This is a summary of Chapter V of “The Sensitive Nervous System” by David Butler. Intro Neurodynamics is the study and relationship of nervous system mechanics and physiology. The testing protocols for neurodynamics assess the nervous system’s ability to lengthen, glide, and change amongst interfacing structures. When discussing neurodynamics, it is important to think of the nervous system as a continuum. Mechanical, electrical, and chemical changes in one part of the nervous system affect other related parts. Gross Movements and Dynamics When having a nervous system, the following qualities, movements, and buffering capabilities are necessary: Slide, glide, strain. Elongate (think gymnasts) and return from elongated position. Compress (ulnar nerve during elbow flexion). Stength (kicking a field goal). Jolting (whiplash). Repetitive forces Bending Fluid/chemical selectivity. Neural Connective Tissue These include the meninges, nerve root complex, and peripheral nerve structures. Broken down as follows: Meninges Dura mater (outer, tougher) Arachnoid mater Pia mater (inner, thinner) Nerve root complex Root Sleeve Dorsal and ventral roots DRG Spinal nerve. Peripheral nerves Epineurium Perineurium Endoneurium Mesoneurium – Sheath that surrounds a nerve. Contracts like an accordion to glide along adjacent tissues. Can become fibrotic with injury. Important Attachments Meningovertebral ligaments – anchor down to spinal canal, which could become symptomatic. Rectus capitus posterior is connected to the dura mater between the occiput and atlas; helping the dura fold. Makes you wonder what you are truly doing when you release this structure. The sympathetic trunk’s proximity to the spinal column makes it susceptible to increased loads
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The Sensitive Nervous System Chapter IV: Central Sensitivity, Response, and Homeostatic Systems
This is a summary of Chapter IV of David Butler’s “The Sensitive Nervous System.” Intro Central sensitization is a phenomenon that occurs in the dorsal horn, which can be best described via 4 different states: 1) Normal: Inputs = outputs; innocuous sensations are perceived as such. 2) Suppressed: Inputs that would hurt do not; think an athlete who injures himself but finishes the game. 3) Increased sensitivity: Pain system has lower activation threshold, leading to pain spreading and pain with light touch and gentle movement. This change occurs because A beta fibers begin taking over C fiber locations in the dorsal horn. 4) Maintained afferent barrage, CNS influences, and morphological changes: Long lasting changes in the dorsal horn from a persistent driver, such as… A fiber phenotype changes. Persistent DRG discharge. Persistent inflammation. Supraspinal influences Gene transcription change in dorsal horn neurons. Inflamed dorsal horn or DRG Maladaptive beliefs, fears, and attitudes. Dorsal horn sprouting; A Beta fibers take over C fiber space. Persistent glutamate activity. Descending Control The CNS has an endogenous pain control system which activates during injury threat, noxious cutaneous input, or expectations and learning. Such an example of this is when you go to a healthcare practitioner’s office and no longer hurt. Another example of when this system is activated is during aggressive manual therapy. Think about how good your body may feel after sustained pressure or even a needle to a trigger point. Central Sensitization Patterns Areas/descriptors Symptoms not in neat anatomical/dermatomal boundaries. Original pain
Read MoreThe Sensitive Nervous System Chapter III: Pain Mechanisms and Peripheral Sensitivity
This is a summary of Chapter III of “The Sensitive Nervous System” by David Butler. Intro When we discuss peripheral issues, we are not only talking about the pathoanatomical source, but pathobiological processes dominating the clinical picture. There are several instances in which the pathoanatomical model falls short: Phantom limb pain. Why pain persists post-healing. Why similar injuries heal faster in certain people. Why 10-14% of the world’s population have an ongoing pain state. Tissues do get injured, but we must not forget the nervous system’s intricate link to injury. When tissues are hurt, they repair but are unlikely to ever be the same again. To protect against further threat, the CNS has the ability to increase nerve sensitivity. This change happens only if the person decides consciously or subconsciously that there is a need for it, and does not occur in everyone. There are two ways in which this sensitivity develops; Primary sensitivity: Increased sensitivity to input at the injury site. Secondary sensitivity: Increased sensitivity to uninjured tissues around the injury. All pain is neurogenic, operates in a continuum, and has many components. Nociception (NOC) NOC is tissue pain that occurs at a neuron’s end that is excited by mechanical, thermal, or chemical stimuli. It does not always match up with tissue health status. A normal nerve ending has a very high firing threshold, and nearly 1/3 will never fire. These are called silent nociceptors. Looking at a chemical process such as inflammation shows us how these nerves fire.
Read MoreThe Sensitive Nervous System Chapter II: A Bird’s Eye View of the Nervous System
This is Chapter II summary of “The Sensitive Nervous System.” Intro Here we develop a framework for understanding the nervous system with pain as the centerpiece. The nervous system is very much misunderstood as an input/output system: Myth: Input/output system. Reality: The nervous system is an active activity constructor. It evolves and learns rather than computes. It is also widely distributed without a master neuron pool for a particular sensation. The nervous system is made up of two components, hardware and wetware. The Hardware Neurons make up the hardware. These components respond and keep a chemical history of many different inputs and outputs. This is true for each individual neuron, which allows each one to be ready to go when called upon. This hardware is one time when the part actual does equal the whole, as one neuron’s activity resembles the entire Central Nervous System’s (CNS) behavior. The nervous system’s size is near-astronomical. There are approximately 100 billion neurons with 1014 synapses. This figure only factors in the functionally known nervous system components. If we throw in 103 nodes/centers (connected by 105 pathways) and the 10:1 glial cell:neuron ratio, and we have an incredibly dense system in place. A pinhead speck of brain tissue has 350 million connections. This hardware is also very redundant, as very few neurons go straight from sensory organ to cortex. There are several feedback loops in place which allows for constant checking and rechecking. The Wetware Wetware includes the different neurotransmitters and neuromodulators. Examples
Read MoreThe Sensitive Nervous System Chapter I: Painting a Bigger Canvas
This is a summary of Chapter I of The Sensitive Nervous System. This book is an all-encompassing manual regarding neurodynamics. This concept is defined as the physical and related physiological abilities of the nervous system. Before delving into neurodynamic nitty-gritty, a brief history of physical therapy is laid out via a very cool brachial plexus design (you have to get the book to see it). There are three different progressions in physical therapy history: manual therapy, exercise, and neurological manual therapy. The first time PTs learned manipulation was in 1916 at St. Thomas Hospital in London. The thought process of the time, as well as most early manual therapy, was predominantly biomechanically joint-centric. Eventually, muscle and other tissues were targeted. These approaches were championed by Geoffrey Maitland’s signs and symptoms approach and Graves’ pathological model. Concomitant with manual therapy has been exercise, which had moved from nonspecific (aerobics, tai chi) to specific movements a la Vladimir Janda and Shirley Sahrmann. On the other side of orthopedic manual therapy were manual techniques from the likes of Bobath’s NDT and PNF. What is sad about these techniques is that they have not interacted much during manual therapy’s development. Butler makes arguably one of the most important statements in the book by saying our patients are ultimately all neurological. We will all meet at the brain. Aside from various manual approaches, recent techniques have been developed including psychology, counseling, exercise physiology, and acupuncture. Butler feels these are nice adjuncts to the plan of
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