Head, Neck and Spine (Part 2) Flashcards by Ishi Datta

What is the neck?

A tube that connects the head to the trunk (rest of the body)

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What are the 3 main functions of the neck?

Structural - supports and moves the head

Visceral functions - contains the airway, oesophagus and some endocrine glands (parts of the respiratory and digestive system)

Conduit (channel) - for blood vessels taken up from the thorax to the head and neck, and nerves taken down from the head and neck to the thorax

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What is fascia?

What are the compartments of the neck?

What are the two major types of fascia in the neck?

Fascia - a connective tissue mainly composed of collagen fibers, and it organises the body into different compartments

Compartments of the neck include: vascular (arteries and veins), visceral (e.g. oesophagus, trachea), and muscles / vertebral

Superficial fascia and investing fascia (also known as deep fascia)

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Which is the outermost layer of the fascia?

What are the 3 layers of the investing (deep) fascia?

Superficial fascia

Pre-trachial fascia - surrounds some of the visceral components of the neck e.g. components of the digestive and respiratory systems, and some endocrine glands

Carotid sheath - surrounds the blood vessels there, and even a nerve (vasculature)

Pre-vertebral fascia - surrounds the muscles found at the back of the neck

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What is contained within the compartment surrounded by the pre-tracheal layer?

What is contained within the compartment surrounded by the carotid sheath layer?

What is a major function of the muscles found within the pre-vertebral layer?

What other major muscles does the investing fascia (blue outline) surround?

Pre-tracheal - trachea (anterior), eosophagus (posterior), thyroid gland (lateral)

Carotid sheath - internal jugular vein, common carotid artery, vagus nerve

Muscles that help move and stabilise the head

Sternocleidomastoid and trapezius muscles

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Where are the two triangles of the neck in this diagram and descrive their positioning / borders?

Which muscle divides the neck up into 2 triangles and describe the positioning of the muscle?

Anterior triangle = green: anterior surface of the sternocleidomastoid muscle, midline of the neck, and inferior border of the mandible

Posterior triangle = blue: posterior surface of the sternocleidomastoid muscle, the trapezius muscle, and the clavicle

Sternocleidomastoid muscle - runs down from the skull to the sternum and clavicle

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The anterior triangle of the neck contains which muscles / structures?

Fill in the labels covered in red:

What are the muscles found in the yellow box?

Muscles, including: platysma (superficial muscle not shown in these diagrams), mylohyoid, digastric, infrahyoid (strap) muscles; Blood vessels, including: carotid arteries

Strap muscles - they go between the hyoid bone or thyroid cartilage to the sternum or scapula (shoulder blades)

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The posterior triangle contains which structures (3 blood vessels and 4 nerves - and what they innervate)?

Fill in the missing labels on this diagram:

Mainly blood vessels and nerves, including: external jugular vein, sunclavian artery, subclavian vein, trunks of the branchial plexus (nerve that supplies the upper limbs), phrenic nerve (supplies diaphragm), vagus nerve (supplies respiratory, cardiovascular and abdominal structures), spinal accessory nerve (moves a pair of muscles in the neck)

The vagus nerve lies anterior to the phrenic nerve, the external carotid artery is much more superficial than the internal carotid artery

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Fill in the labels of the nerves on this diagram:

CN XI - accessory nerve, innervates the sternocleidomastoid and trapezius muscles

Some sensory nerves supplying the skin at the back of the skull, anterior of the neck, and skin over the lateral side of the neck

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What do the internal and external carotid arteries supply?

What are the 8 branches of the external carotid arteries?

Fill in the labels on this diagram:

The common carotid arteries branch directly or indirectly off the aorta

Internal - ascends into the cranial cavity to supply the brain

External - supplies mainly the face

The superior thyroid artery, the ascending pharyngeal artery, the lingual artery, the facial artery, the occipital artery, the posterior auricular artery (supplies the back of the ear and skin at the back of the ear), the superficial temporal artery, and a main branch of the maxillary artery (goes to the cranial cavity to supply the meninges)

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The muscles of facial expression can be divided into which 3 groups?

The muscles of facial expression are innervated by which nerve?

Orbital - principally act on the eyelids, contraction of these muscles constrict and close the eyelids

Nasal - principally act on the nose

Oral - principally act on the mouth

(Some additional muscles include the auricle muscles which

CN VII - the facial nerve

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Inside which structure does the facial nerve divide / branch and does it innervate this structure too?

What are the names of the 5 main branches of the facial nerve?

Fill in the covered labels on this diagram:

The facial nerve divides up in the parotid gland, although it does not innervate the parotid gland

The temporal, zygomatic, buccal, mandibular and cervical branches

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Where is the temporomandibular joint (TMJ)? Between which two bones?

What is the back of the mandible called? What is the bottom of the mandible called? Where do these two meet?

What are the 2 superiorly projecting parts of the mandible?

Fill in the labels on this diagram of the mandible:

Between the mandible and the temporal bone - at the condylar process (which contains a head and neck)

Ramus, Inferior border, angle

Condylar process (which has a head and neck) and the coronoid process

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What type of joint is the TMJ and why is the TMJ important?

Which nerve innervates the muscles of mastication?

What are the 4 main movements of the mandible?

Which movements occur whent the jaw is slightly open?

Which movements occur when the jaw is widely open?

Synovial joint - important for opening and closing the jaw for mastication (chewing)

Mandibular branch of CN V (trigeminal nerve)

Protrusion (forwards), retraction (backwards), elevation (upwards) and depression (downwards)

Hinge action predominates

Hinge and gliding action occur

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What are the names of the 2 superficial muscles that bring about the movement of the mandible?

Where are the found? How do they move the mandible?

Temporalis and masseter muscles

Temporalis - found on the side of the head, from the temporal fascia and attaches to the coronoid process of the mandible, brings about elevation and retraction of the mandible

Masseter - comes from the zygomatic arch and attaches to the ramus and angle of the mandible, causes elevation of the mandible when the mouth is forcibly closed shut

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What are the 2 deeper muscles that move the mandible?

Lateral and medial pterygoid muscles

Lateral pterygoid - attaches to the sphenoid bone, pterygoid plate and the mandible, causes depression and protrusion of the mandible to open the mouth

Medial pterygoid - attaches to the lateral pterygoid plate, the maxilla and the palate, and the angle of the mandible, causes elevation, protraction and lateral (side to side) movement of the mandible for mastication / grinding

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What are the orbits of the eye and what structures do they contain?

The roof of the orbit is made up of which bone? The floor of the orbit is made up of which bone? The medial and lateral sides of the orbit are made up of which bones?

Label the bones that make up the orbit in the diagram:

Orbits - bilateral structures that contain the eyeballs and the muscles that move the eye, the extraoccular muscles, the optic nerve, and other nerves and vessels

Orbital plate of the frontal bone; orbital plate of the maxilla; ethmoid and lacrimal bones; zygoma

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What are the names of the 3 foramina / holes in the eye orbits and what structures pass through them?

Fill in the covered labels on the diagram:

Superior orbital fissure - ophthalmic division of the trigeminal nerve (CN V₁), oculomotor (CN III), trochlear (CN IV), abducens (CN VI), ophthalmic vessels and sympathetic fibres

Optic canal - optic nerve (CN II) and ophthalmic artery

Inferior orbital fissure - maxillary division of the trigeminal nerve (V₂), and infraorbital vessels

What is the name given to the muscles that move the eye?

What are the names of the 4 rectus / straight muscles that move the eye?

What is common between all the rectus muscles?

Which cranial nerve are these rectus muscles supplied by?

Extraocular muscles

Medial, lateral (cut in the diagram), superior and inferior recti

Their origin, they all originate from what is known as the common tenderness ring, and they all insert into the eyeball around 5mm behind the cornea

CN III - oculomotor nerve, except the lateral rectus, which is supplied by CN VI - abducens nerve

What are some other muscles around the eye, other than the rectus muscles, and from where do they arise?

Where do they insert into?

Which CNs are they supplied by?

The superior and inferior oblique muscles, and levator palpebrae superioris:

Superior oblique - arises from the body of the sphenoid bone, and inserts into the superior surface; supplied by CN IV (trochlear)

Inferior oblique - arises from the orbital surface of the maxilla, and inserts into the outer posterior Cortlandt ; supplied by CN III (oculomotor)

Which branch of the ANS is the levator palpebrae innervated by?

What does the levator palpebrae superioris move and why?

Sympathetic branch fibres (in addition to the voluntary muscle fibres innervated by the oculomotor nerve)

The eyelid - lifts up, often in conjunction with the sympathetic NS e.g. in fright, or when you need to look superiorly (up)

How do the muscles:

SR (superior rectus), IO (inferior oblique), LR (lateral rectus), MR (medial rectus), IR (inferior rectus), SO (superior oblique)

move the eye in isolation?

SR = medially and superiorly

IO = laterally and superiorly

LR = laterally

MR = medially

IR = medially and inferiorly

SO = laterally and inferiorly

How are these muscles tested clinically?

What are some issues?

Sometimes more than one muscle contributes to an eyemovement, so the eyeball needs to be positioned in a way, the muscle you want to test is at an advantage

Each eye is tested separately and relatively e.g.

LR = ask to move the left eye to the left, and right eye to the right (lateral movements)

MR = ask to move the left eye to the right (towards the nose) and vice versa (medial movements)

SR = look outwards (laterally), then upwards (superiorly)

IR = look outwards (laterally), then downwards (inferiorly)

SO = look medially / towards the nose, then downwards (inferiorly)

IO = look medially / towards the nose, then upwards (superiorly)

What is meant by the term orbit in medicine?

What are the names of the different nerves found in the orbit of the eye? Fill in the labels on the diagram on the left (of the right orbit, with the nose at the top and back of the head at the bottom of the image):

The image on the right shows a deeper dissection. What are the functions of these deeper structures?

The eye socket - bony cavity perforated for the passage of nerves and blood vessels, occupies the lateral front of the skull beneath the frontal bone

CN IV (trochlear) - supplies motor fibres to the superior oblique muscle

CN II (optic) - brings visual info from the eye back to the brain

The optic chiasm is also on the diagram, where the optics nerves from both eyes cross

CN III (occulomotor) - innervates many eye muscles and carriesautonomic fibers that alter the size of the pupil and the thickness of the lens

CN V₁(trigeminal) - receives sensory information from the frontal and lacrimal divisions, and innervates the lacrimal gland (motor)

Image on the right (deeper dissection) =

Nasociliary branch of the ophthalmic division of the trigeminal nerve

The ciliary ganglion = autonomic ganglion through which parasympathetic CN III nerve fibres pass to the eye for pupil constriction and lens accomodation, and sympathtetic nerve fibres pass to cause dilation of the pupils

What is the cavernous sinus and where is it found? Why is important, especially clinically? On what plane is this image?

Cavernous sinuses are located within the middle cranial fossa, on either side of the sella turcica of the sphenoid bone. They are enclosed by the endosteal and meningeal layers of the dura mater Has many important structures running through it, and clinically, infections can spread from this to the rest of the cranial cavity Coronal view - superior at the top, inferior at the bottom of this pic

# Fill in the labels of the covered structures in this diagram: There are 2 caverous sinuses on either side of the pituitary Which nerve is running from the eyeball to the back of the brain? What sits in the sella turcica / spenoid fossa of the sphenoid bone? What are the different CNs present / passing through the cavernous sinuses?

Optic nerve Pituitary gland

How can injuries to the face back track to to the cranial cavity?

Via the cavernous sinuses, due to the veins and nerves connecting the external world to the cranial via which the infection can pass to the cranial cavity Also the structures passing through the cavernous sinus, passing the walls, they are vulnerable to traumatic injury and inflammation

What is the lacrimal system and what is is made out of? Where is the lacrimal gland located in the orbit using fancy terminology?

System involved in the production, movement and drainage of fluid from the surface of the eye - made up of the lacrimal gland and its ducts, the lacrimal sac, and the nasolacrimal duct Supra lateral quadrant of the orbit

How are the fluids drained in the lacrimal system? Fill in the covered labels of the different parts of the lacrimal system and describe their functions: Which duct empties the nasal cavity? What nerve innervates the lacrimal gland?

Fluid is drained medially (towards the nose). Excess fluid is drained into the nasal cavity, which drains into the nasolacrimal duct Nasolacrimal duct - empties the nasal cavity CN VII (facial) - parasympathetic secretor motor fibres supply the lacrimal gland

What are the nasal cavities and where are they found? What are the structures / bones that separate the nasal cavity from the oral and cranial cavities?

Passage way through which we breathe, and from which fluid from the lacrimal system drains - found in the uppermost part of the respiratory tract, the 2 nasal cavities are separated by a midline septum Spearated from the oral cavity below by the hard palate, and from the cranial cavity above, by parts of a number of bones including the frontal, ethmoidal and sphenoid bones

# Fill in the labels of this diagram by answering the questions below: (Nose on the left on the slide) Which bones stick out into the nasal cavity? (3 names) What are the names of the bones that contribute to the structure of the nasal cavity? (4 names)

The conchae : superior, middle and inferior concha The nasal bone, the maxilla, the sphenoid bone and the palatine bone

What are the names of the structures located between the conchae? What is the purpose of the conchae? Where and what is the pharyngotympanic tube?

The meatuses - superior, middle and inferior meatus Increase the surface area of the nasal cavity, warm and humidify air, and help trap pathogens AKA the eustachian / auditory tube

Which nerves innervate the nasal cavities and what are their functions?

3 CNs and sympathetic nerves from the T1 level of the spinal cord CN I (olfactory) - olfaction / smelling CN V₁ and V₂ (opthalmic and maxillary divisions of the trigeminal) - general sensation in the anterior and posterior regions respectively CN VII (facial) - supplies parasympathetic fibers to the glands of the nasal cavities Sympathetic nerves (from T1) - supply vascular smooth muscle of the nasal cavities

Why do the nasal cavities has a rich blood supply? The arterial supply (circled in grey) is via which big arteries? Why are people susceptible to nosebleeds?

They aid in humidifying and changing the temperature of the respired air Via the internal carotid arteries (grey circle at the top of the diagram) and branches of the external carotid artery (grey circle in the middle of the diagram) Many connections of the different arteries (anastomoses)

Why is there a risk of infections in the nasal cavity to spread to the cranial cavity?

Some of the blood vessels that drain the nasal cavity pass through the cavernous sinus and into the cranial cavity

What are the paranasal sinuses? How many are there? How are they named? What is the purpose of these paranasal sinuses?

Group of air-filled spaces that surround the nasal cavity 4 pairs Named after the bones in which they are found Help reduce the weight of the skull and act as crumple zones in the case of facial trauma. Help to increase the resonance of the voice, and humidify and heat inhaled air. They secrete mucous, which is clinically relevant as they can also become infected

# Fill in the labels on the diagram of the sinuses and which nerves they are innervated by so the brain can receive sensory information from them: Which sinuses are located above the eyes? Which below? Which inbetween the eyes? Which behind the eyes?

Frontal - V1 Maxillary - V2 Ethmoidal - V and V2 Sphenoidal - V1 and V2

The drainage points lie below the conchae, so in this diagram the conchae have been cut away to reveal the drainage points. Fill in the covered labels: Where does the sphenoid sinus drain into and where is it found? Which 2 structures are inferior to the that? What / where is the drainage point of the frontal sinus? Under which structure does the nasolacrimal duct open? Where is the opening of the maxillary sinus found?

Spheno-ethmoidal recess - superior to the superior concha The opening of the ethmoidal cells into the lateral wall of the superior meatus and the opening of the ethmoidal cells Anterior to those are the anterior ethmoidal cells, which are the drainage points of the frontal sinus Under the inferior concha On the floor of the semilunar hiatus

# Fill in the covered labels of the external part of the ear: What is the purpose of the external ear?

Auricle = outside of the ear, which has a rim called the helix Purpose = to transmit sounds towards the tympanic membrane / eardrum

What is attached to the tympanic membrane and what is its purpose? In the inner ear, which structures are responsible for hearing and balance respectively? Which CN innervates these structures? Which CN runs through the middle ear and why? What is the purpose of the pharyngotympanic tube?

Small ossicles / bones - transmits sound into the inner ear Cochlear = hearing, semicircular canals = balance CN VIII (vestibulocochlear) - the vestibular nerve = take signals on balance and orientation from the vestibular system; the cochlear nerve = takes information about sound CN VII (facial) The middle ear is continuous with an opening into the nasal cavity, the fringo tympanic tube. The fringo tympanic tube, equalises the pressure between the middle ear and the atmosphere

Why is CN VII (facial) associated with components of the ear?

Stapedius - v. small muscle in the ear

Describe the functions of the different branches of the facial nerve in this diagram:

How close is the middle cranial fossa to the middle ear and why is this relevant clinically?

V. close to the middle ear Serious middle ear infections, although rare, can transmit into the cranial fossa, leading to serious complications, such as meningitis