Blood Supply to the Head and Neck Part 2 - Tagged 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 thi...

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 supply which on the right side also has a Left Brachio- Brachiocephalic artery. Right Brachio- cephalic Vein cephalic Vein 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 the Right Internal Jugular Jugular right and left Brachiocephalic veins. These are the right subclavian and internal jugular Right Subclavian Left Subclavian and the left subclavian and Left Brachio- internal jugular. (easier than Right Brachio- cephalic Vein arteries as this is symmetrical!) cephalic Vein 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.. Right and left Like with the arterial supply, there is also an Vertebral Veins external counterpart to the internal jugular Right External Left External vein and both sides also have vertebral Jugular Jugular veins. Left Subclavian Similar to the arterial supply, the vertebral Right Subclavian veins drain blood from the spinal cord and Left Brachio- vertebral muscles. cephalic Vein Right Brachio- cephalic Vein The internal and external jugular veins drains Superior Vena Cava 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 Transverse vein forms from the posterior Cervical Vein Posterior External Jugular Vein retromandibular vein and the posterior auricular vein joining. Anterior Jugular Suprascapular Vein This then is joined by the cervical, Vein suprascapular and anterior External Jugular Vein jugular veins to form the external jugular vein before joining the subclavian vein. Subclavian Vein What next? You can remember the branches Transverse of the external jugular vein with Cervical Vein Posterior External Jugular Vein the pneumonic PAST Anterior Jugular Suprascapular Vein Vein P = Posterior External Jugular External Jugular Vein A = Anterior Jugular S = Suprascapular T = Transverse Cervical Subclavian Vein What next? Superficial Temporal Vein Maxillary Vein Posterior Auricular The posterior retromandibular vein Vein Posterior forms from the superficial temporal Retromandibular vein and the maxillary vein. Transverse Vein Cervical Vein Posterior External Jugular Vein The superficial temporal vein drains Anterior Jugular the scalp. Suprascapular Vein Vein External Jugular The maxillary vein is formed from the Vein pterygoid venous plexus (explained later) and drains the palate, nasal cavity, sinuses and nasopharynx. Subclavian Vein What next? Superficial Temporal Vein Maxillary Vein Posterior Auricular The posterior auricular vein drains Vein Posterior the skin from behind the ear. Retromandibular Vein Transverse Cervical Vein Posterior External The cervical and suprascapular veins Jugular Vein drain the muscles of the neck. Anterior Jugular Suprascapular Vein Vein The anterior jugular vein is formed External Jugular by a confluence of multiple Vein 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 diagram cochlear duct Meningeal veins on the right, the internal jugular Pharyngeal Internal Jugular Venous Plexus vein has a lot of tributaries prior Vein to joining the subclavian vein. You Common Facial do not need to know the Vein Lingual Vein background of all of these in detail, but there are some Middle and Sternocleido- superior thyroid important ones to consider. vein mastoid vein Subclavian Vein What about the internal jugular vein? Inferior Petrosal sinus The main elements of the internal jugular vein can be remembered Pharyngeal Internal Jugular Venous Plexus using the pneumonic; Vein M = Middle Thyroid = Many Common Facial Vein Lingual Vein S = Superior Thyroid = Schools L = Lingual = Let Middle and Superior thyroid C = Common facial = 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 sinus drains cochlear duct Meningeal veins large parts of the brain and inner Internal Jugular ear alongside the vein of the Vein cochlear duct and the meningeal veins. Subclavian Vein What about the internal jugular vein? Anterior Retromandibular The common facial vein is formed Vein by a confluence of both the facial Facial Vein Internal Jugular vein and the anterior Vein retromandibular vein. This is an important structure in the head and neck as it drains the Common Facial forehead, eyelids, outer surface of Vein the nose, lips, submental region, masseter, parotid gland and the soft palate (among others). Subclavian Vein What about the internal jugular vein? Internal Jugular Vein Anterior Sup Exte ratro Retromandibular rnal c Vein Exte For completeness see the list of the Buc hlea Nas Mas Lab Sub cina Sub rnal r al veins that form facial vein to the right. ial sete man men to r Pala ric It is not essential that you know all of dibu ta l tine l bita lar or ral these in order off by heart but you Sup ra r io r P a lpeb p f l acia otid Infe Dee Par r should take note of those of dental Ton silla al Lin gu al nge relevance. Many are self explanatory Pha r y erio r T hyr o id from their names. Sup Facial Vein e.g. labial providing drainage from the Common Facial lips, lingual from the tongue, external Vein 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 anaesthetic administration of consideration of spread of dental infections. 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