The Apso skull is modified from the wolf type of 1:1 (cranium to muzzle) to a mildly brachycephalic 2:1. However it is important for survival that the foreface be no less than 1/3 of the total head length.  A very short nose is accompanied by breathing problems resulting from redundant palates, narrowed nasal cavities, and the increased mucus production needed to offset the increased tendency to dry out.  The 1901 standard mentions a large, prominent nose, which the 1935 standard has dropped entirely.  The Apso needs a big nose with large nostrils to take in large volumes of air to compensate for the low oxygen levels at high altitude.  As evidenced in the later standard, 35 years in the West, and this important survival feature seems to have waned in importance. The fact remains that a small, too short, or pinched nose would be lethal at high altitude.

The straight fore face is of utmost importance, as it provides the most efficient air passages - a most important feature at Himalayan altitudes.  There is a tendency toward "down-face" and it's opposite, the "dish face"  seen in many Western Apsos today.  Both not only spoil the typical expression, but are unhealthy at altitude.  Not mentioned in either standard is the need to avoid extreme snipiness, as seen on some Lhasas today. Besides the unpleasant expression and bad dentition that a very narrowed muzzle creates, narrowing of the airway is a handicap to easy breathing at high altitude. Missing or crowded incisors are an indicator of insufficient width of muzzle. Jaws which can hold a full complement of strong well-spaced teeth generally have sufficient bone to house an adequate airway.

In England and on the Continent, much is made of "chin" as an essential component of Apso expression. I find considerable evidence to contradict this view. With a correct level or slightly undershot mouth, a visible chin is only seen in those animals with small, upturned noses and short upper lips. Not only is an adequate nose necessary for survival, but in all early descriptions of the Lhasa, a pointed or prominent nose leather is mentioned. If a Lhasa has the necessary large nose leather and large open nostrils, that nose will "overhang" the lower lip to some degree, making the "chin" relatively inapparent even with a fairly undershot bite. If the nose leather is right, the only way to have a prominent chin is to have a massively undershot or turned up jaw, like a bulldog. The small upturned nose with a short upper lip is a Chinese feature, not seen in Tibetan dogs, but characteristic of the Chin, Pug, Pekinese, and ShihTzu. The Lhasa has a largish nose leather, and a level jaw, in which the teeth may be level or slightly undershot. This confers a blunt finish to the muzzle, but the Apso does not display a prominent "chin" unless his bite or his nose is unsound.

There is another feature of the head, not mentioned in the standard, which is important to the Tibetan Lhasa. The Lhasa has a prominent malar bone which brings the eye into a more frontal position than on most dogs, and protects the eyes from dust, injury, cold and desiccation. This bone supports the outer half of the eye, and imparts an almond shape to the eye. Without this rather prominent bone placed just beneath and behind the eye, the eyelids lack support and tend to fall away from the eyeball, making the eye rounded and more protuberant, thus exposing it to injury and drying. This frontal eye placement is a feature of the heads of all four Tibetan breeds, and has a lot to do with the uniquely "Tibetan" expression they share. (Frontal eye placement also contributes to good binocular vision, necessary in a mountain watchdog.) This malar bone is a facial bone, which adds slightly to the width of the head at the level of the eye, and should not be confused with the skull, (the cranium) which is narrow, nor with the zygomatic arch. The zygomatic arch is a ring of bone, well behind the eye, which allows the muscles of chewing to pass from the lower jaw to a broad attachment on the cranium. In the Lhasa this arch is well developed, and constitutes the widest dimension of the head.

It has been argued that the head "doesn't matter on a Lhasa because it is not a head breed". This argument is a transparent bid for acceptance of poor type. In fact, the standard spends about one third of its words describing the head. Moreover, many aspects of the correct head are essential to survival in the environment of origin, and as such, are the very basis of type in this breed. Judges should be aware of this and try not to award top honors to an animal with a really atypical headpiece.

Here is a composite photo of 4 Apso heads representing the authentic Tibetan type.  They are from widely diverse places and times and yet are remarkably similar - almost identical - in type.  1. is a photo taken in Nepal in the early 1990's.  2. is a gift from the Regent of the Dalai Lama in the early 1940's.  3. is a dog bred in North America in the late 1990's.  4. is a photo taken in Bhutan,  mid 1990's.  Despite the marked similarities of these 4 dogs, 3 from the Himalayas, 1 from USA, you will find that most of the Apsos presently being shown in North America and Europe do not closely resemble these.  There has been a continuous drift away from the original type over the years, until the majority of the breed today has lost the authentic "look" of the original Apso....

The "Illustrated Guide to the Standard" that ALAC uses to instruct judges contains some serious errors in its section on the apso head, especially in it's explanation of the phrase "falling away behind the eyes in a marked degree".  Here is what noted authority Fances Sefton says on the subject:

This rather clearly indicates that the phrase "skull narrow, falling away behind the eyes in a marked degree, not quite flat, but not domed or apple shaped" is referring to the contour of the top of the skull,  as the context of the sentence would also suggest.  Here is a photo of a cut down apso that illustrates the contours described: