Advanced Anatomy of the Neck

Transcription

1 AACE 2018 Advanced Anatomy of the Neck Alex Tessnow, MD, MBA, FACE, ECNU University of Texas Southwestern Dallas, TX Content contributed by: H. Jack Baskin, Daniel Duick, Diana Dean, Robert A. Levine, Mark Lupo, Dev Abraham, John Abele,

2 Thyroid Term derived from Greek word, Thureos, an ancient oblong shield German = Shilddruesse Shield Gland

3 Neck Anatomy Wharton 1656: purpose is to beautify the neck particularly in females to whom for this reason a larger gland.. Deposition Van der Weyden c. 1435

4 Neck Anatomy Derived from endodermal tissue at base of tongue 1 st gland to develop day 24 Embryonal remnants form Thyroglossal duct; pyramidal lobe; lingual thyroid Fuse with C-cells (neural crest origin) C-cells scattered through posterior/superior lobes

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6 Thyroid Anatomy Largest endocrine gland (~20 g) Fills the tracheoesophageal space Overlies RLN bilaterally

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10 Sternocleidomastoid muscle trachea Isthmus Sternohyoid muscle Sternothyroid muscle Omohyoid muscle Internal jugular vein Carotid artery esophagus Parathyroid gland

11 Normal Thyroid Composite View Strap SCM IJ CA R Lobe Trach L Lobe LCM Esoph

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13 Transverse View High Neck

14 Transverse View Mid Neck

15 Transverse View Low Neck STM SHM SCM I RL T LL IJV CA CA

16 Diagnostic Ultrasound Images (13 minimum): Right Trans Inferior Right Trans Mid* Right Trans Superior Right Sag Lateral Right Sag Mid* Right Sag Medial Left Trans Inferior Left Trans Mid* Left Trans Superior Left Sag Lateral Left Sag Mid* Left Sag Medial Isthmus* * = measurements made here

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18 Normal Thyroid R Transverse Superior Mid Inferior

19 Normal Thyroid L Transverse Superior Mid Inferior

20 Left Medial Sagittal View Note tangential image of esophagus

21 Normal Thyroid L Sagittal Lateral Mid Medial

22 Appearance of the Esophagus (post thyroidectomy)

23 ISTHMUS

24 Pyramidal Lobe

25 Measurement of Thyroid Width and Depth

26 Measurement of Thyroid Length (sagittal / longitudinal) Volume = p/6(lxdxw)

27 Thyroid Echogenicity Normal thyroid: High intensity homogeneous echo pattern with little identifiable internal architecture Muscles located anteriorly and anterolaterally are less echogenic

28 Thyroid Echogenicity Normal thyroid (longitudinal view) Note bright homogeneous echotexture Hashimoto s thyroiditis Note heterogeneous (hypoechoic) echotexture

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31 Surgical Levels of the Neck

32 Central Neck (levels I and VI) Level I: from mandible to hyoid, to lateral edge of posterior belly of digastrics/submandibular gland Level VI: Hyoid to Sternum between the carotids Most common location for thyroid cancer recurrence Contains thyroid/bed, cricoid and thyroid cartilages

33 Lateral Neck: II,III, IV, V Level II Skull base (superior) to Hyoid (inferior) Posterior digastric (anterior), lateral edge of SCM (posterior) Can use carotid bifurcation to approximate level of hyoid

34 Level III Medial edge of carotid (medial), Lateral edge of SCM (Lateral) Hyoid (superior) to cricoid (inferior) Includes mid-portion SCM Can use omohyoid crossing the carotid to approximate cricoid cartilage

35 Level IV Medial edge of carotid (medial), Lateral edge of SCM (Lateral) Cricoid (superior) to clavicle (inferior) Includes inferior portion of SCM Level V Lateral edge of SCM to Trapezius Posterior triangle Inferior border is clavicle

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39 Characteristics of Benign Nodes Flattened or oval shape (AP/T <0.5) Echogenic (hilar) line Hilar vascular flow on Doppler Size varies with compartment and is less important than morphology.

40 Normal Lymph Nodes

41 Typical location of Parathyroid Glands

42 Summary Ultrasound is an anatomic imaging tool, whose utility requires a thorough understanding of neck anatomy Think of structures in relationship to one another to help you understand the three dimensional picture Diagnostic ultrasound of the thyroid requires 13 images at a minimum Memorize the borders of the surgical levels of the neck. Your surgeon will thank you!