2. brain


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General thing about brain

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  • Confluence:- The junction of two rivers; an act or process of merging.
  • Cistern: - A water storage tank especially as part of a flushing toilet; an underground reservoir of rainwater.
  • Petrosal: - Relating to or denoting the dense part of temporal bone surrounding the inner ear.
  • Gyri is a plural form of gyrus: - a ridge or fold on the cerebral surface of the brain.Sulci is a plural form ofsulcus: - a groove or furrow especially one on the surface of brain.
  • Ponder: - Consider carefulLepto: - Small, narrow, fine thin and delicate
  • Decussate: - two or more things are cross or intersect.
  • Peduncle: - a stalk like connecting structure.
  • Cuneatus: - Wedge shape Gracilis: -
  • 2. brain

    1. 1.      is the largest and upper part of C.N.S. 1360 gm The brain (encephalon) lies within the cranium The brain receives information from, and controls the activities of, the trunk and limbs mainly through connections with the spinal cord. It also possesses 12 pairs of cranial nerves through which it communicates mostly with structures of the head and neck.
    2. 2.  Five divisions: Cerebrum: largest part  Cerebellum: lies below the posterior part of cerebrum.  Midbrain  Pons  Medulla 
    3. 3. Brain is divided into five parts embryologically: 1. Telencephalon (cerebrum and basal ganglia). 2. Diencephalon(thalamus,hypothalamus,epithal amus,subthalamus and metathalamus: 1 and 2 = forebrain, with a cavity lateral ventricles and third ventricle respectively. 3.Mesencephalon (mid brain), with a cavity of cerebral aqueduct.
    4. 4. 4. metencephalon( pons and cerebellum),with a cavity of upper part of 4th ventricle. 5. myelencephalon( medulla oblongata), with a cavity of lower part of 4th ventricle. 4 and 5=hindbrain, with a cavity of 4th ventricle. Medulla oblongata, pons and mid brain=brain stem. The cerebellum, pons and medulla are collectively called hind-brain
    5. 5.   fibrous and delicate membranes that are internal to the skull. from outer to inner are: dura—arachnoid---pia matter.
    6. 6. Skin Galea Aponeurotica Connective Tissue Bone Dura Mater Arachnoid mater
    7. 7.  Arachnoid:    Loose spider-web of connective tissue. Beneath it is the subarachnoid space – filled with blood vessels and CSF Pia    Deepest and most delicate Covers the brain tissue Follows its every ridge and groove
    8. 8.    Epidural space- is a potential space between periosteum covering the calvaria and dura. contains middle meningeal arteries in the cranial cavity Sub dural space- is a potential space between dura and arachnoid
    9. 9.      Is the tough, external, thick, fibrous two layered membrane of the meninges. Is external to subdural space and internal to epidural space is made up of two layers an external periosteal layer an internal meningeal layers.
    10. 10.     The two layers difficult to separate at some poins (firmly fused) Hence look single but at some areas they are not firmly attached (unfused) Form a potential space –dural venous sinuses It forms dural venous sinuses, spaces between periosteal and meningeal layers
    11. 11.    Large veins from the surface of the brain empty into these sinuses and most of the blood from the brain Ultimately drains through them into IJVs .
    12. 12. 1. Superior saggital sinus (S):  lies in the midline along the convex border of the falx cerebri.  Begins at the crista galli ends internal occipital protuberance at confluence of sinuses (meeting place of SSS,SS,OS and TS  receives the cerebral ,diploic (cranial vein), meningeal and parietal emissary veins
    13. 13. 2- Inferior saggital sinus (S):  lies in the free age of falx cerebri  is joined by great cerebral vein (of Galen) to form straight sinus (union of ISS with great cerebral vein).
    14. 14. 3- Straight sinus (S): runs along the line of attachement of the falx cerebri to the tentorium cerebelli. 4- Transeverse sinus (P): runs laterally from confluence of sinuses along the edge of the tentorium cerebelli.
    15. 15. 5- Sigmoid sinus (P);  is a continuation of the transverse sinus, arches downward and medially in an S-shaped groove on the mastoid part of the temporal bone  enters the superior bulb of IJV (becomes continous as)
    16. 16. 6- Cavernous sinus (P):  are located on each side of sella turcica, on body of sphenoid bone.  The ICA and abducent nerve pass via the sinus   occulomotor, trochlear, opthalmic, and maxillary nerves pass foreward in the lateral wall of the sinus. Communicates with pterygoid plexus by emissary veins and receive superior opthalmic vein.
    17. 17. 7- Superior petrosal sinus (P):  lie in the margin of the tentorium cerebelli,  Running from the posterior end of the veins making up the cavernous sinus to the transeverse sinuses  The site where these sinuses curve inferiorly to form sigmoid sinuses. 8- Inferior petrosal sinus (P):  Drains the cavernous sinus into the bulb of the IJV  Runs in a groove between petrous part of temporal bone and the basilar part of occipital bone.  Basilar plexus connects IPS with internal vertebral venous plexus
    18. 18. 9- Sphenoparietal sinus (P): lies along the posterior edge of the lesser wing of sphenoid bone and drains to cavernous sinus. 10- Occipital sinus (S): lies in the falx cerebelli and drains into the confluence of sinuses 11- Basilar sinus (plexus, S): consist of interconnecting venous channels on the basilar part of occipital bone and connects the two inferior petrosal sinus.  Communicates with the internal vertebral venous plexus.
    19. 19.  At the certain places the inner layer of the dura is stretched and reduplicated to form the followings folds:
    20. 20.     Sickle-shaped Lies in the median groove between the two cerebral hemispheres. Is attached anteriorly to crista galli and posteriorly to the tentorium cerebelli. Its inferior concave border is free and contains inferior saggital sinus,and its upper convex margin encloses the superior saggital sinus.
    21. 21.       Tent-like or crescentric Occupies the cleft between the posterior part of the cerebrum and the cerebellum . Its internal concave border is free and bonds to tentorial notch. its external convex border encloses transverse sinus posteriorly and the superior petrosal sinus anteriorly. The free border is attached to the anterior clinoid process, the attached border is attached to the posterior clinoid process.
    22. 22.     Sickle-shaped Occupies the posterior notch of the cerebellum Is attached to the posterior and inferior parts of the tentorium. Contains occipital sinus in its posterior border.
    23. 23.   Is circular, horizontal fold of dura that forms the roof of sella turcica,covering the pitutary gland or hypophysis. Has a central aperture for the hypophyseal stalk or infundibulum.
    24. 24.    Anterior and posterior ethmoidal branches of V1 in the anterior cranial fossa Meingeal branches of maxillary V2 &V3 in the middle cranial fossa. Meningeal branch of the CN X and by tentorial nerve (V1) in the posterior cranial fossa.
    25. 25.     Dura is supplied by Middle meningeal artery which has anterior and posterior branches, from 1st part of maxillary artery(via foramen spinosum) Acessory meningeal artery from 1st part of maxillary artery (via foramen ovale) Meningeal branches of opthalmic, occipital and vertebral arteries.
    26. 26. Veins accompanying the arteries drain into pterygoid plexus of veins.
    27. 27.    Is a filmy, thin, transparent, and delicate membrane that is connected to pia matter by web-like trabeculations. Separated from the dura by a capillary interval, the subdural space which is occupied by a film of to fluid to moisten and connective tissue. The space between the arachnoid and pia is called the subarachnoid space.
    28. 28.     Filled with C.S.F. Contains fine filaments and trabeculae connecting the arachnoid to the pia The blood vessels of the brain lie in it. In certain places the subarachnoid space is enlarged to form subarachnoid cisterns which contains CSF and soft tissue structures that‖anchor‖ the brain, such as arachnoid trabeculae, vasculature, and in some cases cranial roots. They are named according to the structures related them.
    29. 29. Formed by wide separation of the arachnoid from the pia. The cisterns are.  Cerebellomedullary cistern (cisterna magna) Site: between the back of the medulla and the lower part of the cerebellum divides into postrior and lateral. Receives CSF from the aperature of 4th ventricle pontine cistern Site: in front of the pons it continues with spinal subarachenoid space Contains: the vertebral and basilar arteries.
    30. 30. Interpeduncular cistern: Site: interpedunculaar fossa b/n cerebral peduncles of the mid brain. Contains: the arteries which form the circulus arteriosus  Chiasmatic cistern Site optic chiasma. Cistern of the lateral sulcus (Ambient): Site: lateral sulcus (lateral aspect of the mid brain continous posteriorly with quadrigeminal cistern) Contains: middle cerebral vessels. 
    31. 31.  Cistern of corpus callosum (quadrigeminal cistern) Site: above the corpus callosum or posterior part of the corpus callosum & superior surface of cerebellum. It contains parts of the great cerebral vein. Contains: the anterior cerebral artery
    32. 32.     Pedunculated projections from the arachnoid mater which tend to push themselves inside the venous sinuses of the dura. are tuft-like collections of highly folded arachnoid that project into the superior saggital siunus and the lateral lacunae, which are lateral extensions of the superior saggital sinus. absorb CSF into dural sinuses and often produce erosion or pitting of the inner surface of clvaria (indent bones) They protrude through the meningeal layer of the dural matter into dural venous sinuses, especially the lateral lacunae, and effect transfer of CSF to venous system.
    33. 33.   They are found in large number along there superior sagittal sinus. Their function is to allow the filtration of C.S.F from the subarachnoid to the blood stream in the superior sagittal sinus.
    34. 34.  It is the thinnest and most delicate membrane of the brain.  Covers the gyri and dips into fissures and sulci.  enmeshes blood vessels on the surface of the brain.  Invaginates the interior of the brain forming folds of pia called tela chorioidea which produce C.S.F.
    35. 35. What is leptomeninges? Pia-arachnoid, because they develop from a single layer of mesenchyme surrounding the embryonic brain. 
    36. 36.  Dura-skull interface(extradural or epidural space.  Dura-arachnoid interface(subdural)space.  Arachnoid-pia interface(subarachnoid)space.
    37. 37. Epidural hematoma:  is due to rupture of middle meningeal artery. Subdural hematoma:  is due to rupture of cerebral veins as they pass from brain surface into one of the venous sinuses. Subarachnoid hemorrhage: is due to rupture of cerebral arteries.
    38. 38. Pial hemorrage:  is due to damage to small vessels of the pia and brain tissue. Cavernous sinus thrombophlebitis: is an infectious inflammation of the cavernous sinus with secondary thrombus formation.   Is associated with significant morbidity and mortality because of formation of meningitis (inflammation of the meanings May produce papilla edema(edema of optic disc, probably due to raised intracranial pressure), exophthalmoses (protrusion of the eye ball),and ophthalmoplegia (paralysis of eye muscles) why?
    39. 39.    The midbrain, pons and medulla lie, one below the other below the cerebrum and infront of the cerebellum. Occupies the posterior cranial fossa of the skull They are collectively called (brain- stem).
    40. 40. The brainstem has three broad functions: I. It serves as a conduit for the ascending tracts and descending tracts II. It contains important reflex centers associated with the control of respiration and the cardiovascular system and with the control of consciousness III. It contains the important nuclei of cranial nerves III through XII
    41. 41.   Damage to the brain stem is often devastating and life-threatening. Because it is a structurally and functionally compact region,
    42. 42. GENERAL     It is about one inch long Continuous above with the lower border of the pons Continuous below with the spinal cord at the foramen magnum Its upper half forms part of the floor of the fourth ventricle
    43. 43.     Its lower half is tunneled by the central canal which connects the fourth ventricle with the central canal of the spinal cord. According to 4th ventricle M.O divides into two Upper medulla (open) is motor decussation Lower medulla (closed) is sensory decussation
    44. 44. In the ventral aspect three elevations are present  Pyramid: Is the bundle that lies alongside the anterior median fissure.  Pyramidal decussation: is seen in the lower part of the medulla.  Obliterating the lower end of the anterior median fissure 2. Olive 1.  Is the oval elevation that lies lateral to the pyramid.  Produced by the olivary nucleus.  3. Inferior cerebellar pudencle
    45. 45. we have also groves I. II. Anterior median fissure: lies in the middle line Anterolateral sulcus: Between the olive and the pyramid.  The rootlets of hypoglossal nerve come out along this sulcus III. Posterolateral sulcus: Separates the olive from the inferior cerebellar peduncle  The rootlets of 9, 10 & 11 cranial nerves come out along this sulus
    46. 46.  Hypoglossal nerve: comes out along the anterolateral sulcus  Glossopharayngeal, vagus and accessory nerves: come out along the posterolateral sulcus.
    47. 47. posterior median fissure:    Exists only in the lower half The upper of the posterior surface of the medulla forms part of the floor of the fourth ventricle. Lower medulla Gracile tract and tubercle :     Slender bundle lies alongside the posterior median fissure. Produced by the gracile tract. Ends a small elevation called tubercle which is produced by gracile nucleus.
    48. 48. Cuneat tract and tubercle :    Slender bundle lateral to the fasciculus gracilis Produced by the cuneate tract Ends in small elevation called cuneate tubercle which is produced by cuneate nucleus. Inferior cerebellar peduncle     Thick rope – like bundle that lies lateral to the fasciculus cuneatus. Begins at the middle of the medulla, Extends upwards and laterally to reach the lower part of the back of the pons It bends sharply back-wards between the middle and superior cerebellar penduncle to enter the cerebellum
    49. 49.    Upper ½ of the posterior surface This belongs to the open medulla Forms the floor of 4th ventricle
    50. 50. The following Features seen: Hypoglossal triangle over lies the hypoglossal nucleus  lies near to the posterior median sulcus  Vestibular area Lies in the lateral side of the posterior surface  Produced by the vestibular nuclei
    51. 51.      Vagal triangleDepressed area b/n vestibular and hypoglossal Overlies dorsal nucleus of the vagus Inferior cerebellar peduncle Forms most lateral elevation in the posterior surface
    52. 52.      Nerves attached to the medulla Cranial nerves from 6th -8th are attached at the junction b/n medulla and pons From 9th – 12th are attached to the surface of the medulla 9th, 10th and 11th cranial nerves are attached at the groove b/n olive and inferior peduncle The 12th attached in the anteriolateral groove
    53. 53.  Medulla oblongata: TS at the level of pyramidal decussation centrally central canal of MO  Gray matter surrounding the central canal  decussating pyramidal fibres –separating the ventral gray column and central gray matter 
    54. 54. Fasiculus gracilis- occupying the region behind central gray matter medially Fasiculus cuenatus: occupying the region behind central gray matter laterally Nucleus gracilis: tongue shaped extension central gray matter medially Nucleus cuenatus: tongue shaped extension central gray matter laterally Spinal nucleus of trigeminal nerve : lateral to nucleus cuenatus Cortico spinal fibres: on each side of mid line Medial lemniscus the region behind pyramid on each side of mid
    55. 55. line     sensory decussaion : crossing fibres of medial lemniscus reticular formation: ( scattered neurons mixed with nerve fibres ) : lateral to medial lemniscus. mass of white matter.containing various tracts more
    56. 56.  Is Interposed between the medulla (below) and the midbrain (above) and in front of the cerebellum.
    57. 57.  Anterior surface:  median groove: sulcus basilaris (basilar sulcus of pons) for the basilar artery.  transverse pontine fibers: form many thick transverse bundles.  abducent nerve: emerges between the pons and the pyramid near the middle line.
    58. 58.     Lateral surface Middle cerebellar peduncle: Thick compact bundle Formed by the collection of the transverse pontine fibers. Sinks in to the corresponding cerebellar hemisphere
    59. 59.     Roots of trigeminal nerve: Arises at the point of junction between the pons and the middle cerebellar peduncle. Two roots, a large sensory one medially a smaller motor one laterally
    60. 60.  Pontocerebellar angle: Triangular space between the:  Lower border of middle cerebellar peduncle  Cerenellum  Upper part of the medulla.  Facial and auditory nerves: Attached to the pons in the region of pontocerebellar angel Posterior surface:   forms the upper part of the floor of the 4th ventricle. Three foramina, F. luschka, F. magendi via this CSF moves to subarachenoid space to cisterne magnum
    61. 61. PONS :TS via upper part shows : A . ventral part(basilar) 1. Transverse fibres 2. Vertical fibres – those descending from cerebral cortexto end in pontine Nuclei.         cortico spinal fibres that descend via pons into the medulla where they form pyramid pontine nuclei middle cerebral peduncle- formed from transverse fibres laterally toward cerebellum
    62. 62.     on dorsal surface.(tegmentum) 1. tegmentum continuous with tegmentum of the mid brain superiorly 2. spinal nucleus of trigeminal nerve- medial to peduncles 3. medial lemniscus and other fibres
    63. 63.      Definition: is the shortest part of the brain stem Position: between the pons below and the thalamus above Occupies the notch of Tentorium cerebelli Mid brain cavity:it is tunneled from end to end by a narrow channel called aqueduct which connects the Third ventricle with the fourth
    64. 64.  two cerebral peduncles       Rope-like bundle of fibres (crus of mid brain) Pass in to the anterior part of the pons below Sinks in to the substance of the cerebral hemispheres above Posterior to crus there are substancia nigra and tegmentum respectively two oculomotor nerves emerge medial to the cerebral peduncles
    65. 65. Contains   corpora quadrigemina (colliculi)            form the tectum four rounded swellings a) two superior b) two inferior - the superior colliculi are reflex centers for vision - the inferior colliculi are reflex centers for hearing 2. Trochlear nerve - emerge from the dorsal surface below the inferior colliculi - the trochlear nerve is the only cranial nerve which emerges from the dorsal surface of the brain. b/n the anterior and dorsal parts (two crura of mid brain) forms interpedunclar fossae
    66. 66.  superior brachium quadrigeminum composed of strands of fibres that extend from the superior colliculus to the lateral geniculate body.   inferior brachium quadrigeminum :composed of bundles of fibres that extend from the inferior colliculus to the medial geniculate body
    67. 67.        Shape :diamond shaped Site : at the base of the brain anterior to the pons Boundaries : Anteriorly :optic chiasma Posteriorly : pons On both sides: 1. optic tract (in front) cerebral peduncle(behind
    68. 68.   Important structures in the fossa: posterior perforated substance:    lies in the posterior part of the fossa formed of a layer of gray matter perforated by the central branches of the posterior cerebral arteries. two mamillary bodies :  pair of rounded structrer place side by side immediately in front of the posterior perofrated substance
    69. 69. MID BRAIN Tectum part laying behind a horizontal line drawn via the cerebral aqueduct . Each with three parts from anterior to posterior are     crus cerebri(basis peduncle)- containing large mass of vertically running fibres , they descend from cerebral cortex , some pass via mid brain , to reach pons , while others reach the spinal cord. Substantia nigra- is made up of pigmented gray matter , hence appears dark in color and its damage leads to parkinson’sdisease
    70. 70.      is the largest part of hind brain. in the posterior cranial fossa & covered by tentorium cerebelli 150 gms. ratio : of cerebellum to cerebrum is 1/8 in adult & 1/20 in infant. the cerebellum is composed of two cerebellar hemispheres connected in the middle by a central portion called vermis. Its greatest length is from side to side.
    71. 71.   the superior vermis is not marked clearly from the upper surface of the cerebellar hemispheres. The inferior vermis is marked clearly from the inferior surface of the cerebellar hemispheres as it lies at the bottom of a deep groove called vallecula cerebelli. The cerbellum has two notches and two surfaces:  anterior notch  posterior notch  upper surface  lower surface
    72. 72. Anterior notch  Wide and shallow notch  Occupied by the midbrain, pons and medulla Posterior notch  Narrow and deep  Occupied by a fold of dura called falx cerebelli
    73. 73. Upper surface: (superior)  Looks like a butterfly with outstretched wings; the superior vermis represents the body of the butterfly and the two cerebellar hemispheres represent the wings.  No definite lines of demarcation between the superior vermis and the upper surface of the cerebellum
    74. 74. Lower surface: (inferior)  Is large and rounded  The two cerebellar hemispheres are separated by a deep groove, the vallecula cerebelli in which the inferior vermis lies  The inferior vermis is formed of 3 lobules from before backwards.
    75. 75.      Nodule Uvula Pyramid Two lateral extensions termed floculus and parafloculus extend laterally from each side of the nodule are separated from the rest of the cerebellum by postero-lateral fissure.
    76. 76.     Primary fissure: on the superior surface nearly at the junction of anterior 2/3 with the posterior one thirds of the superior surface. Horizontal Fissure: Sweeps around the margin of the cerebellum from the anterior notch to the posterior notch separates the upper and lower surfaces of each hemisphere.
    77. 77. Postero-lateral fissure:  Separates the flocculus and paraflocculus from the rest of the cerebellum  Secondary fissure: behind the pyramid
    78. 78. 1. Anterior Lobe:  Is uniformly developed.  In front of the primary fissure  Median part: superior vermis in front of the primary fissure  Two lateral extensions: superior surface, anterior to the primary fissure.
    79. 79.  Formed of a narrow median part and a huge lateral extensions.  Median part: superior vermis between the primary and secondary fissures.  Two lateral extensions: formed by the posterior part of the superior surface and the greater part of the inferior surface.
    80. 80.  Formed of a well developed median part (inferior vermis) and rudimentary pairs of lateral extensions (flocculus and paraflocculus
    81. 81. Superior cerebellar artery  Origin: basilar artery  Supplies: superior surface of cerebellum Anterior inferior cerebellar artery  Origin :basilar artery  Supplies :anterior part of inferior surface posterior inferior cerebellar artery  origin : vertebral artery  supplies: posterior part of inferior surface
    82. 82. Is the cavity of hind brain  between the cerebellum behind and the pons and upper part of the medulla in front  tent-shaped (diamond) Lateral boundaries: Upper part: superor cerebellar peduncles Lower part: inferior cerebellar peduncles 
    83. 83. Has four angles:  upper angle  lower angle  two lateral angle
    84. 84.    the superior angle is continuous with the cerebral aqueduct which connects it with the third ventricle. The inferior angle is continuous with the central canal of the medulla. The lateral angle is the meeting of the superior and inferior cerebellar peduncles.
    85. 85. Roof: looks like a tent    Upper part: formed by the superior cerebellar peduncles and the superior medullary velum which consists of ependyma attached to the inner margins of the superior peduncles Middle part: cerebellum Lower part: formed by the inferior medullary velum which consists of ependyma attached to the inner margins of the inferior cerebellar peduncles.
    86. 86. Floor: formed  Above: by the back of the pons  Below: by upper part of the back of the medulla. the floor is divided by transverse band of a nerve fibers called medullary striae in to:    Pontine portion: above Medullary portion: below
    87. 87. Pontine portion:  Is divided in to two longitudinal halves by median sulcus  Inferior cerebellar puduncle forms the floor of the ventricle
    88. 88.     is divided it to two longitudinal halves by median sulcus on either side of the median sulcus there is a longitudinal elevation called median eminence (eminentia medialis) above the middle of the median eminence there is a rounded swelling termed the facial colliculus which is produced by the abducent nucleus and the encircling facial nerve fibers
    89. 89.      shows a small v- shaped depression called the inferior fovea . - the inferior fovea divides the medullary portion in to three trigones 1. Hypoglossal trigone: medial to the inferior fovea (for CN 12) 2. vagal trigone: between the limbs of the inferior fovea (for CN 10) 3. vestibular trigone (for CN 8): lateral to the inferior fovea
    90. 90. 1.median aperture(foramen of magendi) in the inferior medullary velum(lower part of the roof) 2. lateral aperture(foramen of Luschka) is found in the lateral recess which is a pocket-like extension of the fourth ventricle on either sides
    91. 91.    Third ventricle through the cerebral aqueduct central canal of medulla through its inferior angle subarachnoid space through the medial and lateral apertures
    92. 92.      Four cranial nerve nuclei Abducent : opposite the facial colliculus Hypoglossal: hypoglossal trigone Vagus: vagal trigone Vestibular: Vestibular trigone
    93. 93.     is composed of right and left cerebral hemispheres the two hemispheres are to a large extent separated from each other by a longitudinal fissure. The longitudinal fissure is complete in front and behind but is interrupted in the middle by the corpus callosum . The longitudinal fissure is occupied by the falx cerebri.
    94. 94. a) Poles of the cerebral hemispheres: 1. Frontal pole – is rounded - lies opposite the root of the nose and medial part of the supeciliary arch. 2. Occipital pole- is more pointed - lies opposite a spot above and lateral to the external occipital protuberance. 3. temporal pole- is rounded - fits in to the recesses of the lateral part of the middle cranial fossa below the lesser wing of sphenoid.
    95. 95. b) Borders of the cerebral hemispheres: 1. supero-medial border: - is the upper margin of the hemisphere - extends from the frontal to the occipital poles - lies between the medial and lateral surfaces 2. infero-lateral border: - extends from the occipital to the temporal poles - lies between the supero-lateral and inferior surfaces. - presents a notch ,called pre- occipital notch one and half inches in front of the occipital pole
    96. 96. 3. super ciliary border:  extends from the frontal pole to the end of the stem of lateralsulcus. 4. medial orbital:  extends from the frontal pole to the optic chiasma 5. medial occipital border:  extends from the occipital pole to the corpus callosum
    97. 97. c) Surfaces of the hemispheres: 1. supero-lateral surface -large and convex - directed laterally 2. medial surface - flat - directed medially 3. inferior surface -directed inferiorly -divided by a lateral sulcus into two parts: a, orbital surface: lies on the roof of the orbit b, tentorial surface: lies on the tentorium cerebelli
    98. 98. d) sulci which divide the hemeispheres into lobes: 1. central sulcus -lies on the lateral surface 2. posterior ramus of the lateral sulcus: -arise from stem of the lateral sulcus which lies between the oribital and tentorial surfaces. 3. parieto-occipital sulcus: -found mainly on the medial surface -extends for a short distance on the lateral surface. 4. pre-occipital notch: -lies on the inferolateral border 1.5in. in the front of the occipital pole.
    99. 99. 1. frontal lobe: in front of the central sulcus 2. parietal lobe: between: a, central sulcus…….infront b, upper part of the vertical line…..behind c., posterior ramus of the lateral sulcus and the horizontal line below. 3.occipital lobe: behind the vertical line 4. temporal lobe: below the posterior ramus of the lateral sulcus and the horizontal line. 5. insular lobe: deep to lateral sulcus, covered by operculum
    100. 100. Frontal lobe a, sucli of frontal lobes 1. precentral sulcus: -one fingers breadth infront of the central sulcus and is nearly parallel to it. 2. superior frontal sulcus: -begins at the upper part of the precentral sulcus -runs forewards parallel to the upper border.
    101. 101. 3. inferior frontal sulcus: -begins at the lower part of precentral sulcus -runs forewards parallel to the superior frontal sulcus. 4. the two anterior rami of lateral sulcus: -both arise from stem of lateral sulcus -the anterior horizontal –extends forewards. -the anterior vertical –extends upwards.
    102. 102. b) gyri of the frontal lobe : 1. precentral gyrus: -between the central and precentral sulci -contains the motor area of the opposite half of the body. 2. superior frontal gyrus: -lies above the superior frontal sulcus 3. middle frontal gyrus: -lies between the superior and inferior frontal sulci. 4. inferior frontal gyrus -lies below the inferior frontal sulcus.
    103. 103. c) important areas on the frontal lobe: 1. motor area: -found in the precentral gyrus -the body is turned upside down in the areahead,upper limb, trunk,and lower limb from below upwards(somatotopicaaly organized). the area for the lower limb flows over the superiomedial border into the paracentral lobule on the medial surface. premotor area: -is the region infront of the motor area and parallel to it. -is the extrapyramidal motor area for the eye.
    104. 104. 1. 2. 3. 4. Primary Motor Cortex Premotor Cortex Broca’s Area Frontal Eye Field 150
    105. 105. Premotor cortex Primary motor cortex Frontal Eye Field Broca’s Area 151
    106. 106.  Somatotopy - The entire body is represented spatially in the primary motor cortex, i.e., in one region we have neurons controlling hand movements and in another region leg movements, etc. - Neurons controlling movement of different body regions do not intermingle. 152
    107. 107.  Located in the precentral gyrus of each cerebral hemisphere.  Allowing for voluntary motor control. 153
    108. 108. 154
    109. 109.      3. frontal eye field area: -lies in the posterior part of the middle frontal gyrus - is the pyramidal motor area for the eye. 4. Broca’s motor area of speech; -found in the posterior part of the inferior frontal gyrus in the left hemisphere (in right handed people).
    110. 110.    Located just anterior to the primary motor cortex. Involved in learned or patterned skills Involved in planning movements 156
    111. 111.    Typically found in only one hemisphere (often the left), anterior to the inferior portion of the premotor cortex Directs muscles of tongue, lips, and throat that are used in speech production Involved in planning speech production and possibly planning other 157
    112. 112.    Controls voluntary eye movements Found in and anterior to the premotor cortex, superior to Broca’s area What muscles would be affected if this area was damaged? 158
    113. 113.    Found in the frontal lobe just above the orbits Receptors in the olfactory epithelium extend through the cribriform plate and are excited by the binding of oderants. They then send their info to the olfactory cortex Very much 159
    114. 114. 160
    115. 115. Sulci of the parietal lobe: postcentral sulcus: one finger’s breadth behind the central sulcus and is mearly parallel to it. Intraparietal Sulcus Begins close to the middle of the postccentral sulcus and runs backwards to the occipital lobe.
    116. 116.   Gyri of the partietal lobe:    the up turned posterior parts of  posterior ramus of lateral sulcus.  Superior temporal sulcus.  Inferior temporal sulcus. postcentral gyrus: between the central and postcentral sulci. Contains the sensory area for the opposite half of the body
    117. 117.     Superior parietal lobule: is the part above the intraparietal sulcus. inferior parietal lobule: is the part of below the intraparietal sulcus. supramarginal gyrus: surrounds the upper endd of the posterior ramus of the lateral slcus. angular gyrus: surrounds the upper end of the superior temporal sulcus.
    118. 118.      sensory area Found in the postcentral gyrus As in the motor area the body is represented upside down. The sensory area for the lower limb extendes over the superomedial border in to the paracentral lobule on the medial surface. The center for the strage of the memory of written and printed wores is found in the supramarginal and angular gyri
    119. 119.    Found in the postcentral gyrus Neurons in this cortical area receive info from sensory neurons in the skin and from proprioceptors which monitor joint position Contralateral 165
    120. 120. 167
    121. 121.   Found posterior to the primary somatosensory cortex and is neurally tied to it Synthesizes multiple sensory inputs to create a complete comprehension of the object being felt. 168
    122. 122.   Gustatory cortex is involved in taste and is in the parietal lobe just deep to the temporal lobe Vestibular cortex is involved in balance and equilibrium and it is in the posterior insula 169
    123. 123.      The main part of the occipital lobe is found on the medial surface only 2 small part of it appears on the lateral surface. post –calcarine sulcus: may extend on the lateral surface and crrying a part of the center of vision with it. Sulcus lunatus: Curved sulcus Surrounds the posterior end of the postcalcarine sulcus.
    124. 124.    Found in the posterior and medial occipital lobe Largest of the sensory cortices Contralat eral 171
    125. 125.    Surrounds the primary visual cortex Basically vision is the sensation of bars of light on our retinal cells. The primary visual cortex tells which cells are being stimulated and how. The association area lets us “see” what we’re looking at. 172
    126. 126.  sulci of the temporal lobe:  superior temporal sulcus:  runs parallel to the posterior ramus of lateral sulcus and about one finger’s breadth below it.  inferior temporal sulcus  runs parallel to the superior temporal sulcus and about one finger’s breadth below it.
    127. 127.       Auditory association area: surrounds the auditory sensory area and occupies most of the rest of superior temporal gyrus. Responsible for knowing the meaning of the sounds. Inferior surface The inferior surface of the brain is divided by the stem of the lateral sulcus in to: orbital surface_____rests on the orbit. Tentorial surface ________ rests on the tentorium cderebelli
    128. 128.    Found in the superior margin of the temporal lobe, next to the lateral sulcus Sound waves excite cochlear receptors in the inner ear which send info to the auditory cortex There is also an auditory association area which lets us interpret and remember sounds 175
    129. 129.   between the superior temporal sulcus and posterior ramub s of lateral sulcus.    Inferior temporal gyrus: Below the inferior temporaral sulcus. important areas of the temporarl lobe.   Middle temporal gyrus: Between the superior and inferior temporal sulci   superior temporal gyrus: The center of hearing (Heschl’s grus): Found in the middle of the superior temporaral gyrus.
    130. 130.  sulci of the oribital surface   The oldfactory bulb and tract lie in it.    olfactory sulcus: is straight deep sulcus parallel to medial border. Oribital sulci: H-shaped sulcus on the lateral side of the olfactory sulcus. b. gyri of the oribital surface:
    131. 131.       gyrus rectus: between the oldfactory sulcus and the medial border. oribital gyri: Anterior: anterior to the oribital sulcus Posterior: posterior to the oribital sulcus. Medial: medial the oribital sulcus. Lateral___lateral to the oribital sulcus
    132. 132.     . The sulci and gyri of the tentorial surface will be studied with the medial surface. Medial surface sulci of medial and tentorial surface:   Callosal sulcus: Lies above the corpus callosum
    133. 133.    Is the continuation of the callosal sulcus on the tentorial surface. Ends in the uncus.    Hippocampal sulcus: Sulcus cinguli: Parallel to the callosal sulcus and about one finger’s breadth above it. Its posterior and curves upwards to end on the superomedial border just behind the upper end of the central sulcus.
    134. 134.   Its upper end lies on the medial surface just in front of the upturned part of the sulcus cinguli.    Central sulcus Calcarine sulcus: begins on the tentorial surface below the splenium of corpus callosum. Passes upwards and backwards on to the medial surface of the occipital lobe where it joins the paretoccipital sulcus
    135. 135.  The change of name is due to the fact that the two parts develop independently  Post-calcarine sulcus:   Runs downwards and backwards to end the medial surface near the occipital pole. May curve round the occipital pole to end on the superolateral surface.  parieto-ocipital sulcus   Extends from the end of the calcarine sulcus upwards. Cuts the supero-medial border one and half inches above the occipital pole.
    136. 136.    Collateral sulcus. Is the best marked sulcus on the tentorial surface. Extends from the occipital pole to the temporal pole.  Occipito-temporal sulcus   Parallel with the collateral sulcus and about on inch lateral to it. the gyri of the medial and tentorial surfaces:  The cuneus: is the triangular area bounded by the post-calcarine sulcus, parieto-occipital sulcus and the supero-medial border. Importance; contains part of the visual are.
    137. 137.  pre- Cuneus:  guadrate area between the parieto-occipital sulcus and the upturned part of the sulcus cinguli.  Lingual gyrus:    Looks- like the tongue. Lies below the calcarine and post-calcarine sulci. Importance; contains a great part of the visual area.  gyrus cinguli   Lies between the callosal sulcus and the sulcus cinguli Sometimes called parahippocampal gyrus.
    138. 138.   Concerned with the olfactory sense. May contain the center for the sense of taste.  Isthmus of gyrus cinguli:   Narrow strip between the splenium and the anterior part of calacarine sulcus. It connects the hippocample gyrus and gyrus cinguli.
    139. 139. lateral occipito-temporal gyrus:  lies on the lateral side of the occipito-temporal sulcus. Miedal occipitio-temporal gyrus     Medial to the occipito-temporal sulcus between it and the collateral sulcus. Important areas on the medial and tentorial surfaces: Center for sight (vision) lies below the calcarine sulcus and above and below the post-calcarine and around its end.
    140. 140. Visual association area: Surrounds the visual area. Responsible for knowing the meaning of the pictures seen. Hippocampal gyrus:      concerned with the olfactory sese but may contain the center for the sense of taste.
    141. 141.   1. 2. 3. 4. Allows for analysis of sensory input. Multiple inputs and outputs Prefrontal cortex Language areas General interpretation area Visceral association area 188
    142. 142. Prefrontal Cortex    Anterior frontal lobes Involved in analysis, cognition, thinkin g, personality, & much more. Look at its evolution 189
    143. 143. Large area for language understanding and production surrounding the lateral sulcus in the left (language-dominant) hemisphere  Includes: - Wernicke’s area  understanding oral or written words - Broca’s area  speech production  190
    144. 144.  General area integrates multiple stimuli into a single logical “understanding of the situation.” Found on only one hemisphere – typically left.  Contained by 3 lobes: temporal, occipital, and parietal.   Visceral association area is involved in perception of visceral sensations (such as digest).  Located in insular cortex 191
    145. 145. Lateralization     The fact that certain activities are the almost exclusive domain of one of the 2 hemispheres In most people, the left hemisphere has a more control over language, math, and logic While the right hemisphere is geared towards musical, artistic and other creative endeavors Most individuals with left cerebral 192
    146. 146. 193
    147. 147.        Anterior Cereberal Artery Origin: from internal carotid. Course passes foerwaeds and medially towards the middle line. Turns upwards to reach the genu of corpus callosum. Runs backwares along the upper surface of corpus callosum till the splenium. Ends by turning upwards anterior to the parietooccipital sulcus
    148. 148. 1. Central branches  Several slender twigs that pierce the surface of the brain in front of the optic chiasma.  Supplies.  Anterior part of corpus striatum  Anterior limb of internal capsule 2. Cortical branches:    Medial part of oribital surface Medial surface except the occipital lobe Upper inch of the lateral surface except the occipital lobe
    149. 149. 3. Callosal branches:  To all parts of the corpus callosum except the splenium  Important regions supplied by the anterior cerebral artery  Motor and sensory areas of the lowerlimb in the paracentral lobule on the medial surface.  Corpus callosum.
    150. 150.    Effect of lesion in anterior cerebral artery: paralysis and loss of sensation of the lower limb. Apraxia results from a lesion of corpus callosum. Apraxia is the inability of the person to do a purposeful movements although the muscles concerned with these movements are not paralysed.
    151. 151.     Origin: from the internal carotid Course: Runs laterally in the stem of the lateral sulcus. Terminates on the insula by dividing in to several branches on the lateral surface.
    152. 152. 1. centeral branches:  Small numerous arteries that pass through the anterior perforated substance to the interior  Called striate arteries because they are spent chiefly in supplying the corups striatum and internal capsule  They are classified in to medial and lateral groups according to their relation to the lentiform nucleus.  One large branch of these arteries is called the artery of cerebral haemorrhage.
    153. 153. 2. Cortical branches: supply       Lateral part of oribital surface Superolateral surface except. Upper inch (anterior cerebral). Occipital lobe (post cerebral) Importance areas supplied by middle cerebral: Motor and sensory areas of the whole body except the lower limb which is supplied by the anterior cerebral artery Centre of hearing Genu and posterior limb of the internal capsule.
    154. 154.     Posterior Cerebral Artery Origin: one of the two terminal branches of the basilar artery. Course: curves laterally and backwards round the midbrain towards the occipital pole. Enters the calcarine sulcus where it divides in to two terminal branches which run onwards in the postcalcarine and parieto-occipital sulci.
    155. 155. 1. Central branches; two groups.   Medial group: pierce the posterior perforated substance. Lateral group: pierce the side of the midbrain. They supply the thalamus and the midbrain. 2. Cortical branches: supplies.    Tentorial surface except the temporal pole Lower inch of the superolateral surface. Occipital lobe. 3. Posterior choroids artery  artery on the side of midbrain.  Passes inside the brain to supply the choroids plexus of the third and lateral ventricles.
    156. 156.     The centre of vision in the occipital lobe. The centre of smell in the uncus. Thalamus and midbrain. Most of the choroids plexus of third & lateral ventricles
    157. 157. Where’s the insula? What’s the name of this region What’s this called?
    158. 158.  How do you remember which nerve is which number?  Here is a G-rated mnemonic devices:  Old Opie occasionally tries trigonometry and feels very gloomy, vague, and hypoactive.   There are also several R-rated ones Some cranial nerves are sensory, some motor, and some are both (mixed).
    159. 159.      How many noses do you have? Sensory, motor, or mixed? Run from the nasal mucosa to the olfactory bulb. Extend thru the cribriform plate. Lesion to these nerves or cribriform plate fracture may yield anosmia – loss of smell.
    160. 160.      How many eyes do you have? Sensory, motor, or mixed? Begin at the retina, run to the optic chiasm, cross over, continue as the optic tract and synapse in the thalamus. Optic nerve damage yields blindness in the eye served by the nerve. Optic tract damage yields partial visual loss. Visual defects = anopsias
    161. 161.     ―Eye mover‖ Sensory, motor, or mixed? Originate at the ventral midbrain. Synapse on:  Extraocular muscles  Inferior oblique; Inferior, medial, and superior rectus    Iris constrictor muscle Ciliary muscle Disorders can result in eye paralysis, diplopia or ptosis.
    162. 162.     Controls the superior oblique muscle which depresses the eye via pulling on the superior oblique tendon which loops over a ligamentous pulley known as the trochlea. Originates on the dorsal midbrain and synapses on the superior oblique Sensory, motor, or mixed? Trauma can result in double vision.
    163. 163. CN5 Trigeminal Nerves    Sensory, motor, or mixed? Biggest cranial nerve Originates in the pons and eventually splits into 3 divisions:    Ophthalmic (V1), Maxillary (V2), & Mandibular (V3). Sensory info (touch, temp., and pain) from face. Motor info to muscles of
    164. 164.   Sensory, motor, or mixed? Runs between inferior pons and lateral rectus. CN5 Abducens Nerves
    165. 165.       Sensory, motor, or mixed? Originates at the pons Convey motor impulses to facial skeletal muscles – except for chewing muscles. Convey parasympathetic motor impulses to tear, nasal, and some salivary glands. Convey sensory info from taste buds on anterior 2/3 of the tongue. Facial nerve damage may yield Bell’s palsy, total ipsilateral hemifacial paralysis
    166. 166.    Sensory, motor, or mixed? Originates at the pons 2 divisions:  Cochlear  Afferent fibers from cochlea in the inner ear  HEARING  Vestibular  Afferent fibers from equilibrium receptors in inner ear  BALANCE  Functional impairment?
    167. 167.    Sensory, motor, or mixed? Fibers run emerge from medulla and run to the throat. Motor Functions: Motor fibers to some swallowing muscles  Parasympathetic fibers to some salivary glands Sensory Functions:   Taste, touch, heat from pharynx and posterior tongue.  Info from chemoreceptors on the level of O2 and CO2 in the blood. Info from baroreceptors on BP.  Chemoreceptors and baroreceptors are located in the carotid sinus – a dilation in the internal carotid artery. 
    168. 168.   Sensory, motor, or mixed? Only cranial nerves to extend beyond head and neck.   Motor Functions:   Fibers emerge from medulla, leave the skull, and course downwards into the thorax and abdomen. Parasympathetic efferents to the heart, lungs, and abdominal organs. Sensory Functions:  Input from thoracic and abdominal viscera; from baroand chemoreceptors in the carotid sinus; from taste buds in posterior tongue and pharynx
    169. 169.   Sensory, motor, or mixed? Formed by the union of a cranial root and a spinal root.    CR arises from medulla while SR arises from superior spinal cord. SR passes thru the FM and joins with CR to form the accessory nerve. They then leave the skull via the jugular foramen. Cranial division then joins vagus and innervates larynx, pharynx, and soft palate. Spinal division innervates sternocleidomastoids and trapezius.
    170. 170.    Sensory, motor, or mixed? Arise from the medulla and exit the skull via the hypoglossal canal and innervate the tongue. Innervate the intrinsic & extrinsic muscles of the tongue.   Swallowing, speech, food manipulation. Damage?