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
skull_int2.jpg (39540 bytes)
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
§  http://upload.wikimedia.org/wikipedia/commons/d/d7/Gray715.png
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 File:Illu nose nasal cavities.jpg http://upload.wikimedia.org/wikipedia/commons/e/e3/Gray856.png
·         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
File:Processus uncinatus ossis ethmoidalis.PNG
§  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
Gray1003.png
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
 File:Gray311.png
·         http://upload.wikimedia.org/wikipedia/commons/9/96/Gray137.png
§  THE TEETH – NOMENCLATURE AND ANATOMY
·         20  deciduous – two incisors, one canine, two molars in each quadrant
·         http://medicalimages.allrefer.com/large/development-of-baby-teeth.jpg
·         32 Permanent teeth – two incisors, one canine, two premolars, tree molars in each quadrant
·          http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/18162.jpg
·         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
¨       http://upload.wikimedia.org/wikipedia/commons/1/16/Styloglossus.png
¨       http://upload.wikimedia.org/wikipedia/commons/9/92/Mylohyoid_muscle.PNG
§  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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