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Deep dissection of the neck 2017 spring Outline • Prevertebral muscles - Anterior vertebral muscles - Lateral vertebral muscles • Root of neck • Viscera of neck: - thyroid gland - parathyroid gland Anterior Prevertebral muscles: Flex head & neck - Anterior vertebral muscles - Lateral vertebral muscles Separated by the Neurovascular plane Longus coli Ant. Scalene m. Middle Scalene m. Levator scapula m. Anterior vertebral muscles Lie posterior to retropharyngeal space 1. Longus colli 2. Longus capitis 3. Anterior scalene 4 C1 Longus capitis 2 Longus colli Transverse process C3-6 1st rib 4. Rectus capitis anterior C3 Ant. scalene 1 Weak flexor of c- spine C5 3 3 # T3 1st rib Innervation (N): Cervical spinal nerves 1 * * Anterior scalene Transverse process C3-6 1st rib Lateral vertebral muscles Floor of the posterior cervical region 1. Rectus capitalis lateralis 2. Middle scalene 3. Posterior scalene 4. Levator scapularis 5. Splenius capitalis 5 SCM 4 3 Trapezius 2 1 5 Levator scapulae Transverse processes, C2-C6 medial border of scapula Elevate the scapula; Downward rotation of scapula Dorsal scapular nerve (C5), spinal nerves C3,C4 Splenius capitis Levator scapulae Splenius capitis Lat.1/3 of sup. nuchal line, lat. mastoid processnuchal lig., T1-6 spinous proc. Splenius capitis Laterally flexes and rotates head/ neck Root of the neck • Junction area : the thorax and the neck • On the cervical side of superior thoracic aperture • Neurovascular elements and visceral structures Cervical axillary canal T1 Superior thoracic aperture M Superior thoracic aperture : manubrium- 1st rib- T1 Anterior scalene muscle: the landmark Veins at the root Internal jugular vein subclavian vein subclavian v. Brachiocephalic vein (innominate vein) Veins at the root Subclavian vein •Venous angle (*) : thoracic duct (left), lymphatic trunk (right) * * Ant. scalene ms. 1st rib Brachiocephalic vein Arteries at the root Subclavian artery 1. • • • First part Vertebral a. Internal thoracic a. Thyrocervical trunk 2. Second part • Behind ant. Scalene • Costocervical trunk (1 -2 st nd intercostal spaces; deep cervical muscles) 3. Third part • Dorsal scapular a. (arterial anastomosis of the scapula) 12 Thyrocervical trunk Subclavian a. Internal thoracic a. Vertebral artery Cervical part • Between scalene and longus m. • F. transversaria, C1-C6 Vertebral part Suboccipital part Post. Arch of atlas Cranial part Join basilar a. www.chiro.org/LINKS/stroke.shtml Thyrocervical trunk •IT: Inferior thyroid a. •TC: transverse cervical a. MS AS •SS: supra-scapular a. Ascending cervical a. I.T T.C S.S Scapular arcade (Right side, posterior view) Suprascapular a. Suprascapular a. Dorsal scapular a. Circumflex scapular a. Nerves in root of neck Vagus nerve; phrenic nerve; sympathetic trunk Vagus nerve • Jugular foramen; carotid sheath • Right vagus nerve right - Anterior to subclavian a. • Left vagus nerve - between common carotid a. and subclavian a. NG: nodose ganglion Recurrent laryngeal nerves Three cervical branches of vagus mid. constrictor 1. pharyngeal br. (p) – mid. constrictor 2. Sup. laryngeal nerve(sl) • internal branch – mucous membrane above vocal fold • external branch – cricothyroid m. & inf. Constrictor 3. recurrent laryngeal n. (rl) - right ->loop subclavian a.; - left-> loop arch of aorta - posteromedial aspect of thyroid - mucous memb. below vocal fold 18 - all intrinsic m. (except: cricothyroid) Actions of intrinsic muscles of larynx Cricothyroid muscle Cervical sympathetic trunk •on prevertebral fascia, anterolateral to vertebral column •Include 3 sympathetic ganglia Superior cervical ganglion: at level of C1 & C2 vertebrae Larger, landmark Middle cervical ganglion: at anterior aspect of inf. thyroid a. (C6) Superior cervical sympathertic ggl. Inferior: (at transverse proc.,C7) 80% fuses with 1st thoracic gang. Cervicothoracic ganglion (stellate ganglion) Cardiac/peri-arterial plexus Stellate ganglion 21 Thyroid gland • • • • Deep to sternohyoid & sternothyroid muscles. Lie on cricoid cartilage and superior trachea ring Two lateral lobes, connected by isthmus Pyramidal lobe (50%): inferior end of thyroglossal duct Hyoid Thyrohyoid membrane Cricoid cartilage Thyroid cartilage Trachea Thyroid gland • attach to cricoid cartilage & superior tracheal rings • Move as one with the larynx and trachea Hyoid bone 後 前 Thyroid cartilage CC: Cricoid cartilage TS: thyroid sheath = pretracheal fascia TCA: thyroid capsule Venous drainage of the thyroid gland • Superior thyroid veins (2) internal jugular v. • Middle thyroid veins (2) internal jugular v. Superior thyroid artery and vein Middle thyroid vein • Inferior thyroid veins (2) Brachiocephalic vein Inferior thyroid vein Arterial supply -Superior thyroid artery 1st branch of external carotid a. Sup. thyroid v. accompanied -Inferior thyroid artery branch of thyrocervical trunk posterior to carotid sheath recurrent laryngeal nerve ITA Right side (左前 右後) Right side Thyroid ima artery ~10% of people small, unpaired; from brachiocephalic trunk(or other) Pyramidal lobe ~50% of thyroid glands have a pyramidal lobe 27 Nerves of thyroid gland Cervical sympathetic ganglia peri-arterial plexuses vasomotor: constriction of blood vessels 28 Parathyroid gland •Small, oval glands •Usually “4” •superior and inferior parathyroid •external to fibrous thyroid capsule •medial half of posterior surface Locate the parathyroid glands: -point of entry: thyroid arteries Posterior view Parathyroid glands • could be anywhere • from the pharynx to the superior mediastinum Sites & frequency of aberrant parathyroid glandular tissue. 30 Discovery of the parathyroid gland: The glands of Owen Hunterian Museum, Royal College of Surgeons, London Arterial supply - Inferior thyroid artery Venous drainage -thyroid plexus of veins Superior parathyroid gland Inferior thyroid a. Inferior parathyroid gland 32 Lymphatic system of the neck • Superficial lymph nodes • Deep lymph nodes Level Lymph nodes (L.N) Drainage region I Submental, submandibular Face II,III,IV Lateral jugular group Laryngo-tracheal-thyroidal; nuchal V Posterior triangle Nuchal VI Anterior triangle Laryngo-tracheal-thyroidal Lymphatic drainage of the thyroid gland Lymphatic vessels in interlobular connective tissue prepharyngeal, pretracheal, & paratracheal lymph nodes superior & inferior deep cervical lymph nodes 34