Lecture Notes - Scalp, Cranial Cavity, Meninges & Brain

Scalp:

Skin: hair, sweat and sebaceous glands, abundant blood supply.

Connective tissue: dense, rich in blood and nerve supply.

Aponeurosis(epicranial): occipitofrontalis muscle; important in scalp lacerations.

Loose areolar tissue: "dangerous area of the scalp"; emissary veins.

Pericranium: dense; cephalohematoma

Scalp vessels: external and internal carotid arteries.
Scalp nerves: Trigeminal (CN V) and C2-3.

Skull:

Calvaria (cranial vault): emissary foramina
Skull base: anterior, middle and posterior cranial fossae: fractures

Cranial meninges:

Dura mater: (external and internal layers), sensitive to pain; epidural / subdural hematoma; falx cerebri; tentorium cerebelli; falx cerebelli; venous sinuses.
Arachnoid mater: cerebrospinal fluid (CSF); subarachnoid bleeding.
Pia mater: closely applied to brain tissue.

Cranial Nerves:

Number	Name	Foramen	Function
I	Olfactory	cribriform plate of ethmoid	smell
II	Optic	optic canal	vision
III	Oculomotor	superior orbital fissure	eye muscles
IV	Trochlear	superior orbital fissure	eye muscles
V	Trigeminal	(1) Ophthalmic: superior orbital fissure; (2) Maxillary: foramen rotundum; (3) mandibular: foramen ovale	face sensation & mastication
VI	Abducent	superior orbital fissure	eye muscles
VII	Facial	internal acoustic meatus	face muscles; salivary & lacrimal glands
VIII	Vestibulocochlear	internal acoustic meatus	hearing & balance

Number	Name	Foramen	Function
IX	Glossopharyngeal	jugular canal (foramen)	pharynx; tongue & parotid gland
X	Vagus	jugular canal	pharynx, larynx & viscera
XI	Accessory	jugular canal	neck muscles (Trapezius/sternocleidomastoid)
XII	Hypoglossal	hypoglossal canal	tongue muscles

Venous Sinuses:

Superior sagittal sinus: arachnoid granulation; superior cerebral veins; subdural hematoma
Inferior sagittal sinus
Sinus rectus: great cerebral vein
Confluens of sinuses
Transverse sinus: inferior cerebral veins
Sigmoid sinus: internal jugular vein
Occipital sinus
Superior and Inferior petrosal sinuses
Cavernous sinus: Ophthalmic and middle cerebral veins; the III, IV, V1, V2 are in its lateral wall and contains VI, and internal carotid artery. Cavernous sinus thrombosis

Brain:

Subdivisions:
Cerebrum: 2 cerebral hemispheres; lobes: frontal, parietal, occipital, temporal, and insular
Diencephalon: Thalamus and hypothalamus
Brainstem: last 10 cranial nerves attached to it; midbrain (III, IV), pons (V, VI, VII, VIII), and medulla oblongata (IX, X, XI, XII)
Cerebellum: 2 cerebellar hemispheres

Ventricles & CSF:

2 Lateral ventricles: cerebral hemispheres
Third ventricle: in diencephalon
Cerebral Acqueduct (of Sylvius) & Fourth ventricle: in brain stem
Subarachnoid space: CSF: 100-120 ml

Arteries:

Vertebral & basilar
Internal carotid
Circle of Willis: subarachnoid bleeding