Abstract
The medulla spinalis may be an elongated, tubular, nearly cylindrical a
part of the central system nervosa made from nerve tissue which occupies the
upper 2/3 of whole spinal canal, that means, extends from medulla within the brain stem or upper border of atlas to the Lumber region of the spinal column.
The average length is 45 cm and weight is about 30 GMS of adult candidate.
The physiology of medulla spinalis primarily within the transmission of
nerve signal from the motor area to the body, and from the afferent fibers of
the sensory neurons to the sensory cortex. It is helping to coordinate reflexes
and contains reflex arcs which will independently control reflexes. It's also
the situation of groups of spinal interneurons that structure the neural circuit
referred to as central pattern generators. These circuits are liable for
controlling motor instructions for rhythmic movements like walking.
STRUCTURE OF medulla spinalis
- The medulla of the spinal cord consists of gray and white nervous matter, in both of which there's a supporting framework of neuroglial.
- Medulla spinalis are protected by three layers of tissue or membranes called Meninges that surround the canal. The meninges made from by three layers, from outside to in word 1] dura 2] Arachnoid mater 3] meninx.
- Dura mater is that of the outer layer, and it forms a troublesome protective coating between the dura and surrounding bone of the vertebrae may be a space called epidural space.
- The Arachnoid mater is that the middle protective layer of meninges, the space between arachnoid mater and meninx is named subarachnoid mater, and it contains our spinal fluid [CSF].
- Inner layer is meninx, tightly connected with medulla spinalis.
- The Gray mater: It is situated centrally and has the shape of a fluted column which runs through its whole length. It is looking like letter 'H'. It is again divided into two parts, 1] Anterior horn cell, 2] Posterior horn cell.
- The anterior horn cell is directed forwards and somewhat laterally. Posterior horn cell is directed backwards and somewhat laterally. The extension of gray matter extends into the lateral white column, where they form a network termed the FORMATIO RETICULARIS.
- Anatomically, Gray matter consists of neuroglia, nerve cells and nerve fibers. In the whole, neuroglia are arranged within the sort of sponge like network, but within the gelatinous substance round the central canal and on the pieces of the posterior horn it's considerably condensed. The nature of nerve cells are multipolar and vary greatly in size and shape, but they'll be classified in three main groups consistent with their position. They're the cells of the anterior horn, the cells of the lateral horn and therefore the cells of the posterior horn.
- THE WHITE MATTER-- The substantia alba is found outside the gray matter and consists almost totally of MYELINATED MOTER and SENSORY axons. The Columns of substantia alba carry information either up or down the medulla spinalis, and consists chiefly of medullated nerve-fibers. The nerve fibers are arranged in three white columns, they're anterior, lateral and posterior.
- The medulla spinalis proper ends during a region called the CONUS MEDULLARIS, while the meninx continues as an extension called the FILUM TERMINALE, which anchors the medulla spinalis to the coccyx. Now cauda equina forms because the medulla spinalis stops growing long at about age four, albeit the spinal column continues to elongate until adulthood. This extends to sacral spinal nerves originating within the upper lumbar region.
Anatomically, there are 31 pairs of medullae spinalis nerve segments during a
human spinal cord:
1] 8 cervical segments forming 8 pairs of CERVICAL NERVES (C1 spinal
nerves exit the vertebral column between the foramen and therefore the C1
vertebra; C2 nerves exit in between the posterior part of the C1 vertebra and
the lamina of C2; C3–C8 spinal nerves undergo the IVF above their corresponding
cervical vertebrae, except the C8 pair which exit between the C7
and T1 vertebrae)
2] Twelve thoracic segments forming 12 pairs of THORACIC NERVES
3] Fifth lumbar segments forming 5 pairs of LUMBER NERVES
4] 5 sacral segments forming 5 pairs of SACRAL NERVES
5] 1 coccygeal segment
DEVELOPMENT OF THE medulla spinalis
Medulla spinalis is developed from a part of ectoderm during gestational
period.
The cavity of ectoderm within the region of the medulla spinalis becomes
narrowed down of a dorsiventral slit by the expansion of its lateral walls. At
the 5th week of development, a longitudinal groove termed as sulcus limitans
appears on the inner surface of the lateral wall. There are four stages of the
medulla spinalis that arises from the ectoderm.
Beural tube begins to develop, the notochord begins to secrete an
element referred to as sonic hedgehog and as a result the ground plate then
also begins to secrete, this probably induce the basal plate to develop motor
neurons, During maturation of the ectoderm, its lateral walls thicken and form
a longitudinal groove called sulcus limitans. The overlying ectoderm secretes
bone morphogenetic protein. It induces the roof plate to start to secrete
morphogenetic protein, which can induce the Alar plate to develop sensory
neurons. The Alar plate and the basal plate are separated by the sulcus limitans,
the ground plate also secretes netrins. Plexus choroideus tissue and therefore
the central canal of the caudal medulla spinalis is crammed with spinal fluid.
Now massive efferent tracts grow down from the brain into the lateral and
anterior parts of the medulla spinalis, intervening between the surface and
therefore the derivatives of the Alar and basal laminae. Further thickening of
those areas is produced by the passage into them of important ascending tracts,
whose constituent fibers arise from the cells derived from the Alar laminae.
BLOOD SUPPLY OF medulla spinalis
Anatomically, medulla spinalis is supplied by the anterior spinal artery and
therefore the right and left posterior spinal arteries.
Diagnosis of disease of spinal cord
- For the disease of medulla spinalis, these investigations are remarkable
- CSF fluid aspiration
- CT Scan of medulla spinalis
- MRI of medulla spinalis
HOMEOPATHIC MEDICINES ON medulla spinalis DISEASE
ACTEA RECIMOSA 30,200 as per patient's condition for older patient
CAUSTICUM 200 trauma and deviation
GELSEMIUM 200 any deviation
HYPERICUM 200 for injury
KALI PHOS 6X for injury
THUJA OCC 30 for tumor on medulla spinalis
NB: this text is for student and physician.
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