与人类头骨相比，霸王龙的头骨处于中空状态。这种充满窦腔结构的头部更轻，从而提高了坚固度
目前，科学家最新一项研究揭示，像霸王龙等一些凶残恐龙头部处于中空状态，里面有许多空气，这样可使恐龙头部负荷减轻，或许充当着与其他恐龙进行交流通信的“共振室”(resonating chambers)作用。
美国俄亥俄州大学研究员劳伦斯·威特默(Lawrence Witmer)说，“我们知道恐龙的大脑很小，因此曾推测它的头骨处于中空状态，目前这项最新研究证实了之前推测的真实性。”该研究结果进一步支持了威特默和同事们之前的一项研究，他们曾发现鸭嘴龙头骨中的气室部分有助于它们鼻腔发声，或许由此产生清晰的“声音”。
威特默和俄亥俄州大学同事赖安·里奇利(Ryan Ridgely)使用计算机断层摄影技术扫描了两种掠食性恐龙(霸王龙和玛君龙)的头骨，同时还对胄甲龙和包头龙这两种食草性“披甲”恐龙进行了扫描。三维扫描结果显示，较大的鼻腔区域中弯曲的通气道从鼻孔延伸至咽喉和几处窦腔，总体来讲，恐龙头骨内充满空气的区域大于脑腔。
头骨中空区域有助于减轻霸王龙头部负荷重量，这样的中空结构将比一个固体实心头骨轻18%，他们评估一颗完全是由肉质构成的霸王龙头部重量很可能超过500公斤(1100磅)，然而实际上玛君龙的头骨仅重32公斤(70磅)，如果霸王龙的头骨完全由骨质构成，其重量为数百磅。
颈部肌肉和其他身体特征仅起到将恐龙头部抬起的作用，而头骨中空结构却能有助于减轻头部重量，中空的骨骼结构将使霸王龙和玛君龙的头骨变得更加强壮，比如：这种头骨结构能够辅助口腔肌肉咬碎骨骼或撕裂大型猎物尸体。
如同空心管可使建筑物更加坚固，恐龙头骨中的窦腔结构可使头部骨骼更加坚固，而且重量更轻。拥有更轻、更坚固的头部，霸王龙等恐龙便能快速地转动头部。
威特默称，长有“披甲”的食草恐龙与众不同，它们不同于掠食性恐龙的笔直鼻腔气道，研究人员发现食草恐龙的鼻腔气道比较卷曲复杂，有点儿像弯弯曲曲的稻草麦秆。他们发现弯曲的气道在较大血管的周围，表明这起到一种热量转换作用。因此，当披甲恐龙吸入空气时，在气体进入肺部时就已被周围的血管加热。此外，由血管释放的一些热量将中和进入鼻腔的空气温度，避免空气进入头部将血液冷却。
威特默在接受美国生活科学网记者采访时说，“弯曲的鼻腔气道或许还充当着共振室的作用，影响甲龙等恐龙如何发出声音，每种恐龙的气道都可能存在着微妙的差别。”目前，这项最新研究报告发表在近期出版的《解剖学记录》（The Anatomical Record）杂志上。（生物谷Bioon.com）
生物谷推荐原始出处：
The Anatomical Record，Volume 291 Issue 11, Pages 1362 - 1388，Lawrence M. Witmer，Ryan C. Ridgely
The Paranasal Air Sinuses of Predatory and Armored Dinosaurs (Archosauria: Theropoda and Ankylosauria) and Their Contribution to Cephalic Structure
Lawrence M. Witmer *, Ryan C. Ridgely
Department of Biomedical Sciences, College of Osteopathic Medicine, Ohio University, Athens, Ohio
The paranasal air sinuses and nasal cavities were studied along with other cephalic spaces (brain cavity, paratympanic sinuses) in certain dinosaurs via CT scanning and 3D visualization to document the anatomy and examine the contribution of the sinuses to the morphological organization of the head as a whole. Two representatives each of two dinosaur clades are compared: the theropod saurischians Majungasaurus and Tyrannosaurus and the ankylosaurian ornithischians Panoplosaurus and Euoplocephalus. Their extant archosaurian outgroups, birds and crocodilians (exemplified by ostrich and alligator), display a diversity of paranasal sinuses, yet they share only a single homologous antorbital sinus, which in birds has an important subsidiary diverticulum, the suborbital sinus. Both of the theropods had a large antorbital sinus that pneumatized many of the facial and palatal bones as well as a birdlike suborbital sinus. Given that the suborbital sinus interleaves with jaw muscles, the paranasal sinuses of at least some theropods (including birds) were actively ventilated rather than being dead-air spaces. Although many ankylosaurians have been thought to have had extensive paranasal sinuses, most of the snout is instead (and surprisingly) often occupied by a highly convoluted airway. Digital segmentation, coupled with 3D visualization and analysis, allows the positions of the sinuses to be viewed in place within both the skull and the head and then measured volumetrically. These quantitative data allow the first reliable estimates of dinosaur head mass and an assessment of the potential savings in mass afforded by the sinuses.
