Applied Head and Neck Anatomy Flashcards
What is the innervation of sternocleidomastoid?
Spinal accessory nerve
CNXI
What are the attachments of trapezius?
Superior nuchal line
Mastoid processes
Lateral 1/3 of the clavicles
Down to T12
What is the innervation of trapezius?
Spinal accessory nerve
CNXI
What are the boundaries of the anterior triangle in the neck?
Median vertical line of the neck
Inferior margin of the mandible
Anterior margin of sternocleidomastoid
What are the boundaries of the posterior triangle of the neck?
Middle 1/3 of the clavicle
Anterior margin of trapezius
Posterior margin of sternocleidomastoid
What are the four small triangles that make up the anterior triangle?
Carotid triangle
Submandibular triangle
Submental triangle
Muscular triangle
What are the contents of the anterior triangle in the neck?
Carotid artery Internal jugular vein Hypoglossal nerve Recurrent laryngeal nerve Vagus nerve Start of CNXI Trachea Larynx Pharynx Submandibular gland Thyroid gland Lymph nodes and vessels
What are the contents of the posterior triangle in the neck?
External jugular vein
CNXI
Apex of the lung
Roots of the brachial plexus (under scalene)
What muscle divides the posterior triangle?
Omohyoid
Why are fascial planes important in the neck?
Create compartments
Ease of movement
Determine spread of infection
What does the pretracheal fascia contain, and what is its function?
Trachea
Oesophageal
Thyroid
Associated nerves and vessels
Allows independent movement
Describe the deep cervical fascia.
Wraps all the structures in the neck to hold them in place, allowing different planes of movement.
Wraps around sternocleidomastoid and trapezius twice.
What are the contents of the carotid sheath in the neck?
Internal jugular vein (anterolateral)
Vagus nerve (posterior)
Carotid artery (anteromedial)
Deep cervical lymph nodes
What does the prevertebral fascia contain, and where does it extend from and to?
Encloses the pre-, post- and paravertebral muscles and the vertebrae.
Extends from the base of the skull to T2/3
What can cause a retropharyngeal abscess?
An upper respiratory tract infection in children under 5, causing inflammation of the node of Rouviere. Leads to pus production which drains into the retropharyngeal space
What are the symptoms of a retropharyngeal abscess?
Neck pain on movement
Loss of cervical curvature
Difficulty swallowing/breathing
Likely to be septic
May have mediastinitis
What are the problems with a parapharyngeal abscess?
Puts the contents of the carotid sheath at risk, such as potentially causing internal jugular vein thrombosis
What are the symptoms of a parapharyngeal abscess?
Teeth and tonsils commonly affected
Causes a swelling in the neck which the patient has pain in when they turn towards it.
May have complications from involvement of carotid sheath contents
What muscles allow upward movement of the hyoid bone?
Digastric
Mylohyoid
Stylohyoid
Geniohyoid
What muscles allow downward movement of the hyoid bone?
Omohyoid
Sternohyoid
Sternothyroid
Thyrohyoid
What is special about the digastric and omohyoid muscles when comparing them to the other muscles allowing movement of the hyoid bone?
They have two bellies, allowing them to act in two directions. They pass around a fascial sling
What are the branches of the internal carotid artery in the neck?
There aren’t any
What are the branches of the external carotid artery?
Ascending pharyngeal Superior thyroid Linguinal Facial Occipital Posterior auricular Maxillary Superficial temporal (terminal branch)
What nerve supplies the muscles of facial expression?
Facial nerve
CNVII
What are the branches of the facial nerve (CNVII)?
Temporal Zygomatic Buccal Mandibular Cervical
(To Zanzibar By MotorCar)
What nerve supplies the muscles of mastication?
Trigeminal nerve (CNV)
What muscles does the trigeminal nerve (CNV) innervate?
Masseter
Temporalis
Buccinator
Pterygoid
What are the sensory regions supplied by the trigeminal nerve (CNV)
Ophthalmic region
Maxillary region
Mandibular region
(Anterior face)
How many pharyngeal arches are there?
5
1-6
What is in the core of each pharyngeal arch in development?
Artery
Cranial nerve
Cartilage bar
During development, what induces endodermal thickening to create the neural plate?
Notochord signals
What are the 3 areas of the primitive brain?
Forebrain (prosencephalon)
Midbrain (mesencephalon)
Hindbrain (rhombencephalon)
How are cranial nerves classified?
By function and embryological origin
What are the nerves of the pharyngeal arches?
CNV
CNVII
CNIX
CNX
What muscles derive from the first pharyngeal arch, and what nerve are they associated with?
Muscles of mastication Trigeminal nerve (CNV)
What muscles derive from the second pharyngeal arch, and what nerve are they associated with?
Muscles of facial expression Facial nerve (CNVII)
What muscles derive from the third pharyngeal arch, and what nerve are they associated with?
Stylopharyngeus
Glossopharyngeal nerve
What muscles derive from the fourth pharyngeal arch, and what nerve are they associated with?
Cricothyroid
Levator palatini
Pharynx constrictors
Vagus nerve (superior laryngeal branch)
What muscles derive from the sixth pharyngeal arch, and what nerve are they associated with?
Intrinsic laryngeal muscles
Vagus nerve (recurrent laryngeal branch)
What is the sensory function of the glossopharyngeal nerve?
Posterior 1/3 of the tongue
What is the name of the cartilagenous bar in the first arch?
Meckel’s
What is the name of the cartilagenous bar in the second arch?
Reichert’s
What are the derivatives of Meckel’s cartilage in the first pharyngeal arch?
Mandibular prominence - form the malleus and incus
Template for the mandible (endochondral ossification)
What are the derivatives of Reichert’s cartilage in the second pharyngeal arch?
Stapes
Styloid process
Hyoid bone (lesser Cornu and upper body)
What are the derivatives of the cartilage in the third pharyngeal arch?
Lower body of the hyoid bone
What are the derivatives of the cartilage in the fourth and sixth pharyngeal arches?
Thyroid
Arytenoid
Cricoid
What is the fate of the first and second arches of the pharyngeal arteries?
Regress
What is the fate of the third arch of the pharyngeal arteries?
Internal carotid
What is the fate of the fourth arch of the pharyngeal arteries?
Arch of the aorta (L) Brachiocephalic artery (R)
What is the fate of the sixth arch of the pharyngeal arteries?
Pulmonary arch
What is the fate of the second pharyngeal pouch?
Epithelial proliferation and colonisation by lymphoid precursors to form the palatine tonsils
What is the fate of the third and fourth pharyngeal pouches?
3/4 dorsally become the parathyroid glands
3rd ventrally becomes the thymus
What pharyngeal pouch does the middle ear derive from?
First (cartilage bars)
What pharyngeal pouch do the tympanic cavity and auditory tube derive from?
First
What causes branchial cysts or fistulae?
The second pharyngeal arch grows down to cover the other clefts normally, so the first is the only one remaining.
If the sinuses aren’t obliterated, a cyst or fistula can form.
They can form anywhere along the sternocleidomastoid
What are the attachments of sternocleidomastoid?
Superiorly to the mastoid process
Medial head to the sternum
Lateral head to the first 1/3 of the clavicle
Give the borders of the digastric triangle.
Posterior: posterior belly of digastric
Anterior: anterior belly of digastric
Base: body of the mandible
What triangle(s) of the neck is the submandibular gland found in?
Anterior triangle
Digastric triangle
What is a patient with Bell’s palsy at risk of if they are unable to fully close their eyelid?
Exposure keratitis
What does the investing layer of the deep cervical fascia enclose?
Parotid gland
Sternocleidomastoid
Submandibular gland
Trapezius
What triangle would you use to identify the vein for inserting a central venous catheter?
Carotid triangle
Where are lymphatic vessels not found?
Eyeball
Inner ear
Cartilage
Why does more fluid move out of the alveolar side of capillaries than moves in the venule side?
Some small proteins and cell debris are able to filter into the tissue fluid due to the high pressure on the alveolar side, but then are unable to move back in at the other end.
The oncotic pressure prevents the same amount of fluid moving back into the capillary at the other end.
Describe the passage of tissue fluid from tissues to the subclavian veins.
- Lymphatic capillaries
- Afferent lymphatic vessels
- Lymph nodes
- Efferent lymphatic vessels
- Lymphatic trunks
- L/R lymphatic ducts
What is the name of the left lymphatic duct?
Thoracic duct
What is lymphoedema?
Fluid retention and tissue swelling due to a compromised lymphatic system.
Give some examples of things which can compromise the lymphatic system, leading to lymphoedema.
Removal or enlargement of lymph nodes Infection Damage to vessels Lack of limb movement Congenital
Describe the structure of a lymph node.
A dense collagen capsule with a reticular connective tissue centre.
It contains lymphocytes and macrophages.
They can be up to 2-2.5cm, but the majority are microscopic.
What is the function of the lymph node?
Physical and phagocytic filter
What is lymphadenopathy?
Swollen lymph nodes
What is the difference between infective and malignant lymphadenopathy?
Infection - tender, firm, motile
Malignancy - hard, matted, non-tender
What is the difference between regional and terminal lymph nodes?
Regional - superficial and drain specific areas
Terminal - deep and drain a number of regional nodes
What separates the deep and superficial lymph nodes in the neck?
Deep cervical fascia
What structure do the deep cervical lymph nodes lie in?
Carotid sheath
What is waldeyer’s ring?
An annular collection of lymphatic tissue surrounding the superior pharynx.
Pharyngeal tonsil, lingual tonsil, and palatine tonsils
What are the 8 surface lymph nodes?
Submental Submandibular Pre auricular Post auricular Occipital Superficial cervical Posterior cervical Anterior cervical
What are the three deep lymph nodes?
Jugulodigastric (tonsillar node)
Jugulo-omohyoid
Supraclavicular
Which deep lymph node is most likely to be swollen with oral or thyroid cancers?
Juguloomohyoid
Which deep lymph nodes drain the thoracic cavity and abdomen?
Supraclavicular lymph nodes
Where does the right supraclavicular lymph node drain?
Mid section of the chest
Oesophagus
Lungs
What is the significance of the left supraclavicular lymph node?
It is Virchow’s node. Swells with gastric cancer.
Where do the submandibular lymph nodes drain?
Upper lip and teeth Lateral lower lip Face Anterior nasal cavity Cheeks Middle tongue Submandibular and lingual glands
What areas do the occipital lymph nodes drain?
Posterior scalp and neck
What areas do the submental lymph nodes drain?
Lower lip and teeth
Anterior chin
Tip of the tongue
Floor of the mouth
What areas do the superficial cervical lymph nodes drain?
Skin of the neck
What areas do the pre auricular lymph nodes drain from?
Mid/posterior scalp
Lateral ear
Parotid gland
What areas do the posterior auricular glands drain from?
Posterior scalp
Pinna (cranial surface)
External acoustic meatus (back)
What does the jugulodiagastric lymph nodes drain?
Palatine tonsils
Posterior third of the tongue
What does the Juguloomohyoid lymph nodes drain?
Anterior two thirds of the tongue Oral cavity Trachea Larynx Oesophagus Thyroid
Describe the locations of the internal and external jugular veins in the neck.
External - superficial to sternocleidomastoid
Internal - inferior to sternocleidomastoid
What arteries branch from the brachiocephalic trunk in the neck?
Subclavian
Common carotid
What branches does the subclavian artery give in the neck?
Vertebral
Internal thoracic
Thyrocervical
What are the branches of the thyrocervical trunk?
Transverse cervical
Ascending cervical
Supra scapular
Inferior thyroid
Describe the arterial supply to the vertebra in the neck.
The vertebral arteries arise from the subclavian arteries and ascend through the transverse foramen of C6-1.
What is the fate of the vertebral arteries?
Become the basilar arteries as they enter the skull through the foramen magnum.
Where is the most likely location of a carotid artery atheroma?
Bifurcation of the common carotid.
What is the clinical significance of the carotid triangle?
Point of surgical approach to the great vessels (endartectomy)
Access the vagus and hypoglossal nerves
Feel the carotid pulse
Carotid sinus massage
Describe how a carotid sinus massage works and what it can be used to treat.
Supra ventricular tachycardia
It stimulates baroreceptors in the carotid sinus to increase fatal outflow, reducing heart rate.
What branches of the external carotid artery supply the scalp?
Posterior auricular
Superificial temporal
Maxillary
What arteries from the internal carotid artery supply the scalp?
Supraorbital
Supratrochlear
(Branch from the ophthalmic artery)
What are the layers of the scalp?
Skin Connective tissue (loose) Aponeurosis Loose connective tissue Periosteum
In what layer of the scalp do arteries lie?
Subcutaneous connective tissue
Why does bleeding in a laceration of the scalp tend to be profuse and difficult to stop?
The arteries form many anastomoses so it is difficult to block them off with pressure
The walls of the arteries are closely associated with connective tissue which can hold the artery open
If the laceration is deep and through the epicranial aponeurosis (occipitofrontalis), this will also hold the wound open due to opposing pull of the muscle
Why won’t the loss of scalp over a region of skull cause bone necrosis?
The skull has a separate blood supply from the middle meningeal artery.
Describe drainage from the supraorbital and supratrochlear veins.
Into the angular vein at the medial angle of the eye
Then into the facial vein
Where do deep temporal veins drain into?
Pterygoid venous plexus
Describe the venous drainage of the scalp
Veins of the scalp connect to the diploic veins of the skull
Then through emissary veins to the dural venous sinuses.
Why can a superficial infection of the scalp cause meningitis?
The emissary veins connecting the veins of the scalp to the dural venous sinuses are valveless, which can allow a route for infection to spread.
Where is the middle meningeal artery particularly vulnerable?
At the pterion
What is the pterion?
A weak area of skull where the temporal, frontal, sphenoid, and parietal bones join.
Name the dural venous sinuses.
Superior saggital sinus
Inferior saggital sinus
Cavernous sinus
Transverse sinus
What sinus do the dural venous sinuses drain into?
Sigmoid sinus
What does the sigmoid sinus drain into?
Internal jugular vein after passing through the jugular foramen.
Explain the ‘danger triangle’ of the face.
Thrombophlebitis in the facial vein can travel to the dural venous sinuses through the pterygoid venous plexus.
What structures is the cavernous sinus closely associated with?
Internal carotid artery
CN III/IV/VI
Two branches of the trigeminal nerve (CNV1/V2)
Describe how to measure jugular venous pressure.
Sit the patient at 45 degrees and turn their head to the left
Look for pulsation of the internal jugular vein through the sternocleidomastoid
Measure the height from the sternal angle +5cm.
Describe the three atypical cervical vertebrae?
C1 (atlas) - no body or spinous process
C2 (axis) - odontoid process
C7 - non bifid, prominent spinous process. Large transverse processes
Describe a burst fracture of the cervical spine.
Occurs after a fall from a height or an RTC giving a high energy axial load.
The vertebrae fracture in multiple places.
Shards can penetrate surrounding tissue and the spinal canal.
Describe a hangmans fracture.
Hyperextension of the head on the neck, snapping the dens.
This crushes the contents of the spinal cord.
What is the only moveable joint of the skull?
Temporomandibular joint.
What bone makes up the forehead and upper eye sockets?
Frontal bone
What bone makes up the majority of the top and back of the skull?
Parietal
What bone is at the base of the skull at the back?
Occipital bone
What bone makes up the front of the cheek bones?
Zygomatic bone
What is the function of the skull?
Protect the brain and special sensory organs
Provide a specialised environment
Attachment for muscles and the meninges
What are the thickest parts of the skull?
Occipital and frontal bones
What is the thinnest part of the skull?
Pterion
What is the calvaria?
The bony roof of the skull
What are the three fossa of the cranial floor, and what cranial nerves are associated with them?
Anterior fossa - CNI and part of CNII
Middle fossa - CNII-VI
Posterior fossa - CNVII-XII
What are the main bones of the cranial floor?
Palatine
Sphenoid
Temporal
Occipital
Describe the location of the frontal bone.
Anterior skull vault up to the supraorbital ridge.
What artery is the frontal bone associated with?
Superficial temporal artery
Describe the location of the ethmoid bone.
The midline of the anterior cranial fossa
Why might anosmia be found in a patient with an ethmoid bone fracture?
It is closely associated with CNI
Describe the important features of the sphenoid bone.
The central part has the sphenoid sinus
The optic nerve runs along the optic canal
The pituitary gland sits in the sella turcica
Pterygoid process projects downwards
Foramen rotundum contains CNII
Foramen ovale contains CNIII
What is the hardest part of the temporal bone?
Petrous part
What is the function of the condyles of the occipital bone?
Articulate with the atlas
What are the differences in a neonatal skull compared to an adult?
Large cranial sutures held together by a thick connective tissue matrix
Fontanelles in the region of the bregma and lambda
What is cerebral herniation?
Increased pressure in the skull causing the brain tissue to move down through the foramen magnum.
Tends to be caused by a head injury, stroke, or tumour.
Commonly fatal.
Describe a basilar skull fracture.
One which occurs in the floor of the cranial vault
Causes ‘battles sign’, blood in the sinuses, CSF leaking from the nose, ‘raccoon eyes’
Describe a compound skull fracture.
A fracture which puts the outside environment in direct contact with the cranial cavity.
The risk of infection is very high and it may cause pneumocephalus.
Describe a diastatic skull fracture.
When the fracture line traverses one or more sutures of the skull, causing the sutures to widen. They are most common in young children and infants.
In adults, the lambdoidal suture is most likely to be affected.
They are more common with cleidocranial dysphasia and osteogenesis imperfecta.
Describe cervical kyphosis.
Caused by degenerative disc disease, a congenital defect, iatrogenic, and trauma.
It is when the normal inward curvature reverses.
Describe cervical spinal stenosis.
Collapse of the intervertebral discs due to scarring of the annulus.
Causes abnormal pressure on the articulate cartilage, leading to bone spurs, thickened ligaments, and bulging discs.
This can cause pressure on the spinal cord or peripheral nerves, leading to myelopathy and radiculopathy respectively.
What is CNI?
Olfactory nerve
What is the path of the olfactory nerve?
Olfactory mucosa
Cribriform plate of the ethmoid bone
Olfactory tract
Give some causes of anosmia.
Trauma causing a fracture of the cribriform plate
Meningitis
Upper respiratory tract infection (transient)
What is CNII?
Optic nerve
Is the olfactory nerve sensory, motor, or both?
Sensory
Is the optic nerve sensory, motor, or both?
Sensory
Describe the course of the optic nerve.
Retina Optic canal Optic tract Cross at the optic chiasm Primary visual cortex in the occipital lobe
How do you examine the optic nerve?
Colour vision Visual acuity Visual fields Pupillary reflexes Fundoscopy
What is bilateral hemianopsia?
Visual deficiency of the outer fields due to lesions of the optic chiasm
What is papilloedema?
Optic disc swelling due to raised intracranial pressure
What is CNIII?
Oculomotor nerve
Is the oculomotor nerve sensory, motor, or both?
Motor
Parasympathetic
What cranial nerves have parasympathetic contribution?
Oculomotor (III)
Facial (VII)
Glossopharyngeal (IX)
Vagus (X)
Describe the path of the oculomotor nerve.
Oculomotor nucleus
Supraorbital fissure
Extraocular muscles
What muscles does the oculomotor nerve supply?
Levator palpebrae superioris Inferior oblique Medial rectus Superior rectus Inferior rectus
What can cause an oculomotor nerve palsy?
Raised intracranial pressure
Aneurysm
What are the symptoms of an oculomotor nerve palsy?
Down and out pupil
Mydriasis
Ptosos
What in CNIV?
Trochlear nerve
Is the trochlear nerve sensory, motor, or both?
Motor
Describe the course of the trochlear nerve.
Trochlear nucleus
Supraorbital fissure
Superior oblique muscle
What cranial nerve has the greatest intracranial length?
Trochlear nerve
What can cause damage to the trochlear nerve?
Raised intracranial pressure
Tumour
Cavernous sinus thrombosis
What neurovascular structures pass through the cavernous sinus?
Oculomotor nerve
Abducens nerve
Trigeminal nerve (V1/2)
Internal carotid artery
What are the symptoms of trochlear nerve palsy?
Diplopia when walking down stairs
Subtle head tilt
What is CNV?
Trigeminal nerve
Is the trigeminal nerve sensory, motor, or both?
Both
Describe the route of the trigeminal nerve, including branches
Trigeminal sensory nuclei
Trigeminal ganglion
V1 - opthalmic
Through the supraorbital fissure to the forehead, eyes, and nose
V2 - maxillary
Through the foramen rotundum to the cheeks, maxilla, and upper teeth
V3 - mandibular
Through the foramen ovali to the mandible, ears, chin, and lower teeth
What hole in the skull does the opthalmic branch of the trigeminal nerve pass through?
Supraorbital fissure
Where does the opthalmic branch of the trigeminal nerve provide sensory innervation?
Forehead
Eyes
Nose
What hole in the skull does the maxillary branch of the trigeminal nerve pass through?
Foramen rotundum
Where does the maxillary branch of the trigeminal nerve provide sensory innervation to?
Cheeks
Maxilla
Upper teeth
What hole in the skull does the mandibular branch of the trigeminal nerve pas through?
Foramen ovali
What structures does the mandibular branch of the trigeminal nerve provide sensory innervation for?
Mandible
Ears
Lower teeth
Chin
What is trigeminal neuralgia?
Episodes of intense pain in the face due to overactive sensory fibres.
How do you check the afferent fibres of the trigeminal nerve?
Corneal reflex
How do you check the sensory function of the trigeminal nerve?
Touch lightly with cotton wool on each area, close to the midline
How do you test the motor function of the trigeminal nerve?
Clench the jaw and feel for the masseter, temporalis, and pterygoid muscle
What is CNVI
Abducens nerve
Is the abducens nerve sensory, motor, or both?
Motor
Describe the course of the abducens nerve.
Abducens nerve
Supraorbital fissure
Cavernous sinus
Lateral rectus muscle
What is the false localising sign?
In raised intracranial pressure, the abducens nerve is the first to be affected. It can falsely suggest that there is a lesion close to the nerve.
How do you check the function of the abducens nerve?
Ask the patient to follow your finger in a H formation
What is CNVII?
Facial nerve
What are the branches of the facial nerve?
Temporal Zygomatic Buccal Maxillary Cervical
What is the function of the facial nerve?
Anterior 2/3 taste buds
Expression
Salivation
Lacrimation
Describe how you would examine the facial nerve.
Raise eyebrows, forehead should wrinkle Squeeze eyes shut and resist opening (orbicularis oculi) Show teeth (orbicularis oris) Blow cheeks (buccinator) Taste
How can you tell whether a facial nerve lesion is intra or extracranial?
The forehead is only affected if the lesion is extracranial
What is Bell’s palsy?
Idiopathic one-sided facial paralysis.
Potentially due to inflammation at the stylomastoid foramen
May not regain function
What is CNVII?
Vestibulocochlear nerve
Is the vestibulocochlear nerve sensory, motor, or both?
Sensory
Describe the course of the vestibulocochlear nerve.
Cerebellopontine angle
Acoustic meatus
Bifurcate to cochlear and vestibular nerves
Cochlea and semilunar canal
How do you test the vestibulocochlear nerve?
Whisper in each ear
Rinne’s test for conduction
Weber’s test for localisation
What is vertigo and what may cause it?
A feeling of spinning or swaying
Paroxysmal positional vertigo
Menieres disease
Labyrinthitis
What is Meniere’s disease?
A disease of unknown cause which affects the membranous labyrinth of the ear, causing progessive deafness, tinnitis, and vertigo.