Head & Neck Flashcards
1
Q
Root of the neck/thoracic inlet
A
2
Q
Oncological lymph node levels of neck
A
- 1a: submental:
- Medial border = midline
- Inferior border = hyoid bone
- Posterior border = anterior belly of digastrics
- 1b: submandibular:
- Anterior border = anterior belly of digastric
- Posterior border = posterior belly of digastric
- Superior border = inferior border of the mandible
- 2: upper jugular group:
- Superior border = base of skull
- Inferior border = line drawn from the hyoid bone
- Medial border = the lateral border of the sternohyoid muscle
- Posterior border = the posterior border of the SCM
- 2a/b is divided by the spinal accessory nerve (which pierces the SCM)
- 3: middle jugular group:
- Superior border = hyoid bone line
- Inferior border = cricoid cartilage
- Anterior border = anterior border of the SCM
- Posterior border = posterior border of the SCM
- 4: lower jugular group:
- Superior border = cricoid cartilage
- Inferior border = clavicle
- Medial border = medial border of the SCM
- Lateral border = lateral border of the SCM
- 5: posterior triangle of the neck:
- Anterior border = lateral border of the SCM
- Posterior border = anterior border of the trapezius
- Inferior border = clavicle
- 6: anterior/central lymph nodes:
- Pre and para tracheal lymph nodes, precricoid node (delphini node), perithyroid nodes
- Lateral borders = carotid sheath
- Superior border = hyoid bone
- Inferior border = sternal notch
- 7 = superior mediastinum
3
Q
The retropharyngeal, danger and prevertebral fascial spaces
A
- Retropharyngeal
- Bounded
- Anteriorly by the constrictor muscles (the buccopharyngeal fascia)
- Posteriorly by the alar layer of the deep cervical fascia
- Connects posteriorly to the danger space and laterally with the parapharyngeal space
- Inferiorly; inferior margin: the point at which the alar fascia fuses with the middle layer of the deep cervical fascia, typically around the T4 vertebral body
- Superiorly; clivus
- Bounded
- Alar fascia
- Arises from superiorly as the ventral leaf of the prevertebral fascia at its attachment to BOS
- Inferiorly it passes anteriorly to blend with the buccopharngeal (visceral) fascia
- Laterally blends with the carotid sheath
- Danger space
- Bounded
- Superiorly by the skull base
- Anteriorly by the alar fascia
- Posteriorly by the prevertebral fascia
- Ends at the level of the diaphragm
- Danger space infections may track from the anteriorly located retropharyngeal space between the buccopharyngeal fascia and alar fascia and pass inferiorly to the mediastinum and the pericardium, and they may result in conditions such as purulent pericarditis
- Bounded
4
Q
Describe the fascia layers of the neck (infrahyoid)
A
- Central anterior visceral column containing the digestive and respiratory passages and the thyroid gland.
- Posteriorly, the visceral compartment is bounded by the main structural element of the neck, the cervical spine, and its supporting struts of muscle.
- On either side of the visceral cylinder, the large, axial neurovascular structures of the neck pass between the head and the superior thoracic aperture enclosed in the loose, areolar carotid sheath.
- Wrapped around these central neck elements, like the spiral sheath of an electrical cable, are the strong, flat trapezius and sternocleidomastoid muscles.
-
Investing fascia
- Start anatomy here, the structures at this level and to/from the head to thorax
- Encircles the whole neck like a collar (outer cylinder) from superior nuchal line to the scapula and manubrium of sternum
- Splits to enclose the SCM muscle and trapezius, it is attached to hyoid bone
- Roof of the posterior triangle
-
Pretracheal fascia (anterior cylinder)
- Encloses the visceral compartment including thyroid, trachea and oesophagus, in some texts it includes the strap muscles
- From hyoid to fibrous pericardium- doesn’t extend above the hyoid?
- Posterior to the infrahyoid strap muscles
-
Prevertebral fascia (posterior cylinder)
- Encloses the vertebrae and paraspinal muscle, sympathetic(maybe anterior to fascia)* and phrenic nerves – vertebral compartment
- BOS to T4 anterior longitudinal ligament
- Important role in the axillary sheath (brachial plexus and axillary artery) and the danger space
-
Carotid sheath (lateral cylinders)
- (not true fascia – but formed by contributions from the other 3 fascia)
- Extends from base of the skill (carotid canal and jugular foramen) to the arch of the aorta
- Contents:
- Carotid artery
- Jugular vein
- Vagus nerve
- Cranial nerves 9-12 in the upper sheath
- Relations
- Sympathetic chain posteriorly
- Ansa cervicalis embedded in sheath anteriorly
5
Q
Suprahyoid spaces of the extra-axial head
A
Suprahyoid spaces
- First through the suprahyoid neck/extra axial head at the level of the mandible, then move up
- Landmarks
- Mandible TMJ-ramus-body
- Mylohyoid
- Hyoid
- Spaces
- Submental
- Boundaries
- Anteriorly symphysis of the mandible
- Laterally anterior bellies of digastric
- Inferiorly by the superficial fascia platysma
- Contents
- Nil
- Boundaries
- Submandibular
- Hyoid bone to mucosa (of floor of mouth)
- Anteriorly and laterally by the mandible
- Inferiorly by the superficial layer of the deep cervical fascia
- Communicates with the sublingual space as it wraps around the mylohyoid posteriorly
- Sublingual
- Mylohyoid, geniohyoid and genioglossus
- Contents
- Lingual artery and nerve
- Hypoglossal nerve
- Glossopharyngeal nerve
- Whartons duct (submandibular)
- Sublingual salivary gland
- Parotid
- Masticator
- Buccal
- Submental
6
Q
Differential for parotid swelling
A
SIN
Stones
Infections/inflammation
Bacterial
Staph/strep/e coli/TB
Viral
Mumps
Autoimmune
Sjogrens
Neoplasm
Benign
Pleomorphic adenoma
Warthins Tumour
Monomorphic adenoma
Oncocytoma
Malignant (primary or secondary)
Mucoepidermoid carcinoma
Adenoid cystic carcinoma
Adenocarcinoma
Acinar cell carcinoma
Lymphoma
SCC
7
Q
- Define 3 points of surface marking for the parotid gland & 1 for the duct:
A
- Upper pole close to the cartilage of external acoustic meatus/zygomatic arch
- Lower pole lies behind the angle of mandible overlapping posterior belly of digastric/SCM
- Anterior border clasp the ramus of mandible with the muscles overlying the bone – the masseter and medial pterygoid
- Duct enters the mouth inside the cheek opposite the 2nd upper molar
8
Q
Describe the parotid gland
A
- Describe
- 3 surfaces (superficial/lateral, anteromedial, posteromedial)
- 3 contents (nerve, veins, artery)
- The duct
-
Superficial surface
- Flat surface partially overlapping the upper SCM and masseter
- Deep to platysma and SMAS
- Enveloped by the investing layer of the deep cervical fascia
- Inner leaf passes up to the base of the skull (thickening to form the stylomandibular ligament)
- Outer leaf passes up to the zygoma
- Capsule is deep to the SMAS but blends with it in preauricular area
- Greater auricular nerve
- C2-3 nerve roots
- Supplies cutaneous sensation, anterior branch over parotid/earlobe and posterior branch retroauricular skin
- Emerges from mid-posterior SCM and ascends vertically towards the ear under the deep investing fascia, beneath the EJV, to pass over or deep to the parotid (anterior branch can be sacrificed, posterior branch can be preserved)
- External jugular vein
- Forms from retromandibular vein as it emerges from the parotid to join the posterior auricular vein that runs deep and posterior to the gland
- Peripheral branches of facial nerve
- Emerge from under the anterior border of the gland to supply the muscles of the face
- Temporal
- 1cm in front of the ear below the zygomatic arch
- Zygomatic
- 1cm below the midpoint of the zygomatic arch
- Buccal
- Midpoint of a line between the tragus and angle of mandible
- Mandibular
- Region of the angle of the mandible
- Cervical
- Emerges superficial to the EJV (which makes sense because the retromandibular vein is deep to the facial vein)
- Temporal
- Emerge from under the anterior border of the gland to supply the muscles of the face
-
Posterior medial surface
- Cartilaginous outer third of the external auditory canal
- Mastoid process with attached SCM and more medially posterior belly of digastric
- Overlying the deep portion of the gland is the facial nerve which emerges from the stylomastoid foramen, crosses over the styloid process laterally just above the tendon of the stylohyoid muscle
- Deep to the deep portion is the transverse portion of the atlas, internal jugular vein, internal carotid artery and the superior constrictor of the pharynx
-
Anterior medial surface
- Grooved by the ramus of the mandible with attached masseter (superficial) and medial pterygoid muscles (deep)
- Wraps around the capsule of the TMJ
- Parotid duct emerges from the anterior boundary
-
Embedded within the parotid
- Facial nerve
- Emerges from SMF (just posterior to styloid process)
- Crosses lateral to styloid process running deep to superficial
- Enters the posterior medial surface of the gland
- Note the main trunk is in the tissue between the preauricular dissection (above/superficial) and dissection of the digastric/stylohyoid muscle dissection (inferiorly)
- Branches into the upper and lower division
- Retromandibular vein deep to the facial nerve
- External carotid artery deep to the retromandibular vein
- Facial nerve
-
The duct
- 5cm long
- Emerges from the anterior boundary runs parallel 1.5cm below the zygoma
- Lies on the masseter (which arises from zygomatic arch inserts angle of mandible)
- Dives deep around the masseters anterior border to traverse the buccal fat pad and buccinator
- Opens on the oral mucosa opposite the upper 2nd molar
9
Q
Draw the parotid in axial slice to demonstrate its contents and relations (include stylomastoid foramen)
A
10
Q
5 landmarks or techniques to identify trunk of facial nerve during parotidectomy
A
- Tragal pointer (trunk 1cm inferior and 1cm deep)
- Tympanomastoid sulcus (stylomastoid foramen 5mm deep to this)
- Posterior belly of diagastric (trunk 1cm medial to this)
- Post auricular artery (trunk medial to this)
- Retrograde dissection of a peripheral branch
11
Q
Draw arrangement of nerve, vein, artery within the parotid gland
A
12
Q
Describe partoidectomy
A
- Incision
- Raise skin flap
- Pretragal tunnel
- Identify tragal pointer
- Greater auricular nerve and SCM anterior border
- Posterior belly of digastric
- Facial nerve
- Note the main trunk is in the tissue between the pretragal tunnel (above/superficial) and dissection of the posterior digastric/stylohyoid muscle dissection (inferiorly)
- Dissect lower division
- Dissect upper division
- Reflect gland
–
-
Procedure
- Lateral lobe parotidectomy
-
Indication:
- Benign neoplasm
- Low grade malignancy
- Failure of management of sialolithiasis
-
Goals:
- Remove tumour with clear surgical margin to prevent recurrence
- Removal of parotid tissue lateral to the facial nerve
- Preservation of the facial nerve
-
Investigations:
- Usually US +/- MRI or CT
- FNA +/- core biopsy
-
Preparation:
- Review investigations
- Examine patient and consent them, ensure facial nerve paralysis explained
- Patient positioned and preparation
- Shave preauricular region
- 20 degree head up to reduce venous ooze
- Head ring
- Head turned to contralateral side
- Neck slight extension
- Bud in the ear
- Short acting muscle relaxant to allow direct stimulation of the motor nerves
-
Steps:
- Team time out
- Incision and exposure
- Lazy S (preauricular anterior to tragus, around the ear lobule, post auricular over the mastoid and down over the SCM)
- Lift facial-cervical skin flaps deep to SMAS with sharp dissection to anterior border of masseter
- Develop the deep dissection along the anterior border of SCM (cervical dissection)
- Identify greater auricular nerve - ascends vertically towards the ear under the deep investing fascia, beneath the EJV, to pass over or deep to the parotid (anterior branch is sacrificed, posterior branch can be preserved)
- Develop the deep dissection with a pre-tragal tunnel (facial dissection)
- Cartilaginous external auditory canal posterior and parotid anterior dividing the tympano-parotid fascia allowing the parotid to be reflected forward
- Develop a broad dissection front (connecting the facial and cervical dissections) looking for the posterior belly of the digastric and the landmarks to identify the facial nerve
- Landmarks
- Tragal pointer (1cm inferior & 1cm deep) of the cartilage of the EAC
- Tympanomastoid suture line/sulcus leads to stylomastoid foramen (5mm deep)
- Posterior belly of the digastric (1cm deep)
- Retrograde dissection of a peripheral branch
- Postauricular artery just lateral to the main trunk of the facial nerve
- Use fine right angle to dissect the small plane superficial to nerve and follow it into the parotid.
- Landmarks
- Free the lateral gland from the nerve
- Haemostat-scissors dissection
- Open mosquito forceps in direction of nerve branches
- Divide tissues piecemeal with scissors after bipolar diathermy
- Define facial trunk & dissect superficial to it till it bifurcates & sudivides
- Start clearing the upper or lower most branch then work towards the centre. Stay right on the nerve, dissecting through its adventitia
- Haemostat-scissors dissection
- Ligate and divide the parotid duct
- If deep lobe is to be resected
- Divide the stylomandibular ligament which allows mandible to be retracted forwards and deep lobe to be rolled out
- Haemostasis, irrigation
- Small suction drain
- Close
-
Pitfalls:
- Facial nerve palsy - 25% for a temporary palsy (literature range 18–65%), permanent in 1% superficial parotidectomy for benign disease. For deep lobectomy risk 3-5%. Mandibular branch is most vulnerable to palsy as it has the longest course and have little collateral branches. Always warn about ear numbness from greater auricular nerve palsy - common but most recover within 6 months.
- Frey’s syndrome - auriculotemporal syndrome or gustatory sweating over parotid skin and neck - due to cut parasympathetic nerves to salivary glands regenerating with
aberrant innervation of sweat glands. Occurs in 10-63% patients. Best treatment radiologically guided Botox injection which lasts 6 months
- Salivary fistula
- Bail out options:
- Post op care & Follow up:
13
Q
Draw the secretomotor nerve supply to the parotid
A
Innervation of the Parotid
- Secretomotor
- Preganglionic fibres: inferior salivatory nucleus of medulla oblongata glossopharyngeal nerve contributes tympanic branch continues through tympanic plexus becomes lesser petrosal nerve which synapes with
- Cell bodies of otic ganglion
- Post ganglionic fibres: hitch hike on auriculotemporal nerve*
- Sympathetic (vasoconstrictor)
- Superior cervical ganglion
- Fibres hitch on external carotid and middle meningeal arteries plexuses
- *Auriculotemporal nerve
- This is a branch of the mandibular division of the TRIGEMINAL nerve
- Traverses the parotid gland to emerge on the superior border deep to the superficial temporal artery, running up and around the ear to supply sensation to the upper 2/3 ear, EAM and the temporal region (thus the name auriculo-temporal – doh!)
- Postganglionic fibres from the otic ganglion travel for a short distance with the auriculotemporal nerve to supply the secretomotor fibres to the gland
14
Q
Draw the submandibular gland, coronal view with its relations
A
-
Definition:
- The submandibular glands are paired and are the second largest salivary glands
- It consists of a larger superficial portion and a smaller deep portion which are continuous with one another round the free posterior margin of the mylohyoid
- Emerging from the deep portion is the submandibular (Wharton’s) duct, which opens at the base of the frenulum of the tongue
-
Embryology:
- Ectodermal groove in the floor of the mouth becomes converted into a tunnel whose blind end proliferates to form the secreting acini
-
Surface anatomy:
- Submandibular/digastric triangle
- Anterior and posterior bodies of digastric
- Inferior body of mandible
- Floor hyoglossus and mylohyoid
- Roof
- Submandibular/digastric triangle
-
Surrounding structures and relations:
- Superficial portion – lateral, inferior/superficial, medial
- Lateral
- Mandible
- Overlapping the anterior portion of the medial pterygoid insertion
- Grooved on the facial artery which hooks beneath the mandible
- Inferior/superficial (remember that this is under the chin so its upside down)
- Skin
- Platysma
- Nerves (mandibular and cervical branches of facial nerve)
- Investing cervical fascia
- Facial vein
- Submandibular lymph nodes
- Medial
- Mylohyoid and behind this hyoglossus
- Nerves, lingual, hypoglossal
- Lateral
- Deep portion
- Extend forwards between myohyoid and hyoglossus
- Below the lingual nerve
- Above the hypoglossal nerve
- Duct
- 5cm (same length as parotid duct)
- Emerges from the superficial portion of the duct and hooks around the mylohyoid to run anteriorly deep to this
- Passes to open into the floor of the mouth beside the frenulum of the tongue
- On the way it is crossed laterally by the lingual nerve which then turns under the duct to pass medially (travelling to the tongue)
- Submandibular triangle (sagittal view – overview)
- Anterior and posterior bodies of digastric
- Inferior body of mandible
- Floor mylohyoid
- Approximate location of the gland, it spills over these borders particularly under the mandible
- Superficially related structures
- Mandibular and facial branches of the facial nerve
- Emerges from the parotid near angle of mandible
- Descends and runs anteriorly deep to platysma, passes upwards at the level of the facial artery
- Innervates risorius and lower lip deformity with depression of the corner of the mouth and drooling
- Protected by placing incision 4cm inferior to mandible
- Mandibular and facial branches of the facial nerve
- Drawing
- Mastoid
- Mandible
- Hyoid
- SCM
- Digastric
- Myohyoid
- Hyoglossus
- Submandible
- Nerves – cervical and mandibular branches
- Artery/veins – twigs facial and submental
- Relationship to mylohyoid (coronal view – most important view)
- Mandible
- Hyoid
- Superficial investing cervical fascia
- Mylohyoid
- Hyoglossus
- Lingual nerve and submandibular duct
- Deep portion of gland
- Hypoglossal nerve
- Superficial portion of gland
- Superficial portion – lateral, inferior/superficial, medial
-
Arterial supply:
- From the facial artery
-
Venous drainage:
- Veins drain to facial vein
-
Innervation:
- Parasympathetic secretomotor fibres:
- Paraganglionic cell bodies in superior salivary nucleus of the pons nervus intermedius facial nerve chorda tympani lingual nerve
- Postganglionic cell bodies in the submandibular ganglion – suspended from the lingual nerve on the surface of hyoglossus travel to the submandibular gland
- Sympathetic vasoconstrictor fibres come from the plexus around the facial artery
- Parasympathetic secretomotor fibres:
-
Lymphatics:
- To the submandibular lymph nodes
-
Structure within the organ and cell types:
- Mixed serous & mucus glands
15
Q
Describe the branchial arches
A
- Mesodermal condensations in the side walls of the pharynx which fuse in the ventral midline into arches
- 6 arches, but 5th arch is rudimentary, hence only 4 clefts. Clefts lie between arches on the outside, and pouches lie between arches on the inside
- Each arch contains a central cartilage, around which muscles develop, and is supplied by a nerve. Blood supply to arches change during development
- Each pouch (except for the 1st) grows laterally into a dorsal and a ventral diverticulum
1st Branchial Arch (mandibular)
- Forms mandible, incus, malleus, sphenomandibular ligament, anterior 2/3 of tongue, muscles of mastication, mylohyoid, anterior digastric, tensor palati, tensor tympani
- Supplied by mandibular nerve, and maxillary artery
2nd Branchial Arch (hyoid)
- Stapes, styloid process, stylohyoid ligament, lessor horn and superior part of hyoid
- Muscles of facial expression, stapedius, stylohyoid, posterior digastric
- Supplied by facial nerve
3rd Branchial Arch
- Greater horn and inferior part of hyoid
- Stylopharyngeus
- Supplied by glossopharyngeal nerve
4th and 6th Branchial Arches
- Thyroid, cricoid, epiglottic, and arytenoid cartilages
- Muscles - intrinsic muscles of larynx, pharynx, levator palati
- Supplied by laryngeal and pharyngeal branches of vagus (including RLN)
Pouches (endoderm derived)
First Pouch
- Form middle ear and mastoid antrum (separated by the tympanic membrane from the derivative of the first cleft, the external acoustic meatus)
Second Pouch
- Dorsal part forms tympanic cavity, ventral part forms the tonsillar crypts • Supplied by glossopharyngeal
Third Pouch
- Dorsal part forms inferior parathyroid glands (=parathyroid III), ventral part forms thymus
- Descent of thymus drags parathyroid III down, so they end up below parathyoid IV
- Fourth Pouch
- Forms superior parathyroid glands (=parathyroid IV)
Fifth Pouch
- Forms the ultimobranchial body, which gives rise to parafollicular C cells
17
Q
Submandibular gland extraction
A
- In an appropriately consented patient… I would position them
- The submandibular gland is exposed by a skin crease incision about 4cm below the mandible to avoid the marginal mandibular branch of the facial nerve
- Continues through platysma and investing fascia on to the gland – note care that nerves are beneath the platysma and at risk when lifting flaps
- Removal of the gland requires ligation of the facial vein which lies on the gland surface
- The facial artery needs to be separated from the superior portion of the gland which it hooks over to emerge under the mandible, this may need to be ligated.
- Free the gland from the posterior belly of digastric
- Free gland from the anterior belly of digastric
- The hypoglossal nerve, lingual nerve needs to be safeguarded, both particularly when the duct is ligated and divided
- Retract the mylohyoid anteriorly and the gland posteriorly to exposure the sublingual space, the lingual nerve with the submandibular ganglion dipping down to attach to the gland, the nerve is superior, the lingual vein inferior and the duct running inbetween
- The hypoglossal nerve passes along the inferior aspect of the gland
18
Q
What are branchial cysts, sinuses?
A
- The ectoderm overlying the clefts on the outside grow over, starting from the 2nd arch, growing caudally to cover the 2nd, 3rd, and 4th clefts (1st cleft is rostral so remains uncovered - forming the external acoustic meatus), and joining the skin caudal to those
- A long deep horizontal groove forms - the cervical sinus. The lips of the groove then meet and fuse and the imprisoned ectoderm disappears.
- Persistence of nests of ectoderm becomes branchial cyst.
- Persistence of the groove becomes branchial sinus.
- Breaking down of tissue between the floor of the sinus and the endoderm in the pharynx on the other side creates a branchial fistula - usually runs from the region of the palatine tonsil, between the external and internal carotid arteries, and reaches the skin anterior to the lower end of SCM.
19
Q
Imaging findings for partoid tumours
A
-
USS
- Pleomorphic adenoma
- Smooth lobulated contour (popcorn)
- Hypoechoic with
- Posterior acoustic enhancement
- Warthins
- Most tumours tend to be ovoid, with well-defined margins and multiple irregular, small, sponge-like anechoic areas
- Hypervascular
- CT
- PA
- When small homogenous attenuation with prominent enhancement
- Large geterogenous with necrosis and delayed enhancement
- Warthins
- Area of increased density in the posteroinferior segment of the superficial lobe of the parotid, heterogenous solid cystic
- MRI or MRI sialography (doesn’t require cannulation of the duct)
- PA
- T1 low intensity
- T1 C+ (Gd): usually demonstrates homogeneous enhancement
- T2 weighted – very high intensity, rim of decreased signal intensity from fibrous capsule
- WT
- T1 low to intermediate signal with focal high signal within cysts
- T1 with Gd cystic components don’t take contrast while solid parts do
- T2 heterogenous variable signal
- PA
- Radionucleotide imaging:
- WT
- Increased uptake of technetium-99m, which does not wash out following dialogue administration; this finding plays an important role in diagnosis and is related to the presence of oncocytes and their increased mitochondrial content
- WT
- PA
-
FNA
- If either FNA or USS are suggestive of malignancy then assume it is
- Can consider core biopsy if FNA inconclusive
- Pleomorphic adenoma
21
Q
Innervation submandibular gland
A
-
Innervation:
- Parasympathetic secretomotor fibres:
- Paraganglionic cell bodies in superior salivary nucleus of the pons nervus intermedius facial nerve chorda tympani lingual nerve
- Postganglionic cell bodies in the submandibular ganglion – suspended from the lingual nerve on the surface of hyoglossus travel to the submandibular gland
- Sympathetic vasoconstrictor fibres come from the plexus around the facial artery
- Parasympathetic secretomotor fibres:
24
Q
Salivary gland TNM staging
A
26
Q
boundaries contents etc
Draw the posterior triangle of the neck
A
