The anatomical record explores the remarkable interface of cartilage and the skull in a new Special Issue

Unlike people, not all body parts are equally important. We need our spleens, but can largely do without them. Portions of our intestines can be lost; parts of our liver, pancreas, thyroid, and lobes of our lungs are all needed, of course, but we can, more or less, survive while missing them. And while we have spares, an eye, ear, kidney, limb, tooth, or gonad (ouch!) can go. Even large parts of our heart can be grudgingly removed. But of all body parts, the one we can't be without, the pinnacle of all, is, well, our head! Data has shown that, for most humans, loss of the head significantly decreases the quality of life. Just ask (via a seance) Marie-Antoinette or some of Henry VIII's wives!

The scaffold for that remarkable and obviously essential region is the skull. Indeed, how this complex framework came to be evolutionarily and developmentally, and the meanderings that occur in disease and pathology, remain a topic of intense study. Many secrets to seminal patterns of animal form and function reside within the nooks and crannies that lie within. Indeed, few areas of human, comparative, evolutionary, and more recently, developmental, anatomy sensu lato, attract as much investigation as those exploring the skull.

Fascination with the skull probably first occurred when some Pliocene hominid ancestor hit some neighbor atop their head with a rock, heard a cracking sound, and stood fascinated by both the sound and oozing after-effects. In more recent, historical times, systematic exploration of the skull likely appeared with the Egyptians in preparation for mummification processes (see Elhadi et al., 2012; Laitman, 2015; Laitman & Albertine, 2015; Lindsay et al., 2015; Marquez et al., 2015). Various anatomical explorers visited the skull in the ensuing centuries, each looking at differing aspects of the extraordinary container. Vesalius himself noted observations in cranial variation in his short chapter in the Fabrica itself (Vesalius, 1543; see Hast & Garrison, 2000 for discussion) yet commented relatively little on internal structures and, interestingly, never portrayed structures such as the sinuses. Arguably, among the most intriguing of cranial “anatomists” was Leonardo da Vinci. Leonardo had an unrelenting fascination with the skull, particularly the skull base, the cornerstone of this special issue (vide infra). Leonardo's fascination derived, interestingly, not from his desire to uncover the basic anatomy and structure of the cranial base, but to identify the senso comune, “the seat of the soul,” which was a hot topic in his time and argued to reside somewhere within the cranial domain. Leonardo, never a modest soul, believed he indeed found its location, identifying it to be by the anterior part of what we now call the hypophyseal fossa (we hope you gain new reverence for this structure!) Interestingly, once he “discovered” his holy grail, Leonardo largely lost interest in the skull base and its environs (see Laitman & Smith, 2021).

A trove of anatomists and anthropologists (this sub-species flocked to the study of cranial shape, calipers in hand, arguably since the groundbreaking work of Blumenbach, 1790–1820) offers a cacophony of insights and (often misguided) theories on human structure and variation (see, e.g., Gould, 1981). The list would be a treatise onto itself. Yet as the field morphed and changed—a major interest from the 18th through mid 20th century was cranial variation, often used as a vehicle to substantiate racial hierarchical theories (see, e.g., the treatise by Morton, 1839)—focus shifted in the last decades more and more to understanding the basic biology underlying the patterning of skull shape (see review in Fostowicz-Frelik & Tseng, 2023). Underlying this was a concomitant interest in the different types of tissues forming parts of the skull.

This Special Issue focuses on the latter issues, exploring the differing types of tissues that comprise the skull, concentrating largely on the cranial base, the key scaffold for the skull itself. The Special Issue is derived from an Anatomical Record sponsored symposium, entitled “Cartilage and Craniofacial Growth” held at 2022 Annual Meeting of the American Association of Biological Anthropologists in Denver, Colorado (Smith et al., 2025, this issue). This Special Issue is Guest Edited by Timothy Smith from the Department of Health and Rehabilitation Sciences of Slippery Rock University in Pennsylvania and Valerie DeLeon from the Department of Anthropology of the University of Gainsville in Florida (see Figure 1).

The Guest Editors are veterans of publishing in our journal and we pat them on their collective skulls for coming back. A few words of thanks for them are in order. Drs. Smith and DeLeon—Valerie and Tim to us as they are close members of our Anatomical Record family and formalities seem odd—are now senior scientists in their fields and well-known frequent flyers in our journal (for co-author JL seeing these folks as more “senior” scientists makes his sutures close even faster as he has known them since they were students!). First to Valerie, who is a world expert on cranial anatomy, development, and histology, particularly in primates, and has published her research on such many times in our journal (e.g., Organ et al., 2010; DeLeon & Smith, 2014, 2025; Lindsay et al., 2015; DeLeon et al., 2016; Smith et al., 2013, 2016, 2017; Selba et al., 2020). We have to be extra-nice to her as she is also a mainstay of The Anatomical Record's parent body, The American Association for Anatomy, being its Past-President (and who, in that role, was a transformative leader helping open opportunities in our association for many groups not tradionally involved in the anatomical sciences; bravo Valerie!) Valerie's also a lawyer so we tread carefully.

Next to Dr. Smith, Tim is at once one of our most energetic and productive Associate Editors for our journal and arguably a, if not the, leading comparative primate histologist in the world (his humble nature will make him wince at such praise but too bad; its our editorial, and, besides, its true!). He has published scores of papers in our journal, making it the home base for reporting his innovative investigations on developmental aspects of comparative cranial growth, with a special focus upon the morphing and changing of tissues within that most remarkable of superstructures. Beyond his own prodigious science, Dr. Smith has been an energizer-primate in creating and spearheading a number of our most creative Special Issues, including: on primate special senses (Dominy et al., 2004; Laitman, 2004); new approaches in primate functional anatomy and biomechanics (Organ et al., 2010; Laitman & Albertine, 2010); the evolution, development, and comparative anatomy of the vertebrate nose (Laitman, 2014; Laitman & Albertine, 2014; van Valkenburgh et al., 2014); two extraordinary volumes charting “extreme” anatomy among species (Laitman & Albertine, 2020a, 2020b; Smith & Laitman, 2020a, 2020b); the history and intricacies, and anatomy, of the dog-human interface (Laitman & Albertine, 2021; Smith & van Valenburg, 2021); and the ecological morphology and sensory biology of bats (Smith et al., 2023; Smith 2023; Laitman & Smith, 2023). Beyond all this, Tim is an extraordinary artist and has produced many beautiful covers for his Special Issues. Apparently, he also cooks, cleans, is adored by his spouse and kids, and even takes care of homeless dogs. If he were not such a nice guy, one could really learn to hate him!

Combining their energies, this duo of chondro/craniophiles has enlisted a matrix of like-minded scientists to address many questions regarding the complex relationship of cartilage to craniofacial development. Indeed, our collective understanding of cartilage beyond its established importance as the basis of endochondral cranial components is growing daily. With new data from a myriad of species including teleosts, birds, turtles, mice, bats, boars, and humans using a variety of comparative anatomical, histological, cell biological, and genetic approaches, these studies are exposing the many facets of cartilage interactions within the cranio-facial world. This issue, so to speak, puts a new microscope to seeing the world of cartilage, well beyond our present understanding.

“Reality is inside the skull,” as George Orwell wrote in his novel Nineteen Eighty-Four (Orwell, 1949) While the character saying this in Orwell's dystopian novel was speaking more of the powers of the mind, the utterance has more insight than even Orwell could have imagined. Indeed, many secrets to the basis of vertebrate structure lie within the directions given to developmental tissues of the skull and their end products. And much of this can be found within the remarkable universe of cartilage, the forces that direct their growth and diversification, and how this, in turn, affects their environment. Uncovering the mysteries of cartilage will open many windows onto our world. Sit back and enjoy the cutting edge science on cartilage and the skull that we are proud to offer in this month's Special Issue. It may help uncover new realities that lie inside the skull.

Jeffrey T. Laitman: Conceptualization; writing – original draft; writing – review and editing. Heather F. Smith: Writing – original draft; writing – review and editing.