Head and Neck Anatomy

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1. Embryology

1.1. Introduction

- The most important thing to take note of first is that almost nothing in the body is formed for no reason. Every structure will have some form of function or purpose that it will fulfil.

- Similarly, formation of the skull is attempted by minimising material and maintenance.

o It is interesting to note that many spaces and septa within the head actually serve to add

strength against longitudinal forces

 In a way, we are getting something for nothing. o The face is however, vulnerable to horizontal damage. - The neck needs to be overengineered in order to protect it.

o It is structure such that no matter what position it is in, the bones will not disrupt any

existing nerves or blood vessels.

- The key to anatomy is to logically link how, where and why structures are where they are. o There is always a correlation between function and structure.

o It is also important to note that soft tissues such as blood vessels, nerves and muscles form before the bone and therefore, formation of bone accommodates and facilitates these structures

 E.g. Foramena

1.2. The Germ Layers

- The developing embryo forms a three-layered plate shape structure that is made up three germ layers being:

o Ectoderm o Mesoderm o Endoderm

- The ectoderm and endoderm develop first with the mesoderm developing in the third week. - The mesoderm gives rise to connective tissue which gives structure, form and reparative

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1.3. Formation of the Mesoderm

- Formation of the mesoderm begins at week 3 with the development of a structure called the

primitive streak

Figure 1 Formation of the primitive streak at Week 3

- Cells from the ectoderm migrate towards the primitive streak and form a cavity beneath it. - They then spread between the ectoderm and endoderm to form the middle third layer.

o This process continues until the mesoderm fully separates the ecto and endoderm except at the head and tail ends.

- Note that although the head end of the embryo has no mesoderm but we still have mesodermal structures in our head.

o To understand where the mesoderm for the head comes from, the formation of the nervous system needs to be looked at.

1.4. Development of the Nervous System

- Development of the nervous system begins at the head end of the embryo.

- It starts off as a thickening in the ectoderm in this area. This thickening is called the Neural Plate. - The margins of the neural plate then thicken resulting in the margins being raised called Neural

Folds.

- Between the neural folds is the neural groove.

- Neural folds continue to develop towards each other until they meet leading to the formation of the neural tube.

o The neural tube will eventually form the ventricles and central canal of the nervous system.

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Page | 8 - In the diagram above, note the structures that form alongside the growing folds. These are

called Neural Crests

- When the neural tube forms, the neural crest cells separate from the remainder to form a group of cells on their own.

1.5. The Ectomesenchyme

- There is debate over whether or not the neural crest cells are derivatives of the developing nervous cells or a completely distinct group themselves

o For this reason they are sometimes referred to as the Fourth Germ Layer

- Embryonic connective tissues derived from the Neural Crest Cells are termed Ectomesenchyme to distinguish them from cells of the actual mesoderm produced at the primitive streak.

- It reflects the ectodermal origin of Neural Crest Cells but their mesodermal functions.

- The significance of this is that skull and facial bones form in a different manner to other bones in the body due to the fact that they are ectomesenchyme in origin.

o Bones of the face and cranium (except the base of the skull) are formed via

intramembranous ossification as opposed to endochondral ossification of most other

bones.

- The Neural Crest Cells are essential to the development of the embryo as they migrate

extensively around the body and give rise to components of the PNS such as:

o Sensory Ganglia, Sympathetic neurons, Schwann Cells, Meninges and Pigment Cells - Furthermore, they also give rise to the embryonic connective tissues of the facial region and the

cartilages of each branchial arch.

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1.6. Facial Development

- The face develops from five embryonic tissue masses or processes. They all arise from rapid multiplication of neural crest cells.

o Frontonasal Process

o Maxillary Processes (paired) o Mandibular processes (paired)

Figure 3 Processes of the developing face - These serve as the starting points for facial development. 1.6.1. The Stomodeum and Oral Cavity

- The developing mouth is termed the stomodeum or stomatodeum

- It appears during the fourth week of development as a depression in the embryonic surface. o It is at that this point where facial features start being worked out.

o The floor of this depression pushes against the developing GIT. The two are separated by the buccopharyngeal membrane and represents the meeting of ectoderm and

endoderm.

 This buccopharyngeal membrane will eventually break down to allow the stomodeum to open directly into the primitive pharynx.

- Eventually the stomodeum will give rise to the oral cavity.

o At first it is lined by oral ectoderm which gives rise to the teeth before finally becoming the oral epithelium.

- At the sides of the stomodeum, its space becomes limited with the formation of the first pair of

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Page | 10 1.6.2. The Neck

- Development of the neck begins at the same time as development of the face, being in the fourth week of embryonic life.

- It arises from the branchial arches and the primitive pharynx which is part of the digestive tube. o The caudal part of the primitive pharynx forms the oesophagus and a ventral outgrowth

leads to formation of the larynx and trachea.

- The buccopharyngeal membrane eventually breaks allowing for communication between the oral cavity and the pharynx.

1.6.3. The Branchial Arches

- The branchial arches are bulges on the embryo found beneath the developing brain. - Overall there are six branchial arches but the fifth one is lost.

- Each branchial arch develops into different structures and each contain a portion of primitive striated muscle, some nervous tissue from neural crest cells, some vascular tissue and a bar of

cartilage in its mesodermal core.

o Because of this, each arch contains its own major nervous and blood supply

- Each branchial is covered externally by ectoderm and internally by endoderm and support the lateral walls of the pharynx.

o The central component is either mesoderm or ectomesenchyme.

- Damage to any of these arches will cause defects in the structures they specifically give rise to.

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Page | 11 1.6.4. The First Branchial Arch

- Also referred to as the mandibular arch

o Forms the mandible, maxilla, muscles of mastication and the mandibular division of the trigeminal nerve.

o The cartilage found at the centre of this arch is called Meckel’s Cartilage

 This structure gives rise to the incus, malleus, sphenomandibular ligament and the lingual.

 Bones of the mandible and maxilla do not form from this.

- All facial muscles will be innervated by motor neurons of the mandibular division of the trigeminal nerve.

o The nerve migrates with the muscles. - The muscle tissue will develop into:

o Muscles of mastication o Mylohyoid Muscle

o Anterior belly of the digastric muscle - The artery of the first arch does not survive.

- First branchial pouch becomes the auditory tube and middle ear

- First branchial cleft becomes the external auditory meatus and the tympanic membrane 1.6.5. 2nd_{Branchial Arch}

- Also called the Hyoid Arch

- Cartilage is called Reichert’s Cartilage o Stapes

o Styloid Process of the Temporal Bone o Stylohyoid Ligament

- The muscle tissue forms the muscles of facial expression

o And Stapedius muscle, stylohoid muscle and the posterior belly of digastric - It’s nerve is the Facial Nerve (VII)

- Artery of the second branch also degenerates.

- 2nd Pouch becomes the tonsillar fossa which develops into the palatine tonsil.

1.6.6. 3rd_{Branchial Arch}

- Artery becomes the Common Carotid and contributes to the proximal part of the internal carotid

- Cartilage of the 3rd arch contributes to the hyoid bone - Muscle becomes the stylopharyngeus muscle

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Page | 12 1.6.7. 4th_{and 6}th_Arches

- These two arches fuse.

- Their cartilages contribute to most of the laryngeal cartilages - Fourth Arch:

o Superior Laryngeal Branch of the Vagus Nerve o Artery becomes the arch of the Aorta on the left side

 Contributes to the right subclavian and brachiocephalic arteries. - Sixth Arch:

o Recurrent Laryngeal Branch of the Vagus Nerve o Artery contributes to the pulmonary arteries.

1.7. Formation of the Face

- The face develops between the 24th and 38th day of gestation

- During the early stages, development is dominated by changes that result in the formation of the primitive nasal cavities.

- Eventually the nasal and oral cavities will both communicate with the pharynx but not with each

other.

o Palate separates them.

- The frontonasal process develops two nasal pits. Tissue builds up around them in a horse-shoe shape fashion to form the lateral and medial nasal processes.

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Page | 13 1.7.1. Formation of the Palate

- The growth of the maxillary processes pushes the two nasal processes together and towards the midline

o At the midline they fuse to create the middle part of the nose, the middle part of the upper lip and the anterior part of the maxilla and the primary palate. AKA the premaxilla o Failed fusion results in a cleft palate

- Palatine processes then extend out from the maxillary processes and grow towards the primary

palate.

Figure 5 Palatine Processes extending out from the maxillary process towards the primary palate - Take note that it isn’t till after the formation of the secondary palate that the distinction

between the oral and nasal cavities can be made clearly.

o Formation of the secondary palate takes place between the 7th

and 8th weeks of development and results from fusion of the palatine processes.

- Because the difference in formation, the primary and secondary palates have different innervations and blood supplies with the crossover occurring at the canines.

o Therefore when extracting a canine, block both nerves. SO:

- Primary Palate:

o Upper incisors and anterior palate

o Nerve: Incisive Branch of the Long Nasopalatine Branch of the Maxillary Division of the Trigeminal Nerve

- Secondary Palate:

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Page | 14 1.7.2. Formation of the Tongue

- At the midline of the mandibular process, a mesenchymal swelling arises called the tuberculum

impar.

- Two other swellings appear on either side of the tuberculum impar which expand rapidly and merge together with the tuberculum impar to form a large mass.

o This large mass forms the anterior two thirds of the tongue.

 It is this reason why the anterior 2/3s of the tongue are innervated by the mandibular division of the trigeminal nerve as their sensory nerve supply.  The nerve of the second branchial arch supplies the taste fibres to the anterior

2/3s

- The posterior 1/3 of the tongue arises from the hypobrancheal eminence which is a large midline swelling from the third branchial arch. It is innervated by the Glossopharyngeal nerve. 1.7.3. Formation of the Mandible

- The mandible develops in the mandibular process.

- It is important to note that whilst it is located closely to Meckel’s Cartilage, it makes very little contribution to the formation of the mandible.

- The two mandibular processes fuse in the midline to the mandibular arch.

o The bone of the mandible forms in the mesenchymal tissue that condenses laterally to the cartilage. The cartilage begins to disappear.

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Page | 15 - The bone directly above this through forms a series of compartments for the individual teeth. It

then closes over the tooth germs to form a roof over the trough.

- By 10 weeks of development, the rudimentary mandible is formed almost entirely from intramembranous ossification with little influence from Meckel’s cartilage

o Still keep in mind which structures Meckel’s cartilage gives rise to.

o However, there is some evidence to suggest that Meckel’s cartilage may contribute to a small extent to the formation of the mandible anterior to the mental foramen.

1.7.4. Formation of the Maxilla

- Similarly to the mandible, the maxilla develops from condensation of mesenchyme from the first branchial arch.

- The maxilla is also formed by intramembranous ossification - Maxillary sinus forms in the 16th week.

1.8. Congenital Defects

- Although genetic determinants are the primary actors in formation of the head, environmental factors such as drugs can also result in congenital defects.

- Types of environmental factors which can affect the embryo include: o Infectious agents

o Ionising radiation such as X-rays o Drugs

o Hormones

o Nutritional Deficiencies o Stress

- The most common congenital defects are orofacial clefts (and cleft palates)

o These result from failed fusion of the medial nasal processes and the maxillary processes.

- Because of this, the affected person cannot generate the pressure to suck due to not having the seal. This defect can also be unilateral (only on one side)

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2. Osteology of the Skull and Cervical Vertebrae

TO LEARN:

- Be able to draw both a superior and inferior view of the floor of the cranium - Also be able to draw the individual bones.

2.1. Introduction

- As stated in the previous topic, always remember that structures in the skull exist for a reason and will reflect the soft tissue structures within those areas.

o This will help you learn and relate the locations of different structures, both bone and soft tissue

o i.e. Nerves, blood vessels etc. form first with bone then forming around them (which explains the position and existence of foramena)

2.2. The Skull

- The skull is made up of the mandible and the cranium

o The reason for this separation is that the ONLY moveable joint between bones in the skull occurs between the mandible and a specific point on the cranium

- Another way to divide the bones of the skull is as follows: o Bones that make up the face (Facial Bones)

 The upper part is fixed to the calvaria and cannot move.  The lower part is the mandible and has the ability to move.

o Bones that contain the brain (Cranial Bones which together is called the Calvaria)

- It is the most highly modified and specialised region of the skeleton

o It is adapted to support and contain the brain and the special senses with it as well as the opening of the GIT.

- The joints between the bones of the cranium are immovable fibrous joints called sutures o Except the mandible of course

- Sutures allow for the growth of the calvaria and facial bones and many will eventually ossify and

close.

o However the rate of ossification isn’t necessarily proportional to age.

- Sutures are only found the in skull.

- For the sake of identifying and describe the bones of the skull, we will look at them as Single

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2.3. Single Bones

- As per their name, single bones are not bilateral and as a result will lie close to the midline of the skull.

2.3.1. The Frontal Bone

- Overall there isn’t too much that you need to know about the frontal bone. Anterior View

- Initially during development, a suture ran down the midline of the frontal bone called the metopic suture. Whilst the majority of it has ossified, remnants of it can be seen between the glabella and the nasal spine.

- The glabella is the flat surface between the superciliary arches. - The zygomatic process articulates with the zygomatic bone.

Supraorbital Margin Frontal Tuberosity Zygomatic process Superciliary Arches Supraorbital Foramen/Notch Glabella Nasal Spine Remnants of the Metopic Suture

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Page | 18 - The ethmoid notches provide the roof of the nasal cavity and indicates where the ethmoid bone

will fit.

2.3.2. The Occipital Bone

- Located at the back of the head

- One of few parts of the skull that are formed by both intramembranous and endochondral ossification

o The base is mesoderm in origin and is therefore endochondrally formed

 The base is a primary centre involved in facial growth and is important in making orthodontic calculations

o The back is ectomesenchyme in origin and is therefore formed intramembranously. Posterior View of the Occipital Bone

Zygomatic Process Supraorbital foramen Supraorbital Notch Nasal Spine Nasal Spine Ethmoid Notches Orbital Plates Squamous (Broken Egg Shell) part of the

Occipital Bone

External Occipital Protuberance

Superior Nuchal Line

Inferior Nuchal Line Foramen Magnum Condylar Canal Hypoglossal Canal Occipital Condyles

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Page | 19 - The Condylar Canal is an emissary structure meaning that it isn’t present in every single person.

When it is present, an emissary vein runs through it.

o Presence or lack thereof of these structures doesn’t make any difference.

- The Hypoglossal Nerve (cranial nerve XII) runs through the hypoglossal canal located anterior to the foramen magnum.

- The occipital condyles articulate with the first cervical vertebra (C1)

- The nuchal lines run along the back of the occipital bone and indicate the points of attachment of various muscles

Inferior View of the Occipital Bone

- It is helpful to note that any structure with external in its name will have an internal equivalent Pharyngeal Tubercle Occipital Condyles Condylar Canal (Emissary) External Occipital Crest Jugular Process

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Page | 20 2.3.3. The Ethmoid Bone

- Found deep in the skull

- Resembles a crucifix with banners

- Ethmoid bone is a contributor to the nasal septum - The ethmoid bone articulates with many other bones.

Posterior View of the Ethmoid Bone

Superior View of the Ethmoid Bone

- The cribriform plate fits into the ethmoid notches of the frontal bone - The holes in the cribriform plate allow olfactory nerves to pass through

- The crista galli faces anteriorly in the skull and is where the falx cerebri attaches anteriorly. o The falx cerebri is a strong, arched fold of dura mater that descends in the longitudinal

fissure and divides the cerebral hemispheres

Crista Galli Perpendicular Plate Superior Concha Orbital Plate Middle Concha Crista Galli Perpendicular Plate Ethmoidal Air Cells or Sinuses Cribriform Plate

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Page | 21 Figure 6 Sites of attachment for the ethmoid bone

2.3.4. The Sphenoid Bone

- The sphenoid bone is a butterfly-shaped bone that lies posteriorly to the ethmoid bone - It’s main body is hollow as it contains the sphenoid sinuses

- It is a complex bone with many features

Posterior View of the Sphenoid Bone

- The Lesser and Greater Wings of the sphenoid bone are separated by the Superior Orbital

Fissures on each side

- The Lateral Pterygoid Plate serves as a point for muscle attachment - The medial pterygoid plate serves to support the pterygoid hamulus - Nervous supply of the maxilla and palate goes through Foramen Rotundum - An important ligament also attaches to the spine of the sphenoid bone

Sphenoid Bone Sphenoidal Crest

Frontal Bone

Nasal Bone

Vomer Septal Cartilage

of the bone

Superior Orbital Fissures

Foramen Rotundum Body Dorsum Sellae Pterygoid Hamulus Lateral Pterygoid Plate

Medial Pterygoid Plate Spine

Scaphoid Fossa

Pterygoid Fossa

Vaginal Process

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Page | 22 Superior View of the Sphenoid Bone

- The pituitary gland sits in the hypophyseal fossa where it is protected by a meningeal layer - Foramen Ovale is found on the greater wing where the Mandibular Division of the Trigeminal

Nerve runs through it. Tuberculum Sellae Anterior Clinoid Process Posterior Clinoid Process Dorsum Sellae Spine of the Sphenoid Bone Carotid Sulcus Optic Canal Hypophyseal Fossa Foramen Ovale Foramen Spinosum

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2.4. Paired Bone

- Bilateral. i.e. One on each side of the midline 2.4.1. Parietal Bones

- Separated by the sagittal suture

- Have the superior and inferior temporal line which denote the attachments of the temporalis

muscle

- Can also contain an emissary structure called the parietal foramen. When it is present it holds an emissary veins which leads to increased circulation

2.4.2. Temporal Bones

- Contains the middle ear, air sinuses and a very important artery (carotid!) - Made up of four major parts

o Squamous (broken egg shell)

o Mastoid (where the mastoid process is) o Petrous (looks like a stone)

o Styloid Process

External View of the Temporal Bone

- A meatus is a blind canal meaning it stops before the cranium - The condyle of the mandible sits in the glenoid fossa

- The postglenoid tubercle which divides the tympanic plate from the temporal bone Squamous Part

Zygomatic Process of the Temporal

Bone

Styloid Process External Acoustic Meatus

Tympanic Plate Mastoid Part Mastoid Process Glenoid Fossa Articular Tubercle Articular Eminence Postglenoid Tubercle Sheath of the Styloid Process

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Page | 24 Inferior View of the Temporal Bone

- The squamotympanic fissure begins internally to the postglenoid tubercle and continues to run internally.

o It separates the squamous and mastoid parts of the temporal bone

- When the squamotympanic fissure reaches tegmen tympani (thin plate of bone that separates the cranium from the tympanic cavity), it splits off into the petrosquamous fissure (anterior)

and the petrotympanic fissure (posterior)

Internal View of the Temporal Bone

- Petrous part of the temporal bone holds the middle and inner ear - Internal Acoustic Meatus: VII and VIII run through here

Glenoid Fossa Squamotympanic Fissure Petrosquamous Fissure Petrotympanic Fissure Tegmen Tympani Carotid Canal Opening of the Anterior

Canaliculus for Chorda Tympani

Stylomastoid Foramen Digastric Notch Occipital Groove for

Occipital Artery

Articulates with Parietal Bone

Articulates with Greater Wing of

Sphenoid

Articulates with Occipital Bone

Internal Acoustic Meatus Sulcus for

Sigmoid Sinus Arcuate Eminence

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Page | 25 2.4.3. Maxillae

Lateral View of the Maxilla

- The frontal process joins with the maxillary process of the frontal bone via the frontomaxillary

suture

- The alveolar processes hold the sockets of the teeth and disappear upon tooth loss. - Nerves and vessels pass through infra-orbital foramen

Medial view of the Maxilla

- The maxillary hiatus contains the ostium which represents the opening into the maxillary sinus o Clinically, if it closes over, sinusitis will ensue

- Pain from the maxillary sinus can often be referred down to the maxillary teeth. Correct diagnosis is key. Frontal Process Zygomatic Process Maxillary Tuberosity Canine Eminence Infra-orbital Foramen Nasal Notch

Joins with ethmoid bone

Maxillary Hiatus

Nasolacrimal Groove

Greater Palatine Canal

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Page | 26 2.4.4. The Zygomatic Bones

- Not too much we need to know about this one.

- Found joining to the lateral sides of the maxilla and the frontal bone. o Joins to the frontal bone via the frontal process

o Joins to the zygomatic process of the maxilla

o The temporal process of the zygomatic bone joins with the zygomatic process of the temporal bone to form the zygomatic arch

- The inferior border of the temporal process provides the point of attachment for the masseter muscle

- The malar eminence is found on the maxilla underneath the zygomatic process and is known to cause problems when trying to apply anaesthetic and extracting teeth.

2.4.5. The Mandible (THE BIG ONE FOR US)

External View of the Mandible

Condylar Head Condylar Neck/Process Coronoid Process Angle of the mandible Mandibular Notch Mental Tubercle

Mental Protruberance _{External Oblique Ridge}

Mental Foramen

Body of the Mandible Ramus of the Mandible

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Page | 27 Internal View of the Mandible

- The mandibular foramen is the opening into which the Inferior Alveolar Nerve runs. o This is the nerve you target when anaesthetising the lower jaw.

-

The lingula is a little ‘tongue’ of bone that lies over the opening of the mandibular foramen o Anaesthetic is applied just posterior to this structure

- Below is a table denoting the structures in the bone and their corresponding muscle/gland attachments

Structure in the Bone Muscle/Gland

Submandibular Fossa Submandibular Gland

Mylohyoid Ridge Mylohyoid Muscle

Digastric Fossa Anterior Belly of the Digastric Muscle

Sublingual Fossa Sublingual Gland

Genial Tubercles Genioglossus and Geniohyoid muscles

Lingula _Mandibular Foramen Mylohyoid Ridge/Line Submandibular Fossa Sublingual Fossa Digastric Fossa Genial Tubercles

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Page | 28 2.4.6. The Palate

- Recall from embryology that the palate forms via two palatine processes developing out from the maxillary processes

2.4.7. The Hyoid Bone

- Unlike other bones of the skull, the hyoid bone isn’t directly attached to the rest of the skull or

skeleton for that matter

o Instead, it is suspended from the styloid processes of the temporal bone via the

stylohyoid ligaments

- Superiorly, both bellies of the digastric muscle and the geniohyoid muscle attaches to it. - Anteriorly, the mylohyoid and stylohyoid muscles attach

- Inferiorly, the sternohyoid muscle attaches (depresses the hyoid bone)

Figure 7 The hyoid bone and sites for muscle attachment Incisive Fossa

Palatine Processes of the Maxilla

Horizontal Plates of the Palatine Bone

Intermaxillary Suture

Palatomaxillary Suture Greater Palatine

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2.5. The Vertebral Column

- Above is a generic image of the cervical vertebrae from a superior view. All the vertebrae will exhibit the majority of these structures if not all of them

- The transverse foramen provides the passage for the Vertebral Artery and Veins o Only cervical vertebrae have transverse foramen

o Only C1-C6 have the vertebral artery running through

o All the cervical vertebrae have multiple vertebral veins running through - The spinal cord runs through the vertebral foramen

Lateral View of a Typical Cervical Vertebra

- The raised lip on the upper surface of the body serves to limit neck movement

- The anterior and posterior tubercles of the transverse process act as points of attachment for muscles and ligaments

- When vertebra are attached (above and below), an intervertebral foramen is formed by the

superior and inferior vertebral notches through which the spinal nerves emerge

o The anterior and posterior tubercles lie either side of this foramen o The vertebrae are attached by strong ligaments

Body Anterior Tubercle

Posterior Tubercle

Pedicle

Vertebral Foramen Lamina

Superior Articular Facet Inferior Articular

Process Transverse

Foramen

Spinous Processes (Bifid)

Spinous Process Inferior Articular Process Posterior

Tubercle Sulcus for the

Ventral Ramus

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Page | 30 - Only C3 – C6 follow the general pattern as described above. Therefore C1, C2 and C7 must be

looked at separately

o C1 and C2 have variations that allow free head movement  i.e. Head can move without moving the neck with it. 2.5.1. C1 a.k.a. Atlas

- The first thing to take note of is that C1 does not have a body.

- The large superior articular facet is where the occipital condyles will articulate with the vertebra. 2.5.2. C2 a.k.a. Axis

-

Dens slots into the large space behind the anterior arch of Atlas. It is attached to Atlas via the Ligament of Atlas

o

It allows Atlas to rotate around the dens

Facet for Dens Transverse

Process Groove for the vertebral artery Posterior Arch Posterior Tubercle

Transverse Foramen Superior Articular Facet

Outline of Dens (from Axis)

Anterior Tubercle

Dens

Transverse Foramen

Inferior Articular Process

Body

Spinous Process Superior Articular

Surface

Groove for the transverse Ligament of Atlas

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3. Temporomandibular Joint (TMJ)

- The TMJ represents the most complex joint in the body excluding the knee. - It is the site of articulation between the mandible and the cranium

- It is a bilateral synovial joint and plays a key role in mastication o Bilateral meaning there is one on each side of the midline

 Because of this, TMJ disorders must be treated on BOTH sides. - It is made up of parts of the mandible and the temporal bone covered in stress-bearing

fibrocartilage and surrounded by several ligaments as well as the joint capsule

o The condyle of the mandible and the glenoid fossa of the temporal bone

 Between these two bones is a fibrous articular disc which divides the joint into two separate synovial-lined compartments

 Called the meniscus

Figure 8 The TMJ

- The heads of the condyles are ‘football shaped’ and are directed at an oblique angle towards foramen magnum

o Because of this shape and alignment, there is no such thing as perfect rotation of the mandible around the condyle

o Any attempts to rotate the mandible about the condyles will force protrusion of the mandible as well.

- The condyles normally sit in the glenoid fossa, but when it is open, it sits just behind the articular tubercle

o The tubercle actually serves to stop dislocation of the jaw wherever possible. Glenoid Fossa (Temporal

Bone)

Condyle Articulator

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3.1. The Articular Disc (Meniscus)

- It is a biconcave plate of dense fibrous connective tissue.

- The meniscus actually moves with the condylar head during movements - The inferior surface is concave to facilitate the rounded condylar head - The superior surface is convex centrally and concave laterally

o The disc is thickest at the periphery and thinnest in the stress-bearing part of the joint.

- The blood supply to the meniscus is incredibly minimal. Therefore the majority of the nutrition must come from another source, in this case being the synovial fluid of the joint

- Little blood supply means that there will be very little healing capability and also very few

nerves

o Therefore, most pain at the TMJ won’t be from the disc.

3.2. Ligaments

- The ligaments of the TMJ need to be distinguished as either ligaments of the joint or accessory o Ligaments of the joint are directly involved in securing the joint

 They are always true ligaments

o Accessory Ligaments aren’t directly involved in the joint and aren’t nearly as strong as ligaments of the joint.

 They do however play an important role in preventing extreme movements as they contain stretch receptors with automatic reflex cut-off systems  Accessory ligaments can be both true and false

- Fascia are sheets of dense fibrous tissue that ‘groups and packages’ certain muscles and nerves,

arteries and veins to separate them with lubricating fluid between.

3.2.1. Accessory Ligaments _{Fibrous Capsule} Stylomandibular Ligament

Sphenomandibular Ligament

Lateral/Triangular/ TM Ligament

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Page | 33 - The sphenomandibular ‘ligament’ is a false ligament and is actually just a sheet of fascia.

o This ligament needs to be bypassed when injecting anaesthetic. o It is a derivative of Meckel’s cartilage

o Runs between the spine of the sphenoid bone and the lingula of the mandible - The stylomandibular ligament is a genuine ligament which runs between the styloid process of

the temporal bone and the posterior border of the angle of the mandible

- Together, these two ligaments play a suspensory role in letting the mandible hang from the cranium. The stretch receptors play an important role in preventing excessive opening and protrusion of the mandible.

3.2.2. Ligaments of the Joint

- The Fibrous Capsule contains stretch receptors.

o Therefore, any pain from the TMJ is from here.

o Overstretching will ‘sprain’ it and the pain will stop you from straining it further.  i.e. overmove = pain

o Together with the triangular ligament, it restricts movement

- The Fibrous Capsule is reinforced both medially and laterally by bundles of collagen fibres. o Medially, there is a slight thickening of the capsular ligaments.

o Laterally, it is a lot more heavily reinforced by the

Lateral/Triangle/Temporomandibular Ligament

3.3. Innervation

- The joint capsule is highly sensitive due to being heavily endowed with sensory nerve endings from the Auriculotemporal branch of the mandibular division of the trigeminal nerve

- It also receives fibres from the Masseteric branch of the mandibular division

3.4. Blood Supply

- The blood supply to the TMJ occurs via the Maxillary Artery and branches of the Superficial

Temporal Artery.

- Venous drainage occurs via the pterygoid plexus

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3.5. Movements of the Mandible at the TMJ

- The first thing to note is that there exists no such position of the mandible where it is fully

relaxed

o i.e. No matter what position the mandible is in, there is AT LEAST ONE MUSCLE WORKING

- Movements include depression, elevation, protrustion, retrusion and lateral movements - Dislocation of the mandible occurs when the condyle slips out of position and is caught/jammed

past the articular tubercle/eminence

o Retrusion is limited in that the mandible can only be forcibly retruded avbout 1.5mm

- Jaw opening is a combination of depression and protrustion

o Protusion cannot occur without depression as depression brings the teeth out of occlusion so they can move.

- During lateral movements, one condyle is ipsilateral and one is contralateral

o The ipsilateral condyle is the one on the side the mandible is moving towards  It remains in the fossa moving slightly downward and laterally o The contralateral condyle is the one on the opposite side

- Pulled forwards, down and medially

3.6. Ligaments and their Functions

- Generally, they act to limit the range of movement in a joint through their stretch receptors and pain reflexes as well as their tautness

Ligament

Function

Lateral Ligament - Limits the movements of the condyle to an arc-shape

- Limits movements of the contralateral side Medial Thickening of Fibrous Capsule - Limits depression of the mandible

Stylomandibular - Limits depression and prevents dislocation - Runs with the pterygoid fascia

Sphenomandibular - Limits movements of the ipsilateral side Articular Disc/Meniscus - Limits retrusion of the mandible

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4. Muscles of Mastication

- Remember that bones and muscles together form a dynamic system being musculoskeletal. This means that they are responsive to each other and they will alter themselves in response to changes within each other

o E.g. Muscle enlarges? Bone grows accordingly.

- Muscles of mastication are defined as any muscles immediately involved in movements of the

mandible during mastication and speech.

- Main muscles include:

o Masseter o Temporalis o Medial Pterygoid o Lateral Pterygoid - Accessory muscles include:

o Digastric muscle (anterior belly) o Mylohyoid

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4.2. Accessory Muscles

- Their function is dependent on the actions of other surrounding structures - They are called accessory as they do not directly cause movement of the condyle. - They are both suprahyoid muscles (i.e. above the hyoid bone)

4.2.1. The Digastric Muscle

- It is named as so because it is made up of two separate bellies.

- It mainly runs between the mastoid process (temporal bone) down to the mandible at the mental protuberance.

o Part-way between, it becomes a tendon which passes through a pulley attached to the hyoid bone

 This pulley acts to separate the anterior and posterior bellies

 It can pull up the hyoid bone, thereby also pulling up the larynx to close it off when swallowing.

- The position/movement of the hyoid bone can modify the position of this pulley and also determine the function of the muscle.

o The position or movement of the hyoid bone is dependent on the infrahyoid and suprahyoid muscles.

o E.g. If the infrahyoid muscles are contracted, contraction of the suprahyoid will open the jaw. Aids in mastication.

 BUT, relaxation of the infrahyoid and contraction of the suprahyoid will only elevate the hyoid bone

 Swallowing!

- It is important to note that the two bellies can work independently of each other due to having

separate nerve supplies.

Belly Origin Path Action Nerve Supply

Anterior Attaches to the digastric fossa. Found on the medial

aspect of the mandible inferior to the genial tubercles.

Runs superficially down to the hyoid bone beneath the platysma muscle.

Pulls the hyoid bone forward and

up. Also helps retract and depress the mandible. Associated with mastication Originates from first branchial arch so V3

Posterior Digastric notch of temporal bone. Found medial to the

mastoid process.

Runs forward below the mandible beneath the superficial belly of the Submandibular

gland down to the

Pulls the hyoid bone back and up

Mainly associated Originates from second branchial arch and is therefore supplied by the

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Page | 39 hyoid bone pulley with swallowing Facial Nerve (VII) - Infrahyoid + Digastrics = opening of jaw for mastication

- Digastrics on their own = elevate the hyoid bone and larynx for swallowing

4.3.1. Mylohyoid Muscle

- Attaches the tongue to the mandible

- Forms the muscular floor of the mouth and is sometimes referred to as the oral diaphragm - It controls the tongue and helps position it vertically

- The mylohyoid muscle exists as two triangular sheets. They originate at the mylohyoid ridges of the mandible on each side.

- They both then travel posteriorly to attach to the hyoid bone

- The muscles meet at the midline in a tendinous raphe called the Median Raphe o The median raphe travels between the mandible and the hyoid bone. - They are formed from the first brancheal arch and are innervated by the Lingual Nerve

o The lingual nerve is the only motor branch of the posterior division of V3

- Similarly to the digastric muscles, their function is dependent on the position of the mandible

and hyoid bone.

Actions of the Mylohyoid Muscles:

1. If the mandible is held in position, the mylohyoid muscles elevate the hyoid bone and the

tongue

a. Important in the first phase of swallowing

b. Elevation of the hyoid bone is important in closing off the larynx when swallowing 2. If the infrahyoid muscles are contracted, the mylohyoid muscle will aid in depression of the

mandible.

Anterior of Digastric (cut)

Median Raphe Digastric Fossa

Mylohyoid Muscle Mylohyoid Ridge on the Mandible

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5. Muscles of Facial Expression

5.1. Facial Structure

- The basic form of a person’s face is largely determined by the underlying bones of the skull. - These bony structures are then covered by the soft tissue structures being mainly muscles and

subcutaneous fat. These distribution of these soft tissues varies around the skull.

- Muscles of facial expression have been found to mainly act on areas with large amounts of subcutaneous tissue as they are more mobile and therefore play large role in facial expression.

o Hence why they are called Subcutaneous Muscles of Facial Expression  Below the skin, and move the skin.

- All muscles of facial expression are derived from the second branchial arch and are therefore all

innervated by the Facial Nerve (VII)

o Whilst the tongue and eyes also play a role in facial expression, their muscles aren’t regarded as muscles of facial expression.

- Most of the facial expression muscles have a bony origin and insert into the soft tissues of the face

5.2. Muscles of the Lips and Cheeks

5.2.1. Deep Layer

Closely related to Buccal mucous membrane

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Page | 41 5.2.2. Superficial Layer

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5.3. Muscles of the Orbit and Eyelid

5.4. Muscles of the Scalp

- The scalp itself consists of 5 layers.

- From superficial to deep, these layers are (NOTE THE FIRST LETTER OF EACH LAYER ): o Skin

o Connective Tissue o Aponeurosis

 Tendinous sheet

 At the sides of the skull, it unites with the temporal fascia o Loose Connective Tissue

 Permits movement of the aponeurosis o Periosteum

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6. Lymphatic Drainage

- The lymphatic system is a vascular system which performs 3 main functions:

o Removal and return of blood plasma that hasn’t been reabsorbed into the capillaries during circulation

o Absorption of fats from the small intestine

o Most importantly, it plays a huge role in immunity  It is the body’s protective system

- It is made up of:

o Lymphatic capillaries and vessels o Lymph Nodes situated along the vessels

o Organs such as the thymus, spleen and bone marrow o Circulating immune cells

- All blood and lymphatic vessels are lined by endothelium

o Tears In the vessels expose connective tissue which triggers the clotting cascade. - 80-90% of interstitial fluid gets reabsorbed back into capillaries with the remainder being taken

up into the lymphatic system.

- Note that lymphatic vessels run parallel with the venous system and eventually drains back into

it.

o The lymph vessels drain back through the right lymphatic or thoracic ducts which then drain into the subclavian vein.

6.1. Lymphatic Capillaries

- The lymphatic system is purely drainage similar to veins, i.e. there is no arterial part to the lymphatic system

- They begin in vascular tissues as blind-ended lymphatic capillaries o They do not exist in avascular structures

- They are lined by endothelium which overlap each other so form flaps for fluid to enter under hydrostatic pressure. Once the fluid is in the lumen, it cannot go back out.

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Page | 45 - Similarly to veins, lymph capillaries have valves to ensure the fluid travels in one direction;

towards and through the lymph nodes on their way back to the venous circulation

6.2. Lymphatic Nodules

- They are small masses of lymphatic tissue that are distributed strategically around the body to protect the underlying tissues, especially those at risk from penetration by microorganisms from the GIT, respiratory and urinary tracts.

o Remember that GIT, respiratory and urinary tracts are regarded as ‘outside the body’ o They mainly occur in the connective tissue beneath mucous membranes.

- They are packed with lymphocytes. Unlike actual nodes, they do not directly connect to the lymph vessels

- Whilst most nodules exist as small and on their own, they are sometimes found in large clusters called Lymph Nodes

o An example of these are our tonsils.

o Our tonsils form a ring around the entry of the oro and nasopharynx, made up of:  Pharyngeal Tonsil

 Two Palatine Tonsils  Lingual Tonsil

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6.3. Lymph Nodes

- Lymph nodes are small, bean-shaped masses of lymphatic tissues of varying size.

- They are enclosed in a strong fibro-elastic capsule. This capsule extends down into the node forming trabeculae which partially divide the node into separate compartments.

- You’ll notice that lymph nodes strongly resemble the kidneys

- The fluid is forced through a series of channels called Lymphatic Sinuses within the node in order to get to the outgoing vessel.

o These sinuses are lined by lymphocytes and macrophages to filter the fluid. - Lymph nodes are scattered and positioned such that by the time the fluid is returned to the

venous circulation, it has been cleaned of all impurities.

- Lymph node position is therefore important. This is because if we know the route by which a body part is drained and which nodes lie in the drainage part, we can assess those nodes via palpation for swelling and hardness.

- Lymph node positions around the body are divided into regions. For us, the head and neck nodes are important as we can assess them to determine the spread of infection.

6.3.1. Nodes of the Head and Neck

- The nodes of the head and neck can be divided into superficial and deep nodes. The superficial ones are usually more relevant to us clinically since they are much more easily palpated.

Superficial Groups:

- Pericervical Ring

- Nodes accompanying superficial neck veins Deep Groups:

- Perivisceral Ring

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Page | 47 6.3.1.1. Pericervical Ring (Superficial)

- Found around the base of the head and neck (peri = outer; cervical = neck region) - Clinically important and is made up of:

o Submental Group (below the front of the chin)

o Submandibular Group (near the Submandibular gland) o Parotid or Pre-Auricular Group (Anterior to the ear) o Mastoid Group (near the mastoid process)

o Occipital Group (around the back of the neck.

Figure 9 The above diagram shows the drainage patterns of each node group. They all eventually drain into one of the Deep Cervical Nodes. The significance of this will be demonstrated later.

- Note that the further anterior the fluid origin is, the more cervical the Deep Cervical Node it’ll drain into.

o The deep cervical nodes sit on the carotid sheath and drains the whole head. - This pattern is very useful in determining the origin of an infection.

o E.g. Using the diagram above, if there is an infection in the bottom Deep Cervical Node, it must be from the Submental Group of nodes as they are the only ones which drain into this node.

Parotid Nodes Mastoid Nodes Occipital Nodes Submental Nodes Submandibular Nodes

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Page | 48 6.3.1.2. Superficial Neck Nodes (Superficial)

- The nodes which accompany the superficial neck veins are also important since they are easily palpable. They tell us about superficial and systemic infections.

- These lie in two chains which follow the anterior jugular vein and the external jugular vein. o Nodes following the external jugular vein are easily palpated since they lie

superficially to the sternocleidomastoid. 6.3.1.3. Perivisceral Ring (Deep)

- Named due to the fact that it surrounds the viscera of the neck.

- The most anterior group of these nodes are named based on their position as the group ascends the neck. They are:

o Pre-tracheal nodes  In front of trachea o Pre-laryngeal Nodes

 In front of larynx o Infrahyoid Nodes

 Below hyoid bone

- The posterior group are similarly named and are as follows: o Retro-Oesophageal Nodes (behind oesophagus) o Retro-Pharyngeal Nodes (behind the pharynx) 6.3.1.4. The Deep Cervical Chain (Deep)

- Difficult to palpate as it mainly sits deep to the sternocleidomastoid.

- It’s upper and lower ends are defined by two major nodes, named for the muscles near which they lie.

o Jugulo-digastric Node (Upper) o Jugulo-omohyoid Node (Lower)

o The other nodes within this chain are not named.

- All of the lymph from the head and neck will eventually drain into the deep cervical chain on

both sides.

o However, the connections are at different points, a fact which is important in diagnosis.

- The deep cervical drain drains into the Right Lymphatic Duct on the right side and the Thoracic

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7. Arterial Supply to the Head and Neck

- Some questions to think about:

o The head uses 14% of the total blood supply of the body. Is this proportionate with the mass of the head?

o How do we prevent vessels from being crushed when we move the neck? o How do we compensate for heat loss through radiation?

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7.1. The Aortic Arch

- The Aorta is the major artery that leaves the heart.

- Immediately after leaving, it gives off several branches that supply the heart itself, the head and neck and the upper limbs.

- The Brachiocephalic Artery is the first major branch of the aorta and runs upwards on the right side.

o It supplies the right upper limbs and the two major branches to the head. o It gives off the right common carotid and the right subclavian arteries.

- The Left Common Carotid and Left Subclavian arteries branch directly from the aortic arch.

7.2. The Vertebral Artery

- The vertebral artery branches from both subclavian arteries.

o It passes upwards through the transverse foramina of all cervical vertebrae except

C7 before ascending up through Foramen Magnum.

- It is positioned so deep that it is protected from all but the most severe and terminal sorts of trauma.

o This protection is enhanced by the presence of the vertebrae.

o This helps ensure that blood supply to the brain is protected against crushing during movements of the neck and due to trauma.

- Once it has passed through foramen magnum, it lies in the basal part of the occipital bone. o Here, it joins with the vertebral artery from the opposite side to form the Basilar

Artery named because of its location.

 It forms an important part of the cerebral blood supply and circulation.  The only branch we need to know is the Superior Cerebellar Artery which

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 V2 and V3 run near this artery. Sometimes the pulsing of the artery can damage the myelin sheathes of these nerves causing Trigeminal

Neuraglia

7.3. The Carotid Arteries

- Recall that the common carotid arteries arise from different sources on each side of the body. o On the right side, it arises as a branch of the brachiocephalic artery

o On the left side, it arises directly from the aortic arch - Aside from their origins, they follow the same course.

- They run upwards in the neck deep to the sternocleidomastoid until it reaches the level of the Larynx.

o Here, it divides into two branches being the External and Internal Carotid Arteries  The division can palpated just in front of the anterior border of the

Sternocleidomastoid muscle.

 At the point where the common carotid gives off the internal carotid artery, there is a dilation called the Carotid Sinus which contains receptors to monitor blood pressure (baroreceptors)

- The Common and Internal Carotid Arteries are included in the fascia of the Carotid Sheath. o Also contains Internal Jugular Vein and Vagus nerve.

- The External Carotid Artery branches off to supply the superficial parts of the face and scalp. - The Internal Carotid Artery goes intracranially to supply brain by travelling through the Carotid

Canal

Superior Cerebellar

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Page | 52 7.3.1. The External Carotid Artery

- Branches off the Common Carotid and is not included in the Carotid Sheath.

- It provides the majority of the branches and therefore arterial supply to the face and scalp. o Its blood runs into a network of vessels that supply a large capillary plexus, especially

over the face.

o The purpose of this plexus is such that if one vessel is damaged, there will be many other alternative routes of blood supply and won’t deprive the major part of the plexus.

 This system is referred to as redundancy

- The presence of redundancy ensures that damage to a single vessel is unlikely to lead to tissue death.

o This is particularly advantageous in cases of surgery. Excellent blood supply means rapid healing and reduced probability of infection.

 Furthermore, even though it should be avoided, cutting an artery during surgery may not always be incredibly detrimental.

- The External Carotid gives of several branches.

o Some run posteriorly to supply the back of the head and neck.

o Other branches run anteriorly to supply the front of the neck and face.

o Only the Ascending Pharyngeal branch runs straight up to supply the roof of the cranium.

- In order of when they branch (going inferior to superior), the branches of the external carotid are:

o Superior Thyroid Artery (runs anterior)

o Ascending Pharyngeal Artery (deep artery that runs straight up) o Lingual Artery (runs anterior)

o Facial artery (runs anterior) o Occipital artery (runs posterior)

o Posterior Auricular Artery (runs posterior)

Common Carotid Artery Internal Carotid Artery

External Carotid Artery

Superior Thyroid Artery Lingual Artery

Facial Artery Ascending Pharyngeal Artery

Occipital Artery

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Page | 53 - The above image has had all structures cut away for ease of viewing. See below image to see

their relation to other structures of the head and neck.

- The maxillary artery terminates by dividing into the Maxillary Artery and Superficial Temporal

Artery

7.3.1.1. The Lingual Artery

- The Lingual Artery is the third artery to branch from the External Carotid Artery. It branches from the anterior aspect.

- It provides the main source of blood supply to the tongue, floor of the mouth, gums and lingual side of the anterior teeth.

- After branching off, it forms a loop before ascending towards the tongue.

o This loop serves to accommodate for mandibular movement so that the artery isn’t stretched, ruptured or crushed.

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Page | 54 - It runs deep to the superficial muscles into the tongue, deep to the hyoglossus muscle.

o Because it is so deep, it is unlikely that you will damage it during procedures. - During its course, before ascending up to the tongue, it gives off a branch called the sublingual

artery which runs anteriorly to supply the floor of the mouth and the sublingual gland.

7.3.1.2. Facial Artery

- Also an anterior branch of the external carotid. - It arises immediately superior to the lingual artery - It arches up and runs deep to the body of the mandible.

o Here it forms a loop between the Superficial Belly of the Submandibular Gland and the bone. (in the Submandibular fossa)

 This loops serves the same purpose as the loop the lingual artery performs o In this location, it can be damaged during surgery of the region.

- At the end of the loop, it reappears at the lower border of the mandible, crossing over at the anterior margin of the masseter. Here, a facial pulse can be palpated.

- Also at this point, the facial artery gives off a branch called the Submental Artery which runs forwards below the mandible and on the inferior surface of the mylohyoid muscle.

o It then crosses over the chin to anastamose with the inferior labial and mental arteries.

 This forms a plexus for supply the lower lip and chin.

o Before it reaches the chin, it also anastamoses with the sublingual and mylohyoid artery from the lingual branch.

 Forms a plexus to supply floor of mouth and anterior lingual gingiva.

External Carotid Artery Facial Artery Submental Artery Submandibular Gland Inferior Labial Artery Superior Labial Artery

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Page | 55 - After giving off the Submental artery, it ascends obliquely across the face towards the medial

angle of the eye.

o As it passes the lower and upper lips, it gives off the inferior and superior labial

branches

o They both anastomose with the same artery on the other side.

o The inferior labial artery forms a plexus with the mental and submental artery. - Before giving off the Superior Labial Artery, the Facial Artery changes its name to Angular

Artery and runs up to the medial corner of the eye giving off some lateral nasal branches which

contribute to the facial plexus.

- At the corner, it anastamoses with a branch of the ophthalmic artery which joins orbital and

facial circulations

7.3.1.3. Maxillary Artery

Figure 11 Maxillary Artery and its branches. Refer to this diagram for the branches. - One of two terminal branches of the external carotid artery.

o The other part being the Superior Temporal. Will only be mentioned in passing. - Clinically, it is important to us because branches from it supply the upper and lower teeth, the

palate, cheeks and gingivae.

o Surgically, it is incredibly important as it gives off the middle meningeal artery that supplies the Meninges.

- There are many branches to this artery but the ones relevant to us are: o Middle Meningeal Artery

 It communicates with the intracranial circulation. o Inferior Alveolar Artery

 Supplies the mandible o Buccal Artery

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Page | 56 o Superior Dental Artery

 Posterior Dental Artery  Palate

 Supplies the upper teeth o Greater Palatine Artery

o Palatine Artery  Palate o Infraorbital Artery

o Arteries to Muscles of Mastication

- - It arises from the external carotid and runs to the medial side of the ramus of the mandible into the substance of the parotid gland.

o It then runs obliquely to the pterygopalatine fossa where it gives of branches which correspond with the branches of V2

o Only the main branch will reach the pterygopalatine fossa.

Middle Meningeal Artery

- Supplies most of the dura mater in the cranium.

- Therefore, it must enter the cranial cavity and does this by passing through foramen Spinosum. - The Accessory Meningeal Artery also enters via foramen ovale.

- It is important to take note of the relationship between the Auriculotemporal Nerve from V3

and the Middle Meningeal Artery

- In the circled region in the image above, the Auriculotemporal Nerve is shown to split and run around the Middle Meningeal Artery as it heads towards the TMJ.

- The above image is also really handy when looking at the Facial and Trigeminal Nerves Trigeminal

Ganglion

Auriculotemporal Nerve Facial Nerve

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Inferior Alveolar Artery

- The inferior alveolar artery follows more or less the same path as the inferior alveolar nerve and slightly posterior. They both enter the mandible via the mandibular foramen.

- Once in the canal, it gives off the same branches as the nerve.

Buccal Artery

- Follows the same course as the Buccal nerve of V3

- Supplies the tissues in the check and anastamoses with the facial and infraorbital arteries

making the plexus.

Posterior Superior Dental Artery

- Equivalent of posterior superior alveolar nerve - Supplies upper posterior teeth and the palate.

Palatine Artery

-

Divides into smaller Lesser Palatine Arteries which supply part of the soft palate

-

Greater Palatine Artery

o Supplies palatal tissues and palatal gingivae of the teeth

Infraorbital Artery

-

Gives rise to middle and anterior superior dental arteries