clasp-knife spas·ti·ci·ty, clasp-knife rigidity (klaspnīf' spas-tis'i-tē, ri-jid'i-tē) Initial increased resistance to stretch of the extensor muscles of a joint that give way rather suddenly, allowing the joint then to be easily flexed; the rigidity is due to an exaggeration of the stretch reflex.
What is clasp-knife rigidity?
inflexibility or stiffness. clasp-knife rigidity increased tension in the extensor of a joint when it is passively flexed, giving way suddenly on exertion of further pressure; seen especially in upper motor neuron disease.
What is the meaning of the term strap knife rigidity?
You have 3 more open access pages. Clasp knife rigidity describes the phenomenon in a spastic limb where, after an initial resistance to passive movement of a joint, there is a sudden reduction in tone and the limb moves quite freely through the rest of the range of the particular movement.
What is a clasp knives response?
It is one of the characteristic responses of an upper motor neuron lesion. It gets its name from the resemblance between the motion of the limb and the sudden closing of a claspknife after sufficient pressure is applied.
What is the pathophysiology of rigid rigidity?
Rigidity is a hypertonic state characterized by constant resistance throughout range of motion that is independent of the velocity of movement. It is the result of excessive supraspinal drive (upper motor neuron facilitation) acting on alpha motor neurons; spinal reflex mechanisms are typically normal.
What does clasp-knife rigidity indicate?
clasp-knife rigidity increased tension in the extensor of a joint when it is passively flexed, giving way suddenly on exertion of further pressure; seen especially in upper motor neuron disease.
What diseases do you see clasp-knife upper motor neuron rigidity and spasticity?
With upper motor neuron lesions the muscles, after an initial period of rigidity and resistance to movement, suddenly relax or give way, the so-called “clasp-knife” rigidity. Additionally, patients with Parkinson's disease may show a cogwheel type of rigidity.
Is clasp-knife spasticity or rigidity?
Clasp knife rigidity describes the phenomenon in a spastic limb where, after an initial resistance to passive movement of a joint, there is a sudden reduction in tone and the limb moves quite freely through the rest of the range of the particular movement. Links: spasticity.
What is knife clasp syndrome?
Terminology. When a clasp-knife deformity is accompanied by pain on extension secondary to protrusion of the enlarged spinous process (knife blade) into the sacral spinal canal, it is called clasp-knife syndrome 2, also known as spina bifida engagement syndrome.
What causes spasticity vs rigidity?
Whereas spasticity arises as a result of damage to the corticoreticulospinal (pyramidal) tracts, rigidity is caused by dysfunction of extrapyramidal pathways, most commonly the basal ganglia, but also as a result of lesions of the mesencephalon and spinal cord.
Why does UMN lesion cause spasticity?
How does UMN lesion cause spasticity and associated phenomena? The major problem is a loss of control of the spinal reflexes. Spinal reflex activity is normally tightly regulated and if inhibitory control is lost, the balance is tipped in favor of excitation, resulting in hyperexcitability of the spinal reflexes.
What causes rigidity?
Muscle rigidity happens when a muscle or a group of muscles stays contracted or partly contracted for an extended period. The brain continues to send nerve signals telling the muscle to contract even when the muscle is no longer needed for movement. This can sometimes last for several hours or days.
Why Does Parkinson's cause rigidity?
Rigidity – meaning stiff or inflexible muscles – is one of the main motor symptoms of Parkinson's, along with tremor and slowness of movement (bradykinesia). Muscles become rigid because of their inability to relax.
What causes cogwheel rigidity?
When there's less dopamine, the cells in the basal ganglia can't connect or communicate as well. This means they can't keep your motions as smooth as they would otherwise be, which causes rigidity and the other body movement issues common to Parkinson's disease, like tremors.
How common is spina bifida occulta?
Spina bifida occulta is the most common type of spina bifida and the condition affects 10% to 20% of the U.S. population.
What is the other name of clasp knife reflex?
paradoxical pupillary reflexCalled also paradoxical pupillary reflex.
What is a Clasp Knife response?
Clasp-knife response refers to a Golgi tendon reflex with a rapid decrease in resistance when attempting to flex a joint, usually during a neurological examina tion. It is one of the characteristic responses of an upper motor neuron lesion.
What causes muscle tonus to increase?
Cause. When a joint is passively flexed, the resisting force comes from the stretch reflex (or sometimes called tendon reflex) resulting from the extensor muscle being stretched. In upper motor neuron lesions, muscle tonus may increase and resistance of muscle to stretch increases.
Does stretching the triceps increase resistance?
As the muscle tone increases, resistance against flexion of the limb increases as well. However, when flexion is continued, further stretching of the triceps muscle activates an inverse stretch reflex that relaxes the muscle due to autogenic inhibition.
What is clasp-knife rigidity?
clasp-knife rigidity increased tension in the extensor of a joint when it is passively flexed, giving way suddenly on exertion of further pressure; seen especially in upper motor neuron disease. Called also clasp-knife reflex.
What is clasp knot?
clasp-knife spas·tic·i·ty. a type of increased muscle tone due to a pyramidal tract lesion, in which abnormally increased resistance to passive stretch of a muscle abruptly decreases; typically, this appears near the end of the range of joint excursion. See also: lengthening reaction.
What is cogwheel rigidity?
cogwheel rigidity tension in a muscle that gives way in little jerks when the muscle is passively stretched; seen in parkinson's disease. decerebrate rigidity see decerebrate rigidity. decorticate rigidity see decorticate rigidity.
Why is the extensor muscle so rigid?
Initial increased resistance to stretch of the extensor muscles of a joint that give way rather suddenly, allowing the joint then to be easily flexed; the rigidity is due to an exaggeration of the stretch reflex.
What is paratonic rigidity?
paratonic rigidity an intermittent abnormal increase in resistance to passive movement in a comatose patient.
What is rigidity in motor neuron?
Definition. Rigidity is a hypertonic state characterized by constant resistance throughout range of motion that is independent of the velocity of movement. It is the result of excessive supraspinal drive (upper motor neuron facilitation) acting on alpha motor neurons; spinal reflex mechanisms are typically normal.
What is lead pipe rigidity?
Lead Pipe Rigidity - Refers to hypertonic state throughout the range of motion i.e simultaneous co-contraction of agonists and antagonists and this is reflected in an immediate resistance to a reversal of the direction of movement about a joint.
What happens when the balance of inhibition and excitation in the basal ganglia and motor cortex is upset?
When the balance of inhibition and excitation in the basal ganglia and motor cortex is upset, the symptoms and signs of rigidity and involuntary movements supervene along with abnormalities of posture and associated movement.
How to determine if a patent is rigid?
The examiner should hold the hand of the patent above the wrist with one hand and keep it fixed. With other hand he grasps the fingers and the palm and then slowly rotate along the long axis of the hand. If there is rigidity, the examiner will experience resistance during the movement. If the cogwheel phenomenon is positive, the examiner will experience interruption or repeated catch during the movement and if present throughout without any interruption or change with respect to velocity, it is lead-pipe rigidity. Generally in case of idiopathic Parkinson disease only unilateral rigidity is seen which can be compared during the examination with the contralateral side.
What happens if the cogwheel phenomenon is positive?
If the cogwheel phenomenon is positive, the examiner will experience interruption or repeated catch during the movement and if present throughout without any interruption or change with respect to velocity, it is lead-pipe rigidity.
Is muscle tone normal in rigidity?
In rigidity, muscle tone is increased even at rest and is usually presents during passive range of motion in all directions across individual joints. The plantar reflex and tendon reflexes are usually normal. There is absence of synergy.
Is rigidity a disease?
Rigidity, which is often used as a synonym to Hypertonia by many authors, is a common muscle tone disorder in which there is resistance to passive movement irrespective of posture and velocity. It is one of the cardinal features of Parkinson's Disease and is usually present in extrapyramidal disorders.
What is the clasp knife phenomenon?
Clasp - knife phenomenon: The limb experiencing spasticity suddenly gives way after an initial resistance to movement. Much like how a clasp-knife slightly resists before folding in. This can be caused by over-stretching the joint or muscles (during initial movement), the inverse stretch reflex (during sustained movements), and eventually contractures (a condition wherein muscles shorten/harden).
What causes spasticity vs rigidity?
rigidity. Spasticity is generally caused by damage or trauma to the portion of the spinal cord or brain which controls voluntary movement , namely the corticospinal tract . This can lead to an imbalance and ‘disconnection’ between the muscles and the nervous system . This can be caused by the following instances:
How is rigidity different from spasticity?
Rigidity is different from spasticity in that resistance to movement in joints is felt regardless of the speed or direction the joint is moving. Rigidity is bi-directional, meaning that one may experience resistance to movements regardless of which direction the joint and muscles are moving in.
Which muscles are affected by spasticity?
Distribution: The sensation of spasticity is distributed differentially, often affecting antigravity muscles (muscles which are the extensors of the back, hips, and knees, which help to maintain proper posture by resisting the pull of gravity).
What are the two subtypes of rigidity?
2 subtypes: Lead pipe rigidity, which is descriptive of an unvarying increase in tone, and cogwheel rigidity, which often results from a tremor pertaining to the central nervous system.
What is the difference between spasticity and velocity?
Spasticity is often uni-directional, meaning that resistance to movement is only felt when one’s joint or muscle moves in one specific direction. Spasticity is velocity-dependent, meaning that the faster one moves or straightens a joint, the more resistant, tight, or spastic the muscle feels.
Overview
Clasp-knife response refers to a Golgi tendon reflex with a rapid decrease in resistance when attempting to flex a joint, usually during a neurological examination. It is one of the characteristic responses of an upper motor neuron lesion. It gets its name from the resemblance between the motion of the limb and the sudden closing of a claspknife after sufficient pressure is applied.
Cause
When a joint is passively flexed, the resisting force comes from the stretch reflex (or sometimes called tendon reflex) resulting from the extensor muscle being stretched. In upper motor neuron lesions, muscle tonus may increase and resistance of muscle to stretch increases. However, if sufficient force is applied, limb resistance suddenly decreases, presumably mediated by the Golgi tendon reflex (also call autogenic inhibition).
Mechanism
This reflex is observed in patients with upper motor neuron lesions. It was frequently attributed to the action of the golgi tendon organ, likely because of early studies showing that tendon organs are activated by strong muscle stretch and inhibit motoroneurons of the stretched muscle. It was thought that this was a protective reflex, preventing application of so much force that muscles become damaged. More recent work strongly suggests that tendon organs are not involved in th…
Example
Passive flexion of elbow meets immediate resistance due to stretch reflex in the triceps muscle. Further stretch activates inverse stretch reflex. The resistance to flexion suddenly collapses, and the elbow flexes. Continued passive flexion stretches the muscle and the sequence may be repeated.
As the muscle tone increases, resistance against flexion of the limb increases as well. However, …
See also
• Hypertonia
External links
• Lib.mcg.edu