II. Physiology
-
Corticospinal tract (motor, lateral cord) transmits motor signals from the cerebral cortex
- Fibers cross the midline at the Brain Stem and course to the contralateral Muscles
- Motor fibers Synapse in the anterior horn (grey matter of the spinal cord)
- Upper Motor Neurons (UMN) are from the cerebral cortex to the Synapse
- Affect the cerebral cortex, Brainstem and Corticospinal tracts
- Lower Motor Neurons (LMN) are from the Synapse to the Muscle
- Affect the anterior horn (spinal cord), nerve roots, and Peripheral Nerves
- Upper Motor Neurons (UMN) are from the cerebral cortex to the Synapse
III. Causes: Examples
- See Muscle Weakness Causes
- Myasthenia Gravis
- Lambert-Eaton Syndrome
- Guillain Barre Syndrome (other autoimmune polyneuropathies)
- Neuropathy
IV. Signs: Lower Motor Neuron Lesion findings
- Flaccid Paralysis
- Muscular atrophy
- Muscle Fasciculation (Muscle Twitch)
- Involuntary fine Muscle Contractions and relaxations of an entire motor unit synchronously
- May be a benign finding, in the absence of a lower motor lesion
-
Muscle fibrillations
- Small, local Muscle Contractions of single Muscle fibers that contract independently of surrounding fibers
- Contractions are typically rapid, irregular and unsynchronized
- Hyporeflexia
- Absent Babinski Reflex
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Related Studies
| Definition (NCI_FDA) | The occurrence of a single contraction or a series of contractions of a muscle. |
| Definition (NCI) | The occurrence of a single contraction or a series of contractions of a muscle. |
| Concepts | Sign or Symptom (T184) |
| ICD10 | R25.3 |
| SnomedCT | 60238002, 249966004 |
| English | Muscle twitch, Muscle twitching, Twitches, muscle twitches (symptom), muscle twitches, Twitching NOS, jerks, twitches, jerking, muscle twitch, twitch, twitched, muscle twitching, jerk, jerked, TWITCHING, Twitch, Twitching, Muscle twitch (finding), twitching, Twitch(ing) |
| Italian | Contrazione muscolare, Contratture, Contrazione, Contrattura di muscolo |
| Dutch | trekking, trekkingen, spiertrekking, spiertrekkingen |
| French | Contractions musculaires, Soubresauts musculaires, Contractions, CONTRACTION CLONIQUE, Contractions fasciculaires |
| German | Zucken, ZUCKUNGEN, Muskelzucken |
| Portuguese | Fasciculações musculares, Contração muscular, CONTRACCAO CLONICA, Fasciculação e fibrilhação muscular |
| Spanish | Sacudida, Sacudidas, Tirón muscular, SACUDIDA MUSCULAR, tirón muscular (hallazgo), tirón muscular, Sacudidas musculares |
| Japanese | 筋攣縮, ピクピクした動き, 攣縮, ｷﾝﾚﾝｼｭｸ, ﾚﾝｼｭｸ, ﾋﾟｸﾋﾟｸｼﾀｳｺﾞｷ |
| Czech | Svalové fascikulace, Fascikulace, Svalová fascikulace |
| Hungarian | Izomrángás, Izomrángatódzás, Rángatózások |
Ontology: Lower motor neurone lesion (C0442865)
| Concepts | Pathologic Function (T046) |
| SnomedCT | 264077003, 299737009 |
| Italian | Lesione del motoneurone inferiore, Lesione del motoneurone inferiore NAS |
| Dutch | lagere motorische neuronlaesie NAO, lagere motorische neuronlaesie |
| French | Lésion des motoneurones inférieurs SAI, LESION DU MOTONEURONE INFERIEUR, Lésion du motoneurone inférieur |
| German | untere Motorneuronlaesion NNB, NEURONENSCHAEDIGUNG MOTORISCHE UN, untere Motorneuronlaesion |
| Portuguese | Lesão traumática do neurónio motor inferior NE, LESAO DO NEURONIO MOTOR PERIFERIC, Lesão do neurónio motor inferior |
| Spanish | Lesión de neurona motor inferior NEOM, lesión de la neurona motora inferior (hallazgo), lesión de la neurona motora inferior, Lesión de la segunda motoneurona |
| Japanese | 下位運動ニューロンの病変ＮＯＳ, 下位運動ニューロンの病変, ｶｲｳﾝﾄﾞｳﾆｭｰﾛﾝﾉﾋﾞｮｳﾍﾝ, ｶｲｳﾝﾄﾞｳﾆｭｰﾛﾝﾉﾋﾞｮｳﾍﾝNOS |
| English | LOWER MOTOR NEURONE LESION, Lower motor neurone lesion NOS, Lower motor neurone lesion (disorder), Lower motor neurone lesion, Lower motor neurone lesion (finding) |
| Czech | Léze dolního motorického neuronu, Léze dolního motorického neuronu NOS |
| Hungarian | Alsó motoneuron laesio, Alsó motoneuron laesio k.m.n. |
Ontology: Lower motor neuron (C0524459)
| Concepts | Cell (T025) |
| SnomedCT | 91770004 |
| English | lower motor neurons, lower motor neuron, neuron lower motor, Lower motor neuron, Lower motor neuron (cell) |
| Spanish | neurona motora inferior (célula), neurona motora inferior |
Ontology: Fasciculation, Skeletal Muscle (C0541957)
| Concepts | Finding (T033) |
| MSH | D005207 |
| Dutch | fasciculatie skeletspier |
| German | Faszikulation des Skelettmuskels |
| Italian | Fascicolazione di muscolo scheletrico, Fascicolazione muscolo-scheletrica |
| Portuguese | Fasciculação de músculo esquelético |
| Spanish | Fasciculación de la musculatura esquelética |
| Japanese | 骨格筋線維束性収縮, ｺｯｶｸｷﾝｾﾝｲｿｸｾｲｼｭｳｼｭｸ |
| French | Fasciculation d'un muscle squelettique |
| English | Fasciculation, Skeletal Muscle, Fasciculation skeletal muscle, Fasciculations, Skeletal Muscle, Muscle Fasciculation, Skeletal, Muscle Fasciculations, Skeletal, Skeletal Muscle Fasciculation, Skeletal Muscle Fasciculations |
| Czech | Záškuby kosterního svalu |
| Hungarian | Vázizom fasciculatio |
| Norwegian | Skjelettmuskelfascikulasjon, Fascikulasjon, skjelettmuskel |
Ontology: Fibrillation skeletal muscle (C0541960)
| Concepts | Finding (T033) |
| Dutch | fibrillatie skeletspier |
| French | Fibrillation d'un muscle squelettique |
| German | Fibrillation des Skelettmuskels |
| Italian | Fibrillazione di muscolo scheletrico |
| Portuguese | Fibrilhação de músculo esquelético |
| Spanish | Fibrilación de la musculatura esquelética |
| Japanese | 骨格筋線維性収縮, ｺｯｶｸｷﾝｾﾝｲｾｲｼｭｳｼｭｸ |
| Czech | Fibrilace kosterního svalu |
| English | Fibrillation skeletal muscle |
| Hungarian | Vázizom fibrillatio |
