2021/7021MSCOral Biology

Semester 1 2013

Laboratory Manual

Anatomy of the Head and Neck Region

Laboratory 5

Arterial supply,

Venous drainage

Lymphatic drainage

Laboratory 5: Arterial Supply, Venous and lymphatic Drainage

Learning Objectives

Arterial supply of the head and neck

internal carotidExternal carotid

maxillary superficial temporal arteries

Blood supply to the brain

internal carotid vertebral arteries

carotid canal

foramen magnum

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Be able to identify the main arteries and veins of the head and neck as well as in the skull.

Identify the main branches of the external carotid artery and its branches.

Identify the blood vessels and nerves closely related to pharyngeal muscles.

Know the blood supply of structures in the oral cavity.

Be able to locate the major groups of lymph nodes in the head and neck and know the structures drained by each group.

Study the arrangement of structures in the neck using a cross section and appreciate the fascial arrangement of the neck.

The arterial supply to the head and neck arises from the common carotid arteries that divide into the internal and external carotid arteries. The principally supplies the greater part of the cerebral hemisphere. gives off six branches as it extends upwards in the neck and head, terminating near the mandibular condyle by dividing into the

and .

The and supply all blood to the brain. Identify these vessels on head and neck specimens and whole brains.

Where do these arteries arise?

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Are there differences between the left and right sides of the body?

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The internal carotid artery enters the cranial cavity by route of the .

The vertebral artery follows the spinal cord through the .

Station 1

Fig 3.4 pg32, Head & Neck Anatomy for Dental Medicine (2010) Eric W. Baker Ed. Thieme Medical Publishers Inc NY USA

In the space below, draw a simple tree diagram labelling the major branches of the external carotid artery. Identify an adjacent landmark for each branch to aid your recall of where to find the branches in the specimens.

Locate and examine the carotid canal and foramen magnum in the skull in both inferior and internal views.

Fig 1.24 pg13, Head & Neck Anatomy for Dental Medic ine (2010) Eric W. Baker Ed. Thieme Medical Publishers Inc NY USA

Why is the vertebral artery so named? (Hint: what structure does it pass through in the neck?)

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Identify the (Circle of Willis) on whole brain specimens.

The cerebral arterial circle is an example of an anastomosis. What does this term mean?

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What are the clinical implications of the cerebral arterial circle?

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Label the carotid canal and the jugular foramen on this diagram.

Identify the specific vessel that passes through the carotid canal

What blood vessel/s does the vessel passing through the carotid canal connect or anastamose to?

In general, what does the vessel travelling in the carotid canal supply?

cerebral arterial circle

Draw a picture of the cerebral arterial circle (Circle of Willis) and label each of the arteries that contribute to the circle.

Identify the and .

What depression does the anterior cerebral artery run in?

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See Figure 3.8 page 44 Head & Neck Anatomy for Dental Medicine (2010) Eric W. Baker Ed. Thieme Medical Publishers Inc NY USA

Identify the major branches of the maxillary artery (the three main branches and their subsequent branches) and identify the extent of their supply. See table 3.4 page 47 Head & Neck Anatomy for

Dental Medicine (2010) Eric W. Baker Ed. Thieme Medical Publishers Inc NY USA

anterior, middle posterior cerebral arteries

Station 2Maxillary artery:

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DRAW a tree diagram identifying the major divisions/parts of maxillary artery.

State the main branches of each part

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Where, specifically is this plexus situated?

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What is the clinical importance of valveless anastomoses between the facial vein, ophthalmic vein and pterygoid plexus of veins?

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What are the 3 communications between this plexus and the cavernous sinus?

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Pterygoid plexus of veins

Station 3

Neck

Identify the following structures in the anterior neck on the prosected specimens

Common carotid artery

Internal jugular vein

Thyroid gland

Submandibular gland

Branches of the external carotid artery

Superior thyroid artery

Ascending pharyngeal artery

Lingual artery

Facial artery

Occipital artery

Posterior auricular artery

Draw a lateral view of the face and sketch the branches of the external carotid artery, parotid glandand the facial nerve.

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Station 4

Venous drainage of the head and neckexternal jugular vein anterior jugular

posterior auricular vein, and the posterior division of the retromandibular vein

retromandibular vein is formed within the parotid gland from the superficial temporal, and the maxillary veins

External jugular veinAnterior jugular veinsSuperficial temporal veinMaxillary veinRetromandibular vein

The and the vein are the two superficial veins of the neck region. The external jugular vein originates from just behind the mandible's angle, and is formed by the union of the

.The

. The external jugular vein, upon formation descends through the superficial region of the neck obliquely across the sternocleidomastoid muscle. It then pierces the deep fascia of the neck and drains into the subclavian vein just above the clavicle in the posterior triangle of the neck.

Identify the following in specimens:

Fig3.17 pg50, Head & Neck Anatomy for Dental Medicine (2010) Eric W. Baker Ed. Thieme Medical Publishers Inc NY USA

Deep veinsThe internal jugular vein is the main trunk of the deep veins of the neck. The internal jugular veindrains the brain, face, and neck. The internal jugular vein originates at the jugular foramen as the continuation of the sigmoid sinus of the skull. Then the internal jugular vein descends in the carotid sheath (with common carotid artery & vagus nerve) and joins the subclavian vein to form the brachiocephalic vein.

Locate the mid sagittal sinus, the transverse sinus, the occipital emissary vein, the mastoid emissary vein, the condylar emissary veins on the diagram on previous page.Emissary veins, after passing through the bony canal (after which they are named) communicate with the dural sinuses.

What is meant by the term dural sinus?

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The internal jugular vein has several tributaries within the deep region of the neck. Facial Vein (& labial and angular veins); Lingual Vein; Superior & Middle Thyroid Veins

Using your understanding of the deep veins of the head, particularly the pterygoid venous plexus, the cavernous sinus and the deep facial veins and their interconnection, describe how an infection can spread from an infective focus on the upper lip to the cavernous sinus (see Figure 3.20 and text on page 53 Head & Neck Anatomy for Dental Medicine (2010) Eric W. Baker Ed. Thieme Medical Publishers Inc NY USA or page 911 Figure 7.10

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SkullIdentify the location of the following o

cavernous sinus superior sagittal sinustransverse sinus

sigmoid sinus

Briefly state how these veins drain to the internal jugular vein. Where is the blood draining from?

What else drains into the cavernous sinus?

Complete the labels on the diagram of the occipital view of venous structures.

Fig3.21 pg53, Head & Neck Anatomy for Dental Medic ine (2010) Eric W. Baker Ed.Thieme Medical Publishers Inc NY USA

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Station 5

Lymphatics of Head and Neck

• Using the diagrams and models study the lymphatic drainage of the head and neck.

Fig12.5 pg269, Head & Neck Anatomy for Dental Medicine (2010) Eric W. Baker Ed. Thieme Medical Publishers Inc NY USA

Know the location of following nodes:SubmentalSubmandibular Preauricular (Parotid)Post auricular (Mastoid)OccipitalRetropharyngeal nodesDeep cervical nodes

Complete the following table clearly identifying the region/s drained by the lymph nodes (see Table

20.1 page 330-331 in Textbook of Head & Neck Anatomy 4th Edn Hiat JL and Gartner LP Wolters

Kluwer Lippincott Williams and Wilkins Philadelphia PA. See also page 269 in Head & Neck

Anatomy for Dental Medicine (2010) Eric W. Baker Ed. Thieme Medical Publishers Inc NY USA)

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Nodes Drainage area

Submental

Submandibular

Preauricular (Parotid)

Post auricular (Mastoid)

Occipital

Retropharyngeal nodes

Deep cervical nodes.

If only peripheral lymph node groups are affected, then it is likely that the disease process is local to the nodes affected.

Which groups of nodes drain which areas of the face bilaterally?

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Jugulofacial venous junction receives lymphatics from the head (obliquely inferiorly) and

redirects them vertically inferiorly into the neck.

Thus if this group of nodes is enlarged then it may indicate a disease process in the head, oral

or facial regions. If, the other central group (nodes occurring at the venous junctions) the

jugulosubclavian is enlarged then this could reflect even more extensive disease processes.

What is the significance of the junction, with regard to the lymphatic system drainage of the body? (ie which regions drain here)

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What is the significance of the junction, with regard to the lymphatic system drainage of the body? (ie which regions drain here)

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left jugulosubclavian venous

right jugulosubclavian venous

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Where do the deep cervical lymph nodes drain to?

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What are the structures that constitute Waldeyer's ring? And where do they drain?

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Lymphatic drainage from the teeth is directed to which groups of lymph nodes?

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REVIEW

• If you wanted to anaesthetise the nerves that innervate the upper teeth which nerves would you need to target (note the possible variations):

• If you wanted to anaesthetise the nerves that innervate the lower teeth which nerves would you need to target (note the possible variations):

• Revise the bony features of the hard palate.

• If you wanted to anaesthetise the nerves that innervate the hard palate which nerves would you need to target?

Describe the source of motor, sensory and special sensory innervation to the tongue. Be specific as to which nerve innervates which tongue region. You may wish to draw a summary diagram.

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What structures does the vagus nerve innervate in the neck?

What does the recurrent laryngeal nerve innervate?

What nerve innervates the gingivae of the mandible? And the maxilla?

An infection in the loose connective tissue layer of the scalp may result in meningitis, brieflyexplain how the infection may pass into the skull to the meninges.

The occipitofrontalis muscle bellies prevents scalp infection passing into the neck.

Infections of the oral cavity may enter the retropharyngeal space between the buccopharyngeal fascia covering the pharynx and oesophagus and the alar fascia.

If the alar fascia is penetrated by the infection, and enters the space between the alar fascia anterior to the pre-vertebral fascia it may travel into the _______________________, where it can be life threaten

What are the signs and symptoms arising from Ludwig’s angina?

How might you contract Ludwigs angina?

Identify the key treatments needed to treat this condition.

Identify and label on the diagram provided:o Skino Superficial fascia (Platysma)o Arrangement of the deep fascia of the neck.

o Label the following on the diagramo Carotid sheath v What structures lie inside the carotid sheath?o Pretracheal fasciao Buccopharyngeal fasciao Prevertebral fasciao Tracheao Oesophaguso Retropharyngeal space

Explain the advantages of these deep cervical fasciae.

• Revise the intrinsic and extrinsic muscles of the tongue.

• Revise the embryological development of the tongue from the branchial arches.

• Understand the nerve supply to the tongue (appreciate the anterior 2/3 and posterior 1/3 supply is different, due to its embryological development):

o Sensory -

o Taste -

o Motor -

Floor of the mouth and tongue

• How do the taste fibres from CN 7 reach the anterior 2/3 of the tongue?

• Draw a diagram to describe the general sensory and taste innervation of the tongue.

• Hyoglossus:o Study the diagrams or specimens which show the relationships of this muscle to the submandibular gland/duct, lingual and hypoglossal nerves and lingual artery.

• State the path taken by the parasympathetic (secretomotor) fibres to reach the submandibular/sublingual and parotid glands.