Head and Neck, MMED Anatomy, My Class notes, SR1
Head and Neck, MMED Anatomy, My Class notes, SR1
THE SKULL AND FACIAL BONES
v THE SKULL VAULT
Ø Bregma
Ø Lambda
Ø Pterion
§ Provides a surface marking for the anterior branch of the middle meningeal artery on lateral skull radiograph
v THE SKULL BASE
v INDIVIDUAL BONES OF THE SKULL BASE
Ø Sella turcica or pituitary fossa
Ø Tuberculum sella
Ø Sulcus chiasmaticus
Ø Anterior clinoid process
Ø Dorsum Sellae
§ Posterior clinoid process
§ Lamina dura
Ø Temporal Bone
§ Squamous part
§ Petrous part
§ Mastoid part
§ Styloid process
Ø Zygomatic process
Ø Foramen magnum
v CRANIAL FOSSAE
v FORAMINA OF THE SKULL BASE
Ø Optic canals
§ The optic nerve and ophthalmic arteries
§ The optic foramen view
Ø Superior orbital fissure
§ CN V1, III, IV, VI and the superior orbital vein and the muddle meningeal artery
§ Occipitofrontal view
Ø Foramen rotundum
§ V2 – maxillary division of the fifth cranial nerve
§ Occipitofrontal view at 20-25 degrees
Ø Foramen ovale
§ V3 (Mandibular Branch), of the fifth cranial nerve and the accessory meningeal artery
§ Submentovertical (SMV)
Ø Foramen spinosum
§ Middle meningeal artery from the infratemporal to the middle cranial fossa
§ Submentovertical (SMV) projection
Ø Foramen Lacerum
§ Internal Carotid Artery passes through this ragged foramen
§ Submentovertical (SMV) projection
Ø Internal auditory meatus and canal
§ VII and VIII, and internal auditory artery
§ Straight AP view of the skull
Ø Jugular Foramen
§ IX and X and XI cranial nerves, and Internal Jugular Vein. Inferior Petrosal Sinus (which drains into the internal Jugular Vein), and the Ascending occipital and pharyngeal Arterial branches
§ Special views required
Ø Hypoglossal canal
§ XII
§ Special views required
Ø Foramen Magnum
§ Medulla Oblongata, and spinal cord, vertebral and spinal arteries, and the roots of the XI cranial nerve
§ Submentovertical (SMV) projection
v RADIOLOGICAL FEATURES OF THE SKULL BASE AND VAULT
Ø Plain Films
§ Common projections: Lateral, OF20 degrees, and Towns projection
§ Pituitary Fossa is visible on OF20 degrees, FO30 , and SMV views. Most commonly use the lateral view
· 11 – 16mm in width and 8-12mm in depth
· The dorsum sellae should have well defined margins anteriorly and posteriorly
· Pneumatization of the sphenoid sinus – may be rudimentary, preseller, seller
· Seller is most usefulview
· Elongation of the pituitary fossa with a prominent sulcus chasmaticus is known as:
¨ “J-shaped”, “Omega” or “hour-glass” sella and in a normal variant in 5% of children
§ Middle meningeal vessels
§ Diplopic Markings
· Stellate confluence is seen on lateral skull radiograph
§ Dural Sinuses
· The transverse sinus are readily seen on Towns projection – running from the occipital protuberance laterally towards the mastoids before curving down to become the sigmoid sinuses, which run into the jugular vein.
§ Supraorbital artery – superiorly from the orbit on OF skull projections
§ Superficial temporal artery – on lateral projection
§ Arachnoid granulation pits
§ Sutures
· Metopic suture
· Spheno-occipital synchondrosis
§ Wormian bones
§ Thickness of the skull vault
Ø Cross-Sectional imaging
v THE NEONATAL AND GROWING SKULL
v CALCIFICATION ON THE SKULL RADIOGRAPH IN THE NORMAL PERSON
Ø Pineal gland
Ø Habenular commissure
§ 
Ø Glomus of the choroid plexus
§ In the lateral ventricles is frequently calcified – usually symmetrical and bilateral calcification
Ø Dural Calcification
§ Petroclinoid and interclinoid ligaments calcification – especially in the elderly
Ø Arachnoid granulations calcification
Ø Basal ganglia and dentate nucleus calcification
Ø Internal carotid artery calcification - especially in the region of siphon
Ø Lens of the eye – may be calcified in the elderly
v THE FACIAL BONES
Ø THE ZYGOMA
§ Lateral boundary of the temporal fossa above, and the infratemporal fossa below
§ OM projection, modified Towne’s and SMV views
Ø THE BONY ORBIT
§ Apex
· Optic foramen opens – optic nerve and ophthalmic artery from the optic canal
§ Lamina papyracea
§ Lacrimal gland
§ Lacrimal sac and its duct
§ Superior orbital fissure
§ Inferior orbital Fissure
· Communicates with the pterygoidpalatine fossa
§ Infraorbital Groove
§ Periorbita - fibrous ring around the orbit
Ø RADIOLOGY OF THE BONY ORBIT
§ Plain Films
· OF20 and OM projections
· Innominate line
§ Computed tomography
Ø THE NASAL CAVITY AND PARANASAL SINUSES
§ THE NASAL CAVITY
· Turbinates or conchae – dividing the cavity into inferior, middle and superior meati – each laying below the turbinate with the corresponding name.
· The space above the superior turbinate is the sphenoethmoidal recess
¨ Sphenoid air cells
§ THE PARANASAL SINUSES 
· The frontal sinuses
· The ethmoid sinuses
· The sphenoid sinuses
· The maxillary sinuses
¨ Orbital process
¨ Zygomatic process
¨ Alveolar process
¨ Palatine process
Uncinate process – medial wall of the maxillary sinus continued superiorly as the uncinate process
Maxillary ostium – opens superiorly to the infundibulum – ostiomeatal complex
§ RADIOLOGY OF THE NASALCAVITY AND PARANASAL SINUS
· Plain Films
¨ Frontal sinus - Not visible <2 years
¨ Pneumatization of the sphenoid sinus at >3 years
¨ Maxillary sinus – first to appear from a few weeks after birth. Tooth-bearing alveolar process only happen after 6 years. Full pneumatisation after all the teeth have erupted in early adulthood.
· Computed tomography
Ø THE MANDIBLE AND TEETH
§ THE MANDIBLE
· Symphysis menti –
· angle of the mandible
· Coronoid process anteriorly and the condylar process posteriorly – separated by the mandibular notch
· Body – alveolar border with its 16 tooth sockets
· Madibular canal - runs in the ramus and body of the bone, with the inferior alveolar vessels and nerve. Proximal opening in the mandibular foramen and distal opening is the mental forramen
| Bone: Mandibular canal | |
 | |
| The permanent teeth, viewed from the right. The external layer of bone has been partly removed and the maxillary sinus has been opened. | |
§ THE TEMPEROMANDIBULAR JOINT
Temporomandibular fossa: Temporal articular surface consists of a fossa posteriorly – and anteriorly the articular tubercle
· 
§ THE TEETH – NOMENCLATURE AND ANATOMY
· 20 deciduous – two incisors, one canine, two molars in each quadrant
· 
· 32 Permanent teeth – two incisors, one canine, two premolars, tree molars in each quadrant
· 
· Position plotted by a quadrant – milk teeth by Capital Letters and Permanent teeth by number and position.
· Root – embedded in a separate socket
· Neck of the tooth – covered by firm fibrous tissue of the gum covered by mucous membrane
· Crown - Exposed intraoral part and is covered by enamel
· Remainder of the tooth is composed of dentine
· Radiolucent pulp cavity – middle of the tooth and is continuous with the root canal, which transmits nerves and vessels from the supporting bone.
· Root and Neck are surrounded by periodontal membrane
· Lamina dura
§ RADIOLOGY OF THE MANDIBLE AND TEETH
· Plain films
¨ Mandible may be seen on OF, OF20, OM, OM30 and lateral projection
· Cross-sectional imaging
¨ Excellent for TM joint anatomy
· Orthopantomography
¨ Orthopantomography – panoramic image of both dental arches, as well as the mandible, temperomandibular joint and lower maxilla.
· Arthrography
¨ Contrast injected into the synovial spaces under radiographic control
Ø THE ORAL CAVITY AND SALIVARY GLANDS
Ø THE ORAL CAVITY
· The soft pallet – levator and tensor veli palatine
· Palatoglossus and palatopharyngeus
· Fauces and palatine tonsil
· Muscles of the tongue –
¨ Extrinsic muscles – paired muscles that move the tongue and have attachments outside it
¨ Intrinsic muscles – alter the various planes of the tongue
¨ Genioglossus – fans from the symphesis menti to the ventral surface
¨ Hyoglossus or the chondroglossus – from the hyoid bone to the side of the tongue
¨ Styloglossus – from the styloid process to the side of the tongue.
¨ Median raphe – divides the tongue into 2 halves
¨ 
¨ 
§ Lymphatic drainage of the oral cavity is to the submental and submandibular nodes, and the retropharyngeal and deep cervical nodes
§ RADIOLOGY OF THE ORAL CAVITY
· MR is superior to CT for soft tissue review
§ THE SALIVARY GLANDS
· Parotid Gland
¨ Largest of the glands lies behind the angle of the jaw. The smaller deep part is connected around the posterior aspect of the ramus of the mandible via the isthmus
¨ Stensen’s duct
· Submandibular Gland
· Sublingual gland
§ RADIOLOGY OF THE SALIVARY GLANDS
· Sialography
· Cross-sectional imaging
· Ultrasound
Ø THE ORBITAL CONTENTS
§ Limited anteriorly by the orbital septum.
§ Fascial layer, periorbita – lines the orbit and is continuous with the dura mater of the brain through the supraoptic canal and the optic foramen.
§ Globe – cornea, sclera and corneoscleral junction – limbus
§ Anterior and posterior poles
§ Equator – mid-coronal plane of the globe
§ Tenon’s capsule – covers the sclera from the limbus to the exit of the optic nerve from the eye.
§ Conjunctiva – mucous membrane reflected from the inner surface of the eyelids and fuses with the limbus.
§ Annulus of Zinn – the four rectus muscles superior, inferior, middle and lateral arise from a common tendinous ring, the Annulus of Zinn. From the lower border of the superior orbital fissure.
§ Superior oblique – trochlea
§ Levator palpabra superioris
§ Ophthalmic artery with its branch – the central retinal artery
§ Superior and Inferior ophthalmic veins into the cavernous sinus
§ Optic nerve has 4 parts – intraocular part, intraorbilat part, intracranial part, intracranial part
Ø INTERNAL ANATOMY AND COVERINGS OF THE EYE
§ Outermost layer: Sclera posteriorly, cornea anteriorly, limbus – sclera-corneal junction
§ Middle layer: vascular uveal tract. Choroid posteriorly, and ciliary body and iris anteriorly. Ciliary muscle – shape of the lens for accommodation
§ Innermost layer – retina. Anterior limit of the retina – ora serata. Posteriorly optic disc. Macula – lies temporal to the optic disc.
§ Anterior segment of the eye- anterior to the lens has two chambers. Both are filled by aqueous humour and are continuous through the appature of the iris – (the pupil)
· The anterior chamber
· Posterior chamber
§ Posterior segment –
· vitreous body, vitreous or hyaline membrane
§ RADIOLOGY OF THE ORBIT AND EYE
Ø THE LACRIMAL APPARATUS
§ RADIOLOGY OF THE LACRIMAL GLAND
v THE EAR
Ø THE EXTERNAL EAR
Ø THE MIDDLE EAR
Ø THE INNER EAR
Ø THE INTERNAL AUDITORY MEATUS
Ø CROSS-SECTIONAL ANATOMY
Ø RADIOLOGY OF THE MIDDLE AND INNER EAR
v THE PHARYNX AND RELATED SPACES
v THE NASOPHARYNX AND RELATED SPACES
Ø THE NASOPHARYNX
Ø SPACES RELATED TO THE NASOPHARYNX
Ø THE OROPHARYNX AND LARYNGOPHARYNX
Ø CROSS-SECTION ANATOMY OF THE NASOPHARYNX
Ø RADIOLOGY OF THE PHARYNX
v THE LARYNX
Ø CROSS SECTIONAL ANATOMY OF THE LARYNX
Ø RADIOLOGY OF THE LARYNX
v THE TYROID AND PARATHYROID GLANDS
Ø THE TYROID GLAND
Ø CROSS SECTIONAL ANATOMY OF THE THYROID GLAND
Ø RADIOLOGY OF THE THYROID GLAND
Ø THE PARATHYROID GLANDS
Ø RADIOLOGY OF THE PARATYROID GLANDS
v THE NECK VESSELS
Ø THE CAROTID ARTERIES IN THE NECK
Ø RADIOLOGY OF THE CAROTID VESSELS
Ø VENOUS DRAINAGE OF THE HEAD AND NECK
Ø RADIOLOGY OF THE VEINS OF THE HEAD AND NECK
Ø THE SUBCLAVIAN ARTERIES IN THE NECK
Ø THE SUBCLAVIAN VEINS IN THE NECK
Ø RADIOLOGY OF THE SUBCLAVIAN VESSELS
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