Estimation of age plays an integral part in a person’s biological profile employed by forensic anthropologists for the identification of the deceased individual. Age estimation is important especially when the body is in a decomposed state, mutilated, fragmented or skeletonized state.
One of the most important parts of the human body is the skull which holds the answers to the primary question of any investigation and identification procedure. It helps to identify gender, race, stature, and estimate the age of the deceased individual.
Estimation of age from the skull can be done by studying the closure of the fontanelle, fusion of bone, suture closure, secondary changes of the skull, and the oldest technique to estimate age was using cranial suture closures. Sutures are a type of fibrous joint found in between the various bones of the skull. Skull bones are united by sutures and the union begins endocranially and proceeds ectocranially.
There are mainly three types of sutures:
- Vault sutures which include sagittal, coronal, and lambdoid sutures
- Circummeatal sutures include sphenotemporal, parietomastoid, Masto-occipital, and squamous sutures.
- The basal suture is the spheno-occipital.
The age is estimated by looking at the stage of fusion/closure of the skull sutures.
Pattern of Closure
- Sagittal sutures fuse from front to back
- Lambdoid suture fuse from medial to lateral ends
- Coronal suture unites from medial to the lateral end
The most successful estimate is done from sagittal suture, next lambdoid suture, and then coronal suture. According to Krogman, vault sutures fuses between the age of 17 to 50 years and circumneutral suture closes after the age of 50.
A study conducted by Yadav and Suri in the year 1971 on 200 skulls, concluded that the union at the junction of basisphenoid and basioccipital occurs at the age of 18 years in Male and between 17-18 in females and the obliteration is completed by the age of 23 in males and 22-23 in females.
Estimation of Age from Fusion of Skull Suture
In females, the closure of the cranial sutures is 1-2 years later than in males. Studies also suggest that ectocranial fusion is less significant than endocranial fusion.
| Cranial Sutures | Age of Closure |
|---|---|
| Metopic suture | 3-5 years |
| Sagittal | 25-30 years |
| Coronal | 30-35 years |
| lambdoid | 35-40 years |
| Spheno-temporal | 45-60 years |
| Parieto-mastoid | 80-90 years |
| Masto-occipital | 80-90 years |
| squamous | Above 80 years |
| Basal suture | 18-20 years. |
- Metopic Sutures: It is the vertical fibrous joint that divides the two halves of the frontal bone.
- Sagittal Sutures: It is the fibrous connective tissue between the two parietal bones of the skull.
- Coronal Sutures: This suture forms the connection between the frontal and parietal bones.
- Lamboid Sutures: It is the fibrous connective tissue found in the posterior aspect of the skull connecting the parietal and the occipital bones.
- Parieto-Mastoid: It is the articulation between the parietal and the temporal bones posteriorly.
- Masto-Occipital: It is present between the occipital bone and the mastoid portion of the temporal bone.
- Squamous Suture: It is found between the temporal and parietal bones bilaterally.
- Basal Suture: It is the junction between the basisphenoid and basioccipital bones.
Sutures undergo continuous changes at each stage of a person’s growth and the degree to which it is closed helps in estimating an individual’s age. A researcher named Kirk (2007) measured the amount of light reflected off the sutural joints using laser technology and found out that the amount decreased with the increasing age.
Conclusion
Even though estimation of age from cranial sutures has been widely used and is the oldest method. Studies suggest that it is not completely accurate and not much reliable. It is only a general relationship with age and hence chances of it varying among individuals persist. Accurate age estimation can be achieved if other indicators of the aging process are also taken into consideration.
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