neuro- the skull

• Skull


  Overall organization into braincase, face, base and throat
• Skull


  • 22 bones, excluding ossicles of ear
  • Except for mandible, most skull bones are flat bones joined by interlocking joints called sutures

  
• Cranial bones


  • Frontal
  • 2 Parietal
  • 2 Temporal
  • Occipital
  • Sphenoid
  • Ethmoid

  
• Facial bones


  • 2 Nasal
  • 2 Maxillae
  • 2 Zygomatic
  • Mandible
  • 2 Lacrimal
  • 2 Palatine
  • 2 Inferior nasal conchae
  • Vomer

  
• Skull functions


  • Form framework of face
  • Contain cavities for special sense organs
  • Provide openings for air & food passage
  • Secure teeth
  • Anchor muscles eg. muscles of facial expression & mastication

  
• Cranium


  • Upper domed part (calvaria) that covers cranial cavity containing brain
  • Base that consists of floor of cranial cavity
  • Lower anterior part- facial skeleton (viscerocranium)

  
• Calvaria


  • Dome-shaped roof that protects superior aspect of brain
  • Consists mainly of frontal, paired parietal, & occipital bones
• Calvaria


  • Frontal crest: Point of attachment for falx cerebri
  • Groove for superior sagittal sinus
  • Depressions & pits (granular foveolae) - mark location of arachnoid granulations
  • Smaller grooves created by various meningeal vessels

  
• Calvaria sutures


  • Coronal, sagittal, lambdoid sutures

  
• Bregma


  Junction of sagittal & coronal sutures
• Lambda


  Junction of sagittal & lambdoid sutures
• Nasal bones


  Paired bones that meet at midline and form bridge of nose
• Maxillae


  • Forms upper jaw
  • Contains maxillary sinus
  • Has alveolar sockets for upper teeth
  • Palatine process is a horizontal projection that forms ant ¾ hard palate
  • Contains infraorbital foramen, incisive foramen, inferior orbital fissure

  
• Zygomatic


  • Form prominence of cheek
  • Zygomatic arch
• Lacrimal


  • Form part of medial wall of orbit
  • Smallest bones of face
  • Contains lacrimal fossa
  • Articulate with frontal, ethmoid, & maxillary bones

  
• Palatine


  Consist of bony plates that complete posterior portion of hard palate, form part of posterolateral walls of nasal cavity & orbits
• Pterion


  • Junction where frontal, parietal, sphenoid, temporal bones meet
  • Bone in this area is particularly thin & overlies anterior division of middle meningeal artery, - can be torn by a skull fracture in this area - extradural hematoma

  
• Vomer


  • Lies in nasal cavity
  • Forms part of nasal septum
• Inferior nasal concha


  Thin, curved bones in nasal cavity that project medially from lateral wall of nasal cavity
• Mandible


  • Consists of body anteriorly & ramus
  • Meet posteriorly at angle
  • Body divided into lower part (base) & upper part (alveolar part)
  • Alveolar part contains teeth
  • Base has mental protuberance, mental tubercles, mental foramen

  
• Mandible processes


  • Condylar process involved in articulation with temporal bone
  • Coronoid process point of attachment for temporalis muscle
• Skull foramina and structures passing through

  • Supra-orbital foramen: Supra-orbital nerve and vessels
  • Infra-orbital foramen: Infra-orbital nerve and vessels
  • Mental foramen: Mental nerve and vessels
  • Zygomaticofacial foramen: Zygomaticofacial nerve
  • Parietal foramen: Emissary veins
  • Incisive foramina: Nasopalatine nerve; sphenopalatine vessels
  • Greater palatine foramen: Greater palatine nerve & vessels
  • Lesser palatine foramina: Lesser palatine nerves & vessels
  • Pterygoid canal: Pterygoid nerve & vessels
  • Foramen ovale: Mandibular nerve [V3]; lesser petrosal nerve
  • Foramen spinosum: Middle meningeal artery
  • Foramen lacerum: Filled with cartilage
  • Carotid canal: Internal carotid artery & nerve plexus
  • Foramen magnum: Continuation of brain & spinal cord; vertebral arteries & nerve plexuses; anterior spinal artery; posterior spinal arteries; roots of accessory nerve [XI]; meninges
  • Condylar canal: Emissary veins
  • Hypoglossal canal: Hypoglossal nerve [XII] & vessels
  • Jugular foramen: Internal jugular vein; inferior petrosal sinus; glossopharyngeal nerve [IX]; vagus nerve [X]; accessory nerve [XI]
  • Stylomastoid foramen: Facial nerve [VII]

  
• Anterior cranial fossa


  • Lies above nasal cavity & orbits, filled by frontal lobes of cerebral hemispheres
  • Contains frontal crest, foramen cecum, crista galli, cribriform plate of ethmoid bone, chiasmatic sulcus, lesser wing of sphenoid, optic canal
• Middle cranial fossa


  • Consists of parts of sphenoid & temporal bones
  • Contains sella turcica, trigeminal impression, grooves and hiatus for greater and lesser petrosal nerves, arcuate eminence, tegmen tympani

  
• Posterior cranial fossa


  • Largest & deepest of three cranial fossae
  • Contains brainstem (midbrain, pons, and medulla) & cerebellum
  • Bounded anteriorly by dorsum sellae and clivus, laterally by superior border of petrous part of temporal bone, posteriorly by squamous part of occipital bone
  • Contains foramen magnum, internal acoustic meatus, jugular foramen, hypoglossal canal

  
• Internal acoustic meatus

  A small opening on either side of the posterior cranial fossa, through which several cranial nerves (VII, VIII) and blood vessels pass.