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General Anatomy and Radiology

A Nice Presentation on Anatomy of Brain by Dr Rima Pathak

Anatomy resources

• supratentorium: comprised of the frontal lobes, partietal lobes, temporal lobes, and occipital lobes
• Sylvian fissure divides the temporal lobe from frontal and parietal lobes
• central sulcus divides the frontal lobes from parietal lobe
• infratentorium: comprised of the cerebellum, medulla, pons, and brain stem
• ventricular system
• lined with ependymal cells and produces CSF in the roofs of the third and fourth ventricles, in the medial walls of the central body, and the inferior horns of the lateral ventricles
• intraventricular CSF transmission
• foramina of Monro: transmit CSF between the lateral and third ventricles
• aqueduct of Sylvius: transmits CSF between the third and fourth ventricles
• ventricular-subarachnoid CSF transmission
• median foramen of Magendie: transmits CSF between the roof of the fourth ventricle and the subarachnoid space
• lateral foramina of Luschka: transmit CSF between the lateral corners of the fourth ventricle and the subarachnoid space

Meninges Dura (periosteum lining, meningeal layer continuous with spinal cord)
(DSAP) Four septa (falx cerebri, tentorium cerebelli, falx cerebelli, diaphraghma sellae)
Arachnoid (potential spaces filled with CSF, sheath for optic nerves fuses with sclera)
Arachnoid villi project into venous sinuses  CSF diffuses into blood
Pia (vascular membrane extends over the cranial nerves and fuses with epineurium)

Venous Sup/Inf Sagittal and Petrossal, Straight, Transverse, Sigmoid, Occipital, Cavernous
Sinus Beneath dura mater, lined by endothelium, drains brain, orbit and inner ear.

Pituitary Rests in sella turcica of sphenoid, connected to the hypothalamus by infundibulum
Anterior lobe (ACTH/TSH/FSH/LH/GH/PRL) + Posterior lobe (OXY/ADH)
Sup (diaphragm sella), Lat (cavernous sinus), Post (dorsum sella, basilar artery)

Cerebrum Hemispheres connected by corpus callosum, separated by falx cerebri
Cortex (outer) - grey matter arranged into folds (gyri) with fissures (sulci)
Central sulcus divides frontal and parietal lobes above lateral sulcus
Lateral sulcus divides parietal and temporal lobes

Primary motor (pre-central gyrus)
Primary sensory (post-central gyrus)
Broca’s motor area (BMA – lat to sylvian fissure – expressive aphasia – comprehend)
Wernicke’s sensory area (WSA – posterior temporal – receptive aphasia – fluent)

Telenecphalon (olfactory lobes, cerebral cortex, basal ganglia, amygdala)
Diencephalon (thalamus grey matter relay sensory info, hypothalamus, pineal gland)
Mesencephalon (crus cerebri, sup/inf colliculi, tectum, aqueduct)

Brainstem Midbrain (connects diencephalons to hindbrain through tentorial notch)
Pineal body (posterior wall of 3rd ventricle, produces melatonin)
Pons (fibres connect cerebellar hemispheres and forebrain, midbrain and spinal cord)
Medulla oblongata (pyramidal motor decussation)
Olives (cuneat and gracile tubercle) post to pyramids

Cerebellum Controls ipsilateral muscle tone and coordination
Hemispheres separated by the median vermis
Connect to midbrain (sup peduncle), pons (mid peduncle) and medulla (inf peduncles)

Base of Skull

Anterior cranial fossa (frontal lobes)
Anterior (frontal bones)
Posterior (lesser wing of sphenoid)
Anterior (clinoids, medial end of lesser sphenoid
Floor formed by orbital and cribriform plates

Middle cranial fossa
Ant (lesser sphenoid wing), Post (petrous), Med (sphenoid body), Lateral (temporal bones)
Floor formed by greater wing of sphenoid.
Cavernous sinus (III, IV, V1+2, ICA and VI)

Posterior cranial fossa (cerebellum, pons and medullar oblongata)
Ant (petrous temporal bone), Floor (occipital bone and mastoid), Roof (tentorium cerebelli)

Foramen Structures
Anterior cranial fossa Cribiform plate (ethmoid) Olfactory nerve (I)
anterior ethmoidal nerve
Middle cranial fossa Optic canal Optic nerve (II)
Ophthalmic artery
Superior orbital fissure Oculomotor (III)
Trochlear (IV)
Abducent (VI)
Ophthalmic division trigeminal (V1)
Ophthalmic vein
Foramen rotundum Maxillary division trigeminal (V2)
Foramen ovale Mandibular division trigeminal (V3)
Foramen spinosum Middle meningeal artery
Foramen lacerum Internal carotid
Posterior cranial fossa Internal acoustic meatus Facial (VII)
Vestibulocochlear (VIII)
Internal auditory artery
Jugular foramen Inferior petrosal sinus
Glossopharyngeal (IX)
Vagus (X)
Accessory (XI)
Hypoglossal canal Hypoglossal (XII)
Foramen magnum Medulla oblongata
Spinal part of accessory (XI)

Table 1: Foramina of the base ok skull and associated structures

Spinal Cord 31 nerves (8-C, 12-T, 5-L, 5-S, 1-C)
Foramen magnum to L1/L2 (adult) and L2/L3 (children)
Tapers to form conus medullaris and lumbar and sacral roots form cauda equine
Filum terminale (pia mater covering that attaches to the coccyx
Dura  Arachnoid  Pia
Blood supply (vertebral ateries  posterior and anterior spinal arteries)

Ascending (sensory) pathways
Posterior columns (cross in medulla oblongata - proprioception (Romberg’s) and discrimination) Spinothalamic pathway (cross at segmental level – pain, temperature, touch)
Spinoreticular and Spinocerebellar pathways (proprioception)

Descending pathways
Corticospinal tract (cross at decussation of the pyramids – voluntary movements)
Reticulospinal tracts (locomotion and postural control)
Vestibulospinal tract (center of gravity)
Autonomic pathways (sympathetic and parasympathetic fibres)

Movement Root
Shoulder Abduction
Adduction C5
Elbow Flexion
Extension C5-C6
Wrist Flexion
Extension C7-C8
Fingers Flexion
Abduction C7-C8
Hip Flexion
Extension L1-L2
Knee Flexion
Extension S1
Ankle Dorsi-flexion
Plantar flexion L4

Reflex Root

Biceps jerk C5 (C6)
Triceps jerk C6-7
Supinator (C5) C6
Knee jerk L3-4
Ankle jerk L5-S1

1,2 buckle my shoe, 3,4 kick the door,
5,6 pick up sticks, 7-8 lay them straight.

Basic Histology

Pyramidal cells (excitatory, glutamate or aspartate neurotransmission)
Spiny stellate cells (receive afferent input from thalamus/cortex  pyramidal cells)
Smooth stellate cells (GABA inhibitory, provide cross-talk collaterals to other pyramidal cells)

Schwann cells (external to myelin sheath, separated by bare Nodes of Ranvier)

Astrocytes (cellular transport, protoplasmic-grey matter or fibrous-white matter)
Oligodendrocytes (produce myelin)
Microglia (macrophages of the CNS)

External link collections

Link collection 1
Link collection 2

Member created content


Here is a presentation on Medulloblastoma. You can go through this for a nice overview of the subject. Do remember to leave your comments below. Your questions are also welcome.
by PKTK - 06 Feb 2011 19:22

Brain Tumor Foundation India

THE WEBSITE OF THE BRAIN TUMOR FOUNDATION INDIA [http://www.braintumourindia.com/]**
by VIMOJ J NAIR - 12 May 2010 07:08

Welcome to the CNS Sitegroup

FoldUnfold Table of Contents General Anatomy and Radiology Anatomy resources External link collections Member created content Disease classifications Classification of X tumors Individual diseases...
by Indranil Mallick - 05 Dec 2009 20:30

Disease classifications

Classification of X tumors

The Abracadabra Classification

Individual diseases

Tumors of the Y region

ABCD tumor
EFGH tumor

Tumors of the Z region

IJK cancer
LMN tumor

Current issues

Is XYZ classification a complete disaster?
Is drug D going to improve outcomes over the EFG regimen?

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