Deka Dhiraj K, Mitra Satyajit, Hazarika Bornali, Sarma Joydev
Anatomy, Gauhati Medical College and Hospital, Guwahati, IND.
Cureus. 2025 Jun 28;17(6):e86927. doi: 10.7759/cureus.86927. eCollection 2025 Jun.
The lateral sulcus (LS) serves as a vital neuroanatomical landmark involved in hemispheric lateralization, language processing, and neurosurgical navigation. However, discrepancies between cadaveric and imaging-based studies, along with limited demographic integration, have restricted the development of standardized anatomical references. This study aimed to generate fixation-adjusted morphometric data and examine the influence of sex, handedness, and age on LS asymmetry.
A retrospective observational study was conducted on 50 formalin-fixed adult human brains (27 males, 23 females; age range: 21-78 years). Bilateral measurements of the LS and its rami were obtained using digital vernier calipers by three blinded observers. All lengths were corrected for ~20% shrinkage due to formalin fixation based on published correction protocols. Handedness and demographic data were collected from institutional records and next-of-kin interviews. Statistical analysis included paired and independent t-tests, multivariate analysis of variance (MANOVA), Pearson's correlation, and multivariate regression. Effect sizes (Cohen's d) and 95% confidence intervals were reported. Power analysis was performed using G*Power 3.1 (version 3.1, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany).
Significant leftward asymmetry of the LS was observed (mean left: 8.94 ± 0.35 cm; right: 8.43 ± 0.56 cm; p < 0.001; Cohen's d = 1.12, 95% CI: 0.38-0.64), with a mean asymmetry index of 5.9% ± 3.2%. Males and right-handed individuals demonstrated greater asymmetry compared to females and left-handed individuals (p < 0.05). A negative correlation with age was noted (r = -0.32, p = 0.008). Multivariate regression revealed sex, handedness, and age as significant independent predictors (R² = 0.24, p < 0.001).
This cadaveric study affirms the presence of consistent leftward LS asymmetry and highlights its modulation by sex, handedness, and age. By incorporating fixation correction and robust statistical methods, the findings reconcile anatomical and radiological data, offering valuable morphometric benchmarks for neurosurgical planning and future neuroimaging studies. These results should be interpreted as normative anatomical references rather than diagnostic criteria due to the inherent limitations of retrospective postmortem research.
外侧沟（LS）是一个重要的神经解剖学标志，参与半球侧化、语言处理和神经外科手术导航。然而，尸体研究和基于影像学的研究之间存在差异，以及有限的人口统计学整合，限制了标准化解剖学参考的发展。本研究旨在生成固定调整后的形态学数据，并研究性别、利手和年龄对外侧沟不对称性的影响。
对50个福尔马林固定的成人大脑（27例男性，23例女性；年龄范围：21 - 78岁）进行回顾性观察研究。由三名不知情的观察者使用数字游标卡尺对外侧沟及其分支进行双侧测量。根据已发表的校正方案，对所有长度进行校正，以补偿因福尔马林固定导致的约20%的收缩。从机构记录和近亲访谈中收集利手和人口统计学数据。统计分析包括配对和独立t检验、多变量方差分析（MANOVA）、Pearson相关性分析和多变量回归分析。报告效应量（Cohen's d）和95%置信区间。使用G*Power 3.1（版本3.1，德国杜塞尔多夫海因里希-海涅大学）进行功效分析。
观察到外侧沟存在显著的向左不对称（左侧平均：8.94 ± 0.35 cm；右侧：8.43 ± 0.56 cm；p < 0.001；Cohen's d = 1.12，95% CI：0.38 - 0.64），平均不对称指数为5.9% ± 3.2%。与女性和左利手个体相比，男性和右利手个体表现出更大的不对称性（p < 0.05）。观察到与年龄呈负相关（r = -0.32，p = 0.008）。多变量回归显示性别、利手和年龄是显著的独立预测因素（R² = 0.24，p < 0.001）。
这项尸体研究证实了外侧沟存在一致的向左不对称，并强调了其受性别、利手和年龄的调节作用。通过纳入固定校正和稳健的统计方法，研究结果协调了解剖学和放射学数据，为神经外科手术规划和未来的神经影像学研究提供了有价值的形态学基准。由于回顾性尸检研究的固有局限性，这些结果应被解释为规范性解剖学参考，而非诊断标准。
