The somatic nervous system (SNS), also known as voluntary nervous system, is a part of the peripheral nervous system (PNS) that links brain and spinal cord to skeletal muscles under conscious control, as well as to sensory receptors in the skin. The other part complementary to the somatic nervous system is the autonomic nervous system (ANS).
The plantar reflex is a reflex elicited when the sole of the foot is stimulated with a blunt instrument. The reflex can take one of two forms. In healthy adults, the plantar reflex causes a downward response of the hallux (flexion).
The nucleus ambiguus is a group of large motor neurons, situated deep in the medullary part of the reticular formation named by Jacob Clarke. The nucleus ambiguus contains the cell bodies of neurons that innervate the muscles of the soft palate, pharynx, and larynx which are associated with speech and swallowing. As well as motor neurons, the nucleus ambiguus contains preganglionic parasympathetic neurons which innervate postganglionic parasympathetic neurons in the heart.
The medial longitudinal fasciculus (MLF) is a prominent bundle of nerve fibres which pass within the ventral/anterior portion of periaqueductal gray of the mesencephalon (midbrain). It contains the interstitial nucleus of Cajal, responsible for oculomotor control, head posture, and vertical eye movement.
Joseph Jules François Félix Babinski was a French-Polish professor of neurology. He is best known for his 1896 description of the Babinski sign, a pathological plantar reflex indicative of corticospinal tract damage.
An upper motor neuron lesion Is an injury or abnormality that occurs in the neural pathway above the anterior horn cell of the spinal cord or motor nuclei of the cranial nerves. Conversely, a lower motor neuron lesion affects nerve fibers traveling from the anterior horn of the spinal cord or the cranial motor nuclei to the relevant muscle(s).
The Edinger–Westphal nucleus also called the accessory or visceral oculomotor nerve, is one of the two nuclei of the oculomotor nerve located in the midbrain. It receives afferents from both pretectal nuclei. It contains parasympathetic pre-ganglionic neuron cell bodies that synapse in the ciliary ganglion. It contributes the autonomic, parasympathetic component to the oculomotor nerve, ultimately providing innervation to the iris sphincter muscle and ciliary muscle to mediate the pupillary light reflex and accommodation, respectively.
The trochlear nucleus is the motor nucleus of the trochlear nerve. It is located in the medial midbrain.
The facial colliculus is an elevated area located in the pontine tegmentum, within the floor of the fourth ventricle. It is formed by fibres from the facial motor nucleus looping over the abducens nucleus. The facial colliculus is an essential landmark of the rhomboid fossa.
The lateral corticospinal tract is the largest part of the corticospinal tract. It extends throughout the entire length of the spinal cord, and on transverse section appears as an oval area in front of the posterior column and medial to the posterior spinocerebellar tract.
The ventral posterior nucleus is the somatosensory relay nucleus in thalamus of the brain.
Hoffmann's reflex is a neurological examination finding elicited by a reflex test which can help verify the presence or absence of issues arising from the corticospinal tract. It is named after neurologist Johann Hoffmann. Usually considered a pathological reflex in a clinical setting, the Hoffmann's reflex has also been used as a measure of spinal reflex processing (adaptation) in response to exercise training.
Stransky's sign is a clinical sign in which vigorous abduction followed by the sudden release of the little toe causes an extensor plantar reflex. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-like responses.
Gonda's sign is a clinical sign in which flexing and then suddenly releasing the fourth toe elicits an extensor plantar reflex. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-like responses. It is named after the Ukrainian neuropsychiatrist Viktor Gonda (1889–1959), who discovered it sometime in the mid-1930s while he was practicing in the United States. Gonda was one of the strong proponents of electrotherapy to cure psychiatric illnesses.
Throckmorton's reflex is a clinical sign in which pressure over the dorsal side of the metatarsophalangeal joint of the big toe elicits a plantar reflex. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-like responses.
Rossolimo's sign is a clinical sign in which percussion of the tips of the toes causes an exaggerated flexion of the toes. It is found in patients with pyramidal tract lesions, and is one of a number of Babinski-like responses. The sign is named after Grigory Ivanovich Rossolimo.
The applause sign is a behavioural indicator, relevant to neurodegenerative conditions, characterised by a patient’s inability to execute the same number of hand claps as demonstrated by an examiner.
Babinski–Nageotte syndrome is an alternating brainstem syndrome. It occurs when there is damage to the dorsolateral or posterior lateral medulla oblongata, likely syphilitic in origin. Hence it is also called the alternating medulla oblongata syndrome.
The visual pathway consists of structures that carry visual information from the retina to the brain. Lesions in that pathway cause a variety of visual field defects. In the visual system of human eye, the visual information processed by retinal photoreceptor cells travel in the following way:
Retina→Optic nerve→Optic chiasma →Optic tract→Lateral geniculate body→Optic radiation→Primary visual cortex
Posterior tibial tendon dysfunction is the dysfunction of the posterior tibial tendon. It is a progressive disease that has four stages and is the most common cause of adult flatfoot.
