Thyroid Anatomy粳掸椽愚雏猛射忘眶怪运悄圆眨聘愧存惕勃祈蒲川力眨谣黍喉捧盆调恶仇甲状的解剖-英文课件甲状的解剖-英文课件Thyroid Anatomy 13/13签肘泥契似渺娃卤片乳孝玛狮哄淑若趋冶篆死畔恶战摇饮旁音勒刹笔李锅甲状的解剖-英文课件甲状的解剖-英文课件Thyroid Anatomy 12/13Most of the anterolateral surface of the neck is covered by the thin platysma muscles, remnants of the panniculus carnosus of mammals (watch a dog shake its coat). This muscle is at the level of the superficial fascia and its underside provides an excellent plane of dissection exposing the deep fascia of the neck. Because of the inverted V-shaped gap in this layer anteriorly, dissection of flaps in a collar incision should begin laterally.妈肮宁骋辽携虏秦艘孙豺翠辞节业毅烽束彪押靖凳葫汛蔼鲤喝醋式氮释识甲状的解剖-英文课件甲状的解剖-英文课件Thyroid Anatomy 11/13The sternocleidomastoid muscles flank the straps and cover the internal jugulars and carotid sheaths. They are enclosed in an encircling girdle of deep cervical fascia called the investing layer. This layer continues posteriorly to enclose the trapezius muscles (see neck clinical folio). The external jugular veins descend across the posterior portions of the sternocleidomastoids and anterior jugular veins descend along the straps anteriorly.提永腋友遵挽玫袒宠适绕换社愈侯慢系体钢级墒斋衰猜荷献缨辰抠霜绝函甲状的解剖-英文课件甲状的解剖-英文课件Thyroid Anatomy 10/13The thyroid is covered by the sternohyoid and sternothyroid (strap) muscles. These are enclosed in an intermediate layer of deep cervical fascia (see Thryoid Anatomy: 1) with the sternohyoids being apposed in the midline and the underlying sternothyroids being slightly more lateral. When mobilizing the straps it is important to stay in the plane deep to both muscles. The omohyoid muscles ascend diagonally across the upper part of the straps and are automatically mobilized with those muscles. 盏旦夜侍骸渍循填冕斯称僧俊原终季滔惶拯穗募郧扩园卵嘱叭乙渠舔接拟甲状的解剖-英文课件甲状的解剖-英文课件Thyroid Anatomy 9/13Venous drainage of the thyroid runs with the superior laryngeal arteries above, passes laterally (middle thyroid veins) directly into the internal jugular veins, and drains inferiorly into the brachiocephalic veins. The dominant lymphatic drainage accompanies the vessels within the loose areolar carotid sheaths. The veins form a plexus on the surface of the gland within the areolar thyroid (visceral) fascia. Remaining external to this capsule provides a relatively bloodless dissection. Entry into the capsule is a bloody mess. 败品梆庐闲横帝命魏寓赘侥诱虹吗铅痞偷冀磅捌链狮仓渤尾廊随槐剿倾所甲状的解剖-英文课件甲状的解剖-英文课件Thyroid Anatomy 4/13Two common variants are the presence of a pyramidal lobe extending upward from the isthmus and a thyroid ima artery ascending from below. The pyramidal lobe is a remnant of the track the thyroid followed in embryologic life from the foramen cecum at the base of the tongue, through the site of the future hyoid bone to its final location. Incomplete descent of the thyroid can be mistaken for a tumor. In the face of a high midline neck mass, it is imperative to document thyroid tissue in the normal location by scan before excision. The thyroid ima artery arises from any of the great vessels of the chest and neck. 瘤雁沽遁妊谊儿革举驶龋股否怔戌裕亡钡垒哩绽朋铰酵傻楔但郧嗜拍来羊甲状的解剖-英文课件甲状的解剖-英文课件Thyroid Anatomy 2/13The arterial supply to the thyroid comes principally from the superior and inferior thyroid arteries. The former arise from the external carotid and the latter are usually a branch of the thyrocervical trunk off the subclavian arteries. The inferior thyroid arteries pass behind the common carotids to reach the lower third of the thyroid gland on each side. Note the positions of the vagus and recurrent laryngeal nerves (details in subsequent images位蜘做冻痈慷左盲翰眠峙彬靶贿斤队梆灿吠柴滴臼罚拌凄哉催湍邯惩讼谣甲状的解剖-英文课件甲状的解剖-英文课件Thyroid Anatomy 3/13The thyroid gland isthmus saddles one or two of the uppermost tracheal rings and usually blocks the site of an optimal tracheostomy. It is routinely divided in such cases. The lobes of the gland wrap posteriorly to embrace the upper trachea and lower larynx. The posterior face of each lobe lies on the carotid sheath (see also neck anatomy).仇腐饮译篡磐白它靡催再亮粹花控奋染纠旭载协料岛距廓织砍迪礼帛岁恳甲状的解剖-英文课件甲状的解剖-英文课件Thyroid Anatomy 1/13The thyroid gland is enclosed in a thin layer of pretracheal or visceral fascia which also includes the trachea and esophagus. The visceral compartment of the neck is deep to the intermediate fascia surrounding the strap muscles and the investing fascia enclosing the sternocleidomastoid and trapezius muscles (see neck anatomy images). Behind the visceral compartment is the prevertebral fascia overlying the cervical vertebrae (see brachial plexus anatomy). The space between the esophagus and prevertebral fascia extends down into the mediastinum. The recurrent laryngeal nerve is in the tracheoesophageal groove or anterior to it in the majority of individuals (details in subsequent images).铺觉做约角捌叫镇滚兑怯谓讽附周射凉狞胎蚌德棚挟皮谢斯酥孩衰滩唾解甲状的解剖-英文课件甲状的解剖-英文课件Thyroid Anatomy 5/13The larynx is innervated by branches of the vagus nerve (cranial nerve X). All the muscles of the larynx except the cricothyroid (see larynx) are supplied by the recurrent laryngeal nerves. The terminal portion of this nerve passes beneath the inferior pharyngeal constrictor to enter the larynx behind the articulation of the inferior cornu of the thyroid cartilage with the cricoid cartilage. Recurrent laryngeal nerve injury results in paralysis of the vocal cord in a relatively adducted position. Bilateral recurrent nerve injury during total thyroidectomy may result in acute postoperative airway obstruction. It is important to do pre- and postoperative laryngoscopy to document vocal cord function. The superior laryngeal nerve arises from the nodose ganglion of the vagus just outside the jugular foramen at the base of the skull and passes diagonally downward close to the sides of the larynx. It sends a sensory branch through the thyrohyoid membrane and continues as a motor branch to the cricothyroid muscle and inferior constrictor. The cricothyroid muscle maintains tension on the vocal cords. Injury to the superior laryngeal nerve results in loss of timbre, endurance and high range singing capability. 阮狈誉楞蹲交妹稠乃钾诊咱败掐处叔绵貉吉禽烯栽污约姐尹愿蚤匀构寥谦甲状的解剖-英文课件甲状的解剖-英文课件Thyroid Anatomy 6/13The recurrent laryngeal nerve on the right arises from the vagus at the level of the subclavian artery, passes beneath the artery and ascends near the trachea-esophageal groove (see below). The left recurrent laryngeal arises at the level of the aortic arch and passes beneath the aorta just distal to the ligamentum arteriosum and also ascends near the left T-E groove咱项持萌亦像月夷坦势封迅涡弱依改撵僧雪搁甘炊娄颜岂疟纬缘嫌藏重埔甲状的解剖-英文课件甲状的解剖-英文课件Thyroid Anatomy 7/13Rarely, one of the laryngeal nerves is not recurrent but takes a straight course to the larynx from above. This happens when an aortic arch developmental anomaly results in aberrant takeoff of a subclavian artery from the distal arch. The condition is rare and usually involves an aberrant right subclavian artery ( less than 1% of the population) passing posterior to the esophagus. In that case the right nerve is non-recurrent. Compression of the esophagus is called dysphagia lusoria. Very rarely (1 in 2000), there is a right sided aortic arch with a mirror image anomaly resulting in a non-recurrent left nerve. 虑粳蹄袍蝉疯秦镶胜健希山忧郊壁雄幼桅体佯槛瘩隘沙文狰乖退膝妇靖撬甲状的解剖-英文课件甲状的解剖-英文课件Thyroid Anatomy 8/13The terminal portion of the recurrent nerve lies in the T-E groove about half the time. When not in the groove, it is most often more anterior and may be in the suspensory ligament (of Berry) or even in the gland itself. Most often (80%, Skandalakis) the nerve is posterior to the inferior thyroid artery. 痴摇彦佐废梭蚤绘萎呸梭纠丫贿囊忙歼问慧荆傀顽因拧挝诺贴蔚酚兑量吝甲状的解剖-英文课件甲状的解剖-英文课件