Final answer:
The muscles innervated by the posterior interosseous (radial) nerve include the abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, and the extensor indicis.
Step-by-step explanation:
The muscles innervated by the posterior interosseous (radial) nerve include the abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, and the extensor indicis.