The Neck - Anatomy and Sonography PDF

The Neck Anatomy and Sonography Dalhousie School of Health Sciences DMUT 2030 – Topic 1 Neck Anatomy  Neck Structures/Landmarks Blood vessels Carotid artery Jugular vein Trachea Thyroid gland Parathyroid glands Loading… Esop...

The Neck Anatomy and Sonography Dalhousie School of Health Sciences DMUT 2030 – Topic 1 Neck Anatomy  Neck Structures/Landmarks Blood vessels Carotid artery Jugular vein Trachea Thyroid gland Parathyroid glands Loading… Esophagus Muscles Lymph nodes Salivary glands Rumack Fig 18- 2  Vasculature of the Neck Arterial Anatomy Ascending Aorta becomes…  Vasculature of the Neck Arterial Anatomy Ascending Aorta becomes… Aortic Arch Loading…  Vasculature of the Neck Arterial Anatomy Ascending Aorta becomes… Aortic Arch …which has 3 branches  Vasculature of the Neck Arterial Anatomy Ascending Aorta becomes… Aortic Arch …which has 3 branches 1) Right Brachiocephalic Artery (Innominate Artery) 2) Left Common Carotid Artery 3) Left Subclavian Artery  Vasculature of the Neck Arterial Anatomy 3 Branches Right Brachiocephalic Artery (Innominate Artery) Right Common Carotid Artery Right Subclavian Artery Left Common Carotid Artery Left Subclavian Artery  Vasculature of the Neck Arterial Anatomy 3 Branches Right Brachiocephalic Artery (Innominate Artery) Right Common Carotid Artery Right Internal Carotid Artery Right External Carotid Artery Right Subclavian Artery Left Common Carotid Artery Left Internal Carotid Artery Left External Carotid Artery Left Subclavian Artery  Vasculature of the Neck Arterial Anatomy Right Brachiocephalic Artery (Innominate Artery) Right Common Carotid Artery Right Internal Carotid Artery Right External Carotid Artery Right Subclavian Artery Right Vertebral Artery Left Common Carotid Artery Left Internal Carotid Artery Left External Carotid Artery Left Subclavian Artery Left Vertebral Artery  Vasculature of the Neck Venous Anatomy Internal Jugular Vein drains the brain…. External Jugular Vein drains the face and scalp… Into the Subclavian Vein (drains arm) Loading… IJV unites with Subclavian Vein and drains… Into the Brachiocephalic Vein (Innominate) which drains… IJV = Internal jugular vein Into the Superior Vena Cava EJV = External jugular vein RSV, LSV = Rt and Lt subclavian veins RIV, LIV = Rt and Lt innominate veins two veins both lautery SVC = Superior vena cava Innominate = & rain insameplace suc Brachiocephalic  Extracranial Cerebral Vessels Physiology Arteries Supply oxygenated blood to face, scalp, brain and upper extremity Veins Drain deoxygenated blood from face, scalp, brain and upper extremity  Extracranial Cerebral Vessels Physiology Same wall structure as arteries and veins elsewhere in the body Arteries have thicker walls, and are pulsatile carotid won't collapse Veins have thinner walls and are compressible Vein Artery 1. Adventi tia 2. Media 3. Intima  Common Carotid Artery (CCA) Medial to IJV, lateral to thyroid Supplies blood to the face, scalp and brain Through it’s terminal branches (ICA and ECA) Widens near the bifurcation with ICA Carotid Bulb Common area for plaque build-up Low resistance to blood flow S nee ( continous to brain forward flow low resistance  Internal Carotid Artery (ICA) towards brain Larger branch (80% of CCA flow) Posterior and lateral Supplies blood to the brain and retina (opthalmic art.) Lower resistance to blood flow blw both Has no branches (extracranially) Until it becomes intracranial Carotid bulb may extend into ICA origin  External Carotid Artery (ECA) Smaller branch (20% of CCA flow) Anterior and medial Supplies blood to the neck, face and scalp Higher resistance to blood flow Has multiple branches you see branche 1st is superior thyroid artery Responds to “Temporal Tap” > just above - face i scalp ear thumping artifact less diastole flow  Vertebral Artery Branch of the subclavian arteries Ascends within the transverse foramina of the C-spine vertebrae blu bone Supplies posterior aspect of brain via : common Basilar artery droport Lower resistance to blood flow  Thyroid Gland Review 2 lobes Endocrine gland Right and left Secretes hormones directly into the Isthmus (bridge) bloodstream Pyramidal lobe ( Located in anteroinferior aspect of neck Normal variant (10-40%) Straddles trachea Arises superiorly from isthmus Atrophies over time Variable size Thyroid is ~ 4-6 cm long Isthmus is ~2-6 mm /bridge ! Volume measurements may be required Rumack Fig. 19-2  Thyroid Gland Landmarks Lateral “border” Common carotid artery (CCA) Internal Jugular Vein (IJV) Medial “border” Trachea Superior “border” Thyroid cartilage Anterolateral “border” Strap muscles Sternohyoid, sternothyroid, omohyoid Sternocleidomastoid (SCM muscle) Posterior “border” Longus colli muscle  Thyroid Gland Blood Supply Highly vascular gland Paired vessels (each lobe) Arteries (Total = 4) Superior thyroid arteries 1st branch of ECA Inferior thyroid arteries Branch of subclavian artery Veins (Total = 6) Superior, middle and inferior thyroid veins  Thyroid Gland Internal Structure Follicular cells Epithelial lining Secretes colloid (contains T3 & T4 hormones) Parafollicular cells (C-cells) Scattered around follicular cells Secretes Calcitonin  Thyroid Gland Function Regulates basal metabolism Thyroid gland function is regulated by: Hypothalamus Releases TRH (Thyroid Releasing Hormone) Anterior pituitary gland Releases TSH (Thyroid Stimulating Hormone) balance homeostasis TSH Acts on thyroid to produce, secrete and store 3 hormones T3, T4 and Calcitonin  Thyroid Hormones T3 = Tri-iodothyronine (10%) T4 = Thyroxine (90%) Calcitonin Secreted by parafollicular cells (C-cells) Blood calcium levels Prevents hypercalcemia Works opposite of parathormone Secreted by parathyroid glands ↓ blood calcium levels  Parathyroid Glands Endocrine gland Usually 4 Secretes hormones directly into the bloodstream 2 superior 2 inferior Located along posterior surface of thyroid gland Round-oval lobes “Anatomic triangle” we don't Thyroid, longus colli, IJV/CCA Sel Size May be “ectopic” 5-7mm length 3-4mm width 1-2mm thickness we see only w/ abnorm.  Parathyroid Function Maintains homeostasis of blood calcium levels Secretes Parathyroid Hormone (PTH) aka parathormone ↑ blood calcium levels, preventing hypocalcemia Blood flow is via superior and inferior thyroid arteries  Salivary Glands know ! 3 groups Parotid glands Largest Along anterolateral surface of mandible Submandibular glands In submandibular space (under jawbone) Sublingual glands Under tongue, on floor of the mouth Poorly seen with ultrasound Rumack Fig 48-4, 48-5, 48-6, 48-7, 48-8) Neck and Carotid Sonography  Role of Neck Ultrasound Assess thyroid/parathyroid gland and neck Size, echogenicity and echotexture Determine presence/absence of thyroid nodules Size, number and location Determine presence/absence of parathyroid nodules Loading… Size, number and location Determine nature of nodules Solid, cystic, complex, calcifications Determine presence/absence of lymphadenopathy Size, number and location Follow-up studies Provide guidance of needle aspirations/biopsies  Neck Ultrasound Exam Details Patient Preparation Equipment None 12-15 MHz linear transducer Lower frequency (even curved) when thyroid is enlarged Patient History Thyroid medications Technical Parameters Surgical history Adjust focus, depth, gain, TGC appropriately Uniform appearance Imaging studies Color and Spectral Doppler may be necessary Patient Positioning Issues Supine Extension below clavicle Hyperextended neck Movement with swallowing Shoulders on pillow Head turned slightly Not imaging the lateral neck structures Assessment of lymph nodes  Neck Ultrasound Protocol Longitudinal Views Image both RT and LT lobes Include measurements (mid) Length and A-P May need to use extended field-of-view Image with color Doppler of entire gland 1) LG RT THYROID MID 2) LG RT THYROID MED SCAN ENTIRE 3) LG RT THYROID LAT NECK REGION!! 4) LG RT SWEEP gland MED-LAT CLIP  Neck Ultrasound Protocol Transverse Views Image both RT and LT lobes Image isthmus Include measurements (mid) Width of lobes A-P of isthmus 1) TR RT THYROID UP (SUP) 2) TR RT THYROID MID 3) TR RT THYROID LP (INF) 4) TR ISTHMUS SCAN ENTIRE 5) TR RT SWEEP gland SUP-INF CLIP* NECK REGION!! 6) TR SWEEP NECK w/ 1 rep. picture  Thyroid Gland Sonographic Appearance Homogeneous echotexture Medium- to high-level echogenicity Similar to liver, spleen and testes Thin hyperechoic capsule Rich vascularity Uniform distribution with colour Doppler May see vascular branches traversing throughout gland Anechoic tubular (LONG) or round (TR) structures that show flow with colour Doppler  LONG THYROID Rumack Fig 19-2, 19-3, 19-4, 19-5 two carotid then sweep back to thyroid Extended Field of View (FOV) TR THYROID all sweep way & out then back in TR ISTHMUS + color doppler  Neck Muscles Strap Muscles Anterolateral to thyroid Sternohyoid Sternothyroid Closest to thyroid Omohyoid strap muscle  Neck Muscles Sternocleidomastoid Largest muscle in the neck Lateral to thyroid gam  Neck Muscles Longus colli * Posterior to thyroid May be mistaken for pathology Turn on it - elongates Llongus colli  Neck Muscles Sonographic Appearance Hypoechoic to thyroid Shape depends on plane of image LONG on muscle Tubular or triangular TRANS on muscle Round or ovoid  Muscles Rumack Fig 19-2 Sternocleidomastoid Sternothyroid Longus Colli  Esophagus Location Left side (usually) Posterior to left lobe (gut Lateral to trachea Medial to vessels Sonographic Appearance Sagittal signate Tubular, echogenic layers (mucosa) Trans Target shaped Echogenic center (mucosa) Will show peristalsis (swallowing)  Lymph Nodes Routinely seen during thyroid and carotid ultrasound Benign nodes Malignant Nodes Oval Round to oval 1mm to 2 cm Long/Transverse ratio 1hr have a 97% chance of stroke Timely diagnosis is key US asap after symptoms (within 24hrs) Thromboembolytic drugs may be administered (3hr window)  Clinical Manifestations of TIAs/Strokes Hemiparesis/Hemiplegia (contralateral hemisphere) Resided affect It showing , Unilateral extremity weakness, tingling, numbness (hemiparesis) or paralysis (hemiplegia) Arm more than leg Ataxia (contralateral hemisphere) Disturbance of movement coordination dominant Aphasia/Dysphasia/Dysarthria (dominant hemisphere) It side is Inability to speak (aphasia) typical Difficulties with word finding, production, coordination or understanding (dysphasia) Inability to control muscles related to speech, slurred speech (dysarthria)  Clinical Manifestations of TIAs/Strokes Amaurosis fugax (ipsilateral opthalmic artery) Transient monocular blindness “Like a shade being pulled over the eye” Posterior circulation symptoms (Vertebro-basilar) Drop attacks/Syncope (sudden fall with loss of consciousness) Dizziness/vertigo Binocular blindness Diplopia (double vision) Miscellaneous Headaches, neck pain, death  Carotid Ultrasound Exam Details Patient Preparation Technical Parameters No specific prep Gray-scale Patient Positioning Color Doppler Supine Spectral Doppler Neck extended Pt’s head turned slightly toward Technique contralateral side Initial transverse scan May prefer to sit at patient’s head Optimize images Equipment Additional Techniques Real-time Temporal Tap Power Doppler 7-10 MHz linear array transducer  Sonographic Appearance Veins Lumen Anechoic May see occasional RBC reflectors in Compressibl No wall differentiation real-time e Walls Thin, echogenic lines No differentiation of intima, media, or adventitia IJ V Characteristics CC A Changes with respiration Collapses with compression  Sonographic Appearance Arteries Lumen hit 900 for wall Anechoic not for flow Walls Intima-Media Thickness IJ Perpendicular Incidence V Characteristics CC A Non-compressible (generally) & Pulsatile greater than 0 8. 90 Not O 90 8  Sonographic Appearance Arteries Intima-Media (IM) Thickness 2 parallel echogenic lines First = intima Second = adventitia Separated by hypoechoic region Media Best seen with perpendicular incidence Intim Measurement should be