Fig. 8. Vascular anatomy of the branchial arch arteries. (A-D) Intracardiac Indian ink injection of the left ventricle. All images are of the right side of the embryo. (A-C) E11.5 embryos. (D) Normal vessel architecture in a mutant at E9.5. I-IV, first, second, third and fourth branchial arch arteries, respectively; VI, sixth branchial arch artery. ^*A missing sixth arch artery. In C, the vessels are distended while in the control (A), the vessels have become narrow.