Assessment of the nervous system

Functions of nervous system The main function of nervous system is unification and regulation of different physiological processes. That means that nervous system unites, integrates and subordinates all the parts of human body and provides its connection with environment

Functions of nervous system The base of nervous system activity is reflex principle Reflex – is a reaction of our organism to various outside and inside effects. It is provided by nervous system

Reflex consists of: afferent part (which accepts information) central part (that keeps information) efferent part (that creates response) As a result we have a circle – like structure - receptor (primary information centre) – programme centre – executive apparatus

Reflex arch

Reflexes are divided into: simple and complex inborn and trained conditioned and unconditioned

Unconditioned reflexes: They are inborn ones They are phylogenetically old, that means they were formed in course of phylogenesis They are based on certain anatomic structures (segments of spinal cord or brain stem) They exist even without brain cortex influence They are inherited They can be regulated by brain cortex They are basis for the conditioned reflexes

Conditioned reflexes: They are the result of the individual experience and are formed during ontogenesis They are unstable, that means they need constant support They aren’t based on certain anatomic structures They are fixed in brain cortex There are such conditioned reflexes as speaking, writing, reading, calculation, practice

Unconditioned reflexes are divided into: Superficial and deep Simple and complex

Unconditioned reflexes are divided into: Proprioceptive (stretch, periosteal, joint) Exteroceptive (dermal, from mucose membrane) Interoceptive (from mucosa membrane of internal organs – for example urination in case of internal sphincter irritation)

Motor System

Motor system Provides conduction of nervous impulse from brain cortex to muscles. The way of this impulse is known as motorway or tractus corticomuscularis It consists of two neurons: Central – upper motor neuron (UMN) Peripheral – lower motor neuron (LMN)

Upper and lower extremities, neck, trunk and perineum muscles’ innervation The first (central) neuron (upper motor neuron) is called Corticospinal tract tractus corticospinalis The second (peripheral) neuron (lower motor neuron) is called Spinomuscular tract tractus spinomuscularis

Tractus corticomuscularis

Motor Homunculus

Upper Motor Neuron Corticospinal Tract

Lower Motor Neuron Effector: cell body: anterior horn axon: anterior root, spinal nerve axon terminal: neuromuscular junction Effector: skeletal muscle

Spinal nerve gives 4 branches: ramus anterior ( together they form plexus – cervical, brachial, lumbar and sacral) ramus posterior (it is spinal nerve, which innervates posterior trunk muscles) ramus meningeus ramus comunicante albi

Conclusions: The muscles of upper and lower extremities have unilateral cortical innervation from contralateral hemisphere The muscles of neck, trunk and pelvic organs have bilateral innervation from both hemispheres. In case of unilateral pathologic focus these structures do not suffer

Extremities, neck, trunk and perineum muscles’ innervation Neurons of С1-С4 anterior roots – innervate neck muscles С5-Th1 – muscles of upper extremities Th2-Th12 – muscles of trunk L1-S2 – muscles of legs S3 – S5 – muscles of perineum

Face, tongue and pharynx muscles innervation This way is called tractus corticomuscularis The first central neuron (upper motor neuron) is called tractus corticonuclearis (Corticobulbar Tract) The second peripheral neuron (lower motor neuron) is called tractus nucleomuscularis

Face, tongue and pharynx muscles innervation

We can make the following conclusions: The face muscles have bilateral cortex innervation except the mimic muscles and tongue muscles that have unilateral innervation from the opposite hemisphere The muscles of upper and lower extremities, lower mimic muscles and tongue muscles have unilateral cortical innervation All the other muscles (the muscles of neck, trunk, perineum, m. oculomotorial, m. masseter, pharyngeal and palatal muscles) have bilateral cortical innervation

UMN and LMN Syndrome - Paralysis

Paralysis Paralysis (plegia) - means the absence of active movements. It occurs in case of complete lesion of motor way (tractus corticomuscularis) Paresis occurs in case of incomplete lesion of motor way. That means disorders of active movements Clinically can be – hemi-, tetra-, mono-, tri- and paraparesis

Paralysis is divided into: Central (spastic) Peripheral (flaccid) Central or spastic paralysis is caused by the lesion of central neuron and its fibers (tr. corticospinalis or tr. corticonuclearis) Peripheral or flaccid paralysis is caused by the lesion of peripheral neuron (tractus spinomuscularis or tractus nucleomuscularis)

Features of central (spastic) paralysis are: Hyperreflexion of Deep Tendon reflexes Spasticity of skeletal muscles Pathologic reflexes. They are considered to be reliable signs of central paralysis It is a diffuse paralysis Protective reflexes (the reflexes of spinal automatism) Pathologic synkinesis is involuntary movements in paralysed extremity

Spastic hypertonus (Vernike-Mann posture)

Spastic hypertonus features: Tonus is increased in the group of flexors in upper extremities and in the group of extensors in lower extremities “Clasp – knife“ Phenomenon in course of evaluation tonus decreases

Spastic hypertonus in leg

Planter response Normal Pathologic

Features of peripheral paralysis 1. Areflexion or hyporeflexion 2. Atonia or hypotonia 3. Muscular atrophy 4. Fasciculation of muscles 5. It is limited paralysis 6. There is reaction of degeneration

Global wasting of the left arm in a post-traumatic brachial plexopathy

Muscular Atrophy

Wasting of the tongue

Note any of the following common gait disorders: Hemiplegic gait with one-sided weakness - a possible sign of cerebral stroke Spastic gait - a possible sign of cerebral palsy Ataxic gait - a possible indication of cerebellar dysfunction Festinating gait - a possible sign of Parkinson's disease

Bare test (upper)

Bare test (upper)

Bare test (lower)

Mandibular reflex

Palatal reflex

Biceps reflex

Triceps reflex

Carpo-radial reflex

Knee reflex

Ankle reflex