El Paso, TX. Chiropractor, Dr. Alexander Jimenez continues the discussion on the anatomy of nerve fibers, receptors, spinal tracts and brain pathway/s. As the spinal nerve nears the spinal cord, it splits into the dorsal and ventral roots. The dorsal root only contains the axons of sensory neurons. While the ventral roots contain only the axons of motor neurons. Some of the branches synapse with local neurons in the dorsal root ganglion, posterior (dorsal) horn, and even the anterior (ventral) horn, at the spine where they enter.
Other branches travel short distances up or down the spine to interact with neurons at other levels of the spinal cord. A branch can also turn into the posterior (dorsal) column white matter to connect with the brain. Spinal nerve systems that connect to the brain are contralateral, in that the right side of the body is connected to the left side of the brain and the left side of the body is connected to the right side of the brain.
Cranial nerves convey specific sense information from the head and neck directly to the brain. Whereas spinal information is contralateral, cranial nerve systems are for the most part ipsilateral, meaning that a cranial nerve on the right side of the head is connected to the right side of the brain. Some cranial nerves contain only sensory axons. Other cranial nerves have both sensory and motor axons, including the trigeminal, facial and glossopharyngeal. General senses of somatosensation for the face travel through the trigeminal system.
“As might be expected from the types of afferents contained in the posterior columns, this pathway carries information important for the conscious appreciation of touch, pressure, and vibration and of joint position and movement. However, because input from cutaneous receptors also reaches the cortex by other routes, damage to the posterior columns causes impairment, but not abolition, of tactile perception. Complex discrimination tasks are more severely affected than is the simple detection of stimuli. Other functions, such as proprioception and kinesthesia, are classically considered to be totally lost after posterior column destruction. The result is a distinctive type of ataxia (incoordination of movement); the brain is unable to direct motor activity properly without sensory feedback about the current position of parts of the body. This ataxia is particularly pronounced when the patient’s eyes are closed, preventing visual compensation.”
Given the role of the posterior column, the patient should be screened for any abnormalities regarding their sense of fine touch, vibration, barognosis, graphesthesia, stereognosis, kinaesthesia, two-point discrimination and conscious proprioception:
Given the role of the spinothalamic tract, the patient should be screened for any abnormalities regarding their sense of touch, pain, temperature, and pressure sensation.
Screening for such abnormalities is commonly done using gentle pin pricks and cotton wool, to contrast between sharp and soft, following cutaneous sensory nerve root distributions. Hot and cold discrimination can be ascertained using the cold metal arm of a tuning fork, and a warm palm or heated object.
The spinal cord is an important source of information used by the cerebellum in the coordination of movement. This information reaches the cerebellar cortex and nuclei both directly, by way of spinocerebellar tracts, and indirectly, by way of relays in brainstem nuclei. A number of spinocerebellar tracts have been described, some representing the upper extremity and others the lower extremity. Only three have been well characterized.
By RYAN CEDERMARK, DC DACNB RN BSN MSN
https://www.youtube.com/watch?v=TiMcbg7W92o Dr. Alex Jimenez brings you part two of the Functional Medicine episodes where Medical… Read More
https://www.youtube.com/watch?v=nj3H5n77z-I In this Functional Medicine podcast, Dr. Alex Jimenez, Master Nutritionist Ana Paola Rodriguez Arciniega,… Read More
https://www.youtube.com/watch?v=EEJes9pLbk8 In this edition of the Functional Medicine Podcasts Dr, Jimenez, Kenna Lee Vaughn Chief… Read More
https://www.youtube.com/watch?v=Q_WNpts5WnU Today Dr. Jimenez, Kenna Lee Vaughn and Master Nutritionist Present Insights into Fibromyalgia Migrains… Read More
https://www.youtube.com/watch?v=cT9eXwd1ZNI Read More
https://www.youtube.com/watch?v=LZelMl-1f_M Today Dr. Marius Ruja & Dr. Alex Jimenez will discuss Metabolic Syndrome and Associated… Read More