Superior thoracic aperture

Dr Henry Knipe ◉ ◈ et al.

The superior thoracic aperture, also known as the thoracic inlet or outlet, connects the root of the neck with the thorax.

Gross anatomy

The superior thoracic aperture is kidney-shaped and lies in an oblique transverse plane, tilted anteroinferiorly to posterosuperiorly.

Boundaries

posteriorly: T1 vertebral body and costovertebral joints
laterally: first ribs and their costal cartilages
anteriorly: superior border of the manubrium

The list of structures that pass through the superior thoracic outlet is long. Included below are the major structures:

viscera
- thymus
- trachea
- esophagus
- lung apices
vessels, nerves and lymphatics
- common carotid arteries
- subclavian arteries
- confluences of internal jugular and subclavian veins
- phrenic nerves
- vagus nerves
- recurrent laryngeal nerves
- thoracic duct
- sympathetic trunk
prevertebral fascia
muscles
- sternohyoid muscle
- sternothyroid muscle

Related pathology

thoracic outlet syndrome

Quiz questions

{"accessible":false,"alternatives":[{"id":4512,"text":"middle scalene muscle attaches to the first rib between the groove for the subclavian artery and the transverse tubercle"},{"id":4513,"text":"the first rib forms the lateral border of the superior thoracic aperture"},{"id":4514,"text":"brachial plexus travels over the first rib, posterior to the anterior scalene muscle"},{"id":4515,"text":"the first rib features a single articular facet for the costovertebral joint"},{"id":4516,"text":"scalene tubercle serves as a point of attachment for the middle scalene muscle"}],"archived":false,"correctAlternativeId":4516,"explanation":"\u003cp\u003eThe \u003ca title=\"First rib\" class=\"internal\" href=\"/articles/first-rib\"\u003efirst rib\u003c/a\u003e is \u003ca title=\"Atypical ribs\" class=\"internal\" href=\"/articles/atypical-ribs\"\u003eatypical\u003c/a\u003e in the sense that it is very short and thick, and features a single articular facet on its head for the costovertebral joint. It is an important anatomical landmark as it forms the lateral border of the \u003ca title=\"Superior thoracic aperture\" class=\"internal\" href=\"/articles/superior-thoracic-aperture\"\u003esuperior thoracic aperture\u003c/a\u003e and has a number of major structures that pass over it.\u003c/p\u003e\u003cp\u003eIts markings from anterior to posterior include:\u003c/p\u003e\u003cul\u003e\n\u003cli\u003egroove for the \u003ca title=\"Subclavian vein\" class=\"internal\" href=\"/articles/subclavian-vein\"\u003esubclavian vein\u003c/a\u003e\n\u003c/li\u003e\n\u003cli\u003escalene tubercle, serving as attachment for the \u003ca title=\"Anterior scalene muscle\" class=\"internal\" href=\"/articles/scalenus-anterior-muscle-1\"\u003eanterior scalene muscle\u003c/a\u003e (thus rendering the last option above \u003cstrong\u003eFALSE\u003c/strong\u003e)\u003c/li\u003e\n\u003cli\u003egroove for the \u003ca title=\"Subclavian artery\" class=\"internal\" href=\"/articles/subclavian-artery\"\u003esubclavian artery\u003c/a\u003e and the lowest \u003ca title=\"Brachial plexus\" class=\"internal\" href=\"/articles/brachial-plexus\"\u003ebrachial plexus\u003c/a\u003e trunk\u003c/li\u003e\n\u003cli\u003e\n\u003ca title=\"Middle scalene muscle\" class=\"internal\" href=\"/articles/scalenus-medius-muscle\"\u003emiddle scalene muscle\u003c/a\u003e attachment\u003c/li\u003e\n\u003cli\u003etransverse tubercle, which bears an articular facet for the transverse process of T1\u003c/li\u003e\n\u003c/ul\u003e\u003cp\u003e \u003c/p\u003e\u003cp\u003e\u003c/p\u003e","id":897,"imageUrl":null,"nextQuestionPath":"/questions/897/next","relatedArticles":[{"id":27102,"title":"First rib","link":"/articles/first-rib?lang=us"},{"id":24704,"title":"Brachial plexus","link":"/articles/brachial-plexus?lang=us"},{"id":12651,"title":"Scalenus anterior muscle","link":"/articles/scalenus-anterior-muscle-1?lang=us"},{"id":12652,"title":"Scalenus medius muscle","link":"/articles/scalenus-medius-muscle?lang=us"},{"id":24579,"title":"Subclavian artery","link":"/articles/subclavian-artery?lang=us"},{"id":35014,"title":"Subclavian vein","link":"/articles/subclavian-vein?lang=us"}],"stem":"\u003cp\u003eWhich of the following is \u003cstrong\u003eFALSE \u003c/strong\u003eregarding the first rib?\u003c/p\u003e","articleId":"superior-thoracic-aperture","nextQuestionId":null,"containerId":"expandableQuestionsContainer"}