Blood Supply to the Head and Neck Part 2 PDF

Blood Supply to the Head and Neck – Venous Drainage Josh Hudson Oral and Dental Sciences GDC Learning Outcomes 1.1.5 Describe relevant and appropriate dental, oral, craniofacial and general anatomy and explain their application to patient management Intended learning outcomes By the end of this...

Blood Supply to the Head and Neck – Venous Drainage Josh Hudson Oral and Dental Sciences GDC Learning Outcomes 1.1.5 Describe relevant and appropriate dental, oral, craniofacial and general anatomy and explain their application to patient management Intended learning outcomes By the end of this session you will be able to.. Name the major veins in the head and neck Explain what areas these main veins drain Explain the relations of the jugular vein Describe the significance of the pterygoid plexus Why do I need to know this? Why do I need to know this? We are working in a very complicated area, often putting sharp things into it! Need to be aware of the blood supply to the different areas we are working Need to know location of important vessels to avoid them Need to know what is considered ‘normal’ to identify deviations from this How is best to learn this? How is best to learn this? Unfortunately, as with a lot of anatomy this is a challenge! If you engage with the content and use resources available to you it should not put you to sleep. Ultimately comes down to three things 1) Take the time to really look at this a memorise 2) Learn pneumonic which are of relevance to you! 3) Use resources Where do I start?  Wikipedia. (2007) Diagram of the Human Heart [Photograph]. Available from: https://commons.wikimedia.org/wiki/File:Diagram_of_the_human_heart_(no_text).svg [Accessed: 17th August 2022] Lets start with the basics.. Unlike the arterial supply which starts from the aorta and moves upwards, the venous drainage starts from the head and neck and moves down. We will therefore start at this final drainage point and work backwards. The superior vena cava is the end point where all the head and neck blood drains into. This goes into the right atrium of the heart, then right ventricle, then on to the lungs to be oxygenated.  Healthjade. (2022) Superior Vena Cava [Photograph]. Available from: https://healthjade.net/superior-vena-cava/ [Accessed: 17th August 2022] Lets start with the basics.. There are some main tributaries which drain into the superior vena cava. These are the right and left Brachiocephalic veins. This is similar to the arterial Left Brachio- supply which on the right Right Brachio- cephalic Vein side also has a cephalic Vein Brachiocephalic artery. Superior Vena Cava  Healthjade. (2022) Superior Vena Cava [Photograph]. Available from: https://healthjade.net/superior-vena-cava/ [Accessed: 17th August 2022] Lets start with the basics.. Again, there are some main Left Internal tributaries which drain into Right Internal Jugular Jugular the right and left Brachiocephalic veins. These are the right Right Subclavian Left Subclavian subclavian and internal Left Brachio- jugular and the left Right Brachio- cephalic Vein subclavian and internal cephalic Vein jugular. (easier than Superior Vena Cava arteries as this is symmetrical!)  Healthjade. (2022) Superior Vena Cava [Photograph]. Available from: https://healthjade.net/superior-vena-cava/ [Accessed: 17th August 2022] Lets start with the basics.. Right and left Like with the arterial supply, there is Vertebral Veins also an external counterpart to the Right External Left External internal jugular vein and both Jugular Jugular sides also have vertebral veins. Left Subclavian Similar to the arterial supply, the Right Subclavian vertebral veins drain blood from the Left Brachio- spinal cord and vertebral muscles. cephalic Vein Right Brachio- cephalic Vein The internal and external jugular Superior Vena Cava veins drains blood from the brain, skull, oral cavity and superficial structures of the face and neck.  Kenhub. (2022) External Jugular Vein [Photograph]. Available from: https://www.kenhub.com/en/library/anatomy/external-jugular-vein [Accessed: 17th August 2022] What next? Lets first consider the external jugular vein. This has multiple branches that drain areas in the face and neck. This is the green vessel shown in the diagram to the right. What next? Posterior Auricular Posterior Vein Retromandibular Vein The posterior external jugular vein forms from Transverse Posterior External Cervical Vein the posterior Jugular Vein retromandibular vein and Anterior Jugular the posterior auricular Suprascapular Vein vein joining. This then is Vein joined by the cervical, External Jugular Vein suprascapular and anterior jugular veins to form the external jugular vein before joining the subclavian vein. Subclavian Vein What next? You can remember the Transverse branches of the external Cervical Vein Posterior External Jugular Vein jugular vein with the pneumonic PAST Anterior Jugular Suprascapular Vein Vein External Jugular P = Posterior External Vein Jugular A = Anterior Jugular S = Suprascapular Subclavian Vein T = Transverse Cervical  Maxillary Vein What next? Superficial Temporal Vein Posterior Auricular The posterior retromandibular Vein Posterior vein forms from the superficial Retromandibular temporal vein and the maxillary Vein vein. Transverse Cervical Vein Posterior External Jugular Vein The superficial temporal vein Anterior Jugular drains the scalp. Suprascapular Vein Vein The maxillary vein is formed from External Jugular Vein the pterygoid venous plexus (explained later) and drains the palate, nasal cavity, sinuses and nasopharynx. Subclavian Vein  Maxillary Vein What next? Superficial Temporal Vein The posterior auricular vein Posterior Auricular Vein Posterior drains the skin from behind the Retromandibular ear. Vein Transverse Posterior External The cervical and Cervical Vein Jugular Vein suprascapular veins drain the muscles of the neck. Anterior Jugular Suprascapular Vein Vein The anterior jugular vein is External Jugular formed by a confluence of Vein multiple superficial submandibular veins and drains blood from the anterior aspect of the neck. Subclavian Vein  Kenhub. (2022) Internal Jugular Vein [Photograph]. Available from: https://www.kenhub.com/en/library/anatomy/internal-jugular-vein [Accessed: 17th August 2022] What about the internal jugular? Now that we have considered the external jugular vein, we need to consider the internal jugular vein. Again, this has multiple branches that drain areas in the face and neck. This is the green vessel shown in the diagram to the right. What about the internal jugular vein? Inferior Petrosal sinus Vein of the As can be seen from the cochlear duct Meningeal veins diagram on the right, the Pharyngeal Internal Jugular Venous Plexus internal jugular vein has Vein a lot of tributaries prior to Common Facial joining the subclavian Vein Lingual Vein vein. You do not need to know the background of all Middle and Sternocleido- superior thyroid mastoid vein of these in detail, but there vein are some important ones to consider. Subclavian Vein What about the internal jugular vein? Inferior Petrosal sinus The main elements of the internal jugular vein can be Pharyngeal remembered using the Venous Plexus Internal Jugular pneumonic; Vein M = Middle Thyroid = Many Common Facial S = Superior Thyroid = Vein Lingual Vein Schools L = Lingual = Let Middle and C = Common facial = Superior thyroid Confident vein P = Pharyngeal = People I = Inferior Petrosal Sinus = In Subclavian Vein What about the internal jugular vein? Inferior Petrosal sinus Vein of the The inferior petrosal cochlear duct Meningeal veins sinus drains large parts of Internal Jugular the brain and inner ear Vein alongside the vein of the cochlear duct and the meningeal veins. Subclavian Vein What about the internal jugular vein? Anterior Retromandibular The common facial vein is Vein formed by a confluence of both the facial vein and the Facial Vein Internal Jugular anterior retromandibular Vein vein. This is an important structure in the head and neck as it drains the forehead, eyelids, outer Common Facial surface of the nose, lips, Vein submental region, masseter, parotid gland and the soft palate (among others). Subclavian Vein What about the internal jugular vein?InternalVeinJugular Anterior Sup Exte Retromandibular ratro r nal For completeness see the list of Vein chle Exte Buc Na s Mas Lab ar Sub Sub cina rnal the veins that form facial vein al ial sete m an m en tor Pala to the right. It is not essential ric dibu tal tine that you know all of these in bita l lar or ral ra peb Sup l cial order off by heart but you should Infe r io r P a Dee p fa Par otid r silla al take note of those of dental Ton Lin gu nge al y relevance. Many are self Pha r r Th yro id erio explanatory from their names. Sup Facial Vein e.g. labial providing drainage from Common Facial the lips, lingual from the tongue, Vein external palatine from palate, submandibular from anterior part of neck etc Subclavian Vein  Kenhub. (2022) Pterygoid Venous Plexus [Photograph]. Available from: https://www.kenhub.com/en/library/anatomy/pterygoid-venous-plexus [Accessed: 17th August 2022] And finally.. What about that pterygoid venous plexus mentioned earlier? This is a collection of small veins around the pterygoid muscle in the infratemporal fossa and as mentioned, this forms the maxillary vein which drains the palate, nasal cavity, sinuses and nasopharynx. Why does this get a special mention?  Kenhub. (2022) Pterygoid Venous Plexus [Photograph]. Available from: https://www.kenhub.com/en/library/anatomy/pterygoid-venous-plexus [Accessed: 17th August 2022] And finally.. This acts as a venous pump as every time the mouth opens and the muscle contacts, this helps pump blood back to the heart. This is further increased during yawning. It also has 2 points of specific dental relevance; 1) If the patient has an infection, it can quickly spread through this area even extending up into the skull which may have life threatening consequences.  Kenhub. (2022) Pterygoid Venous Plexus [Photograph]. Available from: https://www.kenhub.com/en/library/anatomy/pterygoid-venous-plexus [Accessed: 17th August 2022] And finally.. 2) This is an area we are close to when administering inferior dental nerve blocks. If administered incorrectly, there is a chance of damage to these vessels and formation of a haematoma. It is therefore essential to understand anatomy prior to administering as well as aspirating to ensure you are not administering the anaesthetic into a vessel (aspirating). Summary The venous supply to the head and neck is also complicated Ultimately need to be aware of two main bilateral vessels (internal/external jugular) External jugular drains the anterior neck, posterior ear, sinuses, nasal cavity, nasopharynx and palate among others. Internal jugular drains large parts of the brain, forehead, eyelids, outer surface of the nose, lips, submental region, masseter, parotid gland and the soft palate among others. Understanding of the pterygoid plexus is essential for local Summary It will take time but you will get there! Be weary this can be a a rabbit warren of information and there is a huge amount of detail. You do not need to learn every vessel of the head and neck - be smart and learn the areas that are relevant. Caveat Not everyone is the same and because of this, not all vessels join the same in every case. Due to this, when you undertake further reading you may find some references may have things in a slightly different order as there may be debate on what the most common presentation is. References Image credit; Wikipedia, Kenhub.com, anatomy.tv, Earthslab.com Resources; Kenhub.com – Invaluable resource for further information Anatomy.tv – You all have access to this interactive anatomy package https://www.youtube.com/watch?v=PXq7qwhgqxA