Superficial structures in the neck Flashcards
1
Q
What are the basic compartments of the neck
A
neck is tube-like passageway between the head and the thorax for the Trachea, Oesophagus and various neurovascular structures
- vertebral column in the middle as a dividing structure dividing anterior and posterior compartments in the neck
- Each of these compartments is covered with Deep/Investigating Fascia of the Neck
2
Q
What is in the posterior compartment of the neck
A
- The posterior compartment is the vertebral column itself and its thick associated musculature
- The musculature here (Post and Prevertebral) must be strong to keep the head upright so that it does not fall forwards onto the chest at rest in the upright position
- These muscles are erector spinae, as well as muscles on the anterior aspect of the vertebrae as well (e.g. rectus capitis)
- These are very long and thin muscles that fine tune movement at the back
- The whole compartment is packaged in fascia
3
Q
What is in the anterior compartment of the neck
A
- The anterior compartment (prevertebral muscles) contains the mobile part of the neck (Respiratory Tract, Digestive Tract and Neurovasculature)
- (Prevertebral Muscles) are rather weak as their action is aided by gravity in the upright position
- The posterior column is the one that moves your neck
- At the same time there are lots of structures (Trachea, Oesophagus and Neurovascular Structures) that pass through here which go to the thorax and abdomen:
1. The pharynx and oesophagus
2. The larynx and trachea - These structures need to be freely mobile so we can swallow and breathe, independent to the posterior column of the neck
- Neurovascular Structures and Lymph Nodes (Vascular Compartment) are found posterolateral to the Oesophagus + Trachea (Anterior Compartment) and Anterolateral to the Posterior Compartment
- The Thyroid Gland is found surrounding the Superolateral Aspects of the Anterior Trachea, at the root of the neck
- These two columns need to be able to slide past each other to allow for independent breathing and swallowing and can move independently to one another
- The anterior and posterior compartments are kept as functional distinct units by wrappings of Investing/Deep Fascia which surround the compartments, as if the structures in the anterior compartment separated during motion their function would be restricted
- The Pretracheal Fascia surrounds and Encloses the Trachea, Oesophagus and Thyroid
- This fascia is well defined over the Prevertebral Muscles (Prevertebral Fascia) and in the midline posteriorly between the Posterior Compartment Muscles (Ligamentum Nuchae)
4
Q
Describe the deep cervical fascia (platysma)
A
- outermost layer of fascia underneath the skin
- This has a thin layer of muscle called the platysma embedded into it, extending from the Superficial Cervical Fascia and Skin over the chest and clavicle and sweeps superiorly over the anterior and lateral aspects of the neck to insert into the Deep Fascia of the Neck, Lower border of the Mandible and the Deep Fascia of the Lower Face
- This raises the hair follicles on the face and mainly acts to move the skin of the lower face inferolaterally
- This is innervated by CN VII as it is a muscle of Facial Expression
- Humans have a negligible platysma
- Other animals have a more extensive platysma where the extension reaches the vertebral column
- The bigger muscle is due to the fact that, when it is contracted it makes the animal’s neck appear bigger
5
Q
Describe the deep cervical fascia (where it attaches and descends)
A
- Underlying this is the deep cervical fascia, which encloses the neck all the way around
- The Deep Cervical Fascia is complete around the neck, surrounding the neck from the Mandible Superiorly to the Clavicle inferiorly, enclosing the SCM and Trapezius and extending around the posterior aspect of the neck
- It attaches to the sternum, clavicle laterally, goes posteriorly over the Acromia and Spines of the scapulae to attaches to and encompass the muscle fascia of the trapezius.
- It then goes from the Attachment of the Trapezius up and attaches to the nuchal part of the head, travels anteriorly to cover the Mastoid Process, External Acoustic Meatus, Zygomatic Arch and overlies the Masseter
- It then descends from the Zygomatic Arch and to the Inferior Border of the Mandibular Ramus and Body to attach to the Superior Border of the Sternum and Clavicle
- It completely encloses all of the structures of the neck from the Mandible Superiorly and the Clavicle inferiorly (SCM, Trapezius, Extensor Muscles of the Neck)
- In the Midline of the Anterior Neck inferiorly, the Deep Cervical Fascia splits into an Anterior and Posterior Layer that attaches to the Anterior and Posterior Surface of the Manubrium
- This forms a suprasternal space between the Manubrium Inferiorly, the Bifurcation of the Deep Cervical Fascia superiorly and the Anterior and Posterior Layers of the Deep Cervical Fascia anteriorly and posteriorly
- This contains some fatty tissue and the Jugular Venous Arch (which runs transversely across the Suprasternal Notch to connect the Anterior Jugular Veins)
6
Q
What are the 3 layers of the deep cervical fascia
A
- The outermost layer of the deep cervical fascia is called the superficial/investing/anterior layer
- It encloses the trapezius posteriorly and sternocleidomastoid anteriorly and has an invagination which forms the carotid sheath, which covers the common carotid artery and the
internal jugular vein - The trapezius is slightly outside but is also held by it
- The middle layer is the middle/pretracheal layer is anterior
- This is a sleeve in the Medial Aspect of the Anterior Compartment and encloses the infrahyoid muscles anteriorly, thyroid gland and oesophagus posteriorly
- It is effectively a package of the structures in the moveable anterior compartment which allows it to slide against everything else in this compartment - The deepest layer is the prevertebral/deep/posterior
- This encloses the muscles round the vertebral column and make sure they are separate from other structures (Posterior Compartment)
- It encloses the erector spinae, prevertebral muscles and scaleni
7
Q
Describe the danger space
A
- Whilst the layers of the Deep Cervical Fascia are closely associated with one another, between the pretracheal anteriorly and prevertebral layers posteriorly, there is a little bit of space to allow the movement of the structures in the pretrachial fascia against the prevertebral fascia
- Exudate, blood, pus or other fluids can break through the walls of the fascia that enclose the region containing the structures passing from the neck to the trunk/thorax, allowing infections to spread from the head/pharynx to the thorax
- For example
1. An abscess caused by an issue with a tooth could cause inflammatory problems in the thorax
2. Gangrene from the head and neck could spread to the thorax - This space is therefore called the “danger space”
8
Q
Describe cervical vertebrae
A
- There are always 7
- These have small transverse processes.
- There are holes (foramina transversaria) that run between the rib-analogue and the transverse processes.
- Transverse foramen are only found in cervical vertebra
- The vertebral blood vessel and vein run through here
- These supply and drain blood to/from the brain
- They have characteristic spinous processes which are often bifurcated (two tips), where neck muscles attach.
- They have rather large vertebral canals
- The articular processes have joint facets which are cranially orientated. This is visible in the axial plane (Looking from above or below)
- There are additional joints (e.g. uncinate joints) formed between the uncinate processes of neighbouring vertebral body
- The Cervical Vertebrae provides the neck with a strong musculoskeletal framework whilst allowing it to be mobile
- There are 8 Pairs of Cervical Spinal Nerves as C1 leaves the vertebral Column above the First Cervical Vertebra (Between C1 and the Base of the Skull) whilst the C2-C8 leave via their associated Intervertebral Foramen
- The Dorsal Rami of Cervical Vertebrae provide motor innervation to the Extensor Muscles/Erector Spinae of the Neck and Sensory innervation to the Skin found superficial to them
- C1-C4 = Mixed Spinal Nerves that project inferomedially to supply the neck muscles and provide cutaneous sensation to the neck
- C5-C8 project inferolaterally to join the Brachial Plexus
- The Distal ends of the Transverse Processes of Cervical Vertebrae ends in 2 Tubercles, an Anterior and Posterior Tubercle, through which the Cervical Ventral Rami pass to enter the neck via the Anterior and Middle Scaleni
- C1 (atlas) is a ring structure which has no vertebral body and connects directly to the skull and thus connects the rest of
the vertebral column to the skull via the occipital condyles. - This allows for nodding (flexion/extension)
- C2 (axis): The body of the axis has a process called the dens which fits into the hole in C1. It is secured into this with a ligament behind it.
- This forms a pivot joint (Atlanto-Axial Joint)
- C7 has a spinous process that looks like one belonging to thoracic vertebrae as it has a non-bifurcated spinous process
- C1 and C2 are very important in facilitating head and neck movements
- The Rib, Transverse and Spinous Processes are common attachment sites for Muscles of the Neck
9
Q
Describe C1,C2 and C7
A
- C1 (atlas) is a ring structure which has no vertebral body and connects directly to the skull and thus connects the rest of
the vertebral column to the skull via the occipital condyles. - This allows for nodding (flexion/extension)
- C2 (axis): The body of the axis has a process called the dens which fits into the hole in C1. It is secured into this with a ligament behind it.
- This forms a pivot joint (Atlanto-Axial Joint)
- C7 has a spinous process that looks like one belonging to thoracic vertebrae as it has a non-bifurcated spinous process
- C1 and C2 are very important in facilitating head and neck movements
- The Rib, Transverse and Spinous Processes are common attachment sites for Muscles of the Neck
10
Q
Describe scaleni muscles
A
- They are found Lateral to the Cervical Vertebral Column, Anterolateral to the Erector Spinae (Deepest Muscle of the Lateral Neck)
- They are lifters of the first and second ribs when the neck is fixed, but also laterally bend the neck
- There are three scaleni; anterior, middle and posterior
- They originate from the Anterior (Anterior Scalene) and Posterior (Middle and Posterior Scaleni) Tubercles of the Transverse processes of the cervical vertebrae
- The anterior and middle scalene insert onto the first rib
- The posterior scalene inserts onto the first and second ribs
- The Middle Scalene can sometimes also attach onto Ribs 2 as well as Rib 1
- Between the anterior and middle scaleni there is a gap called the scaleni gap, through which the roots and the trunks of the brachial plexus pass
- They are innervated via the mostly the cervical and a bit of the brachial plexi (C4 – C8)
11
Q
What are the strap/infrahyoid muscles
A
- These are seen as slender strips inferior to the Hyoid, deep to the Investing Deep Fascia and SCM but Anterior/Superficial to the Laryngeal Cartilage and Thyroid Gland
- They are found superficial to the Scaleni
- They lower the hyoid and larynx (during swallowing) or can fix the Hyoid when they act with Suprahyoid Muscles
- Fixation of the Hyoid Bone by the action of the Infrahyoid Muscles and the Muscles of the Mouth Floor produces a stable bony basis on which the tongue can move
- They all have an attachment below and from the hyoid
- They all have different insertion points
- The Thyrohyoid first elevates the Thyroid Cartilage towards the Hyoid, then the Sternothyoid depresses the Larynx.
- This rise and fall of the Larynx can be clearly seen in the neck during each swallow
- The Sternohyoid is found superficial to Thyrohyoid Superiorly and Sternothyroid Inferiorly
- The Sternohyoid is also found in the same plane as the Omohyoid but is medial to Omohyoid
12
Q
What are the innervation and attachments of omohyoid
A
- Innervated by C1 – C3 via ansa cervicalis
- The Inferior Belly of Omohyoid originates from the Superior part of the Scapula and passes anteriorly over the root of the neck
- The Superior Belly originates from the Inferior Border of the Hyoid
- The Intermediate tendon passes through a fascial sling which is attached to the fascia on the deep surface of the SCM
- The Inferior Belly of omohyoid is posterior to the sternocleidomastoid
- This is found lateral to the Sternohyoid and like the other Infrahyoid Muscles, it depresses the Hyoid
13
Q
What are the innervation and attachments of the sternothyroid
A
- Innervated by C1 – C3 via ansa cervicalis
- This is found deep to Sternohyoid and is in continuity with the Thyrohyoid superiorly
- This originates from the Posterior Aspect of the Manubrium and travels superiorly to the Oblique Line on the Thyroid Cartilage
14
Q
What are the attachments and innervation of thyrohyoid
A
- Innervated by C1 fibres (Thyrohyoid Nerve) that travel with CN XII but do not form the Ansa Cervicalis, running separately to innervate Thyrohyoid and Geniohyoid
- This connects the thyroid cartilage to the hyoid and is the superior continuation of the Sternothyroid
- This originates from the Oblique line of the Thyroid Cartilage and inserts onto the Inferior Border of the Hyoid
- This is found deep to the superior parts of the Omohyoid and the entirety of Sternohyoid (It is the Most Superior Infrahyoid Muscle)
- The sternohyoid, sternothyroid and thyrohyoid are fairly midline muscles
15
Q
Describe the trapezius
A
- The lower fibres of the trapezius can move the neck
- The descending part (Vertical fibres projecting inferiorly which originate on the Skull) can rotate the head on the opposite side
- If you contract the left part of the trapezius, the head moves to the right
- It positions the scapula relative to the head and neck
- It is innervated by the spinal accessory nerve (XI) and C3 and C4 for its motor function and the cervical plexus for its sensory innervation
16
Q
Sternocleidomastoid
A
- This is an important muscle for locating structures in the neck
- This originates as a round tendon from the Anterior Surface of the Manubrium and the Medial 1/3rd of the Clavicle as a flat muscular sheet
- These two sets of fibres fuse as they ascend on their way to insert onto the Mastoid process of the Skull and lateral aspect of the Posterior Nuchal Line on the Posterior surface of the Occipital Bone, covering the anterior and lateral aspects of the neck
- It is quite strong and important for a lot of head movements
- It also assists breathing mechanics by lifting the sternum to increase thoracic volume
- If it is activated unilaterally, there is lateral bending of the neck to the same side and rotation of the neck/head to the opposite side
- If it is activated bilaterally, the head comes forward through neck flexion and head extension
- It is innervated by the spinal accessory nerve (XI) for its motor function and the cervical plexus for its sensory innervation
17
Q
Describe the 3 styloid muscles
A
- These pass through the branches of the Carotid Tree, from their common origin on the Styloid Process on the base of the Skull, on the deep aspect of the side of the neck
- These are the Styloglossus, Stylopharyngeus and Stylohyoid
Styloglossus
- This is an Extrinsic Muscle of the Tongue that passes through the Superior and Middle Pharyngeal Constrictors to reach its insertion
- It originates from the Styloid Process of the Temporal Bone, between the External and Internal Carotid Arteries, and runs anteroinferiorly to insert onto the Posterior Tongue
- It acts to pull the tongue superiorly and posteriorly, notably during swallowing and speech
Stylopharyngeus
- Stylopharyngeus passes with CN IX, proximally between the Internal and External Carotid Arteries and then anteriorly over the Upper Border of the Middle Constrictor to enter the Wall of the Pharynx
- It is a longitudinal Muscle of the Pharynx that passes deep to the other Styloid Muscles
- Once inside the Pharynx, it inserts onto the Internal Surface of the Thyroid Cartilage
- Its proximal association with CN IX means it can be used as a guide for the position of CN IX
Stylohyoid
- It originates from the Styloid Process of the Temporal Bone and runs along the Superior Border of the Posterior Belly of the Digastric
- This is the most superficial Styloid Muscle and runs around the Anterior Surface of the Carotid Tree (Like CN XII) to insert onto the Hyoid Bone, at the junction between the Body and the Greater Cornu/Horn
- At its insertion, its tendon splits, with the Intermediate Tendon of the Digastric Muscle passing through this split, through which it can glide and move.
- The Stylohyoid Ligament passes deep to the Stylohyoid and attaches to the Lesser Horn of the Hyoid, onto which part of the Middle Pharyngeal Constrictor Originates
- It acts to retract the Hyoid Bone/pull it posteriorly and elevate it
18
Q
What is the posterior triangle of the neck
A
- This is outlined by the Posterior Border of the Sternocleidomastoid anteriorly, middle 1/3rd of the Clavicle inferiorly (Base of the Triangle) and Anterior Border of the Trapezius posteriorly
- It contains the:
1. The spinal accessory nerve (XI) - This enters the deep aspect of SCM close to the mastoid Process and leaves its substance about 1/3rd of the Way down its posterior border - CN XI then travels posteroinferiorly across the Posterior Triangle within the Deep Investing Fascia to enter and innervate the Trapezius about 1/3rd of the way down its posterior border
1. Lesser occipital nerve
2. Supraclavicular nerves
3. Superior trunk of
the brachial plexus
4. External jugular vein - The external jugular vein is found on the posterior border of the sternocleidomastoid
19
Q
Describe the anterior triangle
A
- This is bordered by the Anterior Border of the Sternocleidomastoid laterally, the Inferior Border of the Mandible superiorly (Base of the triangle) and the midline of the neck medially (The 2 Anterior Triangles are continuous with one another medially)
- This contains the contents of the anterior column of the neck
20
Q
What is the main arterial supply for the vasculature in the neck
A
- The main supply stems directly from the aorta from the internal and external carotid arteries
- The external carotid supplies everything on the outside of the skull and the neck
21
Q
What is the main arterial supply in the neck
A
- The main supply stems directly from the aorta from the internal and external carotid arteries
- The external carotid supplies everything on the outside of the skull and the neck
22
Q
Describe the carotid arteries and where they arise from
A
- The common carotid arises from the Brachiocephalic Trunk on the RHS and Aorta on the LHS
- They ascend in the neck, posterolateral to the Midline Trachea and Oesophagus before dividing into the internal (more posterior branch) and external (more anterior branch) arteries near the superior border of the thyroid cartilage (near the Angle of the Mandible).
- The Right Common Carotid branches from the Brachiocephalic Trunk just before ascending through the Superior Aperture of the Thorax
Internal carotid
- This continues upwards and enters the skull through the carotid canal without releasing any branches (it has no branches in the Neck)
- It supplies the cerebrum and meninges
- Initially, CN IX-XII are found quite close to the Internal Carotid Artery and Vein. However, as these nerves run down the neck, they spread out to reach their destinations and associate with branches of the Carotid Tree (From the ECA) to form Neurovascular Bundles
External carotid:
- This ascends up the neck to supply the larynx, pharynx, mouth, nose and scalp and shares the supply to the thyroid glands (Most of the Head, Neck, Face and Scalp)
- These are supplied by anterior, medial, posterior and terminal branches
- The anterior branches are important for supply of the face
- The medial branch goes to the back of the mouth, pharynx and the Infratemporal Fossa
- The posterior branches supply the Occipital Bone and the posterior aspects of the scalp
- The terminal branches (Superior Temporal Branch) ascends to supply the mid-scalp and back of the head
23
Q
What is the carotid sinus and carotid body
A
- There are two clumps of nervous tissue found around the Bifurcation of the Common Carotid
1. One clump, usually referred to as the carotid sinus is: - A dilation of the lower end of the internal carotid artery and is situated behind the bifurcation of the common carotid artery
- Sensitive to arterial blood pressure changes due to many baroreceptors being located here
1. This is a small patch of particular receptor tissue embedded into the wall of the blood vessel (Carotid Body) - The carotid body functions as a chemoreceptor and a baroreceptor monitoring blood gases and blood pressure
- It is also called the glomus caroticum as is found in close vicinity to the carotid sinus and contains chemoreceptors
- These monitor O₂/CO₂ pressures, pH values and temperature of the arterial blood
- The main innervation to both the carotid sinus and body is derived from the carotid branches of the glossopharyngeal nerve (IX)
- The cervical sympathetic trunk and the vagus nerve also contribute
- There is therefore parasympathetic innervation from the glossopharyngeal and vagus nerves and sympathetic innervation to these regions from the cervical sympathetic trunk
24
Q
What are vertebral arteries
A
- The vertebral arteries supply the cerebrum and meninges
- They are the first branch of the Subclavian arteries and run in the transverse foramina of the cervical vertebrae
- They enter into the skull via the foramen magnum
25
What is the thyrocervical trunk
- The Thyrocervical trunk has shared supply to the thyroid gland, scalene muscles and the Inferior parts of the sternocleidomastoid and trapezius muscle (Superficial Muscles of the Neck) via its 4 main branches
- This trunk comes off the Subclavian Arteries, lateral to where the Vertebral Arteries arise (2nd Branch of the Subclavian Artery)
- This trunk gives blood vessels (Transverse Cervical Artery) to supply the Lateral Aspect of Trapezius on the Top of the shoulder, lower neck and shoulder
- The Inferior Thyroid Artery is the most important branch of the Thyrocervical Trunk and ascends to supply the Thyroid Gland - It is the continuation of the Trunk after it gives off the Suprascapular and Transverse Cervical Arteries, which project posteriorly to supply the Shoulder Region and Scapular Muscles
26
Internal jugular vein
- It enters the neck via the Jugular Foramen, arising here as the Superior Jugular Bulb (Swollen region of the IJV)
- Initially, it runs lateral to the the Internal Carotid and then the Common Carotid Arteries as it descends towards the Neck
- As it descends, it receives superficial venous drainage from the scalp, face and neck as well as deep tributaries of the Neck
- As it descends, it runs anteriorly to pass towards and then posterior to the Sternoclavicular Joint, to lie between the 2 Heads of SCM
- At the root of the neck, the Internal Jugular and Subclavian Veins join to form the Brachiocephalic Vein, which fuse Posterolaterally to the Manubrium on the LHS to form the SVC
- Just proximal to the Confluence of the IJV and Subclavian Veins, the IJV Swells to form the Inferior Jugular Bulb
- There are valves just above the Inferior Jugular Bulb to prevent Backflow of Blood into the IJV when Intrathoracic Pressure is raised
27
What is the cervical plexus
- The cervical plexus is normally found lateral to the common carotid and internal jugular underneath the sternocleidomastoid
- The anterior/Ventral spinal nerve roots of C1 – C4 form the cervical plexus
- C1 – C3 form the ansa cervicalis of the cervical plexus
28
Hypoglossal nerve 12
- The Hypoglossal Nerve mainly travels through the neck without innervating structures
- The hypoglossal nerve (XII) begins as the most Medially placed CN and comes out of the skull from the hypoglossal canal/anterior condylar foramen which is found in the occipital condyles
- The occipital condyles are where the skull connects with the atlas
- It travels anteroinferiorly in the shape of a wide arc, to travel around the anterior surface of the Internal and External Carotids, the Carotid Tree and anteroinferior to the Loop of the Lingual Artery.
- As it descends it runs along the Anterior Border of Stylopharyngeus, crossing under CN XI and over CN X in the Neck to run superoanteriorly to supply motor innervation to the tongue
29
Glossopharangyeal nerve
- The glossopharyngeal (IX) nerve leaves the skull via the jugular foramen
- As it descends, it crosses over the Anterior Surface of the Internal Carotid Artery (Not within the Carotid Sheath) to end Medial/Deep to the External Carotid Artery
- The Superior Ganglion of the Glossopharyngeal Nerve (Contains sensory cell bodies) is found in close proximity to the jugular foramen
- It follows the styloid process anteriorly between the external and internal carotid
- When it reaches the upper border of the Middle Pharyngeal Constrictor, it provides sensory innervation to the pharynx
- After this, it runs just lateral to the Palatine tonsil in the wall of the Pharynx to supply the posterior 1/3rd of the Tongue
- As CN IX approaches the Bifurcation of the Common Carotid Artery, it gives off the Carotid Sinus Nerve (Small Nerve) which runs down to the Bifurcation of the Common Carotid Artery to supply the Carotid Body and Sinus
- It follows the stylopharyngeus muscle, crossing underneath the accessory and over the vagus nerve in the neck to reach the back of the tongue and the pharynx
30
Mandibular division of trigeminal nerve
- The Mandibular Nerve leaves the Cranial Cavity via the Foramen Ovale whilst the Facial Nerve exits the Cranial Cavity via the Stylomastoid Foramen
- The Mandibular Nerve then runs deep to the Mandible whilst the Facial Nerve runs superficial to the Mandible
- The Mandibular Nerve innervates structures in the mouth whilst the Facial Nerve innervates the Muscles of the Face
31
What is the sympathetic trunk in the neck
- The Cervical Sympathetic Trunk extends from the base of the skull superiorly to the Superior Thoracic Opening where it is continuous with the Thoracic Sympathetic Trunk inferiorly
- These are coming off the fibres of the spinal nerve roots, but C1 does not supply many fibres to the sympathetic trunk
- The Sympathetic Trunks are located alongside the carotid sheaths, anterior to the transverse processes of the cervical vertebrae
- It contains three ganglia:
1. The superior/upper cervical ganglion (C1–4)
2. The middle cervical ganglion (C5–C6)
3. The inferior/lower/thoraco-cervical/stellate ganglion (C7–T1)
- The Thoracocervical Ganglion is just behind the clavicle, on the neck of Rib 1, and is often formed by the Fusion of the Inferior Ganglion and the First Thoracic Ganglion
- It is a very important ganglion as it lies in close vicinity to lots of structures and it can be quite compressed when the individual has issues with lymphadenopathy
- This can result in issues with sympathetic outflow when there is something wrong in the chest
- Postganglionic SNS Fibres arise in all 3 ganglia and many of them ascend along blood vessels to reach their destination in the Head and Neck
- SNS Fibres from the Superior Cervical Ganglion climb alongside the Internal and External Carotids
- SNS FIbres from the Middle Cervical Ganglion climb alongside the Middle Thyroid Arteries
- SNS Fibres from the Inferior/Thoracocervical Ganglion climb alongside the Vertebral Arteries
- A small branch of the Middle Cervical Ganglion loops under the Subclavian an Ascends to rejoin the Thoracocervical Ganglion (Ansa Subclavia) - This gives some SNS Fibres to the Subclavian Artery destined for the upper limb
- Sympathetic innervation to the head results in:
1. Dilation of the pupil
2. Relaxed ciliary muscle
3. Reduced secretion of salivary glands
4. Reduced secretion of lacrimal glands
5. Increases secretion from sweat glands
6. Constricted blood vessels
- Parasympathetic supply of head and neck is provided by cranial nerves
32
What are the lymph nodes in the neck and how are the superficial lymph nodes arranged
- Head and neck lymphatics are to be considered as a combined system
- The General pattern seen is that superficial lymph vessels of both the head and neck to drain to superficial cervical nodes
- Superficial Cervical Nodes then drain to a Deep Cervical Nodes which are found underneath the sternocleidomastoid clustering around the internal jugular vein and Carotid Sheath along their length
- Some more superficial structures of the Head and Neck drain directly to deep cervical nodes instead of draining to Superficial Nodes first
- Deep cervical nodes drain to lymphatic duct and thoracic duct
- They are arranged in a ring-shape around the base of the neck/inferior aspect of the head
- They mostly receive lymph from the scalp and face and often follow the distribution
of the arterial blood supply
- There are 5 groups discerned (posterior to anterior) and each can have subgroupings:
1. Occipital nodes (near occipital artery from the ECA) - These are found near the Base of the Occipital Bone posteriorly (at the lateral border of Trapezius)
- They drain the Occipital Region of the Scalp and the muscles on the Posterior Head and Neck
1. Mastoid nodes, including posterior auricular nodes (near auricular artery)
2. These are found posterior to the Ear on the Mastoid Process of the Temporal Bone.
- These also drain the Posterior Neck, Ear and regions of the Scalp
1. Parotid and/or preauricular nodes (near superficial temporal artery)
- These are located anterior to the Auricle of the Ear
- They drain the Superficial Areas of the Face and the Temporal Nodes
1. Submandibular nodes (near facial artery)
- These found inferior to the Mandibular Body, at roughly its midpoint
- This drains the Lips, Tongue, Cheeks and Lateral Nose
1. Submental nodes (near facial artery)
- These are found superficial to the Mylohyoid, just inferior to the Chin/Mandibular Symphysis
- These drain the Floor of the Mouth, Tongue Apex and Central Lower Lip
- For the Occipital and Mastoid Nodes, they drain to Superficial Cervical Nodes that follow the External Jugular Veins whilst the Parotid/Preauricular, Submandibular and Submental Nodes drain directly into Deep Cervical Nodes
33
Describe deep cervical lymph nodes
- These Deep Nodes are found as a connected chain of nodes lying along the Vascular Pathways of the Neck, notably surrounding the Internal Jugular Vein and Carotid Sheath, beneath the Sternocleidomastoid
- They are labelled as Upper vs Lower in relation to their position relative to the Omohyoid Muscle
- There are 4 groups of Regional Deep Lymph Nodes in the Neck that are associated with the Internal Jugular Vein:
1. Posterior - Posterior to the Internal Jugular Vein
2. Anterior - Anterior to the Internal Jugular Vein
3. Superior - Upper Members of the Posterior and Anterior Groups
4. Inferior - Lower Members of the Posterior and Anterior Groups
- The Jugulodigastric Node is the most superior of the Deep Nodes and is found in the Angle between the Digastric Muscle superiorly and the Internal Jugular Vein posteriorly - This is a large node drains the Palatine Tonsil, Tonsillar Bed and posterior aspect of the Tongue (Posterior Mouth) and can become painful and inflamed in Tonsillitis
- It is a member of the Anterosuperior Group of Deep Cervical Nodes
- The Jugulo-omohyoid Node is found in the Posteroinferior Group of Deep Cervical Nodes, Found at the Posterior Angle of where the Posterior Belly of the Omohyoid crosses the Internal Jugular Vein (Boundary of Upper and Lower Nodes)
- This is a large node that drains the tongue
- All Lymph from the Head and Neck is eventually drained via this chain of deep nodes
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Lymphadenopathy and branchial cysts
- Enlarged lymph nodes can be due to tonsillitis, TB, carcinoma and a whole host of other issues
- They usually produce solid, lateral one-sided or symmetric neck swellings
- Branchial cysts and fistulae are also located in the lateral neck and usually present as fluctuant, one-sided swellings
- Branchial cysts occur when branchial clefts do not obliterate or when branchial arches do not fuse properly
- Cysts then develop along the anterior border of the sternocleidomastoid
