1- CEREBRUM Two (2) cerebral hemispheres. Connected to:1. Each other by CORPUS CALLOSUM.2. Brain stem by CEREBRAL PEDUNCLES.- Outer gray matter (cerebral cortex) contains certain areas with specific functions.- Inner white matter composed of nerve fibers conducting impulses TO & FROM cerebral cortex
EACH cerebral hemisphere divided into :FOUR ( 4 ) LOBES:1. Frontal2. Parietal3. Temporal4. Occipital
2- Brain stemFormed of : 1- Midbrain 2- Pons 3- MedullaConnected to: 1. Cerebral hemisphere by cerebral peduncles2. Cerbellum by cerebellar peduncles
BRAIN STEM contains motor nuclei of cranialnerves:• 3 & 4 in MIDBRAIN• 5, 6 &7 in PONS• 9, 10, 11 & 12 in MEDULLAN.B. 1, 2 & 8are sensory nerves have nomotor nuclei
CLASSIFICATION OF CRANIAL NERVES• SENSORY : contain only sensory fibers 1- Olfactory 2- Optic 8- Vestibulocochlear• MOTOR : contain only motor fibers 3- Oculomotor 4- Trochlear 6- Abducent 11- Accessory 12- Hypoglossal• MIXED : contain both sensory and motor fibers 5- Trigeminal 7- Facial 9- Glossopharyngeal 10- Vagus
Sensory cranial nervesN. Name Function Assessment1 Olfactory Smell Examination of smell2 Optic Vision Acuity, field & fundus8 Vestibular Equilibrium Caloric and part rotational chair Cochlear Hearing Watch test, part Weber test
Motor cranial nervesN. Name Function Assessment3 Oculomotor Motor to superior, inferior and Ptosis, pupil, eye medial recti; inferior oblique & movements & levator palpebrae superioris squint Parasympathetic to sphincter papillae and ciliary muscle4 Trochlear Motor to superior oblique Look to opposite shoulder6 Abducent Motor to lateral rectus Lateral eye movement11 Accessory Motor to sternocleidomastoid Elevaton of and trapezius shoulders and neck rotation12 Hypoglossal Motor to muscles of tongue Tongue movements
Mixed cranial nervesN. Name Function Assessment5 Trigeminal Muscles of Face sensations & mastication & power of muscles of sensations of face mastication7 Facial Muscles of facial Muscles of facial expression & taste expression & taste sensation in ant. 1/3 sensation in ant. 1/3 of of tongue tongue10 Vagus Sensation and Palatal and pharyngeal movements of reflexes & movements of Larynx, pharynx, uvula thoracic and abdominal organs9 Glossopharyngeal Taste in post 2/3 of Taste & general tongue & gen. sensation and sensation pharyngeal reflex
3- CEREBELLUM• Behind the brain stem• Formed of : * Medline vermis * Two cerebellar hemispheres• Composed of : Outer grey matter and inner white matter
CEREBELLAR PEDUNCLES MB Pons C MO Superior peduncle connects cerebellum with MIDBRAIN. Middle peduncle connects cerebellum with PONS. Inferior peduncle connects cerebellum with MEDULLAOBLONGATA
CEREBELLAR HEMISPHERES AND VERMISLeft rightHemisphere hemisphere VERMIS Cerebellar Hemispheres are the two bilateral structures. Vermis is the unpaired midline structure between the two hemispheres.
UPPER MOTOR NEURON (pyramidal system)* Originates in motor area 4 & premotor area 6* Terminates at the anterior horn cells (AHCs)of the different levels of the spinal cord.* It supplies the opposite side of the body.
LOWER MOTOR NEURON• Formed of AHCs & Peripheral motor nerves (which transmit the motor impulses to the voluntry muscles).
EXTRA PYRAMIDAL SYSTEM• Originates from centers at various levels of CNS mainly the BASAL GANGLIA.• It controls the opposite side of the body. CEREBELLAR SYSTEM• Composed of Neo, Archi & Paleo- cerebellum.• It co-ordinates the movements of the same side of the body.
UMNL LMNLTone Increased, with Decreased ‘clasp knife’ qualityClonus Present AbsentFasciculations Absent PresentMuscle Wasting Absent, but disuse Present (within 2-3 atrophy eventually weeks) resultsTendon Reflexes Increased. Extensor Decreased or plantar reflexes. absent. Flexor plantar reflexes.Distribution Whole limbs, with Specific muscle more weakness in groups affected (e.g. the upper limb in the distribution of extensors and lower a spinal segment, or limb flexors just the proximal muscles, etc.)