scholarly journals A New Horizontal Plane of the Head

2018 ◽  
Vol 6 (5) ◽  
pp. 767-771 ◽  
Author(s):  
Ehab El Kattan ◽  
Mohamed El Kattan ◽  
Omnia A. Elhiny
Keyword(s):  
Soft Tissue ◽  
Horizontal Plane ◽  
Head Position ◽  
The Other ◽  
Reference Plane ◽  
Head Orientation ◽  
Mean Values ◽  
The Subject ◽  
Frankfurt Horizontal ◽  
Frankfort Horizontal Plane

AIM: This study aimed to attempt to introduce a new extracranial horizontal plane of the head (K plane that extends from SN to SAE bilaterally) that could act as a substitute to the Frankfurt horizontal intracranial reference plane; both clinically and radiographically.MATERIAL AND METHODS: The new K plane depended on three points of the head. The first was the soft tissue nasion (NS) on the interpupillary line when the subject looked forward at a distant point at eye level. The other two points were the superior attachments of the ears (SAE).RESULTS: The student “t” test comparing mean values of K/V and FH/V was not significant; -0.21.  The coefficient of correlation between different variables was highly positively significant (r = 0.98 with probability = 0.001).CONCLUSION: Within the limitations of this prospective study, the new K plane was found to be both reliable and reproducible. It can be used as a reliable reference plane instead of Frankfort horizontal plane both clinically and radiographically; as it is an accurate tool for head orientation in the natural head position.

scholarly journals Computed tomography–generated anthropometric measurements of orbital relationships in normal infants and children

2016 ◽  
Vol 18 (2) ◽  
pp. 201-206 ◽  
Author(s):  
Garrett M. Pool ◽  
Ryne A. Didier ◽  
Dianna Bardo ◽  
Nathan R. Selden ◽  
Anna A. Kuang
Keyword(s):  
Soft Tissue ◽  
Horizontal Plane ◽  
Pediatric Population ◽  
Age Groups ◽  
Population Based ◽  
Age Group ◽  
Craniofacial Anomalies ◽  
Craniofacial Abnormalities ◽  
The Mean ◽  
Frankfort Horizontal Plane

OBJECTIVE The aim of this study was to develop soft-tissue and bony anthropometric orbital measurements in a normal pediatric population based upon CT scans. METHODS This was a retrospective stratified study of children with ages ranging from birth to 36 months. Head CT images for 204 children were available and obtained with 0.625–1-mm slice widths. Soft-tissue and bone windows were reviewed. Images were oriented in the Frankfort horizontal plane, and the intercanthal (IC), bony interorbital (IO), and bony lateral orbital (LO) distances were measured. Age group stratifications were 0–3, > 3–6, > 6–9, > 9–12, > 12–18, > 18–24, > 24–30, and > 30–36 months. Patients with known syndromes or craniofacial abnormalities were excluded. Statistical analysis included the mean, SD, SEM, 95% CI, and an evaluation of IO:LO ratio. RESULTS There was an average of 25.5 patients in each age group (range 25–27 patients). All soft-tissue and bony measurements consistently showed rapid increase from 0–6 months of age, which tapered after age > 12 months. The mean IC, bony IO, and bony LO distances started at 22.22 ± 1.13 mm, 14.16 ± 0.74 mm, and 65.56 ± 1.76 mm, and at 12 months were 27.74 ± 1.01 mm, 16.21 ± 0.75 mm, and 77.98 ± 1.57 mm, respectively. The bony LO position was equivalent to the lateral canthal position and measurements. The IC distance was approximately one-third the lateral canthal distance for all age groups. CONCLUSIONS This study established and reported normal anthropometric orbital measurements in a pediatric population using fine-cut craniofacial CT. These measurements are essential when evaluating children with craniofacial anomalies.

Body and gaze centered coding of touch locations during a dynamic task

2012 ◽  
Vol 25 (0) ◽  
pp. 195
Author(s):  
Lisa M. Pritchett ◽  
Michael J. Carnevale ◽  
Laurence R. Harris
Keyword(s):  
Reference Frame ◽  
Opposite Direction ◽  
Head Position ◽  
Head Orientation ◽  
Computer Screen ◽  
Dynamic Conditions ◽  
Dynamic Task ◽  
Visual Scale ◽  
The Subject

We have previously reported that head position affects the perceived location of touch differently depending on the dynamics of the task the subject is involved in. When touch was delivered and responses were made with head rotated touch location shifted in the opposite direction to the head position, consistent with body-centered coding. When touch was delivered with head rotated but response was made with head centered touch shifted in the same direction as the head, consistent with gaze-centered coding. Here we tested whether moving the head in-between touch and response would modulate the effects of head position on touch location. Each trial consisted of three periods, in the first arrows and LEDs guided the subject to a randomly chosen head orientation (90° left, right, or center) and a vibration stimulus was delivered. Next, they were either guided to turn their head or to remain in the same location. In the final period they again were guided to turn or to remain in the same location before reporting the perceived location of the touch on a visual scale using a mouse and computer screen. Reported touch location was shifted in the opposite direction of head orientation during touch presentation regardless of the orientation during response or whether a movement was made before the response. The size of the effect was much reduced compared to our previous results. These results are consistent with touch location being coded in both a gaze centered and body centered reference frame during dynamic conditions.

scholarly journals The Relationship Between Estimated and Registered Natural Head Position

2007 ◽  
Vol 77 (6) ◽  
pp. 1019-1024 ◽  
Author(s):  
Jiuhui Jiang ◽  
Tianmin Xu ◽  
Jiuxiang Lin
Keyword(s):  
Correlation Analysis ◽  
Strong Correlation ◽  
Head Position ◽  
Reference Plane ◽  
Subjective Perception ◽  
Pretreated Patients ◽  
The Subject ◽  
Objective Meaning ◽  
The Relationship

Abstract Objective: To study the inherent relationship between registered and estimated natural head position and further explore the nature of natural head position. Materials and Methods: Thirty-one pretreated patients were included in this study. Both registered natural head position (RNHP) and estimated natural head position (ENHP) were obtained. For RNHP, mirror orientation was used to help to adjust the subject's head position. For ENHP, two approved standard photographs were studied by the assessors before estimation. Correlation analysis was used to analyze the relationship between two angles: Rphoto/Rxray and Ephoto/ Eray. Results: A significant correlation was found between RNHP and ENHP, both on the photographs and on the cephalograms. Conclusion: There is a strong correlation between RNHP and ENHP. RNHP is the subjective perception of the subject and gets some objective meaning by mirror orientation. ENHP is the subjective perception of assessors and gets objective meaning by a standardization session in advance. The mirror orientation of RNHP and the advance standard study of ENHP are crucial for validity and accuracy of NHP as an extracranial reference plane.

scholarly journals The Influence of Impression Material on the Accuracy of the Master Cast in Implant Restorations

2018 ◽  
Vol 12 (1) ◽  
pp. 1123-1136
Author(s):  
Spyridon Stefos ◽  
Stefanos Kourtis ◽  
Aspasia Sarafianou ◽  
Panagiotis Zoidis
Keyword(s):  
Horizontal Plane ◽  
Computer Software ◽  
Optical Microscope ◽  
The Other ◽  
Impression Material ◽  
Mean Values ◽  
The Third ◽  
Impression Materials ◽  
Metal Framework ◽  
Medium Viscosity

Aim: The precise framework fit is important for the success of implant restorations. The purpose of the present study was to examine the effect of two different impression materials both of their medium viscosity on the master cast accuracy when parallel and inclined implants were used. Materials and Methods: An epoxy master cast with three implants was fabricated. The first two implants were parallel to each other and perpendicular to the horizontal plane and the third implant had a 250 inclination in reference to the other two. A passively fitting metal framework that was fabricated over this master cast was used to measure accuracy of fit. Five closed tray impressions for each medium viscosity material (polyether and polyvinyl-siloxane) tested were taken and the respective ten stone casts with three implant analogs were fabricated. The metal framework in the master cast, was fixed in the new specimens and the micro-gap between this prosthesis and the implant analogs was evaluated. The specimens were observed to an optical microscope and digital photography. Results and Conclusion: The data were statistically analysed using a computer software and t-test. Polyether exhibited higher micro-gap mean values (93,4 to 61,8 μm) compared to polyvynil siloxane (30,47 to 14,83μm). The differences were statistically significant only for implant B. The categorical regression analysis (p < 0.01) for all implants showed that the marginal micro-gap was affected by the impression material (94.1%) and significantly by the type of it. The micro-gap values were higher for polyether compared to polyvinyl-siloxane. The torqued implant did not exhibit any statistically significant effect.

scholarly journals Evaluating the Reliability of CBCT Airway Measurement: A Pilot Study

2020 ◽  
Author(s):  
Brent L. Jorgensen ◽  
Jae Hyun Park ◽  
R. Curtis Bay
Keyword(s):  
Horizontal Plane ◽  
Head Position ◽  
Average Difference ◽  
Cross Sectional ◽  
Significant Difference ◽  
Tongue Position ◽  
T1 And T2 ◽  
Jaw Position ◽  
Volume Acquisition ◽  
Frankfort Horizontal Plane

Abstract Background Many studies have analyzed treatment effects on the airway using CBCT scans of the airway as evidence, but no study to date has been published that validates a repeatable protocol for acquiring CBCT airway measurements. Our objective is to evaluate a protocol for standardization of CBCT volume acquisition of the airway. Methods Ten participants (6 females and 4 males, median age 30.03 ± 3.53 years) were radiographed 2 times each (T1 and T2, the average time between T1-T2 was 15.8 ± 3.65 days), for a total of 20 CBCT scans. The participants’ head position was placed so that the Frankfort horizontal plane was parallel to the floor. Participants were given specific instructions regarding jaw position, tongue position, swallowing and breathing before each of the 2 scans. Minimum cross-sectional area (MCA) and total volume (TV) of each airway scan were measured between the distal most point of the hard palate (superior limit) and the superior most point of the epiglottis (inferior limit). T1 and T2 were compared to determine the repeatability of our proposed protocol for CBCT airway acquisition. Results There was no statistically significant difference between T1 and T2 measurements for TV and MCA. The average difference between T1 and T2 MCA and TV measurements for each participant was 34.18 ± 30.55 mm2 and 2.51 ± 2.05 cc, respectively. Conclusions Using our proposed standardization protocol, the measurements of MCA and TV of the airway were reliable to within 34.18 ± 30.55 mm2 and 2.51 ± 2.05 cc, respectively.

scholarly journals Three-Dimensional Reproducibility of the Soft Tissue Landmarks Taken by Structured-Light Facial Scanner in Accordance with the Head Position Change

Healthcare ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 428
Author(s):  
Seung-Hoon Oh ◽  
Jung-Soo Park ◽  
Jae-Jun Ryu ◽  
In-Seok Song ◽  
Seok-Ki Jung
Keyword(s):  
Soft Tissue ◽  
Horizontal Plane ◽  
Structured Light ◽  
Three Dimensional ◽  
Orbital Plane ◽  
Head Position ◽  
Position Change ◽  
3D Images ◽  
Structured Light Scanner ◽  
Facial Scanning

The aim of this study was to evaluate the three-dimensional reproducibility of the structured-light facial scanner according to the head position change. A mannequin head was used and angle of the mannequin’s axis-orbital plane to the true horizontal plane was adjusted to +10, +5, 0, −5, and −10°. Facial scanning was conducted 30 times, respectively, and 150 3D images were obtained. Reoriented landmarks of each group were compared and analyzed. Reproducibility decreased as the distance from the facial center increased. Additionally, the landmarks below showed lower reproducibility and higher dispersion than landmarks above. These differences occurred mainly in the anteroposterior direction as opposed to other directions. Positive inclination of the head position showed superior reproducibility compared to a negative inclination. This study showed that reproducibility of a structured-light scanner could be varied depending on the head position. Inaccuracies of landmarks in the anteroposterior direction are greater than in other directions. This means that evaluations of the profile using a structured-light scanner should be made carefully. Therefore, the proper head position should be set to ensure the accuracy of the image.

Golgi Apparatus and Melanogenesis: Ultrastructural Study of a Human Cellular Blue Nevus (Melanocytoma)

1973 ◽  
Vol 31 ◽  
pp. 380-381
Author(s):  
S.R. Allegra
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Apparatus ◽  
Ultrastructural Study ◽  
The Other ◽  
Blue Nevus ◽  
Normal Complement ◽  
Golgi Vesicles ◽  
Golgi System ◽  
The Subject ◽  
Cellular Blue Nevus

The respective roles of the ribo somes, endoplasmic reticulum, Golgi apparatus and perhaps nucleus in the synthesis and maturation of melanosomes is still the subject of some controversy. While the early melanosomes (premelanosomes) have been frequently demonstrated to originate as Golgi vesicles, it is undeniable that these structures can be formed in cells in which Golgi system is not found. This report was prompted by the findings in an essentially amelanotic human cellular blue nevus (melanocytoma) of two distinct lines of melanocytes one of which was devoid of any trace of Golgi apparatus while the other had normal complement of this organelle.

“Channeling” the powers of God’s Word

2010 ◽  
Vol 4 (2) ◽  
pp. 135-156 ◽  
Author(s):  
Dorothea E. Schulz
Keyword(s):  
The Other ◽  
Border Zone ◽  
Focus Attention ◽  
Spiritual Power ◽  
New Materials ◽  
God's Word ◽  
Audio Recordings ◽  
Heated Debate ◽  
The Subject ◽  
The One

Starting with the controversial esoteric employment of audio recordings by followers of the charismatic Muslim preacher Sharif Haidara in Mali, the article explores the dynamics emerging at the interface of different technologies and techniques employed by those engaging the realm of the Divine. I focus attention on the “border zone” between, on the one hand, techniques for appropriating scriptures based on long-standing religious conventions, and, on the other, audio recording technologies, whose adoption not yet established authoritative and standardized forms of practice, thereby generating insecurities and becoming the subject of heated debate. I argue that “recyclage” aptly describes the dynamics of this “border zone” because it captures the ways conventional techniques of accessing the Divine are reassessed and reemployed, by integrating new materials and rituals. Historically, appropriations of the Qur’an for esoteric purposes have been widespread in Muslim West Africa. These esoteric appropriations are at the basis of the considerable continuities, overlaps and crossovers, between scripture-related esoteric practices on one side, and the treatment by Sharif Haidara’s followers of audio taped sermons as vessels of his spiritual power, on the other.

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