<prompt> The posterior triangle of the neck is bounded by the following ExceptTrapeziusSplenius cervicisSternocleidomastoidClavicle  <response>: Posterior TriangleThe posterior triangle is a space on the side of the neck situated behind thesternocleidomastoid muscle.BoundariesAnterior: Posterior border of sternocleidomastoidPosterior :Anterior border of trapeziusInferior or base: Middle one- third of clavicleApex lies on the superior nuchal line where the trapezius And sternocleidomastoid meetRoof : Investing layerFloor: Formed by a prevertebral layer of deep cervical fascia coveringthe following muscle: a. splenius capitisb. Levator scapulae; c.Scalenus medius and occasionally scalenus posterior. 