Topographic anatomy of the brain and brain part of the

skull

Rustam Sultonov

Borders of the head: From the chin

along the lower border of mandible to its angle and then from the mastoid process along the superior nuchal line to external occipital protuberance

Divisions

The facial part Includes: • Orbits • Initial parts of

respiratory system• Initial parts of GI

tract

Brain part

Fornix capitis Consists of several regions: Frontal, Parietal, Occipital, Temporal, and Mastoidal

Basis cranii Has got internal and external

surfaces

The division line: Stretches from supraorbital margin zygomatic arch superior margin of external acoustic meatus mastoid process

Topographic anatomy of fornix capitis

Frontal region Boundaries: lower border of

frontal region at the place of junction of nasal bones with frontal bone (nasion) diverge in different sides along the superciliar arch then crossing zygomatic process of frontal bone the border goes up along the projectional line of coronal suture and end on siggital suture

Blood supply: a. supratrochlearis, a. supraorbitalis (from a. ophtalmica)

Venous drainage: v. supratrochlearis, v. supraorbitalis

Lymph drainage: lymph vessels drain into nodi lymphatici parotidei superficiales

Innervation: Sensitive nerves are n. supratrochlearis, n. supraorbitalis (from n. ophtalmicus. Motor nerves: rami temporalis n. facialis (branches go to m. frontalis)

Parietal region Boundaries: good visible only

in the skull. Borders are along the projectional lines of coronal, saggital, lambdoidal sutures and temporal line

Blood supply: branches of a. temporalis superficialis Venous drainage: branches of v. temporalis superficialis Lymph drainage: lymph vessels drain into nodi lymphatici mastoidei Innervation: branches from nn. Supraorbitalis et frontalis, n. auriculotemporalis, n. occipialis major

Occipital region Boundaries: borders of the region

from above and on the sides correspond to the location of lambdoidal suture; below borders correspond to the line that stretches from the bases of one mastoid process to the basis of another one through the external occipital protuberance

Blood supply: a. occipitalis, a. auricularis posterior Venous drainage: v. occipitalis, v. vertebralis Lymph drainage: lymph vessels drain into nodi lymphatici occipitalis Innervation: Sensory nerve is n. suboccipitalis; Motor nerves are n. occipitalis major, n. occipitalis minor

Layers and spaces of frontal, parietal and occipital regions

1. Skin (cutis) – in these areas is thick and covered by hair (except frontal region), tightly connected with subcutaneous fat and m. epicranius by CT septa

2. Subcutaneous fat (panniculus adiposus) contains CT septa, fat drops and vascular net. Vascular and lymphatic vessels are tightly fixed in septa and that’s why due to injuries they do not dissipate and severe bleeding might occur

3. M. epicranius – consists of 2 bellies (venter frontalis and venter occipitalis) and galea aponeuotica between them. Innervation: n. facialis

4. Stratum fasciale – the layer of the loose tissue localized between m. epicranius and periostium

5. Periosteum – tightly connected to bones only in the are of sutures, in other places it can easily be detached

6. Skull bones (ossa cranii) - thickness varies in different zones. These bones do not possess ability to regenerate ( that’s why defect after trepanation is closed only by fibrous tissue). Skull bones have 3 layers: lamina externa, diploe(spongy layer), lamina interna7. Epidural space (cavitas epiduralis) – between internal laminae and dura mater 8. Dura mater encephali – consists of dense fibrous CT9. Spatium subdurale – a space between dura mater and arachnoidea encephali containing fluid 10. Arachnoidea encephali – passes from one gyri to another, not dropping in sulci.11. Cavitas arachnoidalis – contains cerebrospinal fluid12. Pia mater encephali – contains many blood vessels. Covering all the brain enters into sulci 13. Gray matter of brain

Topographic anatomy of brain

Brain meninges Dura mater

encephali

Arachnoidea encephali

Pia mater encephali

Dura mater encephali A thick whitish CT membrane

is outermost in position. External surface is in direct

contact with skull bones for which it serves like periosteum

The inner surface facing the brain is lined with endothelium and is therefore smooth and shiny

Between it and cerebral arachnoid mater is narrow subdural space filled with a small amount of fluid

Inner surface gives off several processes, which penetrate between the parts of the brain and separate one part from another:

The Falx cerebri – lies sagittal between both cerebral hemispheres. Anterior narrow end grows into the crista galli, while the wide posterior end blend with the superior surface of tentorium cerebelli

The Tentorium cerebelli – separates the cerebral occipital lobes from the cerebellum

The Falx cerebelli – lies in saggital plane and separates cerebellar hemispheres

Blood supply: a. meningea anterior, a. meningea media, a. meningea posterior, ramus meningeus a. occipitalis

Innervation: r. tentorii n. ophtalmici, r. meningeus n. maxillaris, r. meningeus n. mandibularis, r. meningeus n. vagi

Arachnoidea encephali

Forms Middle layer of brain meninges

Separated from dura mater by a capillary subdural slit-like space

In contrast to pia mater it does not penetrate into the sulci and depressions of the brain but bridges them as a result of which subarachnoidal spaces filled with fluid forms

In some places sunarachnoidal spaces are particularly well developed and form wide and deep reserviours filled with cerebrospinal fluid – cisternae1. Cisterna

cerebromedullaris 2. Cisterna

interpeduncularis3. Cisterna chiasmatis 4. Cisterna fossae lateralis

cerebri

Pia mater Is in intimate

contact with the brain and dips into all sulci and fissures on its surfaces

It contains blood vessels and vascular plexuses

BRAIN VENTRICLES

The brain is bathed by the cerebrospinal fluid (CSF)

Inside the brain, there are spaces (ventricles) filled with CSF

There are 4 ventricles 2 lateral

ventricles are in the brain hemispheres

3rd ventricle is in the diencephalon

4th ventricle is between the pons, open medulla and the cerebellum

The 3rd & the 4th ventricles are connected by the cerebral aqueduct

Ventricular system

Lateral Ventricle

Lateral Ventricle

3rd Ventricle

4th Ventricle

Cisterna Magna

Intervertebral foramen/Monro

Cerebral aqueduct

Lateral aperture (Lushka)

Median aperture (Magendie)

Lateral aperture (Lushka)

Intervertebral foramen/Monro

Major gyri and sulci

Lobes Frontal lobe

in front of central sulcus and above lateral sulcus, line from central sulcus down to corpus collosum

Parietal lobes behind central sulcus and above lateral sulcus. A line between

parieto-occipital sulcus and preoccipital notch and middle of the line above to the lateral sulcus (See Picture 13-1 on P261)

Temporal lobes lateral sulcus and line described above, a line from anterior end of

calcarine sulcus and preoccipital notch (see Pic 13-2 on P 262) Occipital lobe

medial surface of the hemisphere, separated from temporal lobe. Insula

bottom of lateral sulcus.

THANK YOUFOR

your attention! Any question? No ? Great! Bye!)))