A high-density cable of a type suitable for transmitting ultrasound signals from an ultrasonic probe to multiplexing circuitry during a medical ultrasound procedure is provided. The cable includes one or more flexible circuits arranged within a flexible sheath that surrounds and confines the flexible circuits. Each flexible circuit includes an elongate flexible substrate with oppositely-disposed surfaces and multiple conductors on at least one of these surfaces. The opposing longitudinal ends of the substrate define integral connectors for connecting with respective output connectors and/or electronic devices, such as an ultrasonic probe or multiplexing circuitry.