Related Experiment Video
Updated: Sep 15, 2025
Endoscopic Septoplasty with Limited Two-line Resection: Minimally Invasive Surgery for Septal Deviation
Published on: June 20, 2018
Anatomical Variations in Keystone Area in Nepalese Noses: A Descriptive Cross-sectional Study
Urmila Gurung1, Kripa Dongol1, Pabina Rayamajhi1
1Department of ENT-Head and Neck Surgery, Maharajgunj Medical Campus - Tribhuvan University Teaching Hospital Institute of Medicine, Maharajgunj, Kathmandu, Nepal.
Introduction:
The keystone area, a crucial part of the nasal dorsum that maintains its structural stability, is known to have anatomical variations. This study aimed to evaluate these anatomical variations in Nepalese noses.
Methods:
This was an observational, analytical study done at a tertiary center after taking ethical approval {208(6-11)E2-077/078}. Thirty-one cadaveric noses consisting of 26 males and five females aged 24 to 70 years were dissected. The shape of the caudal margin and the overlap pattern of the nasal bone over upper lateral cartilage were assessed. The proportion of overlap was calculated. The lengths of the lateral and dorsal keystone and dorsal quadrangular cartilage were measured.
Results:
The most common shape of the nasal bone caudal margin was curvilinear 15 (48.39%) followed by paramedian retractions 8 (25.81%). Elongated midline was the least commonly seen in 1 (3.23%) female only. The length of the dorsal keystone ranged from 1-12 mm (mean 6.97±2.57) whilst the lateral keystone measured 1-4 mm (mean 2.22±1.20). The dorsal quadrangular cartilage measured 21-39 mm (mean 29.77±4.6). The mean overlap proportion was 23.82±7.33 (11 - 40)%.
Conclusions:
Anatomical variations in the structural components of the keystone area in Nepalese was seen in the study.
More Related Videos
15:40An Effective Manual Deboning Method To Prepare Intact Mouse Nasal Tissue With Preserved Anatomical Organization
Published on: August 10, 2013
10:23Author Spotlight: Three-Dimensional Cephalometric Landmark Annotation Demonstration on Human Cone Beam Computed Tomography Scans
Published on: September 8, 2023
Related Concept Videos
01:24Nose and Nasal Cavity
01:27Cranial Bones: Lateral View
The temporal bone forms the lower lateral side of the skull. The temporal bone is subdivided into several regions. The flattened upper portion is the squamous portion of the temporal bone. Below this area and projecting anteriorly is the zygomatic process of the temporal bone, which forms the posterior portion of the zygomatic arch. Posteriorly is the mastoid portion of the temporal bone. Projecting...
01:29Anatomy of Respiratory System I: Upper Respiratory Tract
Nose and nasal cavity
The nose and nasal cavity represent the main external openings of the respiratory tract....
01:14Cranial Bones: Superior and Posterior View
The frontal bone is the single bone that forms the forehead. At its anterior midline, between the eyebrows, there is a slight depression called the glabella. The frontal bone also forms the supraorbital margin of the orbit. Near the middle of this margin is the supraorbital foramen, the opening that provides passage for a sensory nerve to the forehead. The frontal bone is thickened just above each supraorbital margin,...
01:30Epistaxis
Etiology
Possible causes of this condition include high blood pressure, trauma, low humidity, upper respiratory tract infections, allergies, foreign bodies, nasal inhalation of corticosteroids or illicit drugs, excessive use of decongestant nasal sprays, facial or nasal surgery, anatomic malformation, tumors, or systemic...
01:08Overview of the Skull
The cranial vault surrounds and protects the brain and houses the middle and inner ear structures. This cavity is bounded superiorly by the rounded top of the skull, which...