S2 Dissection Summary

S2 Dissection Summary

Part 1 - Posterior Neck

Part 2 - Vasculature

    • Cut the left brachiocephalic v. at its midpoint
        • Reflect both ends of the left brachiocephalic vein (and their tributaries) laterally to expose the arch of the aorta and its branches
    • Locate the thoracic duct at the division of the L. brachiocephalic v. into left IJV and subclavian v.
    • Expose the vicinity of the proximal portion of the L. subclavian a.
    • Locate and carefully clean the anterior scalene m.
    • Laterally reflect the R. subclavian v. from the right venous angle to reveal the:
        • anterior scalene m.
        • R. subclavian a.
        • 1st rib.
    • Detach the anterior scalene m. from the first rib and reflect superiorly
    • Identify the roots (rami) and trunks of the brachial plexus

Part 3 - Vagus n.

    • Locate the vagus n. in the carotid sheath.
    • Locate where the superior laryngeal n. branches from the vagus n.
    • Follow both vagus nn. inferiorly to the root of the neck
    • Find both recurrent laryngeal nn.

Part 4 - Expose Lamina

    • Reflect the trapezius m.
    • On each side of the spinous processes, move all of the superficial back musculature (rhomboid mm.) laterally
    • Pull and reflect the:
        • splenius mm.
        • erector spinae mm.
        • serratus posterior superior mm.
    • Remove remaining musculature from the laminae with a chisel, which will allow clean and precise cuts for the laminectomy

Part 5 - Laminectomy Procedure

    • Make two cuts per vertebra
        • Cuts should be on the lateral-most extent of the lamina before the transition to the transverse processes at an angle
    • After completing all cuts, remove the posterior wall of the vertebral column

Part 6 - Spinal Cord

    • Make a shallow midline incision using scissors through the dura mater
    • Observe the arachnoid mater
    • Observe the pia mater
    • Observe the various structures and landmarks of the spinal cord
        • The cervical enlargement
    • Transect the spinal cord, and examine the spinal cord in cross section