Part 1 - Skull & Face

• Bones of the skull


  • 22 bones
  • Neurocranium (8 bones)
  • Viscerocranium (14 bones)

  
• Bones of the neurocranium


  • 4 singular bones centred on the midline: Frontal, Ethmoid, Sphenoid, Occipital
  • 2 sets of bones occurring bilaterally: Temporal, Parietal

  
• Bones of the viscerocranium


  • 2 singular bones centred on the midline: Mandible, Vomer
  • 6 sets of bones occurring bilaterally: Maxillae, Inferior nasal conchae, Zygomatic, Palatine, Nasal, Lacrimal

  
• Cranial nerves


  • CN I Olfactory
  • CN II Optic
  • CN III Oculomotor
  • CN IV Trochlear
  • CN V Trigeminal (V1 Ophthalmic, V2 Maxillary, V3 Mandibular)
  • CN VI Abducens
  • CN VII Facial
  • CN VIII Vestibulocochlear
  • CN IX Glossopharyngeal
  • CN X Vagus
  • CN XI Accessory
  • CN XII Hypoglossal
• Frontal bone


  • Forms the skeleton of the forehead
  • Articulates inferiorly with the nasal and zygomatic bones
  • Also articulates with lacrimal, ethmoid and sphenoid bones
  • Supra-orbital foramen- passage for supra-orbital nerve and vessels
  • Super-ciliary arch- prominence deep to the eyebrows
  • Glabella- smooth, slightly depressed area between the super-ciliary arches
  • Nasion- intersection between frontal and nasal bones

  
• Zygomatic bones


  • Form the prominences of the cheeks
  • Lie on the inferolateral sides of the orbits
  • Rest on the maxillae
  • Zygomaticofacial foramen- pierces lateral aspect of the bone
  • Articulates with frontal, sphenoid, temporal bones and maxillae

  
• Nasal region


  • Piriform aperture- pear-shaped anterior nasal opening in the cranium
  • Bony nasal septum- made of ethmoid (perpendicular plate) superiorly and vomer inferiorly
  • Nasal conchae- curved bony plates on the lateral wall of each nasal cavity (inferior nasal concha is an independent bone, middle and superior nasal conchae are part of ethmoid)
• Maxillae


  • Form the upper jaw
  • Alveolar processes- tooth sockets and supporting bone for maxillary teeth
  • The 2 maxillae are united at the intermaxillary suture in the median plane
  • Surround most of the piriform aperture
  • Form the infraorbital margins medially
  • Broad connection with zygomatic bones laterally
  • Infraorbital foramen- inferior to each orbit for passage of infraorbital nerve and vessels

  
• Mandible


  • U-shaped bone
  • Body- horizontal portion
  • Ramus- vertical portion
  • Mental foramina- inferior to the 2nd premolar teeth for mental nerves and vessels
  • Mental protuberance- forms the prominence of the chin inferior to the mandibular symphysis
  • Mandibular symphysis- union of the halves of the infantile mandible

  
• External acoustic meatus opening


  • Entrance to the external acoustic meatus leading to the tympanic membrane
• Mastoid process of temporal bone


  • Postero-inferior to the external acoustic meatus opening

  
• Styloid process of temporal bone


  • Anteromedial to the mastoid process
  • Slender needle-like, pointed projection

  
• Zygomatic arch


  • Formed by the union of the temporal process of the zygomatic bone and the zygomatic process of the temporal bone

  
• Pterion

  • H-shaped formation of sutures that unite the frontal, parietal, sphenoid (greater wing) and temporal bones

  
• External occipital protuberance

  • Easily palpable in the median plane
  • Inion- a craniometric point defined by the tip of the protuberance
• Bones of the skull


  • 22 bones
  • Neurocranium (8 bones)
  • Viscerocranium (14 bones)

  
• Bones of the neurocranium


  • 4 singular bones centred on the midline: Frontal, Ethmoid, Sphenoid, Occipital
  • 2 sets of bones occurring bilaterally: Temporal, Parietal

  
• Bones of the viscerocranium


  • 2 singular bones centred on the midline: Mandible, Vomer
  • 6 sets of bones occurring bilaterally: Maxillae, Inferior nasal conchae, Zygomatic, Palatine, Nasal, Lacrimal

  
• Cranial nerves


  • CN I Olfactory
  • CN II Optic
  • CN III Oculomotor
  • CN IV Trochlear
  • CN V Trigeminal (V1 Ophthalmic, V2 Maxillary, V3 Mandibular)
  • CN VI Abducens
  • CN VII Facial
  • CN VIII Vestibulocochlear
  • CN IX Glossopharyngeal
  • CN X Vagus
  • CN XI Accessory
  • CN XII Hypoglossal
• Frontal bone


  • Forms the skeleton of the forehead
  • Articulates inferiorly with the nasal and zygomatic bones
  • Also articulates with lacrimal, ethmoid and sphenoid bones
  • Supra-orbital foramen- passage for supra-orbital nerve and vessels
  • Super-ciliary arch- prominence deep to the eyebrows
  • Glabella- smooth, slightly depressed area between the super-ciliary arches
  • Nasion- intersection between frontal and nasal bones

  
• Zygomatic bones


  • Form the prominences of the cheeks
  • Lie on the inferolateral sides of the orbits
  • Rest on the maxillae
  • Zygomaticofacial foramen- pierces lateral aspect of the bone
  • Articulates with frontal, sphenoid, temporal bones and maxillae

  
• Nasal region


  • Piriform aperture- pear-shaped anterior nasal opening in the cranium
  • Bony nasal septum- made of ethmoid (perpendicular plate) superiorly and vomer inferiorly
  • Nasal conchae- curved bony plates on the lateral wall of each nasal cavity (inferior nasal concha is an independent bone, middle and superior nasal conchae are part of ethmoid)

  
• Maxillae


  • Form the upper jaw
  • Alveolar processes- tooth sockets and supporting bone for maxillary teeth
  • The 2 maxillae are united at the intermaxillary suture in the median plane
  • Surround most of the piriform aperture
  • Form the infraorbital margins medially
  • Broad connection with zygomatic bones laterally
  • Infraorbital foramen- inferior to each orbit for passage of infraorbital nerve and vessels

  
• Mandible


  • U-shaped bone
  • Body- horizontal portion
  • Ramus- vertical portion
  • Mental foramina- inferior to the 2nd premolar teeth for mental nerves and vessels
  • Mental protuberance- forms the prominence of the chin inferior to the mandibular symphysis
  • Mandibular symphysis- union of the halves of the infantile mandible

  
• External acoustic meatus opening


  • Entrance to the external acoustic meatus leading to the tympanic membrane
• Mastoid process of temporal bone


  • Postero-inferior to the external acoustic meatus opening

  
• Styloid process of temporal bone


  • Anteromedial to the mastoid process
  • Slender needle-like, pointed projection

  
• Zygomatic arch


  • Formed by the union of the temporal process of the zygomatic bone and the zygomatic process of the temporal bone

  
• Pterion


  • H-shaped formation of sutures that unite the frontal, parietal, sphenoid (greater wing) and temporal bones

  
• External occipital protuberance


  • Easily palpable in the median plane
  • Inion- a craniometric point defined by the tip of the protuberance

  
• External occipital crest


  • Descends from the external protuberance toward the foramen magnum
• Superior nuchal line


  • Marks the superior limit of the neck
  • Extends laterally from each side of the occipital protuberance
• Hard palate


  • Formed anteriorly by the palatal processes of the maxillae
  • Formed posteriorly by the horizontal plates of the palatine bones

  
• Posterior nasal spine


  • Projection of the free posterior border of the palatines posteriorly in the median plane
• Incisive foramen


  • Posterior to the central incisor teeth
  • Depression in the midline of the bony palate into which the incisive canals open

  
• Choanae (posterior nasal apertures)


  • Superior to the posterior edge of the palate
  • Separated from each other by the vomer
• Vomer


  • Flat, unpaired bone
  • Articulates inferiorly on the midline with the maxillae and the palatines, superiorly with the sphenoid via its wings, and antero-superiorly with the ethmoid

  
• Sphenoid


  • Irregular unpaired bone with 3 pairs of processes: Greater wings, Lesser wings, Pterygoid processes

  
• Palatine


  • L-shaped paired bones making the posterior hard palate
  • Perpendicular plate is appressed tightly to the maxilla anteriorly and between the pterygoid plates of sphenoid posteriorly
  • Articulate with vomer, ethmoid and inferior nasal conchae
  • Horizontal plate- forms posterior third of the hard palate
  • Has greater and lesser palatine foramina

  
• Anterior cranial fossa


  • Formed by the frontal bone anteriorly, ethmoid bone in the middle and lesser wings and body of sphenoid posteriorly
  • Frontal bone forms the roof of orbits and supports frontal lobe of the brain
  • Ethmoid: Cribriform plate, Crista galli, Perpendicular plate