurium. The axons are bundled together into groups called fascicles, and each fascicle is wrapped in a layer of connective tissue called the perineurium. Finally, the entire nerve is wrapped in a layer of connective tissue called the epineurium. Nerve cells (often called neurons) are f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suboccipital Muscles
The suboccipital muscles are a group of muscles defined by their location to the occiput. Suboccipital muscles are located below the occipital bone. These are four paired muscles on the underside of the occipital bone; the two straight muscles (''rectus'') and the two oblique muscles (''obliquus''). The muscles are named *'' Rectus capitis posterior major'' goes from the spinous process of the axis (C2) to the occipital bone. *'' Rectus capitis posterior minor'' goes from the middle of the posterior arch of the atlas to the occipit. *'' Obliquus capitis superior'' goes from the transverse process of the atlas to the occiput. *'' Obliquus capitis inferior'' goes from the spine of the axis vertebra to the transverse process of the atlas. They are innervated by the suboccipital nerve. Additional images File:Suboccipital muscles - animation01.gif, Position of suboccipital muscles. Animation. File:Suboccipital muscles - animation04.gif, Close up. Seen from below. File:Suboccipita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Splenius Muscles
The splenius muscles are: *Splenius capitis muscle *Splenius cervicis muscle Their origins are in the upper thoracic and lower cervical spinous process The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...es. Their actions are to extend and ipsilaterally rotate the head and neck. References Muscles of the torso {{Muscle-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotatores Muscles
The rotatores muscles (rotatores spinae muscles) lie beneath the multifidus and are present in all spinal regions but are most prominent in the thoracic region; they are eleven in number on either side. Each muscle is small and somewhat quadrilateral in form; it arises from the superior and posterior part of the transverse process, and is inserted into the lower border and lateral surface of the lamina of the vertebra above, the fibers extending as far as the root of the spinous process. The first thoracic rotatores muscle is found between the first and second thoracic vertebrae In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebrae and they are intermediate in size between the cervical ...; the last, between the eleventh and twelfth. Sometimes the number of these muscles is diminished by the absence of one or more from the upper or lower en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semispinalis Muscle
The semispinalis muscles are a group of three muscles belonging to the transversospinales. These are the semispinalis capitis, the semispinalis cervicis and the semispinalis thoracis. The semispinalis capitis (''complexus'') is situated at the upper and back part of the neck, deep to the splenius, and medial to the longissimus cervicis and longissimus capitis. It arises by a series of tendons from the tips of the transverse processes of the upper six or seven thoracic and the seventh cervical vertebrae, and from the articular processes of the three cervical vertebrae above this ( C4-C6). The tendons, uniting, form a broad muscle, which passes upward, and is inserted between the superior and inferior nuchal lines of the occipital bone. It lies deep to the trapezius muscle and can be palpated as a firm round muscle mass just lateral to the cervical spinous processes. The semispinalis cervicis (or ''semispinalis colli''), arises by a series of tendinous and fleshy fibers from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multifidus
The multifidus (multifidus spinae : ''pl. multifidi'' ) muscle consists of a number of fleshy and tendinous fasciculi, which fill up the groove on either side of the spinous processes of the vertebrae, from the sacrum to the axis. While very thin, the multifidus muscle plays an important role in stabilizing the joints within the spine. The multifidus is one of the transversospinales. Located just superficially to the spine itself, the multifidus muscle spans three joint segments and works to stabilize these joints at each level. The stiffness and stability makes each vertebra work more effectively, and reduces the degeneration of the joint structures caused by friction from normal physical activity. These fasciculi arise: * ''in the sacral region:'' from the back of the sacrum, as low as the fourth sacral foramen, from the aponeurosis of origin of the sacrospinalis, from the medial surface of the posterior superior iliac spine, and from the posterior sacroiliac ligaments. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erector Spinae
The erector spinae ( ) or spinal erectors is a set of muscles that straighten and rotate the back. The spinal erectors work together with the glutes (gluteus maximus, gluteus medius and gluteus minimus) to maintain stable posture standing or sitting. Structure The erector spinae is not just one muscle, but a group of muscles and tendons which run more or less the length of the spine on the left and the right, from the sacrum, or sacral region, and hips to the base of the skull. They are also known as the sacrospinalis group of muscles. These muscles lie on either side of the spinous processes of the vertebrae and extend throughout the lumbar, thoracic, and cervical regions. The erector spinae is covered in the lumbar and thoracic regions by the thoracolumbar fascia, and in the cervical region by the nuchal ligament. This large muscular and tendinous mass varies in size and structure at different parts of the vertebral column. In the sacral region, it is narrow and pointed, and at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrate
Vertebrates () comprise all animal taxon, taxa within the subphylum Vertebrata () (chordates with vertebral column, backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described. Vertebrates comprise such groups as the following: * Agnatha, jawless fish, which include hagfish and lampreys * Gnathostomata, jawed vertebrates, which include: ** Chondrichthyes, cartilaginous fish (sharks, Batoidea, rays, and Chimaeriformes, ratfish) ** Euteleostomi, bony vertebrates, which include: *** Actinopterygii, ray-fins (the majority of living Osteichthyes, bony fish) *** lobe-fins, which include: **** coelacanths and lungfish **** tetrapods (limbed vertebrates) Extant taxon, Extant vertebrates range in size from the frog species ''Paedophryne amauensis'', at as little as , to the blue whale, at up to . Vertebrates make up less than five percent of all described a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
