The trapezius muscle flap is a versatile reconstructive option for defects of the head and neck. It has a complex and variable vascular supply. It is described as a type II flap in the Mathes-Nahai classification – having one dominant and several minor pedicles. This literature review sought to clarify the documented variations in the blood supply to trapezius, and implications on clinical applications of the flap. The aim was to determine whether the current Mathes-Nahai classification remains an accurate representation of its reconstructive value. A literature search was conducted using biomedical databases for cadaveric and clinical case series specifically investigating the trapezius muscle flap, and examples of whole and segmental use. Vascular dominance had a variable origin from its main feeding vessel, the transverse cervical artery, and nomenclature was inconsistent between its major branches. Furthermore, there is both anatomical and clinical evidence that the muscle has a viable segmental supply, which is infrequently cited or utilised. Anatomical uncertainty and lack of clarity surrounding segmental use of the trapezius flap appears to limit its clinical application. Hence, clarification of evidence supporting its reclassification as a Mathes-Nahai type V flap, with both a major pedicle and segmental supply, may assist in popularising the diversity of its use.