<prompt> Fascia over the posterior triangle is pierced by:Spinal accessory nerveSuprascapular nerveExternal jugular veinInternal jugular vein  <response>: Ans. C. External jugular veinExternal jugular veina. Posterior triangle boundariesb. In front- posterior border of sternomastoidc. Behind- Anterior border of trapeziusd. Base- Claviclee. Roof- Skin, superficial fascia, platysma and investing layer of deep cervical fasciaf. Investing layer of deep cervical fascia is pierced by branches of cervical plexus and external jugular veins 