I HEAD, NECK, BRAIN AND UPPER SPINAL CORD

Head, Neck, Brain and Upper Spinal Cord



Skull of full-term fetus – A from the front; B from above


Image



1  Right parietal bone


2  Left parietal bone


3  Anterior fontanelle


4  Parietal tuberosity


5  Right frontal bone


6  Left frontal bone


7  Frontal tuberosity


8  Frontal (metopic) suture


9  Coronal suture


10  Supra-orbital margin


11  Infra-orbital margin


12  Right maxilla


13  Left maxilla


14  Right nasal aperture


15  Left nasal bone


16  Anterior nasal aperture


17  Nasal septum


18  Ramus of mandible


19  Body of mandible


20  Symphysis menti


21  Sagittal suture


22  Posterior fontanelle


23  Lambdoid suture


24  Occipital bone


Skull of full-term fetus – C from the left


Image



1  Left frontal bone


2  Frontal tuberosity


3  Coronal suture


4  Parietal bone


5  Parietal tuberosity


6  Lambdoid suture


7  Occipital bone


8  Mastoid fontanelle


9  Petrous part of temporal bone


10  Stylomastoid foramen


11  Tympanic ring


12  Squamous part of temporal bone


13  Condylar process of mandible


14  Ramus of mandible


15  Body of mandible


16  Maxilla


17  Septal cartilage


18  Nasal bone


19  Zygomatic bone


20  Greater wing of sphenoid


21  Sphenoidal fontanelle



Normal postnatal closure of the six fontanelles:


  Sphenoidal (anterolateral) fontanelle (left and right) – 3 months


  Posterior (median) fontanelle – 3 months


  Mastoid (posterolateral) fontanelle (left and right) – 12 months


  Anterior (median) fontanelle – 18 months


Adult skull – from the right


Image



1  Supra-orbital foramen


2  Nasion


3  Nasal bone


4  Frontal process of maxilla


5  Lacrimal bone


6  Anterior lacrimal crest


7  Posterior lacrimal crest


8  Fossa for lacrimal sac


9  Orbital part of ethmoid bone


10  Orbital surface of maxilla


11  Zygomatic bone


12  Infra-orbital foramen


13  Anterior nasal spine


14  Maxilla


15  Mental protuberance of mandible


16  Mental foramen of mandible


17  Body of mandible


18  Ramus of mandible of mandible


19  Condylar process of mandible


20  Coronoid process of mandible


21  Zygomatic process of temporal bone


22  Greater wing of sphenoid


23  Sphenosquamosal suture


24  Sphenofrontal suture


25  Squamosal suture


26  Squamous part of temporal bone


27  External acoustic meatus


28  Tympanic part of temporal bone


29  Mastoid process of temporal bone


30  Occipitomastoid suture


31  Parietomastoid suture


32  External occipital protuberance


33  Lambdoid suture


34  Occipital bone


35  Parietal bone


36  Coronal suture


37  Superior temporal line


38  Inferior temporal line


39  Frontal bone


40  Circled – position of pterion


41  Frontozygomatic suture


Adult skull with individual bones coloured – from the left


Image



1  Mandible


2  Maxilla


3  Zygomatic bone


4  Ethmoid bone


5  Lacrimal bone


6  Nasal bone


7  Frontal bone


8  Parietal bone


9  Occipital bone


10  Temporal bone


11  Sphenoid


12  Nasomaxillary suture


13  Coronal suture


14  Sphenofrontal suture


15  Sphenosquamosal suture


16  Squamosal suture


17  Lambdoid suture


18  Parietomastoid suture


19  Occipitomastoid suture


20  Temporozygomatic suture


21  Frontozygomatic suture


22  Circled – position of pterion



Normal postnatal closure of the cranial sutures:


  Generally the sutures narrow by 6 months and then begin to interlock within the first year.


  They assume the adult typical serrated (meandering line) appearance by 2 years of age.


  Sutures fuse in the second decade and complete their ossification in the third decade.


  It is not uncommon for the two halves of the fetal frontal bone to fail to fuse resulting in a persistent frontal (metopic) suture.


Adult skull, median sagittal section hence removal of midline structures forming the nasal septum – from the left


Image



1  Ramus of mandible


2  Mandibular foramen


3  Lingula of mandible


4  Angle of mandible


5  Body of mandible


6  Mylohyoid line of mandible


7  Anterior nasal spine of maxilla


8  Nasal crest of maxilla


9  Hard palate


10  Nasal crest of palatine bone


11  Inferior meatus


12  Conchal crest


13  Middle meatus


14  Ethmoidal crest


15  Frontal process of maxilla


16  Nasal bone


17  Frontal sinus


18  Ethmoidal air cells


19  Maxillary sinus


20  Medial pterygoid plate of sphenoid


21  Sphenoidal sinus


22  Clivus


23  Anterior margin of foramen magnum


24  Hypoglossal canal


25  Mastoid process


26  Posterior margin of foramen magnum


27  Jugular foramen


28  Groove for inferior petrosal sinus


29  Internal acoustic meatus


30  Groove for sigmoid sinus


31  Groove for transverse sinus


32  External occipital protuberance


33  Internal occipital protuberance


34  Occiput


35  Occipital bone


36  Lambdoid suture


37  Parietal bone


38  Squamosal suture


39  Squamous part of temporal bone


40  Dorsum sellae


41  Sella turcica


42  Groove for middle meningeal vessels


43  Squamous part of frontal bone


44  Orbital part of frontal bone


Adult skull, median sagittal section with removal of the nasal septum and individual bones coloured – from the right


Image



1  Ethmoid bone


2  Nasal bone


3  Inferior nasal concha


4  Maxilla


5  Palatine bone


6  Mandible


7  Sphenoid


8  Temporal bone


9  Occipital bone


10  Parietal bone


11  Frontal bone


12  Groove for middle meningeal vessels


13  Coronal suture


14  Squamosal suture


15  Parietomastoid suture


16  Lambdoid suture


17  Occipitomastoid suture



The nasal conchae:


  The superior and inferior nasal concha are integral parts of the ethmoid bone.


  The inferior nasal concha is an entirely separate bone that is attached by its anterior and posterior ends to the maxilla and palatine bone, respectively


Cranial vault coverings – from above


Image



1  Skin and dense subcutaneous tissue


2  Epicranial aponeurosis


3  Frontal belly of occipitofrontalis


4  Occipital belly of occipitofrontalis


5  Loose connective tissue and pericranium


6  Bones of cranial vault


7  Dura mater


8  Arachnoid mater


9  Cerebral hemisphere covered by pia mater



The scalp consists of five distinct layers:


  Skin.


  Dense subcutaneous tissue.


  Epicranial aponeurosis and the two bellies of the occipitofrontalis muscle.


  Loose connective tissue.


  Pericranium (periosteum of cranial vault).


The cranial vault:


  Is formed by the union of the frontal, occipital and two parietal bones.


The meninges:


  Comprise the three connective tissue membranes that line both the cranial cavity and vertebral canal to enclose both the brain and spinal cord.


  The dura mater is the outermost and by far the thickest of the meninges. It has a cerebral part that lines the cranium and has an outer endosteal layer and an inner meningeal layer; although the two layers adhere tightly together with one another, in certain areas they separate to form distinct cavities, the venous sinuses; and a spinal part, continuous with the cerebral part, forms a tubular sheath within the length of the vertebral column.


  The arachnoid mater lies inside the dura mater, separated from it by the subdural space.


  The pia mater is the thinnest of all the membranes and it adheres tightly to the surface of both the brain and spinal cord.


Brain, with arachnoid mater and underlying blood vessels removed from the right hemisphere – from above


Image



1  Occipital pole


2  Parieto-occipital sulcus


3  Arachnoid granulations


4  Superior cerebral veins


5  Frontal pole


6  Longitudinal cerebral fissure


7  Superior frontal sulcus


8  Middle frontal gyrus


9  Precentral gyrus


10  Central sulcus


11  Postcentral gyrus


12  Postcentral sulcus



The cerebral cortex:


  Is formed into smooth, broad, convoluted folds that are termed gyri (singular gyrus).


  The spaces between the gyri are termed sulci (singular sulcus).


Brain, with arachnoid mater covering intact – from the left


Image



1  Artery of central sulcus


2  Superior anastomotic vein


3  Superior cerebral veins


4  Lateral sulcus


5  Inferior anastomotic vein


6  Inferior cerebral veins


7  Superior cerebral artery


8  Basilar artery


9  Vertebral artery


10  Frontal pole


11  Occipital pole


12  Temporal pole


13  Cerebral hemisphere



The cerebellar cortex:


  Consists of multiple folds, much finer in structure than that of the cerebrum, termed folia and are not individually named.


Brain, with arachnoid mater and underlying blood vessels removed – from the left


Image



1  Central sulcus


2  Precentral gyrus


3  Postcentral gyrus


4  Precentral sulcus


5  Inferior frontal sulcus


6  Superior frontal sulcus


7  Inferior frontal gyrus


8  Orbital gyri


9  Postcentral sulcus


10  Lateral sulcus


11  Superior temporal gyrus


12  Superior temporal sulcus


13  Middle temporal gyrus


14  Inferior temporal sulcus


15  Inferior temporal gyrus


16  Parieto-occipital sulcus


17  Lunate sulcus


18  Anterior occipital sulcus


19  Pons


20  Flocculus


21  Cerebellar hemisphere


22  Medulla oblongata


23  Frontal pole


24  Temporal pole


25  Occipital pole


26  Frontal lobe


27  Parietal lobe


28  Occipital lobe


29  Temporal lobe


Brain, median sagittal section, with arachnoid covering intact – from the right


Image



1  Left vertebral artery


2  Anterior inferior cerebellar artery


3  Basilar artery


4  Anterior cerebellar artery


5  Medial frontobasal artery


6  Callosomarginal artery


7  Pericallosal artery


8  Anteromedial frontal artery


9  Intermediomedial frontal artery


10  Posteromedial frontal artery


11  Paracentral artery


12  Precuneal artery


13  Parieto-occipital branch of posterior cerebral artery


14  Calcarine branch of posterior cerebral artery


15  Cerebellar hemisphere


16  Anterior lobe of cerebellum


17  Fourth ventricle


18  Pons


19  Mamillary body


20  Optic nerve (II)


21  Body of fornix


22  Genu of corpus callosum


23  Body of corpus callosum


24  Splenium of corpus callosum


25  Pineal body



The brain consists of the:


  Cerebrum.


  Brainstem.


  Cerebellum.


The brainstem consists of:


  Midbrain.


  Pons.


  Medulla oblongata.


The cerebrum has two cerebral hemispheres each with a:


  Frontal, parietal, occipital, temporal, insula (insular lobe) and limbic lobe.


The midbrain consists of:


  The two cerebral peduncles.


Brain, median sagittal section, with arachnoid and underlying blood vessels removed – from the right


Image



1  Superior frontal gyrus


2  Cingulate sulcus


3  Cingulate gyrus


4  Corpus callosal sulcus


5  Body of corpus callosum


6  Genu of corpus callosum


7  Splenium of corpus callosum


8  Body of fornix


9  Caudate nucleus (head) in wall of lateral ventricle


10  Third ventricle


11  Foramen of habenular commisure


12  Thalamus


13  Massa intermedia (interthalmic adhesion)


14  Anterior commisure


15  Pineal body


16  Posterior commisure


17  Superior calliculus


18  Aqueduct of midbrain


19  Inferior calliculus


20  Mesencephalon


21  Hypothalamus


22  Mamillary body


23  Infundibulum


24  Uncus


25  Optic nerve (II)


26  Oculomotor nerve (III)


27  Trochlear nerve (IV)


28  Parahippocampal gyrus


29  Rhinal sulcus


30  Pons


31  Midbrain


32  Pontine tegmentum


33  Fourth ventricle


34  Nodulus


35  Anterior lobe of cerebellum


36  Parieto-occipital fissure


37  Calcarine sulcus


38  Cerebellar hemisphere


39  Tonsil of cerebellum


40  Inferior cerebellar peduncle


41  Pyramid of medulla oblongata


42  Medulla oblongata


Dura mater and meningeal vessels – from the left


Image



1  Skin and dense subcutaneous tissue of scalp


2  Bones of cranial vault


3  Dura mater


4  Anterior branch of middle meningeal artery


5  Posterior branch of middle meningeal artery


6  Position of pterion (circled)



The pterion:


  Is an area identifiable by a distinct ‘H’-shaped arrangement of cranial bone sutures formed by the union of the frontal bone, parietal bone, squamous part of the temporal bone and greater wing of the sphenoid.


  It is a very important landmark because it immediately overlies the anterior branch of the middle meningeal artery, a vessel prone to severe damage (rupture) by a blow to the side of the head.


Cranial cavity, paramedian sagittal section, hence the preservation of the falx cerebri and nasal septum – from the right


Image



 A  Anterior cranial fossa


M  Middle cranial fossa


 P  Posterior cranial fossa


1  Frontal sinus


2  Ethmoidal air cells


3  Sphenoidal sinus


4  Nasal septum


5  Hard palate


6  Presulcal part of dorsum of tongue


7  Genioglossus


8  Postsulcal part of dorsum of tongue


9  Uvula


10  Soft palate


11  Posterior nasal aperture


12  Opening of auditory tube


13  Nasal part of pharynx (nasopharynx)


14  Posterior of foramen magnum


15  Anterior margin of foramen magnum


16  Clivus


17  Pituitary gland


18  Sigmoid sinus


19  Transverse sinus


20  Tentorium cerebelli


21  Free margin of tentorium cerebelli


22  Straight sinus


23  Internal occipital protuberance


24  Occipital bone


25  Superior sagittal sinus


26  Falx cerebri


27  Inferior margin of falx cerebri


28  Parietal bone


29  Frontal bone


30  Crista galli of ethmoid bone


Base of adult skull, external surface – from below


Image



1  First central incisor


2  Second lateral incisor


3  Canine


4  First premolar


5  Second premolar


6  First molar


7  Second molar


8  Third molar


9  Incisive fossa


10  Palatine process of maxilla


11  Horizontal plate of palatine bone


12  Greater palatine foramina


13  Zygomatic process of temporal bone


14  Articular tubercle of temporal bone


15  Mandibular fossa of temporal bone


16  Lateral pterygoid plate


17  Medial pterygoid plate


18  Posterior nasal aperture


19  Vomer


20  Body of sphenoid


21  Pharyngeal tubercle


22  Foramen lacerum


23  Apex of petrous part of temporal bone


24  Foramen ovale


25  Carotid canal


26  Jugular foramen


27  Condylar canal


28  Superior nuchal line


29  External occipital crest


30  Foramen magnum


31  Occipital bone


32  Occipital condyle


33  Occipital groove


34  Mastoid notch


35  Mastoid process


36  Stylomastoid foramen


37  Styloid process


38  Foramen spinosum


39  Pterygoid hamulus


40  Pyramidal process of palatine bone


Base of adult skull, internal surface – from above


Image



 A  Anterior cranial fossa


M  Middle cranial fossa


 P  Posterior cranial fossa


1  Foramen caecum


2  Crista galli of ethmoid bone


3  Cribriform plate of ethmoid bone


4  Orbital part of frontal bone


5  Lesser wing of sphenoid


6  Greater wing of sphenoid


7  Optic canal


8  Sella turcica


9  Clivus


10  Foramen magnum


11  Hiatus and groove for greater petrosal nerve


12  Hiatus and groove for lesser petrosal nerve


13  Tegmen tympani


14  Squamous of temporal bone


15  Petrous part of temporal bone


16  Mastoid angle of parietal bone


17  Occipital bone


18  Internal occipital crest


19  Internal occipital protuberance


20  Groove for superior sagittal sinus


21  Groove for transverse sinus


22  Groove for sigmoid sinus


23  Jugular foramen


24  Internal acoustic meatus


25  Trigeminal impression


26  Apex of petrous part of temporal bone


27  Foramen lacerum


28  Foramen ovale


29  Foramen spinosum


30  Groove for frontal branch of middle meningeal artery and vein


Brain, base, cerebellum and brainstem, with arachnoid mater and blood vessels removed from the left hemisphere – from below


Image



1  Inferior surface of frontal lobe


2  Olfactory bulb


3  Olfactory tract


4  Medial olfactory stria


5  Lateral olfactory stria


6  Inferior temporal sulcus


7  Collateral sulcus


8  Optic chiasma


9  Infundibulum


10  Optic nerve (II)


11  Oculomotor nerve (III)


12  Trochlear nerve (IV)


13  Trigeminal nerve (V)


14  Facial nerve (VII)


15  Vestibulocochlear nerve (VII)


16  Flocculus


17  Glossopharyngeal nerve (IX)


18  Vagus nerve (X)


19  Cranial part of accessory nerve (XI)


20  Medulla oblongata


21  Hypoglossal nerve (XII)


22  Vertebral artery


23  Abducent nerve (VI)


24  Basilar artery


25  Pons


26  Optic tract


27  Mamillary body


28  Occipital pole


29  Cerebellum


30  Tonsil of cerebellum


31  Labyrinthine artery


32  Parahippocampal gyrus


33  Internal carotid artery


34  Inferior surface of temporal pole


35  Temporal pole


36  Frontal pole


37  Longitudinal cerebral fissure


A Cranial cavity, base – from above


Image



 A  Anterior cranial fossa


M  Middle cranial fossa


 P  Posterior cranial fossa


1  Frontal sinus


2  Crista galli of ethmoid bone


3  Olfactory nerve filaments (I)


4  Olfactory bulb


5  Olfactory tract


6  Diaphragma sellae


7  Infundibulum


8  Optic nerve (II)


9  Internal carotid artery


10  Oculomotor nerve (III)


11  Abducent nerve (VI)


12  Trochlear nerve (IV)


13  Free margin of tentorium cerebelli


14  Tentorium cerebelli


15  Straight sinus at junction of falx cerebri and tentorium cerebelli


16  Transverse sinus


17  Sigmoid sinus


18  Superior petrosal sinus and cut edges of attached margins of tentorium cerebelli


19  Vestibulocochlear nerve (VIII)


20  Facial nerve (VII)


21  Spinal root of accessory nerve (XI)


22  Medulla oblongata


23  Vertebral artery


24  Basilar artery


25  Inferior petrosal sinus


26  Trigeminal nerve (V)


27  Mandibular nerve (V3)


28  Middle meningeal artery


29  Posterior margin of lesser wing of sphenoid


30  Anterior clinoid process


B Isolated pituitary gland, actual size as presented at dissection


Image



1  Infundibulum of pituitary stalk


2  Adenohypophysis (anterior) lobe of pituitary gland


3  Neurohypophysis (posterior) lobe of pituitary gland



Main blood supply to the brain is via:


  The vertebral arteries.


  The internal carotid arteries.


  A series of communicating vessels between the vertebral and internal carotid arteries form a ring-like anastomosis on the undersurface of the brain to create the arterial circle of Willis.


Cranial cavity, brain and upper spinal cord in a paramedian sagittal section, with removal of the falx cerebri and nasal septum – from the right


Image



1  Skin and dense subcutaneous tissue of scalp


2  Parietal bone


3  Occipital bone


4  Frontal bone


5  Frontal sinus


6  Nasal bone


7  Superior sagittal sinus


8  Transverse sinus


9  Occipital pole


10  Frontal pole


11  Corpus callosum


12  Lateral ventricle


13  Tentorium cerebelli


14  Straight sinus


15  Cerebellar hemisphere


16  Pineal body


17  Midbrain


18  Brainstem


19  Pons


20  Fourth ventricle


21  Posterior margin of foramen magnum


22  Medulla oblongata


23  Cisterna magna


24  Posterior arch of atlas (first [CI] cervical vertebra)


25  Anterior margin of foramen magnum


26  Dens of axis (second [CII] cervical vertebra)


27  Spinal medulla (spinal cord)


28  Optic chiasma


29  Optic nerve (II)


30  Pituitary gland


31  Sphenoidal sinus


32  Spheno-ethmoidal recess


33  Superior nasal concha


34  Middle nasal concha


35  Inferior nasal concha


36  Opening of auditory tube


37  Anterior arch of atlas (first [CI] cervical vertebra)


38  Nasal part of pharynx (nasopharynx)


39  Soft palate


40  Uvula


41  Hard palate


42  Genioglossus


43  Body of mandible


44  Epiglottis


45  Oral part of pharynx (oropharynx)


Cranial cavity, brain and upper spinal cord in a paramedian sagittal section, with removal of the falx cerebri and nasal septum and exposure of cranial nerves in situ from the right


Image



1  Free margin of tentorium cerebelli


2  Inferior colliculus


3  Glossopharyngeal nerve (IX), vagus nerve (X), cranial part of accessory nerve (XI)


4  Facial nerve (VII), vestibulocochlear nerve (VIII)


5  Trigeminal nerve (V)


6  Trochlear nerve (IV) on free margin of tentorium cerebelli


7  Oculomotor nerve (III)


8  Ophthalmic artery


9  Optic chiasma


10  Optic nerve (II)


11  Olfactory tract


12  Olfactory bulb


13  Abducent nerve (VI)


14  Clivus


Cranial cavity, cavernous sinus, cranial nerves in situ – from the left above and slightly behind


Image



 A  Anterior cranial fossa


M  Middle cranial fossa


 P  Posterior cranial fossa


Dotted area denotes extent of the cavernous sinus


1  Falx cerebri


2  Falx cerebri attached to crista galli of ethmoid bone


3  Olfactory bulb


4  Olfactory tract


5  Optic nerve (II)


6  Cortical branches of middle cerebral artery


7  Ophthalmic artery


8  Pituitary gland


9  Oculomotor nerve (III)


10  Posterior cerebellar artery


11  Trochlear nerve (IV)


12  Superior cerebellar artery


13  Trigeminal nerve (V)


14  Trigeminal ganglion


15  Internal carotid artery


16  Posterior margin of lesser wing of sphenoid bone


17  Ophthalmic nerve (V1)


18  Maxillary nerve (V2)


19  Mandibular nerve (V3)


20  Frontal branch of middle


21  Parietal meningeal artery


22  Lesser petrosal nerve


23  Greater petrosal nerve


24  Facial nerve (VII)


25  Labyrinthine artery


26  Vestibulocochlear nerve (VIII)


27  Nervous intermedius


28  Glossopharyngeal nerve (IX)


29  Vagus nerve (X)


30  Cranial part of accessory nerve (XI)


31  Spinal root of accessory nerve (XI)


32  Cerebellar hemisphere


Cranial cavity, optic and olfactory nerves in situ from above


Image



 A  Anterior cranial fossa


M  Middle cranial fossa


 P  Posterior cranial fossa


1  Crista galli of ethmoid bone


2  Filaments of olfactory nerves (I)


3  Olfactory bulb


4  Olfactory tract


5  Posterior margin of lesser wing of sphenoid


6  Free margin of tentorium cerebelli (reflected superiorly on right side)


7  Tentorium cerebelli


8  Ophthalmic artery


9  Optic chiasma


10  Optic nerve (II)


11  Eyeball within orbital cavity


12  Cribriform plate of ethmoid bone (outlined)



Olfactory nerve (I):


  Not a single nerve as the name implies, but numerous fine nerve filaments enseathed in dura that pass through the roof of the nose into the anterior cranial fossa via multiple foramina within the cribriform plate of the ethmoid bone.


  The nerve filaments then enter the under-surface of the olfactory bulb.

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Jan 22, 2018 | Posted by in ANATOMY | Comments Off on I HEAD, NECK, BRAIN AND UPPER SPINAL CORD
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