surface anatomy of the neck.pdf

Surface Anatomy of the Neck Mr Fraser Chisholm [email protected] Where this fits: Anatomy Lectures Dissection Guided studies Thoracic Wall 1&2 Osteology of the thoracic cage Overview of the thoracic cage Thoracic cavity 1&2 Removal of the anterior thoracic wall Changes to circulation...

Surface Anatomy of the Neck Mr Fraser Chisholm [email protected] Where this fits: Anatomy Lectures Dissection Guided studies Thoracic Wall 1&2 Osteology of the thoracic cage Overview of the thoracic cage Thoracic cavity 1&2 Removal of the anterior thoracic wall Changes to circulation at birth Heart and pericardium Cross-sectional anatomy of the thorax Heart: internal structure and surface anatomy Surface anatomy of the neck Superior Mediastinum Coronary circulation and conduction Posterior mediastinum Foetal circulation Development of heart and great arteries Nerves of the thorax 2 Learning Outcomes: After this lecture, time spent in the dissecting room, and further private study you should be able to: 1. Describe the general structure of the neck as composed of vertical columns surrounded by fascial sheets with potential spaces between 2. Describe the concept of the anterior and the posterior triangles of the neck, and their boundaries 3. Describe the form and position of the common and internal carotid arteries and the internal jugular vein 4. Describe the form and position of the external carotid artery, external jugular vein and anterior jugular vein 5. Discuss the nerves, lymph nodes and muscles adjacent to the above vessels 6. State the bony and cartilaginous landmarks used to locate and demonstrate the above structures on a living model or patient 3 Recommended Reading, Related elements • Moore et al. Clinically Oriented Anatomy 7th Ed, 2014 © Wolters Kluver. In Section 8 Neck: "Fascia of neck", “Lateral cervical region" “Anterior cervical region" • Spratt et al. Weir and Abraham’s Imaging Atlas of Human Anatomy, 5th Edition, 2017 © Elsevier Inc. 4 Overview Fascial Sheets & Potential spaces Boundaries of Anterior and Posterior Triangles Bony and Cartilaginous landmarks Common, Internal and External Carotids Internal, External and Anterior Jugular Veins Nerves and Lymphatics 5 General Structure • • • All are Deep Fascias Potential spaces between each Names can change Neurovascular column x2 – carotid sheath Boney muscular/ Neuromuscular column – “Prevertebral” fascia Visceral column – “pretracheal” fascia/ “Buccopharyngeal” Fascia Everything in an outer Layer of “Investing” Fascia 6 Fascias 7 Potential Spaces – more in MD3002 and MD4001 Carotid sheath Pretracheal Alar Fascia Prevertebral 8 Potential spaces • Retropharyngeal space • Split by Alar fascia • True Retopahrangeal space • Limited at T3/4 • Alar Space – Danger space • Continuous base of skull→ Diaphragm, via posterior mediastinum 9 Clinical Relevance Infection in the neck • "True" Retropharyngeal Space • Permits movement during swallowing of pharynx, oesophagus, trachea and larynx • Danger Space • Major pathway for the spread of infection to mediastinum • Retropharyngeal abscesses • Nasopharynx, paranasal sinuses or middle ear infections • Dental abscesses can spread into mediastinum Case courtesy of Ian Bickle, Radiopaedia.org, rID: 30018 10 Triangles of the neck – subdivisions and detail in MD4001 Posterior Triangle Borders: Ant. – Posterior border of Sternocleidomastoid Post. –Anterior border of Trapezius Inf. – Middle 1/3 of Clavicle Anterior Triangle Borders: Sup. – Inferior border Mandible Lat. – Anterior border of SCM Med. - Midline 11 Clinical Relevance – Neck lumps • Location • Anterior triangle • Posterior triangle • Midline • Tenderness • Heat/Inflammation • • • • Size/Depth Pulsatile Solitary or multiple lumps Movement • Swallowing • Sticking out tongue 12 Skull and Bony Landmarks Styloid Process Mastoid Process Transverse process of C1 Angle of Mandible 13 Hyoid bone and Larynx Greater Horn Body Lesser Horn 14 Larynx – Thyroid cartilage • Largest cartilage of the laryngeal skeleton • Two lamina, lesser and greater horns • Laryngeal Prominence • Fusion of inferior 2/3 of two lamina • Adam’s Apple – prominent in males • Articulates with cricoid cartilage • Rotation and gliding of thyroid cartilage • Change length/sound of vocal cords 15 Branches of Aorta 16 Brachiocephalic trunk • Largest branch of arch of aorta • Anteriorly covered by; • Right sternohyoid and sternothyroid muscles • Passes superolateral to the right and divides • Right common carotid and right subclavian arteries • Posterior to the sternoclavicular joint 17 Subclavian Artery – remember MD2002 – even more in MD4001 • Passes Rib 1 on way to upper limb • 3 parts, according to the anterior scalene muscle • 1st part • Vertebral artery • Thyrocervical trunk • Internal thoracic artery • 2nd part • Costocervical trunk • 3rd part • Dorsal scapular artery • Becomes the axillary artery Fig 7.13 Grants Dissector 16e Chpt 7 18 Common carotid artery • Bifurcates at the level of superior border of thyroid cartilage – C3 • • Internal carotid artery External carotid artery • Proximally covered by muscles • Distally exposed allowing palpation of pulse • Normally internal carotid artery 19 Carotid Bifurcation • Level of the superior border of the thyroid cartilage • External carotid artery • Internal carotid artery • Dilatation of proximal internal carotid artery • Good for flow? • Never palpate bilaterally – why? 20 Carotid body and Carotid sinus • Nerve innervation • Afferent - glossopharyngeal • Carotid sinus nerve • Efferent - Vagus nerve • Carotid Sinus - Baroreceptor • Reacts to change in arterial blood pressure • Carotid Body – Chemoreceptor • Monitors the partial pressure of CO2 21 Internal Carotid Artery • Covered by the carotid sheath • Carotid sheath • Internal jugular • Internal carotid • Vagus nerve • Supplies intracranial structures 22 External Carotid Artery • • • • • • • • Some Anatomists Like Freaking Out Poor Medical Students 23 Venous Drainage • Cranial veins – draining skull and cranial cavity • • • • Cerebral veins Dural venous sinuses Diplopic veins Emissary veins • Facial veins – Draining face • Superficial • Deep • Cervical veins – Connect to above and drain into thorax • External jugular vein • Anterior jugular vein • Vertebral vein 24 Cranial Veins • Drained by • Dural venous sinuses • • • • Superior sagittal sinus Inferior sagittal sinus Sinus rectus Sigmoid sinus • Jugular foramen • Becomes internal jugular vein 25 Internal Jugular Vein • Drains intracranial structures, superficial parts of face and neck • Within the carotid sheath • Vagus and internal carotid artery • Initially lies posterior to the internal carotid artery, moves laterally then anterior of the common carotid • Jugular Venous Pulse Wave is visible along the trajectory of the IJV 26 Relationships - IJV • Many very important structures! • Vagus • Phrenic nerve • Brachial plexus Internal Jugular Vein Phrenic N. Brachial Pl. Vagus N. 27 Clinical Relevance – central venous access/catheterisation • Most commonly inserted in the internal jugular vein (sometimes subclavian) • Measure central venous pressure (CVP) • Normal CVP is <8 cm H2O • Administration of fluids, medications • Complications • Pneumothorax • Puncture of subclavian artery • Nerve injury Note: Risk of air embolism if external jugular vein used 28 External Jugular vein • Descends from the angle of the mandible to the middle of the clavicle • Formed by; • • Posterior division of the retromandibular vein Posterior auricular vein • Crosses the SCM obliquely, deep to the platysma, and enters the anteroinferior part of the posterior triangle. • Pierces the investing fascia at the posterior border of the SCM. • Descends and terminates in the subclavian vein. • Drains most of the scalp and side of the face. 29 Anterior jugular Vein • Inferior to the hyoid bone • Drains into external jugular or subclavian veins • Anterior jugular veins of both sides join • Jugular venous arch 30 Nerves in the neck • Cutaneous branches of the cervical plexus • Erb's point – four cutaneous branches become superficial • • • • Lesser occipital Great auricular nerve Transverse cervical Supraclavicular • Accessory nerve • • Motor control of trapezius and SCM Passes across the posterior triangle 31 Lymph nodes in the neck • There’s a lot! – for MD4001 • Superficial Cervical • Alongside External Jugular • Deep cervical • Alongside Internal jugular • No lymph nodes in the scalp or face • Except parotid/buccal region 32 Sources of figures and Images • DAFFNER: Daffner & Hartman. Clinical Radiology. The Essentials ,4th Ed, 2014 © Lippincott Williams & Wilkins. • DRAKE: Drake et al. Gray’s Atlas of Anatomy 2nd Ed, 2018 © Elsevier. • KELLEY: Kelly&Petersen. Sectional Anatomy for Imaging Professionals, 3rd Edition, 2013 © Mosby, Elsevier Inc • MOORE: Moore et al. Clinically Oriented Anatomy 8th Ed, 2018 © Wolters Kluver. • SNELL: Snell R. Clinical anatomy by Regions, 9th Ed, 2011 © Lippincott Williams & Wilkins • SOBOTTA: Putz&Pabst. Sobotta Atlas of Human Anatomy, 14th Edition, 2006 © Urban and Fischer Verlag, Elsevier Inc • SPRATT: Spratt et al. Weir and Abraham’s Imaging Atlas of Human Anatomy, 5th Edition, 2017 © • Elsevier Inc. 33