Learn the organization first, then use it to understand sensation, movement, reflexes, autonomic responses, pain and endangerment sites.
CNS: brain + spinal cord. PNS: neural structures outside CNS connecting it with the body. Sensory/afferent information travels toward the CNS; motor/efferent output travels toward effectors.
Dendrites receive input. The cell body contains the nucleus. The axon carries action potentials away from the cell body. Myelin increases conduction efficiency along many axons. At a synapse, signaling crosses to another cell, commonly using neurotransmitters.
| Cerebrum | Conscious perception, voluntary movement, cognition, language, memory and many higher functions. |
| Diencephalon | Includes thalamus and hypothalamus. The hypothalamus is central to homeostatic and autonomic/endocrine regulation. |
| Cerebellum | Coordinates movement, balance and motor learning. |
| Brainstem | Midbrain, pons and medulla; contains pathways/nuclei involved in vital functions and cranial nerve activity. |
The spinal cord transmits information and participates in reflexes. Spinal nerves form from dorsal sensory and ventral motor roots. After exiting, nerves branch and may join plexuses. A dermatome is a skin region associated primarily with a spinal nerve root; a myotome refers to muscles/movements associated primarily with a spinal nerve root.
A basic reflex pathway includes a receptor → sensory neuron → integration center → motor neuron → effector. Reflexes can produce rapid responses without requiring conscious decision before the response begins.
| Sympathetic | Parasympathetic |
|---|---|
| Supports mobilization during challenge: increases cardiac activity, redirects resources and supports fight/flight responses. | Supports rest/digest functions such as digestive activity and energy conservation. |
Both divisions participate continuously in regulation. “Sympathetic = bad, parasympathetic = good” is an oversimplification.
Mechanoreceptors respond to mechanical stimuli. Nociceptors respond to potentially tissue-threatening stimuli. Thermoreceptors respond to temperature. Proprioceptors provide information about body position/movement. Muscle spindles are sensitive to muscle length/change in length; Golgi tendon organs respond to tension/force at musculotendinous regions.
Nociception is neural processing of noxious stimuli; pain is a personal sensory and emotional experience and is not a direct tissue-damage meter. Context, prior experience, threat, attention, sleep, stress and many other factors can influence pain.
Sharp, burning, electric, shooting, radiating, numb or tingling sensations can indicate neural irritation. Do not chase these sensations with deeper pressure. High-yield caution regions include the posterior triangle/brachial plexus region, radial nerve along the humerus, ulnar nerve at the cubital tunnel, sciatic region, common fibular nerve near fibular head and tarsal tunnel.
Peripheral neuropathy: altered peripheral nerve function can reduce sensation and change pressure/thermal safety. Carpal tunnel syndrome: median nerve compression at wrist; avoid irritating symptomatic neural tissue. Multiple sclerosis: CNS demyelinating disease with variable symptoms and fatigue; adapt to current presentation. Headache: many types/causes exist; sudden severe or neurologically concerning headache is a red flag rather than a massage diagnosis.
Older massage curricula may discuss Arndt-Schulz, Pflüger's laws, Hilton's law and the law of facilitation. Know them in the historical/course context, but do not treat broad historical formulations as modern proof that a specific massage technique causes a guaranteed nervous-system outcome.
Toward CNS? Afferent/sensory. Away toward effector? Efferent/motor. Coordination? Cerebellum. Major homeostatic brain region? Hypothalamus. Skin root map? Dermatome. Muscle length receptor? Muscle spindle.