202 Living Anatomy and Ultrasound 2023-24 PDF

Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. 202: Living Anatomy and Ultrasound Learning Outcomes: By the end of the module you should be able to: 1. Describe and draw the surface marking projections of the musculature of the neck 2. Describe and draw the blood supply in...

Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. 202: Living Anatomy and Ultrasound Learning Outcomes: By the end of the module you should be able to: 1. Describe and draw the surface marking projections of the musculature of the neck 2. Describe and draw the blood supply in the neck 3. Describe and draw the surface marking projections of the main components of the viscera of the neck, including the larynx and pharynx 4. Describe the anatomy of the head and neck as viewed through ultrasound 5. Apply an understanding of the nervous system in the neck to clinical scenarios. Student Worksheet As with the previous living anatomy session that you have participated in, you will be working in small teams. This session is divided into 2 tasks and will involve locating the surface markings on the head and neck, requiring some palpation of your fellow students. It is hoped that all students will be prepared to palpate and be palpated; however, students who have a reason for not wishing to participate in these activities need only make this clear to their colleagues and staff members in the session. Materials to be used in session • Alcohol gel for preparing hands prior to palpation • Coloured pens for drawing surface markings • Ultrasound machine Before you begin your examination prepare your hands using the alcohol gel. Living Anatomy and Ultrasound Dominic O’Brien 28/11/2022 1 Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. Clinical Application Ultrasound is frequently used for central line insertion and internal jugular vein cannulation, in addition to examination of thyroid for nodules, adenomas and malignancy. Task A. Living Anatomy Having studied the features of the head and neck, you will now try locating some of these features on a living subject. As a group, take it in turns to act as an examiner and subject. Materials to be used in this part of the session: • Alcohol gel for preparing hands prior to palpation • Coloured pens for drawing surface markings Osteology Skull: On the anterior aspect: • • • • • Palpate the frontal, parietal, temporal and occipital bones. Palpate the bones of the midfacial skeleton; the orbit (eye socket), zygomatic bone (cheek bone), and maxilla (upper jaw). Locate the region of the bregma by palpating the frontal bone in the midline and moving posteriorly. To locate the lambda, palpate the occipital bone in the midline and move anteriorly until the sagittal suture is felt. Identify the region where the pterion is located. Work from the superior surface of the zygomatic arch and the lateral edge of the orbit. Palpate the occipital bone, external occipital protuberance, and superior and inferior nuchal lines. Vertebrae: • • Palpate the spinous processes of the cervical vertebrae. (Note you may have to ask them to gently flex and extend their neck) Palpate the transverse processes (this may be difficult, so please do so gently). Questions Which artery runs through the transverse foramen in the cervical vertebrae? Which artery is found lying deep to the pterion? What could be the clinical significance of a fracture at the pterion? Living Anatomy and Ultrasound Dominic O’Brien 28/11/2022 2 Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. Figure 08-02A and Figure 08-02B. Gray’s Surface Anatomy and Ultrasound Bones of the skull. A, Bones of the adult skull. B, Superior aspect of infant's skull. (Modified from Drake, RL, Gray's Anatomy for Students, 3rd ed, 2015, Churchill Livingstone, Elsevier.) Living Anatomy and Ultrasound Dominic O’Brien 28/11/2022 3 Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. Triangles of the neck • Locate the sternocleidomastoid muscle. The anterior border can be made visible and traced from the manubrium to the mastoid process. Draw a line along its anterior border which will form the posterior boundary of the anterior triangle, and a line along its posterior border which will form the anterior boundary of the posterior triangle. Draw the anterior triangle: • Locate and mark the midline of the neck and the inferior border of the mandible. • Draw a line over the omohyoid muscle in the anterior triangle to create the carotid triangle and the muscular triangle. • Palpate the digastric muscle and draw on the submandibular and submental triangles. Draw the posterior triangle: • Locate the clavicle. Draw a line along its superior border. • Locate the trapezius muscle from its attachment at the occipital bone to the lateral third of the clavicle. Draw a line along its anterior border creating the posterior boundary. • Locate the omohyoid muscle to further subdivide the posterior triangle into the occipital and omoclavicular triangles. Once you have drawn the triangles, use the image on the following page to check your work. Viscera of the neck Anterior aspect of the neck • Palpate the thyroid cartilage by gently placing the thumb and index finger either side. • Move your finger inferiorly to palpate the cricoid cartilage. • Observe the movement of the larynx during swallowing. Questions How is lymphatic tissue of the head and neck arranged in relation to the triangles of the neck? If the GP palpated soft tender enlarged nodes what is this likely to tell you? If the GP palpated enlarged firm hard fixed nodes, what is this likely to tell you? Using your anatomical knowledge about the lymphatic drainage of the tongue, where would the GP be likely to find abnormal nodes? Living Anatomy and Ultrasound Dominic O’Brien 28/11/2022 4 Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. Figure 08-19. Triangles of the neck. Gray’s Surface Anatomy and Ultrasound CaT, carotid triangle; Cl, clavicle; Dig, digastric (anterior belly); JN, jugular notch; Ma, mandible; MT, muscular triangle; OcT, occipital triangle; Om, omohyoid; OT, omoclavicular triangle; Scm, sternocleidomastoid; StH, sternohyoid; SubmaT, submandibular triangle; SubmeT, submental triangle; Trap, trapezius. Living Anatomy and Ultrasound Dominic O’Brien 28/11/2022 5 Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. Task B. Ultrasound of the Head and Neck Ultrasound technique It is best to hold the transducer close to its base using one hand, much like you would hold a pen. The marker on the transducer should point either cephalic (towards the head) or to your left-hand side. In this session, we will use ultrasound to examine the muscles and viscera of the neck and eye. Ultrasound provides and effective tool for examining a range of structures in the head and neck. In particular B-mode imaging is used to examine the glands in the neck, especially important for the identification of metastatic malignant nodes. The thyroid gland is often assessed using ultrasound, to identify thyroid nodules. During trauma ultrasound may be used to assess injury to the larynx or trachea. Doppler ultrasound is also frequently used to examine the blood flow within the carotid arteries (try using this during the session). Neck Refer to page 158-90 in Gray’s Surface Anatomy and Ultrasound. Imaging is performed with the subject sitting and the head rotated to the side. Position the linear transducer on the anterior surface of the neck, immediately superior to the clavicle, to the right or left side of the midline. The orientation marker should point towards the left. Scan in a superior direction following the sternocleidomastoid muscle. Ø Identify the sternocleidomastoid muscle, common carotid artery, and internal jugular vein. Locate the vagus nerve and carotid sheath. Ø Identify the thyroid gland, the isthmus and the trachea. Moving the transducer higher (page 185 Gray’s Surface Anatomy and Ultrasound) to the angle of the mandible, locate the parotid gland. Use the notes section overleaf to sketch the main features and to make any notes. Living Anatomy and Ultrasound Dominic O’Brien 28/11/2022 6 Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. Figure 08-30. Gray’s Surface Anatomy and Ultrasound Ultrasound of the right carotid system. A, Inferior neck. B, Mid neck. C, Superior neck. CCA, common carotid artery; CrT, cricothyroid; EC, external carotid; ICa: internal carotid; IJV, internal jugular vein; InT, inferior trunk; LonC, longus colli; MiT, middle trunk; Om, omohyoid; Pla, platysma; PN, phrenic nerve; ScA, scalenus anterior; Scm, sternocleidomastoid; ST, superior trunk; StH, sternohyoid; StT, sternothyroid; TG, thyroid gland; VN, vagus nerve. Scale bar = 1 cm. Living Anatomy and Ultrasound Dominic O’Brien 28/11/2022 7 Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. Figure 08-27. Gray’s Surface Anatomy and Ultrasound Ultrasound of the right parotid gland. A, Immediately inferior to the ear. B, Inferior level. ECA, external carotid artery; LN, lymph node; Mas, masseter; PG, parotid gland; RM, ramus mandible; RmV, retromandibular vein; Scm, sternocleidomastoid. Scale bar = 1 cm. Living Anatomy and Ultrasound Dominic O’Brien 28/11/2022 8 Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. Notes Living Anatomy and Ultrasound Dominic O’Brien 28/11/2022 9 Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. Eye Refer to page 183 Gray’s Surface Anatomy and Ultrasound Imaging is performed with the subject sitting. It is important that the eye remains closed during the exam to prevent gel from entering the eye. Apply adequate gel to the linear transducer and gently position the probe over the eye lid so that the marker is pointing towards the left. Tilt the probe slightly inferiorly. Avoid pressure onto the eye. After performing this examination, carefully wipe off any excess gel ensuring the eye is clean to prevent irritation. Before you begin: Ø Examine the upper and lower eyelid and locate the medial and lateral commissures. Ø Identify the lacrimal papilla and punctum. Ø Locate the sclera, iris and pupil. The eyeball can be seen as a hypoechoic globe-shaped ball. The vitreous (postrenal) chamber, which contains vitreous humor, fills much of the space. At the front of the eyeball, the cornea appears as a thin hyperechoic line. Sitting between the anterior and vitreous chambers, the iris and lens can be seen. The inner layer of the eyeball, the retina, has a mid-grey texture compared to the underlying middle layer, the choroid, which is relatively hypoechoic. The outer dense layer of the eyeball, the sclera, appears as a mid to light-grey thick layer. Behind the eye, the optic nerve may be in view as a hypoechoic shadow. Ø Locate the vitreous chamber Ø Identify the lens and cornea Ø Locate the optic nerve Use the notes section overleaf to sketch the main features and to make any notes. Living Anatomy and Ultrasound Dominic O’Brien 28/11/2022 10 Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. Figure 08-26. Gray’s Surface Anatomy and Ultrasound Ultrasound of the right eye. *, eyelid; AnC, anterior chamber; CB, ciliary bodies; Ch, choroid; Cor, cornea; Ir, iris; Le, lens; On, optic nerve; PoC, postremal chamber; Ret, retina; Sc, sclera. Scale bar = 1 cm. Living Anatomy and Ultrasound Dominic O’Brien 28/11/2022 11 Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. Notes Living Anatomy and Ultrasound Dominic O’Brien 28/11/2022 12 Module 202: Neuroscience and Behaviours: Living Anatomy and Ultrasound. Checklist Review all the markings you have examined today and ensure that you can complete the checklist below: 1. Describe and draw the surface marking projections of the musculature of the neck 2. Describe and draw the blood supply in the neck 3. Describe and draw the surface marking projections of the main components of the viscera of the neck, including the larynx and pharynx 4. Apply an understanding of the nervous system in the neck to clinical scenarios 5. Understand the structures of the head and neck as viewed by ultrasound. Living Anatomy and Ultrasound Dominic O’Brien 28/11/2022 13