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Filum Terminale Externum
The filum terminale ("terminal thread") is a delicate strand of fibrous tissue, about 20 cm in length, proceeding downward from the apex of the conus medullaris. It is one of the modifications of pia mater. It gives longitudinal support to the spinal cord and consists of two parts: * The upper part, or filum terminale internum, is about 15 cm long and reaches as far as the lower border of the second sacral vertebra. It is continuous above with the pia mater and contained within a tubular sheath of the dura mater. In addition, it is surrounded by the nerves forming the cauda equina, from which it can be easily recognized by its bluish-white color. * The lower part, or filum terminale externum, closely adheres to the dura mater. It extends downward from the apex of the tubular sheath and is attached to the back of the first segment of the coccyx in a structure sometimes referred to as the ''coccygeal ligament''. The most inferior of the spinal nerves, the coccygeal nerve l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagittal
The sagittal plane (; also known as the longitudinal plane) is an anatomical plane that divides the body into right and left sections. It is perpendicular to the transverse and coronal planes. The plane may be in the center of the body and divide it into two equal parts ( mid-sagittal), or away from the midline and divide it into unequal parts (para-sagittal). The term ''sagittal'' was coined by Gerard of Cremona. Variations in terminology Examples of sagittal planes include: * The terms ''median plane'' or ''mid-sagittal plane'' are sometimes used to describe the sagittal plane running through the midline. This plane cuts the body into halves (assuming bilateral symmetry), passing through midline structures such as the navel and spine. It is one of the planes which, combined with the Umbilical plane, defines the four quadrants of the human abdomen. * The term ''parasagittal'' is used to describe any plane parallel or adjacent to a given sagittal plane. Specific named parasag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conus Medullaris
''Conus'' is a genus of predatory sea snails, or cone snails, marine gastropod mollusks in the family Conidae.Bouchet, P.; Gofas, S. (2015). Conus Linnaeus, 1758. In: MolluscaBase (2015). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=137813 on 2015-11-12 Prior to 2009, cone snail species had all traditionally been grouped into the single genus ''Conus''. However, ''Conus'' is now more precisely defined, and there are several other accepted genera of cone snails. For a list of the currently accepted genera, see Conidae. Description The thick shell of species in the genus ''Conus'' sensu stricto, is obconic, with the whorls enrolled upon themselves. The spire is short, smooth or tuberculated. The narrow aperture is elongated with parallel margins and is truncated at the base. The operculum is very small relative to the size of the shell. It is corneous, narrowly elongated, with an apical nucleus, and the impression ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nerve Fibres
An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action potentials away from the nerve cell body. The function of the axon is to transmit information to different neurons, muscles, and glands. In certain sensory neurons (pseudounipolar neurons), such as those for touch and warmth, the axons are called afferent nerve fibers and the electrical impulse travels along these from the periphery to the cell body and from the cell body to the spinal cord along another branch of the same axon. Axon dysfunction can be the cause of many inherited and acquired neurological disorders that affect both the peripheral and central neurons. Nerve fibers are classed into three typesgroup A nerve fibers, group B nerve fibers, and group C nerve fibers. Groups A and B are myelinated, and group C are unmyelinated. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coccygeal Nerve
A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into the corresponding cervical, thoracic, lumbar, sacral and coccygeal regions of the spine. There are eight pairs of cervical nerves, twelve pairs of thoracic nerves, five pairs of lumbar nerves, five pairs of sacral nerves, and one pair of coccygeal nerves. The spinal nerves are part of the peripheral nervous system. Structure Each spinal nerve is a mixed nerve, formed from the combination of nerve fibers from its dorsal and ventral roots. The dorsal root is the afferent sensory root and carries sensory information to the brain. The ventral root is the efferent motor root and carries motor information from the brain. The spinal nerve emerges from the spinal column through an opening (intervertebral foramen) between adjacent vertebrae. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomical Terms Of Location
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabularies for subdisciplines of anatom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cauda Equina
The cauda equina () is a bundle of spinal nerves and spinal nerve rootlets, consisting of the second through fifth lumbar nerve pairs, the first through fifth sacral nerve pairs, and the coccygeal nerve, all of which arise from the lumbar enlargement and the conus medullaris of the spinal cord. The cauda equina occupies the lumbar cistern, a subarachnoid space inferior to the conus medullaris. The nerves that compose the cauda equina innervate the pelvic organs and lower limbs to include motor innervation of the hips, knees, ankles, feet, internal anal sphincter and external anal sphincter. In addition, the cauda equina extends to sensory innervation of the perineum and, partially, parasympathetic innervation of the bladder. Structure In adulthood, the cauda equina is made of lumbosacral spinal nerve roots. Development In humans, the spinal cord stops growing in infancy and the end of the spinal cord is about the level of the third lumbar vertebra, or L3, at birth. Because the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dura Mater
In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. The other two meningeal layers are the arachnoid mater and the pia mater. It envelops the arachnoid mater, which is responsible for keeping in the cerebrospinal fluid. It is derived primarily from the neural crest cell population, with postnatal contributions of the paraxial mesoderm. Structure The dura mater has several functions and layers. The dura mater is a membrane that envelops the arachnoid mater. It surrounds and supports the dural sinuses (also called dural venous sinuses, cerebral sinuses, or cranial sinuses) and carries blood from the brain toward the heart. Cranial dura mater has two layers called ''lamellae'', a superficial layer (also called the periosteal layer), which serves as the skull's inner periosteum, called the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Cord
The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spinal cord, which contains cerebrospinal fluid. The brain and spinal cord together make up the central nervous system (CNS). In humans, the spinal cord begins at the occipital bone, passing through the foramen magnum and then enters the spinal canal at the beginning of the cervical vertebrae. The spinal cord extends down to between the first and second lumbar vertebrae, where it ends. The enclosing bony vertebral column protects the relatively shorter spinal cord. It is around long in adult men and around long in adult women. The diameter of the spinal cord ranges from in the cervical and lumbar regions to in the thoracic area. The spinal cord functions primarily in the transmission of nerve signals from the motor cortex to the body, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pia Mater
Pia mater ( or ),Entry "pia mater" in Merriam-Webster Online Dictionary ', retrieved 2012-07-28. often referred to as simply the pia, is the delicate innermost layer of the , the membranes surrounding the and . ''Pia mater'' is medieval Latin meaning "tender mother". The other two meningeal membr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Connective Tissue
Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tissue is found in between other tissues everywhere in the body, including the nervous system. The three meninges, membranes that envelop the brain and spinal cord are composed of connective tissue. Most types of connective tissue consists of three main components: elastic and collagen fibers, ground substance, and cells. Blood, and lymph are classed as specialized fluid connective tissues that do not contain fiber. All are immersed in the body water. The cells of connective tissue include fibroblasts, adipocytes, macrophages, mast cells and leucocytes. The term "connective tissue" (in German, ''Bindegewebe'') was introduced in 1830 by Johannes Peter Müller. The tissue was already recognized as a distinct class in the 18th century. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebral Canal
The spinal canal (or vertebral canal or spinal cavity) is the canal that contains the spinal cord within the vertebral column. The spinal canal is formed by the vertebrae through which the spinal cord passes. It is a process of the dorsal body cavity. This canal is enclosed within the foramen of the vertebrae. In the intervertebral spaces, the canal is protected by the ligamentum flavum posteriorly and the posterior longitudinal ligament anteriorly. Structure The outermost layer of the meninges, the dura mater, is closely associated with the arachnoid mater which in turn is loosely connected to the innermost layer, the pia mater. The meninges divide the spinal canal into the epidural space and the subarachnoid space. The pia mater is closely attached to the spinal cord. A subdural space is generally only present due to trauma and/or pathological situations. The subarachnoid space is filled with cerebrospinal fluid and contains the vessels that supply the spinal cord, namely th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coccyx
The coccyx ( : coccyges or coccyxes), commonly referred to as the tailbone, is the final segment of the vertebral column in all apes, and analogous structures in certain other mammals such as horses. In tailless primates (e.g. humans and other great apes) since ''Nacholapithecus'' (a Miocene hominoid),Nakatsukasa 2004, ''Acquisition of bipedalism'' (SeFig. 5entitled ''First coccygeal/caudal vertebra in short-tailed or tailless primates.''.) the coccyx is the remnant of a vestigial tail. In animals with bony tails, it is known as ''tailhead'' or ''dock'', in bird anatomy as ''tailfan''. It comprises three to five separate or fused coccygeal vertebrae below the sacrum, attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between the sacrum and the coccyx. Structure The coccyx is formed of three, four or five rudimentary vertebrae. It articulates superiorly with the sacrum. In each of the first three segments may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
