The largest known T. rex skull is 1.52 meters (5 ft) in length.
Large fenestrae (openings) in the skull reduced weight, as in all carnivorous theropods.
In other respects Tyrannosaurus's skull was significantly different from those of large non-tyrannosaurid theropods.
It was extremely wide at the rear but had a narrow snout, allowing unusually good binocular vision.
The skull bones were massive and the nasals and some other bones were fused, preventing movement between them; but many were pneumatized (contained a "honeycomb" of tiny air spaces) and thus lighter.
These and other skull-strengthening features are part of the tyrannosaurid trend towards an increasingly powerful bite, which easily surpassed that of all non-tyrannosaurids.
The tip of the upper jaw was U-shaped (most non-tyrannosauroid carnivores had V-shaped upper jaws), which increased the amount of tissue and bone a tyrannosaur could rip out with one bite, although it also increased the stresses on the front teeth.

The teeth of T. rex displayed marked heterodonty (differences in shape).
The premaxillary teeth, four per side at the front of the upper jaw, were closely packed, D-shaped in cross-section, had reinforcing ridges on the rear surface, were incisiform (their tips were chisel-like blades) and curved backwards.
The D-shaped cross-section, reinforcing ridges and backwards curve reduced the risk that the teeth would snap when Tyrannosaurus bit and pulled.
The remaining teeth were robust, like "lethal bananas" rather than daggers, more widely spaced and also had reinforcing ridges.
Those in the upper jaw, twelve per side in mature individuals, were larger than their counterparts of the lower jaw, except at the rear.
The largest found so far is estimated to have been 30.5 centimeters (12 in) long including the root when the animal was alive, making it the largest tooth of any carnivorous dinosaur yet found.
The lower jaw was robust.
Its front dentary bone bore thirteen teeth.
Behind the tooth row, the lower jaw became notably taller.
The upper and lower jaws of Tyrannosaurus, like those of many dinosaurs, possessed numerous foramina, or small holes in the bone.
Various functions have been proposed for these foramina, such as a crocodile-like sensory system or evidence of extra-oral structures such as scales or potentially lips.

The vertebral column of Tyrannosaurus consisted of ten neck vertebrae, thirteen back vertebrae and five sacral vertebrae.
The number of tail vertebrae is unknown and could well have varied between individuals but probably numbered at least forty.
Sue was mounted with forty-seven of such caudal vertebrae.
The neck of T. rex formed a natural S-shaped curve like that of other theropods.
Compared to these, it was exceptionally short, deep and muscular to support the massive head.
The second vertebra, the axis, was especially short.
The remaining neck vertebrae were weakly opisthocoelous, i.e. with a convex front of the vertebral body and a concave rear.
The vertebral bodies had single pleurocoels, pneumatic depressions created by air sacs, on their sides.
The vertebral bodies of the torso were robust but with a narrow waist.
Their undersides were keeled.
The front sides were concave with a deep vertical trough.
They had large pleurocoels.
Their neural spines had very rough front and rear sides for the attachment of strong tendons.
The sacral vertebrae were fused to each other, both in their vertebral bodies and neural spines.
They were pneumatized.
They were connected to the pelvis by transverse processes and sacral ribs.
The tail was heavy and moderately long, in order to balance the massive head and torso and to provide space for massive locomotor muscles that attached to the thighbones.
The thirteenth tail vertebra formed the transition point between the deep tail base and the middle tail that was stiffened by rather long front articulation processes.
The underside of the trunk was covered by eighteen or nineteen pairs of segmented belly ribs.


The shoulder girdle was longer than the entire forelimb.
The shoulder blade had a narrow
The largest known T. rex skull is 1.52 meters (5 ft) in length. Large fenestrae (openings) in the skull reduced weight, as in all carnivorous theropods. In other respects Tyrannosaurus's skull was significantly different from those of large non-tyrannosaurid theropods. It was extremely wide at the rear but had a narrow snout, allowing unusually good binocular vision. The skull bones were massive and the nasals and some other bones were fused, preventing movement between them; but many were pneumatized (contained a "honeycomb" of tiny air spaces) and thus lighter. These and other skull-strengthening features are part of the tyrannosaurid trend towards an increasingly powerful bite, which easily surpassed that of all non-tyrannosaurids. The tip of the upper jaw was U-shaped (most non-tyrannosauroid carnivores had V-shaped upper jaws), which increased the amount of tissue and bone a tyrannosaur could rip out with one bite, although it also increased the stresses on the front teeth.
The teeth of T. rex displayed marked heterodonty (differences in shape). The premaxillary teeth, four per side at the front of the upper jaw, were closely packed, D-shaped in cross-section, had reinforcing ridges on the rear surface, were incisiform (their tips were chisel-like blades) and curved backwards. The D-shaped cross-section, reinforcing ridges and backwards curve reduced the risk that the teeth would snap when Tyrannosaurus bit and pulled. The remaining teeth were robust, like "lethal bananas" rather than daggers, more widely spaced and also had reinforcing ridges. Those in the upper jaw, twelve per side in mature individuals, were larger than their counterparts of the lower jaw, except at the rear. The largest found so far is estimated to have been 30.5 centimeters (12 in) long including the root when the animal was alive, making it the largest tooth of any carnivorous dinosaur yet found. The lower jaw was robust. Its front dentary bone bore thirteen teeth. Behind the tooth row, the lower jaw became notably taller. The upper and lower jaws of Tyrannosaurus, like those of many dinosaurs, possessed numerous foramina, or small holes in the bone. Various functions have been proposed for these foramina, such as a crocodile-like sensory system or evidence of extra-oral structures such as scales or potentially lips.
The vertebral column of Tyrannosaurus consisted of ten neck vertebrae, thirteen back vertebrae and five sacral vertebrae. The number of tail vertebrae is unknown and could well have varied between individuals but probably numbered at least forty. Sue was mounted with forty-seven of such caudal vertebrae. The neck of T. rex formed a natural S-shaped curve like that of other theropods. Compared to these, it was exceptionally short, deep and muscular to support the massive head. The second vertebra, the axis, was especially short. The remaining neck vertebrae were weakly opisthocoelous, i.e. with a convex front of the vertebral body and a concave rear. The vertebral bodies had single pleurocoels, pneumatic depressions created by air sacs, on their sides. The vertebral bodies of the torso were robust but with a narrow waist. Their undersides were keeled. The front sides were concave with a deep vertical trough. They had large pleurocoels. Their neural spines had very rough front and rear sides for the attachment of strong tendons. The sacral vertebrae were fused to each other, both in their vertebral bodies and neural spines. They were pneumatized. They were connected to the pelvis by transverse processes and sacral ribs. The tail was heavy and moderately long, in order to balance the massive head and torso and to provide space for massive locomotor muscles that attached to the thighbones. The thirteenth tail vertebra formed the transition point between the deep tail base and the middle tail that was stiffened by rather long front articulation processes. The underside of the trunk was covered by eighteen or nineteen pairs of segmented belly ribs.

The shoulder girdle was longer than the entire forelimb. The shoulder blade had a narrow
Tyrannosaurus