other Flashcards
destructive interference
bash and currents are out of sync
if constructive, is in sync
pain gaiting
Following an injury, pain signals are transmitted to the spinal cord and then up to the brain.Melzack and Wall suggest that before the information is transmitted to the brain, the pain messages encounter “nerve gates” that control whether these signals are allowed to pass through to the brain. In some cases, the signals are passed along more readily and pain is experienced more intensely. In other instances, pain messages are minimized or even prevented from reaching the brain at all. This mechanism takes place in the spinal cord and both small nerve fibers (pain fibers) and large nerve fibers (normal fibers for touch, pressure, and other skin senses) both carry information to two areas of the spinal cord. One area is excitatory and carries the painful information up the spinal cord to the brain, whilst the other area inhibits the sensory information from being sent to the brain. Small nerve fibre/pain fibres stimualte the excitatory area whilst large diamter fibers stimulate the inhibitory area. When there is more large fiber activity in comparison to pain fiber activity, people tend to experience less pain. Therefore, the gate control theory of pain asserts that non-painful input closes the “gates” to painful input, which prevents pain sensation from traveling to the central nervous system and hence, suppress the pain
give a brief explanation of what this is and provide an example of a clinical condition that
would fall under this contra-indication/precaution:
inbuilt stimulator
a) inbuilt stimulator - Sound waves reflected at a device–tissue interface could possibly cause tissue heating
eg a pacemaker for ultrasound
give a brief explanation of what this is and provide an example of a clinical condition that
would fall under this contra-indication/precaution:
circulatory insuffciency
b) a circulatory insufficiency is defined as a general or specific failure of the circulation, either cardiac or peripheral in nature. Adequate blood circulation is needed to avoid excessive heat accumulation in areas treated with superficial heating agents. eg PVD in ultrasound
give a brief explanation of what this is and provide an example of a clinical condition that
would fall under this contra-indication/precaution:
risk if dissemation
c) conditions with know or accepted risks ed. acute infection, malignancy, tuberculosis, and osteomyelitis. Eg acute infection and heat pack could spread
give a brief explanation of what this is and provide an example of a clinical condition that
would fall under this contra-indication/precaution:
exacerbation of existing conditions
d) Don’t want to increase the severity of exsiting conditions eg acute infective or inflammatory conditions, skin dsorders, regions treated within 3-6 months of radiotherapy, haemorrhagic conditions, severe organs states such as cardiac failure
give a brief explanation of what this is and provide an example of a clinical condition that
would fall under this contra-indication/precaution:
sensory loss
e) sensory loss - unable to distinguish hot or cold, sharp or blunt could result in heat or ice burns or periosteal burns in ultrasound
wearing shoes
grounds circuit because can’t travel through rubber
- wants the travel through path off less resistance but rubber is extremely good insulator
standing waves
Reflected wave superimposed on incident wave • Result in waves with peaks of high pressure and others of no pressure • Stasis of cells in blood vessels or marked heating • Endothelial damage leading to thrombus formation • Periosteal burns
accomodation
when the nerve stops feeling/responding so need to increase intensity
periosteal burns
• Ache or sharp pain when applying US due to heating at
bone surface
• Due to reflection at bone/soft tissue interface and shear
waves
• Also bone absorbs US easily
• Care in superficial bony regions
FES
NEED INTACT PERIPHERAL NERVOUS SYSTEM
