Head and Neck anatomy Flashcards
Where is the foramen ovale found and what are its contents?
Found in the Sphenoid bone
OVALE
- Otic gangliong
- V1 division of trigeminal nerve (mandibular nerve)
- Accessory meningeal artery
- Lesser petrosal nerve
- Emissary veins
What are the 6 foramen in the sphenoid bone?
- Foramen ovale
- Foramen spinosum
- Foramen rotundum
- Foramen lacerum
- Optic canal
- Superior orbital fissure
What are the contents of foramen spinous?
- Middle meningeal artery
- Meningeal branch of the mandibular nerve
Through which foramen does the maxillary nerve (V2) transmit?
Foramen rotundum
What do foramen does the Internal carotid artery pass through?
First, travels through the carotid canal and then enters the skull through Foramen lacerum
What 3 structures transmit through the optic canal?
- Optic nerve
- Ophthalmic artery (branch of ICA)
- Sympathetic nerves
How does raised intra-cranial pressure affect the optic nerve?
The optic nerve is covered by 3 layers of dura.
Raised pressure in the dura will then also affect the optic nerve and cause papilloedema
What will damage or occlusion of the ophthalmic artery cause clinically?
Sudden blindness
What are structures that pass through the Superior orbital fissure?
Live Free Sarah To See No Ignorant Ass Individuals
- Lacrimal branch of ophthalmic (V1)
- Frontal branch of ophthalmic (V1)
- Superior ophthalmic vein
- Trochlear (CN IV)
- Superior division of oculomotor nerve
- Nasociliary branch of ophthalmic (V1)
- Inferior division of oculomotor
- Abducens nerve )CN VI)
- Inferior ophthalmic vein
In which part of the skull is the jugular foramen found?
Temporal bone
Which foramen are located in the temporal bone?
- Jugular foramen
- Stylomastoid foramen
What 2 structures transmit travel through the stylomastoid foramen?
- Stylomastoid artery
- Facial nerve
What structures travel through the carotid canal?
SIDE
- Sympathetic plexus around arteries
- ICA
- Deep petrosal nerve
- Emissary veins
What are the 12 cranial nerves?
1- Olfactory nerve
2- Optic nerve
3- Occulomotor nerve
4- Trochlear nerve
5- Trigeminal nerve
6- Abducens nerve
7- Facial nerve
8- Vestibulocochlear nerve
9- Glossopharyngeal nerve
10- Vagus nerve
11- Accessory nerve
12- Hypoglossal nerve
What structures travel through the Jugular foramen?
Anterior: Inferior petrosal sinus
Intermediate: CN 9, 10, 11
Posterior: Sigmoid sinus, Internal Jugular vein
Where is the foramen magnum found?
Occipital bone
Which 3 vessels pass through the foramen magnum?
- Vertebral arteries
- Anterior spinal artery
- Posterior spinal artery
Where is a patient likely to have a lesion if they have bitemporal hemianopia?
Optic chiasm
In bitemporal hemianopia, how can the location of the optic chiasm lesion be distinguished?
Upper quadrant > lower quadrant = Inferior chiasma compression (pituitary tumour)
Lower quadrant > upper quadrant = Superior chiasma compression (craniopharyngioma)
In patients with Homonymous quadrantanopia, how can a parietal vs temporal lesion be differentiated based on clinical findings?
PITS - lesions in the optic radiation
Parietal - Inferior quadrantanopia
Temporal - Superior quadrantanopia
A patient has homonymous hemianopia with macular sparing. Where is the lesion?
Occipital cortex
Where does the transverse sinus of the cranium drain into?
Drains into the sigmoid sinus
What does the sigmoid sinus drain into?
Internal jugular vein
End of sigmoid sinus is the beginning of the Int Jugular vein
Which 3 cranial sinuses converge and drain into the confluence of sinuses?
- Superior sagittal sinus
- Straight sinus
- Occipital sinus
Which sinus drains into the straight sinus?
Inferior sagittal sinus
Which sinuses drain into the sigmoid sinus?
- Superior petrosal vein
- Inferior petrosal vein
- Transverse sinus
How many paired and unpaired dural venous sinuses are there?
4 unpaired
6 paired (incl cavernous sinus)
What is the course of the cavernous sinus?
Paired. Found on the body of the sphenoid bone
Runs from the Superior orbital fissure to the Petrous temporal bone
What structures drain into the cavernous sinus?
- Superior ophthalmic vein
- Inferior ophthalmic vein
- Superior petrosal sinus
- Inferior petrosal sinus
- Basilar plexus of veins (posteriorly)
How can an infection of the face spread to brain?
If the infection spreads into the Superior and/or Inferior ophthalmic veins, the infection will spread, as these veins drain directly into the cavernous sinus
What are the contents of the cavernous sinus and what are its lateral wall components?
O TOM CAT
Lateral wall (from top to bottom)
- Oculomotor nerve (CN 3)
- Trochlear nerve (CN 4)
- Ophthalmic nerve (V1 of CN5)
- Maxillary nerve (V2 of CN5)
Contents (from medial to lateral):
- ICA (SN plexus)
- Abducens nerve (CN 6)
What is cavernous sinus syndrome usually caused by and what are clinical signs associated?
Most commonly caused by cavernous sinus tumours
Signs:
- Pain
- Ophthalmoplegia
- Proptosis
- Trigeminal nerve lesion
- Horner’s syndrome
Which structure divides the anterior and posterior triangles of the neck?
SCM (sternocleidomastoid muscle)
What are the origins and insertions of the SCM?
Attaches at the clavicle and sternum and inserts into the mastoid
Which nerve innervates the SCM?
Accessory nerve
What are the borders of the posterior triangle of the neck?
Anterior: SCM
Posterior: Trapezius
Inferior: Middle 1/3 of clavicle
What muscles of the neck are found in the posterior triangle and make up its floor?
From superior to inferior
- Splenius capitis
- Levator scapulae muscle
- Posterior scalene
- Scalene medius muscle
- Anterior scalene muscle
What receives sensory information from the SCM?
Ansa cervicalis
What is the surface anatomy of the spinal part of the accessory nerve?
Located by drawing a line between the lower 2/3 of the trapezius muscle to the upper 1/3 of the SCM
How can the spinal part of the accessory nerve be damaged?
Surgery in the posterior neck (e.g. lymph node dissection)
If the accessory nerve is damaged in the posterior neck, which muscle is likely to be affected?
Trapezius muscle
At the point in which the accessory nerve is found in the post triangle, the SCM has already received its innervation and trapezius has not
What is the function of the scalene’s anterior and medius?
Elevate 1st rib and laterally flex the neck to the same side
What is the function of Scalenus posterior?
Elevate 2nd rib and tilt neck to the opposite side
What innervates the scalene muscles?
Spinal nerves C4-C6
What structures travels between the anterior and middle scalene muscles?
- Brachial plexus
- Subclavian artery
Go through a space called scalene hiatus
What is the relation of the subclavian vein and phrenic nerve to the anterior scalene muscle?
They pass anteriorly to it over the 1st rib
What is thoracic outlet syndrome and how is it caused?
Caused by compression of the brachial plexus and subclavian artery and vein by the scalene muscles as they pass between scalene anterior and medius.
Patients will present with neuro-vascular symptoms in the upper limbs (e.g. cold extremities, numbness, weakness)
What are the boundaries of the anterior triangle of the neck?
Posterior: Anterior border of the SCM
Anterior: Midline of the neck
Superior: lower border of the mandible
What are the 3 sub triangles found in the anterior triangle of the neck and what do they contain?
- Submandibular triangle (digastric): contains Hypoglossal nerve + facial vessels + submandibular nodes and glands
- Muscular triangle: contains strap muscles and External Jugular vein + external carotid art.
- Carotid triangle: contains carotid sheath (common carotid / Vagus / Int jugular vein) AND Ansa cervicalis
How is the digastric muscle divided and what is its nerve supply?
Digastric has an anterior (inferior border of Digastric triangle) and posterior belly (border of carotid triangle).
Anterior: Mylohyoid nerve
Posterior: Facial nerve
Where is the external carotid artery found in the neck?
In the muscular triangle of the anterior triangle of the neck
What path does the hypoglossal nerve take to exit the carotid sheath?
Crosses over the ICA soon after the bifurcation of the common carotid (into ICA and ECA) and exits anterior to the ICA
What path does the glossopharyngeal nerve take to exit the carotid sheath?
Crosses over the ICA anteriorly and then exits the carotid sheath posterior to the ECA (as the ECA exits the sheath)
What nerves and vessels are found in the posterior triangle of the neck?
Nerves:
- Accessory nerve
- Phrenic nerve
- C2-C4 nerve roots (supraclavicular nerve / Transverse cervical nerve / Great auricular nerve / Lesser occipital nerve)
Vessels:
- Ext. jugular vein
- Subclavian artery (3rd part at the inferior border)
Muscles:
- Inferior bely of omohyoid
- all scalene muscles
What is the embryological origin of the parathyroid glands and how does this affect the position of the glands anatomically?
Derived from the 3rd and 4th pharyngeal pouches.
Parathyroids from the 4th pharyngeal pouch are located SUPERIORLY (associated with thyroid)
Parathyroids from the 3rd pharyngeal pouch are located INFERIORLY (associated with thymus)
If you are unable to located the inferior glands of the parathyroid at its expected position, where else could they be located in view of their embryological origin?
Superior mediastinum
Inferior glands originate from the 3rd pharyngeal pouch which is associated with the thymus
What is the blood supply of the parathyroid glands?
Derived from the Inferior and Superior thyroid arteries (thyrocervical trunk and ECA respectively)
Rich anatomies between the 2 vessels
What are the relations of the parathyroid?
Laterally: Common carotid
Medially: Recurrent laryngeal nerve AND Trachea
Anteriorly: Thyroid
Posterior: Pre-tracheal fascia
What structure connects the right and left lobes of the thyroid?
Isthmus
At what vertebral level is the superior thyroid notch found and what is the anatomical significance of this level?
Superior thyroid notch = C4
Level of bifurcation of the common carotid artery
What is the arterial supply of the thyroid and the origin of these vessels?
- Superior thyroid artery (1st branch of ECA)
- Inferior thyroid artery (thyrocervical trunk from subclavian artery)
- Thyroidea ima (10% of population from brachicephalic artery/aorta)
Where does the inferior thyroid vein drain into?
Brachiocephalic vein
Where do the superior and middle thyroid vein drain into?
Internal Jugular vein
What is the embryological origin of the thyroid?
Foramen caecum at the base of the tongue