Head, Neck, Brain and Upper Spinal Cord
Skull of full-term fetus – A from the front; B from above
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
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
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
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.
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
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
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.
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
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
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
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
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
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.
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
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
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
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
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
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.
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)
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
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
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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