Osteobiography of the Alamo North Wall Cranium

David M. Glassman and D. Gentry Steele

Introduction

This report describes the morphology of the cranium excavated at the Alamo site, 41BX6, during the 1979 North Wall field season. The fragmentary
cranium is the sole human skeletal material recovered from the site during this excavation.

Skeletal Description

The recovered fragments of the 41BX6 cranium are pieced and glued to approximate normal articulation. The cranium is missing the entire region of
the face inferior to the frontal border, except for portions of the left and right nasal bones. The neurocranium (comprised of the frontal, parietal,
occipital, and temporal bones) is present although a few areas are fragmentary, particularly on the base of the skull and in the pterion (spheno-frontal)
areas. The zygomatic arches are fragmentary and consist solely of portions of the zygomatic process of the temporal bones for both the left and right
sides. Portions of the sphenoid bone are present on the cranial base and sides of the neurocranium. The left and right mastoid processes are present,
as are portions of both auditory canals. Neither the mandible nor any of the dentition is present.

The preservation of the cranium is very good. A minor degree of distortion is present and is attributable to external pressure compressing the skull
while it was buried. This pressure appears to have caused some cracking of the cranial surface, particularly in the region of the sagittal suture where a
series of cracks is found to radiate laterally. Burial pressure may also be responsible for the complex network of surface cracking on the frontal bone.
There is little or no indication of animal activity on the bones and little alteration from the infiltration of vegetation. The color of the cranial bones is a
light brown to tan, indicating little or no exposure to the sun during the interment period.

Morphological Observations

The overall appearance of the cranium is small and gracile. The metopic (medio-frontal) suture is retained on the frontal bone. This suture, which
separates the two infant frontal bones, generally becomes fused and obliterated within the first two years after birth. The retention of this suture into
adolescence or adulthood is rare, occurring in less than 10 percent of the individuals in most populations. The neurocranial sutures remain unfused
ectocranially (the outer surface of the cranium). It appears that initial endocranial fusion of the neurocranial sutures had begun, although this is
difficult to determine given the present condition of the cranial remains. The spheno-occipital synchondrosis (basilar suture) appears to have been
unfused.

General morphological characteristics of the cranium include a slight appearance of the supraorbital ridges, a blunt superior border of the eye orbit,
small to moderately sized mastoid processes with a small supra-mastoid crest on the left side only, a small to moderately sized foramen magnum with
small to moderately sized occipital condyles, and a small degree of frontal bossing. Cranial musculature indicated by the development of the areas of
muscle attachment (principally the attachment areas of the temporal and nuchal muscles) is not pronounced.