Head and neck anatomy Flashcards
Where are level 1a lymph nodes found? what are they called?
Submental: between anterior bellies digastric
Where are level 1b lymph nodes found? What are they called?
Submandibular: between anterior and posterior bellies digastric
What is the clinical significance of enlargement of level 1a nodes?
Tumours or infections of:
1) Floor of mouth
2) Anterior tongue
3) Lower lip
What is the clinical significance of enlargement of level 1b nodes?
Tumours or infections of:
1) oral cavity
2) anteiror nasal cavity
3) Soft tissue structures of mid face
4) Submandibular gland
Where are level 2 lymph nodes found? What are they called?
Upper jugular or jugulodigastric nodes anatomical landmarks:
1) Anterior to posterior border sternocleidomastoid
2) Posterior to posteiror border submandibular gland
3) Along a line from base of skull to lower border hyoid bone
What is the clinical significance of enlargement of level 2 lymph nodes?
Tumours or infections from:
1) Oral cavity
2) Nasal cavity
3) Nasopharynx
4) Oropharynx
5) Hypopharynx
6) Larynx
7) soft tissue face or ear
8) Parotid gland
Where are level 3 lymph nodes found? What are they called?
Middle jugular nodes, anatomical landmarks:
1) Anterior to posterior border sternocleidomastoid
2) Along a line from the lower border of hyoid bone and lower border of cricoid cartilage
What is the clinical significance of enlargement of level 3 nodes?
Oral cavity, nasopharynx, oropharynx, larynx
Where are level 4 lymph nodes? What are they called?
Lower jugular. Anatomical land marks:
1) Between the lower border of cricoid cartilage and clavicle
What is the clinical significance of enlargement of level 4 lymph nodes?
Tumours or infection from:
1) Larynx
2) Hypopharynx
3) Thyroid
4) Cervical oesophagus
Where are level V nodes?
Poseterior triangle. Landmarks:
1) Va: above course of spinal accessory nerve
2) Vb: below course of spinal accessory nerve
Clinical significance level V node enlargement
Thyroid, subglottic larynx, cervical trachea, hypopharynx, cervical oesophagus
Level VII nodes: What are they called and what are their landmarks?
Superior mediastinal. Landmarks:
1) between common carotid arteries and posterior surface manubrium sternum in superior mediastinum
Level VII nodes clinical significance:
Enlarged in tumours or infection from lung, chest wall, thyroid
What determines neck dissection classification?
Classified according to lymph node groups removed and vital structures that need to be sacrificed
What are different types of neck dissection?
-Radical neck dissection
-Modified radical neck dissection
-Selective neck dissection
-Extended radical neck dissection
What is radical neck dissection
Level I-V lymph nodes
Sacrificing the:
-Spinal accessory nerve
-INternal jugular vein
-SCM muscles
Modified radical neck dissection
Level I-V lymph nodes
Preserving one or more of:
-Spinal accessory nerve
-INternal jugular vein
-SCM muscle
Selective neck dissection
-Removal of one or more levels of lymph node groups
-None of vital structures are sacrificed
Extended neck dissection
Removal of additional lymphatic or non-lymphatic structures not routinely inluded in traditional neck dissections
eg:
-Parapharyngeal and para-tracheal lymph nodes
-Carotid artery
-Hypoglossal nerve
-Vagus nerve
Label features of cervical vertebra
1: Vertebral body
2: Transverse foramen
3: Transverse process
4: Superior articular process
5:Vertebral foramen
6: Lamina
7: Bifid spinous process
What are characteristic features of typical cervical vertebra?
-Broad body
-Small and bifid spine
-Transverse process has foramen tranversarium which transmits vertebral artery, vertebral vein and sympathetic nerves
-Plane of facet joint is oblique
(lumbar vertebra comparison)
How does C1 differ from typical cervical verebra? What is it called?
C1 (atlas) has superior articular facets for articulating with occipital condyles of skull. It is kidney shaped and lacks spinous process or body.
How does C2 differ from typical cervical vertebra?
C2 vertebra (axis) contains a peg like dens (odontoid process). It does not have a bifid spine.
How does C7 differ from typical cervical vertebra? What is it also known as
-Vertebra prominens.
-Spinous process is long and not bifid
-Transverse process is large but foramina are small, does not transmit vertebral arteries
-Transverse foramina C7 transmits vertebral vein
Which joint permits flexion and extension of neck? How is it formed?
Atlanto-occipital joint, formed by articular surfaces C1 vertebra and occipital condyles
What type of joint is atlanto-occipital joint?
synovial joint. Surrounded by loose capsule.
What prevents excess rotation at atlanto-occipital joint>
alar ligaments (which connect dens to occipital condyles)
What is the function of dens of C2?
Dens (odontoid process) is portion of C2 vertebra about which C1 and skull rotate as a unit
Describe clinical significance of fracture to Dens
-Dens can impact spinal cord, injuring or even severing it resulting in quadriplega.
-Dens extends superiorly into ring of C1, therefore is susceptible to shearing forces and fracture from C1 in neck injuries
What is hangman’s fracture?
Involves fracture of both pars interarticularis of C2, snd results from hyperextension injuries
Describe the anatomy of the thyroid gland
-Two lobes joined by isthmus
-C5-T1 vertebrae
-Isthmus lies anterior to 2nd +3rd tracheal rings
-Surrounded by capsule
-Capsule surrounded by pretracheal fascia
What is function of thyroid gland
-Produce T3 and T4 via thyroid follicular cells
-Parafollicular cells produce calcitonin, important in calcium metabolism
Lymphatic drainage thyroid
Paratracheal and deep cervical lymph nodes
Complications of surgery to thyroid gland
-Pain, bleeding, seroma, infection, scar
-Nerve injury to:
1) Superior laryngeal nerve: damage to cricothyroid muscle, loss of high pitched voice
2) Recurrent laryngeal nerve injury: difficulty in phonation, airway obstgruction if bilateral
-Hypocalcaemia if parathyroid removed
-Need for thyroid replacement
Describe nerve supply to larynx
Vagus nerve via following branches:
Superior laryngeal nerve: divides into
1) External laryngeal nerve supplying cricothyroid muscle (tensor muscle of larynx and cord adductor)
2) Internal laryngeal nerve: sensory to laryngeal mucosa above vocal cords
Recurrent laryngeal nerve: supplies remaining intrinsic laryneal muscles, sensory innervation to mucosa below cords
What is most common thyroid cancer?
Papillary carcinoma
What are the features of papillary thyroid carcinoma?
65-70% of thyroid malignancy
more common in women
3rd-4th decade
lymphatic metastases
Features of follicular carcinoma
30% of thyroid malignancy
more common in women
5th decade
haematogenous metastases
Features of medullary carcinoma
originates from parafollicular c cells of thyroid
men and women equally affected
coiuld present as a part of MEN 2a and 2b
can be monitored with calcitonin
Features of anaplastic carcinoma
Rare
7th decade
usually presents as rapidly enlarging neck mass
Submental triangle boundaries
Lateral: anterior belly digastric
Inferior: hyoid bone
Medial: midline
Submental triangle contents
Anterior jugular vein
Lymph nodes
Digastric (submandibular) triangle borders:
Anterior: anterior belly digastric
Posterior: posterior belly digastric
Superior: mandible
Digastric (submandibular) triangle contents
Arteries:
-Facial artery, submental artery
Vein:
-facial vein
Nerves
-Hypoglossal nerve
-marginal mandibular
-lingual
-nerve to mylohyoid
Other
-Submandibular gland
-Lymph nodes
Carotid triangle boundaries
Anteiror: superior belly omohyoid
Posteiror: scm
Superior: posterior belly digastric
Carotid triangle contents
Arteries:
-Common carotid bifurcation, branches external carotid
Veins
-Internal jugular vein and tributaries
Nerves
-Vagus nerve, superior branches ansa cervicalis
Muscular triangel boundaries
Superior: hyoid bone
Medially: imaginary midline of neck
Supero-laterally: superior belly omohyoid
Infero-laterally: Inferior portion SCM
Muscular triangle contents
Infrahyoid strap muscles:
-Sternohyoid
-Sternothyroid
-thyrohyoid
Larynx
Thyroid
Parathyroid glands
lymph nodes
boundaries occipital triangle
Anterior: posterior border sternocleidomastoid
Posterior: anterior border of trapezius
Inferior: inferior belly of omohyoid
Contents occipital triangle
Vein: external jugular
Nerves: spinal accessory, upper trunk brachial plexus (deep)
Occipital lymph nodes
Boundaries supraclavicular (subclavian) triangle
Anterior: posterior border sternocleidomastoid
Posterior/superior: inferior border omohyoid
Inferior: clavicle
Contents supraclavicular triangle:
Arteries: subclavian, suprascapular
Veins: subclavian vein
Nerves: lower trunk brachial plexus, phrenic
Others: Supraclavicular lymph nodes, apex of lung,, thoracic duct left side
Differential diagnosis swelling in anterior triangle of neck
Thyroglossal cyst
salivary gland swellings
branchial cyst
thyroid pathologies
carotid body tumour
skin conditions incluidng malignancies
lymphadenopathy
Differential diagnosis posterior triangle of neck
cystic hygroma
cervical rib
subclavian artery aneurysm
skin conditions including malignancies
lymphadenopathy
Describe course of facial nerve
-Mixed nerve comprising large motor and smaller sensory component
–>Motor component from pons,
–>sensory component from nervus intermedius
–>Emerges from junction between pons and medulla
–> petrous temporal bone via internal auditory meatus
–> Runs through facial canal
–> gives off ‘tear, hear, taste’ branches in facial canal
–> Exits skull via stylomastoid foramen
–> gives off posterior auricular nerve, nerve to posterior belly digastric, nerve to stylohyoid
–> enters parotid gland between superficial and deep lobes
–> gives off 5 branches within parotid
Venous drainage of scalp
-Veins same as arteries (supraorbital, supratrochlear, superficial temporal, posterior auricular, occipital)
-valveless emissary veins connect superficial veins of scalp with diploic veins of skull
-these drain into intracranial venous sinuses
Surgical considerations when closing scalp wound
-Rich blood supply, may bleed profusely
-Lacerations deep to aponeurosis may gape, making wound closure more difficult
-inelastic nature of tissue may require undermining adjacent tissue
-Larger lesions may need flap/ssg
clinical significance of infections involving scalp
-can spread intracranially via venous system as emissary veins have no valves
-Can involve dural venous sinuses
Name orbital bones
Many zebras enjoy lazy summer
-Maxillary
-Zygomatic
-Ethmoid
-Lacrimal
-Sphenoid
Superior oblique action
Abducts, depresses and laterally rotates globe
Inferior oblique action
Abducts, elevates, laterally rotates globe
Name foramina in middle cranial fossa
Optic canal
Superior orbital fissure
Foramen rotundum
Foramen ovale
Foramen spinosum
Foramen lacerum
Hiatus greater petrosal nerve
Carotid canal
Name foramina in posterior cranial fossa
Internal acoustic meatus
Jugular foramen
Condylar canal
Hypoglossal canal
Foramen magnum
complications of cavernous sinus thrombosis
Can cause symptoms related to orbital and cranial nerve involvement
-Orbital symptoms: periorbital oedema, ptosis, chemosis, proptosis
-Cranial nerve palsies: 3, 4, 6, V1, V2
What techniques are available to arrest epistaxis?
Conservative:
-Nasal pressure/packing
Surgical:
-Silver nitrate cautery
-Electrocautery
-Anteiror/posterior ethmoidal artery ligation
-Sphenopalatine artery ligation
-maxillary artery ligation
-external carotid artery’s ligation
What arteries supply nasal cavity
Sphenopalatine artery (maxillary)
Greater palatine artery (maxillary)
Anterior ethmoid artery (ophthalmic)
Posterior ethmoid artery (ophthalmic)
Superior labial artery (facial artery)
Structures attachign to styloid process
stylohyoid ligament
Stylomandibular ligament
and the stylohyoid
stylopharyngeus
styloglossus muscles
What is kiesselbach’s plexus
Littles area: region in atnerioinferior part of nasal septum where four arteries form anastamosis
-Anterior ethmoidal (from ophthalmic artery)
-Sphenopalatine (terminal branch maxillary artery)
-Greater palatine (maxillary artery)
Septal branch superior labial (from facial)
How are fascial layers of neck broadly divided?
Superficial cervical fascia
Deep cervical fascia
Where is superficial cervical fascia located? What are its contents?
-Superficial cervical fascia lies deep to dermis, surrounds muscles of facial expression and platysma
-Contains fat, neurovascular bundles, lymphatics
Name different layers deep cervical fascia
-Superficial layer (external investing layer)
-Middle layer (pre-tracheal fascia/carotid sheath)
-Internal layer/prevertebral fascia
Name different layers deep cervical fascia
-Superficial layer (external investing layer)
-Middle layer (pre-tracheal fascia/carotid sheath)
-Internal layer/prevertebral fascia
Where is superficial layer (external investing) of deep cervical fascia found?
Layer that surrounds neck and wraps around scm, trapezius, muscles of mastication, submandibular + parotid glands
Describe how middle layer is subdivided
Divided into two parts: carotid sheath, pretracheal fascia
What are the contents of carotid sheath?
Carotid artery (common and internal), internal jugular vein, vagus nerve, deep lymph nodes
What are the components of the pretracheal fascia?
Muscular part: encloses infrahyoid muscles
Visceral part: encloses thyroid and parathyroid glands
Buccopharyngeal fascia: encloses pharynx and oesophagus
Describe internal layer of deep fascia/prevertebral fascia
Limited to posterior neck and much thicker than middle layer
Encloses vertebral column and associated prevertebral muscles
Describe internal layer of deep fascia/prevertebral fascia
Limited to posterior neck and much thicker than middle layer
Encloses vertebral column and associated prevertebral muscles
What are the layers of the scalp?
Skin
Connective tissue
Aponeurosis (Galea)
Loose areolar tissue
Periosteum
In which layer of scalp does neurovascular bundle lie?
Connective tissue layer
Describe arterial supply to scalp
2 front, 2 sides, 2 back
-Supratrochlear, supraorbital (internal carotid–> ophthalmic)
-Zygomaticotemporal (internal carotid–> ophthalmic)
-Superficial temporal (ext carotid
-Posterior auricular, occipital (external carotid)
Through which layer of scalp do soft tissue infections spread and why?
Loose areolar tissue, because valveless emissary veins open here: infections can be transmitted intracranially
What medical conditions can arise from superficial temporal artery?
Migraines
Giant cell arteritis
What are the signs and symptoms of temporal arteritis?
Constitutional: fever, night sweats
MSK: PMR
Specific: -thrombosed, hardened and pulseless superficial temporal artery
-Scalp tenderness, jaw claudication, visual disturbance
What eye conditions associated with GCA, what is commonest type?
-Anterior ischaemic optic neuropathy (most common)
-Amaurosis fugax
-Double vision
How would you investigate gca
ESR, CRP
US (dark halo around artery), temporal artery biopsy
What would be histological features arterial biopsy gca?
-Granulomatous inflammation (usually involving internal elastic lamina)
-Fibrinoid necrosis
-Skip lesions
What is main treatment for GCA?
Pred 1mg/kg, max 60mg for 2/52, then tapering
Treatment 18mths-2yrs
If visual disturbance: ophthalmology referral, methypred
What are signs and symptoms of trigeminal neuralgia?
Sharp stabbing pain in distrubution trigeminal nerve
Unilateral, does not cross midline
triggered when brushing teeth, shaving
Mask like face: movement painful
What are drug treatments for trigeminal neuralgia?
Carbamazapine, lamotrigine
What are surgical options for trigneminal neuralgia?
gamma knife radiosurgery
Microvascular decompression (decompress vessels around trigeminal nerve)
What are main sutures of cranial vault and what do they separate?
Frontal bones: metopic
Sagittal: parietal bones
Coronal: frontal and parietal
Lamdoid: parietal/occipital
Squamous: parietal/temporal
At what ages do the fontanelles fuse? What is significance of sphenoid fontanelle, what bones abut it?
Anterior: frontal/parietal bones (18-24 months-last fontanelle)
Posterior: 2-3 months (first)
Sphenoid fontanelle: pterion when fuses (comprises parietal, temporal, frontal, sphenoid bones)
What pathologies are associated with improper fusion of suture lines?
Craniosynestosis: improper/premature fusion sutures lines
Clinical significance:
-Hydrocephalus
-Speech and language development
What bones make up pterion? What is its clinical significance?
Frontal, parietal, temporal, greater wing of sphenoid
Weakest part of skull
Middle meningeal travels underneath pterion: rupture can cause extradural
What are the main parts sphenoid bone?
Greater wing
lesser wing
Body
Sella turcica
Pterygoid plates
What are main components of sella turcica?
Tuberculum sellae
Dorsum sellae
Hypophyseal fossa
Diaphragma sellae (dural roof hypophyseal fossa, with hole allowing passage pituitary stalk)
Clinoid processes (2 front, 2 back)
Name boundaries anterior cranial fossa
Anterior and lateral: inner surface of frontal bone
Posteriorly and medially: limbus of the sphenoid bone. Limbus is a bony ridge that forms the anterior border of the prechiasmatic sulcus (a groove running between the right and left optic canals).
Posterior and lateral: lesser wings of the sphenoid bone
Floor: frontal bone, ethmoid bone, lesser wing sphenoid
Name boundaries middle cranial fossa
Anteriorly and lateral: lesser wings of the sphenoid bone
Anteriorly and medially: limbus
Posteriorly and lateral: petrous part of the temporal bone
Posteriorly and medial: dorsum sellae.
Floor: body and greater wing of the sphenoid, squamous and petrous parts of the temporal bone.
Boundaries posterior cranial fossa
Anteriorly and medially: dorsum sellae
Anteriorly and laterally: petrous part of the temporal bone.
Posteriorly: internal surface of the squamous part of the occipital bone.
The floor consists of the mastoid part of the temporal bone and the squamous, condylar and basilar parts of the occipital bone
Foramina posterior cranial fossa (and bones)
Temporal bone:
-Internal acoustic meatus
Occipital bone
-Foramen magnum
-jugular foramen
-Hypoglossal canal
Internal acoustic meatus contents and bone
-Petrous part of the temporal bone.
-VII, VIII, labyrinthine artery
Foramen magnum
Bone: occipital bone
Contents:
-Arteries: vertebral arteries forming basilar artery, anterior and posterior spinal arteries
-Veins: spinal veins
-Nerve: Spinal part of accessory nerve (ascends up and joins cranial part of accessory nerve to exit via jugular foramen)
-Soft tissue: End of medulla and beginning of spinal cord, meninges
Jugular foramen: contents and bone
Occipital bone
-IX, X, XI (descending)
-Inferior petrosal and sigmoid sinuses uniting to form IJ vein
-Posterior meningeal arteries
Superior orbital fissure
Bone: sphenoid
Lazy french tarts sit nakedly in anticipation
-Lacrimal branch V1
-Frontal branch V1
-Trochlear nerve
-Superior division oculomotor nerve
-Nasociliary branch V1
-Inferior division oculomotor
-Abducens
Plus superior ophthalmic vein, sympathetic fibres
Foramen rotundum (bone and contents)
V2
Bone: sphenoid
Foramen ovale contents and bone
Bone: sphenoid
Otic ganglion
V3
Accessory meningeal artery
Lesser petrosal nerve
Emissary veins
Foramen spinosum (bone and contents)
-Middle meningeal artery
-Middle meningeal vein
-Meningeal branch of V3.
Sphenoid bone
Carotid canal bone and contents
Petrous part temporal bone
Internal carotid artery
What structures are in relation to the clivus and what is it’s significance?
-Midbrain and pons
-Basilar artery
-VI cranial nerve
–> has long intracranial course, first to be affected in raised icp.
Trauma: line from clivus to top of dens should intersect radiologically without disruption. Line can be disrupted in # dens/c1
What is the embryological origin of pituitary gland?
Anterior: rathke’s pouch
Posterior: continuation of hypothalamus arising from neural tube
What is blood supply to anterior and posterior pituitary glands?
Internal carotid
–>anterior: superior hypophyseal artery
–> posterior: inferior hypophyseal artery
What hormones are secreted by anterior and posterior pituitary glands?
Anterior: growth hormone, ACTH, TSH, FSH, LH, prolactin
Intermediate lobe: MSH (melanocyte stimulating hormone)
Posteiror: ADH, oxytocin
What does pineal gland secrete?
Melatonin
What structures pass through the optic canal?
-Optic nerve
-Ophthalmic artery
-CSF, meninges
-Central retinal artery and vein
-Sympathetic nerve
Which part of optic pathway is affected if pt has bitemporal inferior quadrantinopia?
Superior part optic chiasm (craniopharyngioma)
Which part optic pathway affected if pt has bitemporal hemianopia?
Optic chiasm
Which part optic pathway affected if pt has superior quadrantanopia?
Inferior part optic chiasm (pituitary adenoma from below)
Which part of brain affected with contralateral homonymous hemianopia?
MCA strokes, temporal lobe
Which nerves are responsible for the corneal reflex?
Afferent: nasociliary branch V1
Efferent: Temporal + zygomatic branches of facial (orbicularis oculi muscle)
Where does stylomandibular ligament attach and what is its function?
Styloid process –> mandible
Prevents excessive opening of mouth
Spinothalamic tract location, function, testing
Location:
-Anterolateral cord
Function
-Pain and temperature from opposite side of body
Testing
-Pinprick
Spinothalamic tract location, function, testing
Location:
-Anterolateral cord
Function
-Pain and temperature from opposite side of body
Testing
-Pinprick
Corticospinal tract location, function, testing
Location:
-anterior and lateral cord
Function
-Motor power same side of body
Testing
-Voluntary muscle contractions, involuntary response to painful stimuli
Dorsal colums location, function, testing
Location
-Posteromedial
Function:
-Proprioception, vibration, light touch
Testing
-Position sense
-Tuning fork
