SKULL Flashcards
FACIAL
PAIRED: palatine, lacrimal, maxilla, nasal, inferior nasal concha, zygomatic
UNPAIRED: vomer, mandible
The point of meeting and articulation of the frontal, parietal, squamous temporal and great wing of sphenoid
PTERION
Skull fracture at PTERION
May lacerate the MIDDLE MENINGEAL ARTERY and cause an EPIDURAL or EXTRADURAL HEMATOMA
May compress the lateral part of a Cerebral hemisphere and RESULT IN HERNIATION OF THE MEDIAL PART OF TEMPORAL LOBE - COMPRESS THE BRAINSTEM
Initially - lucid asymptomatic interval, followed by WEAKNESS OF LIMB MUSCLES, DILATED PUPIL (compression of CN III) and DETERIORATION of CARDIOVASCULAR AND RESPIRATORY FUNCTIONS
May cause blood or CSF to escape from the ear, hearing loss and facial nerve damage
Petrous portion of the temporal bone
Anosmia, periorbital bruising / raccoon eyes and CSF leakage from the nose / rhinorrhea
Anterior cranial fossa
Fractures of the MAXILLAE
Le Fort I - horizontal fracture superior to the maxillary alveolar process
Le Fort II - posterolateral parts of the maxillary sinuses, CENTRAL PART of the FACE SEPARATED FROM CRANIUM
Le Fort III - horizontal fracture that passes through the superior orbital fissure, ethmoid and nasal extending to greater wing of sphenoid, MAXILLAE AND ZYGOMATIC SEPARATED FROM CRANIUM
Layers (SCALP)
Skin - sweat and sebaceous glands, hair follicles
Connective tissue - vascularized subcutaneous layer
Aponeurosis (GALEA APONEUROTICA) - tendinous sheet coverring the calvaria
Loose connective tissue - allows free movement of the scalp proper, EMISSARY VEINS - DANGER AREA
Pericranium/Periosteum
Premature closure of SAGITTAL suture
Frontal and occipital expansion
Long and narrow skull
Scaphocephaly
Premature closureof CORONAL suture
Short, high skull
“Tower skull”
Oxycephaly/Acrocephaly
Premature closure of coronal and lambdoid sutures on one side of the skull
Plagiocephaly
3 primary brain vesicles
Forebrain/Prosencephalon
Midbrain/Mesencephalon
Hindbrain/Rhombencephalon
5 weeks of development
Prosencephalon divides into TELENCEPHALON and DIENCEPHALON
MESENCEPHALON - no division
Rhombencephalon divides into METENCEPHALON and MYENCEPHALON
Derivatives of the Brain Vesicles
Telencephalon- Cerebrum
Diencephalon - Thalamus
Mesencepphalon - Midbrain
Metencephalon - Pons, Cerebellum
Myelencephalon - Medulla
NEURAL TUBE diffentiates into the CNS
NEURAL CREST gives rise to the cells that forms the PNS and ANS, CRANIAL and SPINAL AUTONOMIC GANGLIA
Neural crest derivatives
Sensory ganglia of cranial and spinal nerves
Neurolemmal sheath of Peripheral nerve
Meninges
Pigment cells of retina
Cells of adrenal medulla
Defective closure of the neural tube (4th week)
Etiologies:
Nutritional factors
Environmetal factors
Recent evidence proves that Folic acid/folate reduces the incidence of NTDs by as much as 70% if 400mg is taken daily beginning 3 months prior to conception and continuing throughout gestation
Neural tube defect
Anatomical Levels of NS
SUPRATENTORIAL LEVEL
INFRATENTORIAL/POSTERIOR FOSSA LEVEL
SPINAL LEVEL
PERIPHERAL LEVEL
Located ABOVE TENTORIUM CEREBELLA
Cerebrum, basal ganglia, thalamus, hypothalamus, CN I and II
SUPRATENTORIAL LEVEL
Located BELOW TENTORIUM CEREBELLI but ABOVE FORAMEN MAGNUM
Cerebellum, brainstem (midbrain, pons and medulla oblongata), CN III to XII
INFRATENTORIAL/POSTERIOR FOSSA LEVEL
Located BELOW FORAMEN MAGNUM but contained WITHIN the VERTEBRAL COLUMN
Spinal cord, spinal nerves within the vertebral column
SPINAL LEVEL
Located OUTSIDE the SKULL and VERTEBRAL COLUMN
Neuromuscular structures located outside skill and vertebral column including CNs and spinal nerves and their peripheral branches
PERIPHERAL LEVEL
The brain and spinal cord are surrounded by 3 protective membranes or MENINGES
Dura mater
Arachnoid mater
Pia mater
CRANIAL
PAIRED: parietal, temporal
UNPAIRED: frontal, occipital, sphenoid, ethmoid
Dura mater of the brain (2 layers)
ENDOSTEAL LAYER
MENINGEAL LAYER
Periosteum covering the inner surface of skull bones
Endosteal layer
Dura mater proper
Dense string fibrous membrane covering the brain and is continuous through the foramen magnum with the dura mater of the spinal cord
Meningeal layer
Falx cerebri
Sickle
Shaped fold of dura mater that lies in the midline between two cerebral hemispheres
Its narrow anterior end is attached to the frontal crest and crista galli
Tentorium cerebelli
Crescent
Shaped fold of dura mater that roofs over the posterior cranial fossa
Covers the upper surface of the cerebellum and supports the occipital lobes of the cerebral hemispheres
Small, sickle
Shaped fold of dura mater attached to the internal occipital crest and projects forward between the two cerebellar hemispheres
Falx cerebelli
Diaphragma sella
Small, circular fold of dura mater that forms the roof for the sella turcica
The DURA mater receives its sensory nerve supply from the TRIGEMINAL AND THE FIRST THREE CERVICAL NERVES
the Dura ABOVE THE TENTORIUM is innvervated by the TRIGEMINAL NERVE and headache is referres to the forehead and the face
The Dura BELOW THE TENTORIUM is innervated by the CERVICAL NERVES AND THE HEADACHE IS REFERRED TO THE BACK OF THE HEAD AND NECK
FALX CEREBRI
Delicate, impermeable membrane covering the brain and lying between the pia mater internally and the dura materr externally
Separated from the dura by a potential space, SUBDURAL SPACE
Separated from pia mater by the SUBARACHNOID SPACE which is filled with tthe CEREBROSPINAL FLUID/CSF
ARACHNOID MATER
Vascular membrane covered by flattened mesothelial cells
Closely invests the brain covering the Gyri and descending into the deepest Sulci
PIA MATER
