Superior Thoracic Aperture

The superior thoracic aperture contains structures emerging from the thorax and entering the head, neck, and upper limb. In this specimen, both clavicles, key venous structures, and other musculature have been removed. Despite this, other important components of anatomy can be observed.

Key Structures

• Trachea: Seen most superiorly with a thick ring of cartilage.
• Rib One: Exposed prior to meeting its costal cartilage, traveling in a lateral to medial direction.
• Anterior Scalene Muscle: Inserting into Rib One superiorly.

Blood Supply

• Right Subclavian Artery: Seen superior to Rib One, giving off the thyrocervical trunk to supply the neck.
• Left Subclavian Artery: Also seen superior to Rib One, giving off the suprascapular artery.
• Common Carotid Arteries: Both left and right can be seen superiorly, with the left also containing a clear left vagus nerve.

Nerve Pathways

• Vagus Nerve: Travels inferiorly from the cranium, following the common carotid arteries in the carotid sheath, visible in the left common carotid artery.
• Left Phrenic Nerve: Remains unclear until it emerges in the mediastinum.
• Brachial Plexus: Components of the left brachial plexus can be seen, from roots to trunks, with numerous smaller branches moving off, including the dorsal scapular nerve.

Mediastinum

Key Structures

• Right Phrenic Nerve: Traced posteriorly to the heart, shifted from its normal anterior position during dissection.
• Left Phrenic Nerve: Still contained in its connective tissue, located anteriorly to the heart until reaching the diaphragm for innervation.
• Left Vagus Nerve: Seen posterior to the heart, easier to identify superiorly following the left common carotid artery in the carotid sheath. Note the left recurrent laryngeal nerve moving under the aorta.

Major Vessels

• Arch of Aorta: Giving branches of the brachiocephalic and left common carotid arteries superior to the heart.
• Left Subclavian Artery: Seen just posterior to the left common carotid artery.
• Pulmonary Trunk: Exiting immediately superior to the heart.
• Left Anterior Descending Artery: Observed cascading anteriorly on the heart.
• Superior Vena Cava: Seen to the right of the aorta and posterior.

Inferior Thorax

Ribs and Musculature

• Ribs 8 through 12: Visible on the specimen, with the musculature in-between these ribs also observed.
• External Intercostal Muscle: Direction inferomedially progressing into a layer of fascia.

Diaphragm

• Right Hemidiaphragm: Located more superiorly than the left hemidiaphragm due to the presence of the liver on the right side of the abdominal cavity.