The Mastiff is a large, massive, symmetrical dog with a well-knit frame. The impression is one of grandeur and dignity. Dogs are more massive throughout. Bitches should not be faulted for being somewhat smaller in all dimensions while maintaining a proportionally powerful structure. A good evaluation considers positive qualities of type and soundness with equal weight.
In general outline giving a massive appearance when viewed from any angle. Breadth greatly desired. Eyes set wide apart, medium in size, never too prominent. Expression alert but kindly. Color of eyes brown, the darker the better, and showing no haw. Light eyes or a predatory expression is undesirable. Ears small in proportion to the skull, V-shaped, rounded at the tips. Leather moderately thin, set widely apart at the highest points on the sides of the skull continuing the outline across the summit. They should lie close to the cheeks when in repose. Ears dark in color, the blacker the better, conforming to the color of the muzzle.
Neck, Topline, Body
Neck powerful, very muscular, slightly arched, and of medium length. The neck gradually increases in circumference as it approaches the shoulder. Neck moderately "dry" (not showing an excess of loose skin). Topline - In profile the topline should be straight, level, and firm, not swaybacked, roached, or dropping off sharply behind the high point of the rump. Chest wide, deep, rounded, and well let down between the forelegs, extending at least to the elbow. Forechest should be deep and well defined with the breastbone extending in front of the foremost point of the shoulders. Ribs well rounded. False ribs deep and well set back. Underline - There should be a reasonable, but not exaggerated, tuck-up. Back muscular, powerful, and straight. When viewed from the rear, there should be a slight rounding over the rump. Loins wide and muscular.
Shoulders moderately sloping, powerful and muscular, with no tendency to looseness. Degree of front angulation to match correct rear angulation. Legs straight, strong and set wide apart, heavy boned. Elbows parallel to body. Pasterns strong and bent only slightly. Feet large, round, and compact with well arched toes. Black nails preferred.
Hindquarters broad, wide and muscular. Second thighs well developed, leading to a strong hock joint. Stifle joint is moderately angulated matching the front. Rear legs are wide apart and parallel when viewed from the rear. When the portion of the leg below the hock is correctly "set back" and stands perpendicular to the ground, a plumb line dropped from the rearmost point of the hindquarters will pass in front of the foot. This rules out straight hocks, and since stifle angulation varies with hock angulation, it also rules out insufficiently angulated stifles. Fault - Straight stifles.
Outer coat straight, coarse, and of moderately short length. Undercoat dense, short, and close lying. Coat should not be so long as to produce "fringe" on the belly, tail, or hind legs. Fault Long or wavy coat.