the basics neuroanatomy just the basics brain and spinal … · neuroanatomy just the basics ......
TRANSCRIPT
Slide 1
NeuroanatomyJust the basics
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 2 The Basics
• CNS – brain and spinal cord
• PNS – Nerves and ganglia outside of the brain and spinal cord. Connects the CNS to the limbs and organs.
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 3 CNS
The Brain consists of:
• Frontal lobe
• Temporal lobe
•Parietal lobe
•Occipital lobe
•Cerebellum
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 4 CNS
•Brain stem
Pons
Midbrain
Medulla oblongata
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 5 Vascular Supply
•Circle of Willis – a circle of arteries surrounding the base of the brain; supplies blood to the brain and
surrounding structures
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 6 Vascular Supply
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 7 Circle of Willis –with detail
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 8 Circle of Willis
• The circle of Willis is formed when the internal carotid artery(ICA) enters the cranial cavity bilaterally and divides into the anterior cerebral artery (ACA) and middle cerebral artery(MCA). The anterior cerebral arteries are then united by an anterior communicating (ACOM) artery. These connections form the anterior half (anterior circulation) of the circle of Willis. Posteriorly, the basilar artery, formed by the left and right vertebral arteries, branches into a left and right posterior cerebral artery (PCA), forming the posterior circulation. The PCAs complete the circle of Willis by joining the internal carotid system anteriorly via the posterior communicating (PCOM) arteries.
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 9 Occlusions
• Anterior cerebral artery – supplies medial portions of the frontal and parietal lobes.
- weakness or paralysis of contralateral side, incontinence, personality changes, mutism (conscious unresponsiveness)
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 10 Occlusions
• Middle cerebral artery - supplies the lateral portion of the cerebral cortex, temporal lobes
- Contralateral hemiplegia and sensory impairment.
- Damage to dominate hemisphere (usually the left) includes global, Broca’s or Wernicke’s aphasia
- Damage to non-dominate hemisphere causes contralateral neglect
- Deviation conjugee – gaze preference to the side of the lesion, especially in acute phase.
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 11 Occlusions
• Posterior cerebral artery – supplies the occipital lobe
- Thalamic pain syndrome, abnormal sensation of pain, temperature, touch and proprioception
- Cortical blindness – eye is normal but there is full or partial vision loss.
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 12
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 13
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 14 The spinal cord
• The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain (the medulla oblongata specifically).
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 15 Spinal Cord
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 16 Spinal Cord Cont.
• Where does it end?
(Page 187 – Mansfield, Neuman)
• What is the implication if there is damage at or below this region??
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 17 Spinal Cord Cross Section
Sensory = afferent Motor = efferent
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 18 Motor and sensory tracts
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 19 Ascending Tracts (sensory)• Spinothalamic tracts- Lateral : pain and temperature
- Anterior: light touch and pressure
• 1st Order Neuron – arise from the sensory receptors of the body and enter the tip of the posterior gray horn
• 2nd Order Neuron –cross to the opposite side and ascend to brainstem in the lateral or anterior tract then end at thalmus.
• 3rd Order Neuron – arise from the thalmus, pass through the internal capsule, enter the postcentralgyrus (sensory cortex of the cerebrum)
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 20 Lateral Spinothalamic Tract
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 21 Ascending tracts (continued)
• Dorsal column tracts: Fasciculus cuneatus Fasciculus gracilis
•deep touch and pressure
•Proprioception
•Vibration sensation
• Spinocerebellar tract: posture and coordination
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 22 Dorsal Tracts
• 1st Order Neuron – arise from sensory receptors of the body, enter the dorsal column, ascend to the medulla oblongata
• 2nd Order Neuron – Crosses to the opposite side of the medulla oblongata, ascends through brainstem, ends in thalmus
• 3rd Order Neuron – arises from thalmus, pass through internal capsule, ends in postcentral gyrus
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 23 Dorsal column tractsFasciculus Cuneatus and Fasciculus Gracilis: Carry sensations of
• Fine touch
-2 pt. discrimination
• Pressure
• Vibration
• proprioception
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 24
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 25 Spinocerebellar Tract
•1st Order Neurons – from sensory receptors to the
posterior grey
horn of the
spinal cord
•2nd Order Neuron arise from Clark’s Column, ascends
spinocerebellar
tract & enters
the Cerebellum.
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 26
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 27 Lesions• Lesion in spinal cord – loss of pain, temp,
light touch and pressure on opposite side but loss of proprioception on same side of body.
• Lesion above decussation=loss of all sensation on opposite side of body
• Lesion below level of decussation = loss of sensation on SAME side of body
• Lesion in internal capsule = hemiplegia/hemiparasthesia
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 28 Descending Tracts (Motor)
• Corticospinal Tracts (Pyramidal tracts) –concerned with skilled voluntary movement.
• Lateral – decussate
• Anterior – uncrossed
Damage results in + Babinski
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 29
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 30 Babinski
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 31 Extrapyramidal Tracts
•Reticulospinal - inhibits/facilitates voluntary movements
• Tectospinal – reflexive postural movements in response to visual/auditory stimuli
•Rubrospinal – activates spinal muscles and inhibits extensor muscles
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 32 Extrapyramidal Tracts
•Vestibulospinal – activates extensor muscles and inhibits flexor muscles
•Olivospinal – arises in the medulla oblongata, is an intermediate pathway
•Descending autonomic fibers –controls sympathetic and parasympathetic systems
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 33 Upper vs. Lower Motor NeuronsUMN – originates in the motor cortex, any neuron that doesn’t stimulate the target muscle.
Lesion: spasticity, weakness, decreased motor control, increased spinalReflexes, (+) Babinski
LMN– stimulates the target muscleLesion: decreased tone, decreased strength, decreased reflexes, atrophy
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 34 Brachial Plexus
**Know major UE muscle
Innervations
What is the relationship
Of the plexus to the
body?
RTDCB = Robert Taylor
Drinks Cold Beer
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 35 Brachial Plexus Injuries
• Injuries occur as a result of trauma, tumors, inflammation, or difficult childbirth. Increasing incidence with larger birth size, mother with DM.
• Upper brachial plexus lesion – caused by excessive lateral neck flexion. Erb’s Palsy results in waiter’s tip deformity
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 36 Erb’s Palsy
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
Slide 37 Brachial Plexus Injuries
• Lower brachial plexus lesion – caused by a sudden upward pulling on an abducted arm. C8-T1 damage causes paralysis of intrinsic muscles of the hand and the wrist and finger flexors. Klumpke’s paralysis(Claw hand)
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________
___________________________________