Approach To UMN Flashcards by Deependra Singh

UMN
Corticospinal ➕ Corticobulbar fibers ➕ Extra pyramidal fibers
🧠⚡he drove a hondaCRVTOdisneyland ⚡

Descending motor tracts (Corticospinal tract ➕ Extra pyramidal system) that merge on AHC or Cranial Nerve nuclei

⭐ Descending Tracts

Corticospinal tract (Lateral & Anterior)
Rubrospinal tract
Vestibulospinal tract
Tectospinal tract
Olivospinal tract

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Descending Tracts in Lateral Column
🧠⚡ RL⚡
🧠⚡CR-v to ⚡

Rubrospinal Tract
Lateral Corticospinal tract

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Descending Tracts in Anterior Column
🧠⚡ A VOTe⚡

Anterior Corticospinal tract
Vestibulospinal tract
Olivospinal tract
Tectospinal tract

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All tracts in spinal cord is represented in ARRANGEMENT except

🧠⚡ ML ➡️ CTLS⚡

Cervical ➡️ Thoracic ➡️ Lumbar ➡️ Sacral

⭐ Dorsal Column
ML ➡️ SLTC
SACRAL ➡️ LUMBAR ➡️ THORACIC ➡️ CERVICAL

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ViP makes you STAND UP

Sit on Rubber mat

Vestibular spinal tract
Pontine Reticulo-spinal tract

Sit down
1. Rubrospinal tract
2. Medullary Reticulo-spinal Tract

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Vestibular Apparatus
Function

✨ For standing up
✨ Activates and Increases tone of ANTI-GRAVITY Muscles

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Red Nucleus functions
Rubrospinal Tract

Increases tone of GRAVITY muscles
Flexors of Upper limb

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Corticospinal Tract

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Steps for Movement
Managed by?

Plan
Posture
Tone
Position of Proximal muscles
Inhibition of Opposite muscle

⭐ Integration of zskill: CST
⭐ Planning, Position and other things managed by EPS

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Finesse to the movement is given by

Cerebellum

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Corticospinal tract: Cortex

60% FIBERS FROM: FRONTAL LOBE

30% fibers: Originate from 1deg MOTOR CORTEX

30% FIBERS: Originate from PREMOTOR CORTEX (Area 6,8) and Supplementary Motor Cortex

40% fibers: Originate from Area 3,1,2 (SENSORY CORTEX): PARIETAL LOBE

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Cell of BETZ

Giant pyramidal neurons WITH LARGE MYELINATED AXONS in Lamina 5 in MOTOR CORTEX
⬇️
LOWEST THRESHOLD FOR EXCITABILITY

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Extra pyramidal fibers
Originate from

Pre-motor Cortex and Supplementary Motor Cortex

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Corticobulbar fibers to the cranial nerve nuclei in the BRAINSTEM have B/L representation in the CORTEX
EXCEPT

7th CN: Facial Nerve

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⭐ Cell of BETZ end on:

⭐ Other Corticospinal fibers end on:

⭐ Cell of BETZ end on: DIRECTLY ON ALPHA MOTOR NEURON

⭐ Other Corticospinal fibers end on: INTERNEURONS

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UMN Lesion of 7th Cranial Nerve

LMN lesion of 7th CRANIAL NERVE

⭐ LOWER HALF of the FACE is affected while UPPER PART IS SPARED
➕
ANGLE OF MOUTH DEVIATED TO OPPOSITE SIDE

⭐ LMN lesion of 7th CRANIAL NERVE:
One HALF of the FACE AFFECTED

CORTICOBULBAR INVOLVEMENT ON ONE SIDE, CLINICAL FEATURES

No manifestation
Except: FACIAL NERVE

CORONA RADIATA: Packaging

Internal Capsule: Packaging

LOOSE PACKAGING: Fibers of CST descend

⭐ DENSE PACKAGING: IN INTERNAL CAPDULE

White MATTER in Cerebrum
Parts
🧠⚡ACP ⚡

⭐ Association Fibers
⭐ Commissural Fibers
⭐ Projection Fibers

Example of PROJECTION FIBER
Connects Cortical structure with Subcortical structures

Internal Capsule
Parts:
1. Ant Limb
2. Genu
3. Posterior Limb

Relations of INTERNAL CAPSULE

Fibers passing through INTERNAL CAPSULE
🧠⚡ROP ⚡
🧠⚡ SAU PPT⚡

If Corticospinal lesion at LEVEL OF INTERNAL CAPSULE, KNOWN AS
🧠⚡3H ⚡

DENSE HEMIPLEGIA
⭐ dense HEMIPLEGIA
⭐ Hemi-sensory loss
⭐ Homonymous Hemianopia

Main BLOOD SUPPLY of INTERNAL CAPSULE

Middle CEREBRAL ARTERY

Others:
Anterior Cerebral Artery
Anterior Choroidal Artery

Blood supply of INTERNAL CAPSULE 🧠⚡UPPER PART OF Each part is supplied by SAME ARTERY: LENTICULOSTRIATE BRANCH OF MIDDLE CEREBRAL ARTERY ⚡

⭐ Medial Striate Artery is a BRANCH OF ⭐ Lateral Striate Artery is a BRANCH OF ⭐ Posterior Striate Artery is a BRANCH OF

⭐ Medial Striate Artery is a BRANCH OF ACA ⭐ Lateral Striate Artery is a BRANCH OF MCA ⭐ Posterior Striate Artery is a BRANCH OF PCA

CHARCOT BOUCHARD ANEURYSM

Aneurysm seen in STRIATE BRANCH OF MIDDLE CEREBRAL ARTERY

Artery of CHARCOT Hemorrhage

Lateral Striate Artery

Huebner's Artery

Recurrent branch of ANTERIOR CEREBRAL Artery

CST in Midbrain

UMN Lesion in MIDBRAIN Known as?

⭐ CROSSED HEMIPLEGIA (OR) ALTERNATING HEMIPLEGIA ⬇️ I/L LMN CN palsy ➕ C/L UMN LESION (Weakness)

CST in PONS

Present as DISJOINED FASICLES at BASILAR PART OF PONS ⚡ Why? ⭐ Fibers of Nuclei Pontis ⭐ Crossing fibers of MIDDLE CEREBRAL PEDUNCLES

Medulla Oblongata

Termination of Corticospinal Tract

⭐ % of Fibers of CST that end at CERVICAL REGION ⭐ % of Fibers of CST that end at THORACIC REGION ⭐ % of Fibers of CST that end at LUMBAR REGION

⭐ % of Fibers of CST that end at CERVICAL REGION ⚡⚡55% ⭐ % of Fibers of CST that end at THORACIC REGION ⚡⚡20% ⭐ % of Fibers of CST that end at LUMBAR REGION ⚡⚡25%

HEMIPLEGIA Possible CAUSES

⭐ OPPOSITE CORTEX (CORTICAL) 🎯 MCA 🎯 ACA ⭐ OPPOSITE Subcortex ⭐ OPPOSITE Brainstem