Peter O. Gerrits

Evaluation of anthropometric accuracy and reliability using different three-dimensional scanning systems.

The aim of this study was to evaluate the accuracy and reliability of standard anthropometric linear measurements made with three different three-dimensional scanning systems namely laser surface scanning (Minolta Vivid 900), cone beam computed tomography (CBCT), 3D stereo-photogrammetry (Di3D system) and to compare them to physical linear measurements. The study sample consisted of seven cadaver heads. The reliability and accuracy were assessed by means of a series of 21 standardized, linear facial measurements derived from 15 landmarks taken both directly on the face with a set of digital callipers and indirectly from a three-dimensional (3D) soft tissue surface models derived from CBCT, laser surface scans and 3D photographs. Statistical analysis for the reliability was done by means of intraclass correlation coefficients (ICCs). Accuracy was determined by means of the absolute error (AE) and absolute percentage error (APE) by comparison of the 3D measurements to the physical anthropometrical measurements. All the 3D scanning systems were proved to be very reliable (ICC>0.923-0.999) when compared to the physical measurements (ICC; 0.964-0.999). Only one CBCT measurement (t-g) and one Di3D measurement (t-sn left) had a mean AE of more than 1.5mm. There are clear potential benefits of using 3D measurements appose to direct measurements in the assessment of facial deformities. Measurements recorded by the three 3D systems appeared to be both sufficiently accurate and reliable enough for research and clinical use.

Emotional Motor System

This chapter focuses on the emotional motor system. It also discusses the somatic motor system in order to point out the similarities and differences between the two systems. The idea of the existence of an emotional motor system is primarily based on anatomical organization. The pathways of the somatic and emotional motor system are always separate until their termination on premotor interneurons or motoneurons. The function of the somatic and emotional motor system pathways is different. The emotional motor pathways play a role in basic survival behavior. The somatic or voluntary motor system, and especially its cortical parts, starts operating only after a relatively long time of processing environmental data, combined with information from the extensive memory banks in the various regions around the primary cortices. Moreover, the behavioral differences between animals and humans are not located in the emotional, but in the somatic motor system, which, as pointed out earlier, is nothing more than a tool of the emotional, or limbic system to fulfill its needs. In that respect, humans differ only slightly from other animals.

Accuracy and reliability of facial soft tissue depth measurements using cone beam computer tomography

It is important to have accurate and reliable measurements of soft tissue thickness for specific landmarks of the face and scalp when producing a facial reconstruction. In the past several methods have been created to measure facial soft tissue thickness (FSTT) in cadavers and in the living. The conventional spiral CT is mostly used to determine the FSTT but is associated with high radiation doses. The cone beam CT (CBCT) is a relatively new computer tomography system that focuses on head and neck regions and has much lower radiation doses. The aim of this study is to determine the accuracy and reliability of CBCT scans to measure the soft tissue thicknesses of the face. Seven cadaver heads were used. Eleven soft tissue landmarks were identified on each head and a punch hole was made on each landmark using a dermal biopsy punch. The seven cadaver heads were scanned in the CBCT with 0.3 and 0.4mm resolution. The FSTT at the 11 different sites (soft tissue landmarks) were measured using SimPlant-ortho volumetric software. These measurements were compared to the physical measurements. Statistical analysis for the reliability was done by means of the interclass coefficient (ICC) and the accuracy by means of the absolute error (AE) and absolute percentage error (APE). The intra-observer (0.976-0.999) and inter-observer (0.982-0.997) correlations of the CBCT and physical measurements were very high. There was no clinical significant difference between the measurements made on the CBCT images and the physical measurements. Increasing the voxel size from 0.4 to 0.3mm resulted in a slight increase of accuracy. Cone beam CT images of the face using routine scanning protocols are reliable for measuring soft tissue thickness in the facial region and give a good representation of the facial soft tissues. For more accurate data collection the 0.3mm voxel size should be considered.

Pontine and medullary projections to the nucleus retroambiguus: A wheat germ agglutinin‐horseradish peroxidase and autoradiographic tracing study in the cat

The nucleus retroambiguus (NRA) in the caudal medulla oblongata plays a role in expiration, vocalization, vomiting, and possibly lordosis. The present study tried to determine which structures, in turn, control the NRA. One cell group is the periaqueductal gray (PAG), which is considered to be the final integrator of defensive and aggressive behaviors, micturition, vocalization, and lordosis. Structures rostral to the PAG seem to bypass the NRA. With respect to the existence of cell groups caudal to the PAG projecting to the NRA, the situation is less clear.

Motivation for body donation to science: More than an altruistic act

BACKGROUND In recent years the Netherlands has witnessed a steep increase in the number of bodies donated for medical research and training. To explore this upward trend and motives for donation, a survey was conducted among registered body donors in the database of the Department of Anatomy at the University Medical Center of Groningen (UMCG). METHODS In November 2008, postal questionnaires were sent to 996 people enrolled at the UMCG body donor database. The present study focuses on motives for donation and social background characteristics of the body donors. FINDINGS Registered donors responded quickly and the survey response rate was high (76%). The mean age of respondents was 69 years and the majority described themselves as Dutch (98%) and non-church affiliated (79%). One quarter (25%) of the respondents are/were health care professionals and 11% involved in education. Principal factor analysis revealed three dimensions underlying ten different motivations for body donation: a desire to be useful after death, a negative attitude towards funerals and expression of gratitude. Despite the current economic recession only 8% of respondents are prompted by money motives to bequeath their bodies. CONCLUSIONS The majority of motives for body donation stem from the wish to be useful after death. However, the present survey suggests that body donation is more than an altruistic act; people are also motivated by personal benefit. Results of our survey contradict the notion that body donation stems from loneliness. Many donors have a supportive social network and meaningful social relationships. People moreover propagate body donation within their social networks.

Descending Projections From The Nucleus Retroambiguus To The Iliopsoas Motoneuronal Cell Groups In The Female Golden Hamster: Possible role in reproductive behavior

In the cat, the nucleus retroambiguus (NRA) projects to expiratory motoneurons in the brainstem and spinal cord. Recently, it has been demonstrated that the NRA sends fibers to a specific set of motoneurons in the lumbosacral cord, which pathway is thought to play a crucial role in mating behavior. The question is whether such projections exist in the hamster, because the female of this species displays a very distinctive receptive behavior. In the hamster, lumbosacral cord injections of wheat germ agglutinin‐horseradish peroxidase (WGA‐HRP) combined with hemisection 1 or 2 segments rostral to injection sites in three of the five cases demonstrated retrogradely labeled neurons in the NRA at levels 1.0–2.25 mm caudal to the obex, contralateral to the injection sites. Injections of WGA‐HRP into the NRA and adjoining reticular formation revealed that NRA fibers crossed the midline in the caudal medulla and descended in the contralateral lateral and ventrolateral funiculi to terminate bilaterally, but mainly contralaterally, in the motoneuronal cell groups of the abdominal wall and iliopsoas muscles. NRA projections to levels caudal to lumbar segment 5 were virtually absent. Electron microscopic examination revealed that, of the 162 labeled NRA terminal profiles found in the ultrathin sections, 144 (89%) made monosynaptic contacts with retrogradely labeled dendrites of iliopsoas motoneurons. These NRA terminals formed asymmetrical synapses and contained spherical vesicles indicative of an excitatory function. The results indicate that, in the hamster, direct contralateral NRA projections exist to iliopsoas motoneurons. A concept is discussed in which this pathway plays a crucial role in mating behavior. J. Comp. Neurol. 403:219–228, 1999.

Accuracy and repeatability of anthropometric facial measurements using cone beam computed tomography

Objective The purpose of this study was to determine the accuracy and repeatability of linear anthropometric measurements on the soft tissue surface model generated from cone beam computed tomography scans. Materials and Methods The study sample consisted of seven cadaver heads. The accuracy and repeatability were assessed by means of a series of 21 standardized, linear facial measurements derived from 11 landmarks taken both directly on the face with a set of digital calipers and indirectly from a three-dimensional soft tissue surface model generated from a cone beam computed tomography scan of the heads using SimPlant® Ortho Pro software. The landmarks and measurements were chosen to cover various regions of the face with an emphasis on the oral-nasal region. The cone beam computed tomography measurements were compared with the physical measurements. Statistical analysis for the repeatability was done by means of the intraclass coefficient. Accuracy was determined by means of the absolute error and absolute percentage error. Results The cone beam computed tomography measurements were very accurate when compared with the physical measurements (0.962 to 0.999). Except for one measurement, between point tragion (t) and nasion (n) (mean, 1.52 mm), all the measurements had a mean absolute error of less than 1.5 mm. Conclusions The three-dimensional surface models derived from cone beam computed tomography images are sufficiently precise and accurate for the anthropometric measurements.

Staining sections of water-miscible resins

Penetration of hydrophilic acid and basic dyes into sections cut from glycol methacrylate (GMA)‐embedded tissues was studied; as were the effects on such staining of superficial coatings of thin layers of GMA.

Anatomist on the dissecting table? Dutch anatomical professionals' views on body donation

Anatomical professionals know better than anyone else that donated bodies are a valuable asset to anatomical science and medical education. They highly value voluntary donations, since a dearth of bodies negatively affects their profession. With this in mind, we conducted a survey (n = 54) at the 171st scientific meeting of the Dutch Anatomical Society in 2009 to see to what extent anatomical professionals are willing to donate their own body. The results reveal that none of the survey participants are registered as a whole body donor and that only a quarter of them would consider the possibility of body donation. We argue that the two main constraints preventing Dutch anatomical professionals from donating their own body are their professional and their social environments. In contrast to the absence of registered body donors, half of the anatomical professionals are registered as an organ donor. This figure far exceeds the proportion of registered organ donors among the general Dutch population. Clin. Anat. 25:168–175, 2012.

Personality and motivation for body donation

BACKGROUND This study examines the relationship between motivation for body donation to science and personality characteristics using a body donor survey (N=759) conducted by the University Medical Centre Groningen (UMCG) in The Netherlands. The survey expands on anthropological studies that suggest an association between donor motivation and personality. METHODS A structural equation model was used to investigate the relationship between personality and motivation for body donation. FINDINGS The results show that, compared to society at large, body donors have a similar spectrum of personality characteristics. However, we found statistically significant positive relationships between donor motivation and Big Five personality traits. Together the personality traits explain between 5% and 15% of the variance in motivation for body donation. CONCLUSIONS We argue that donor campaigns should not focus solely on altruistic motives, but should include the aspect of possible personal achievement by the donor. This is a fruitful starting point for approaching potential donors and anticipating their needs.