The lacertus fibrosus substantially Alters flexion and supination moment arms: A cadaveric study

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics Pub Date : 2025-05-19 DOI:10.1016/j.jbiomech.2025.112760

Mark Carl Miller , Patrick J Schimoler , Alexander Kharlamov , Jon Hammerstedt , Gregory Angelides , Gonzalo Sumarriva , Owen Corcoran , Peter Tang

{"title":"The lacertus fibrosus substantially Alters flexion and supination moment arms: A cadaveric study","authors":"Mark Carl Miller , Patrick J Schimoler , Alexander Kharlamov , Jon Hammerstedt , Gregory Angelides , Gonzalo Sumarriva , Owen Corcoran , Peter Tang","doi":"10.1016/j.jbiomech.2025.112760","DOIUrl":null,"url":null,"abstract":"<div><div>This study evaluated the effect of the lacertus fibrosus on the biceps brachii moment arms to determine the lacertus importance in forearm strength. The work proceeded from the null hypothesis that the lacertus fibrosus has no effect on flexion/extension and supination/pronation.</div><div>Ten fresh-frozen cadaveric specimens were mounted in an elbow simulator to measure tendon excursion, elbow flexion/extension (FE) and forearm pronation/supination (PS) angles. FE moment arms were calculated throughout FE excursion at multiple, constant PS angles and PS moment arms were measured throughout PS excursion at multiple, constant FE angles. Tests included the lacertus intact, the superficial lacertus transected, and the entire lacertus transected along with any connections to surrounding tissue.</div><div>The intact lacertus increased the FE moment arm of the biceps with the elbow in less than 40° flexion and decreased the FE moment arm with the elbow in greater than 80° flexion, where the decrease could exceed 50%, depending on the flexion angle. The intact lacertus decreased the PS supination moment arm at all flexion angles; the intact lacertus even caused the biceps to act as a pronator at full elbow extension.</div><div>The intact lacertus assists in early elbow flexion and the lacertus hinders elbow flexion at greater than 80° flexion. The lacertus hinders the biceps function of supination, especially in a supinated position. Injury of the lacertus without direct biceps tendon damage can be tested best at the ends of the flexion ROM and at higher supination angles. Lacertus syndrome may be more quickly diagnosed with provocative tests that isolate the lacertus function.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"187 ","pages":"Article 112760"},"PeriodicalIF":2.4000,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of biomechanics","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0021929025002726","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"BIOPHYSICS","Score":null,"Total":0}

引用次数: 0

Abstract

This study evaluated the effect of the lacertus fibrosus on the biceps brachii moment arms to determine the lacertus importance in forearm strength. The work proceeded from the null hypothesis that the lacertus fibrosus has no effect on flexion/extension and supination/pronation.

Ten fresh-frozen cadaveric specimens were mounted in an elbow simulator to measure tendon excursion, elbow flexion/extension (FE) and forearm pronation/supination (PS) angles. FE moment arms were calculated throughout FE excursion at multiple, constant PS angles and PS moment arms were measured throughout PS excursion at multiple, constant FE angles. Tests included the lacertus intact, the superficial lacertus transected, and the entire lacertus transected along with any connections to surrounding tissue.

The intact lacertus increased the FE moment arm of the biceps with the elbow in less than 40° flexion and decreased the FE moment arm with the elbow in greater than 80° flexion, where the decrease could exceed 50%, depending on the flexion angle. The intact lacertus decreased the PS supination moment arm at all flexion angles; the intact lacertus even caused the biceps to act as a pronator at full elbow extension.

The intact lacertus assists in early elbow flexion and the lacertus hinders elbow flexion at greater than 80° flexion. The lacertus hinders the biceps function of supination, especially in a supinated position. Injury of the lacertus without direct biceps tendon damage can be tested best at the ends of the flexion ROM and at higher supination angles. Lacertus syndrome may be more quickly diagnosed with provocative tests that isolate the lacertus function.

查看原文本刊更多论文

纤维撕裂肌实质上改变了屈曲和旋后力矩臂：一项尸体研究

本研究评估了纤维撕裂肌对肱二头肌力矩臂的影响，以确定撕裂肌在前臂力量中的重要性。该研究的基础假设是，纤维角肌对屈伸和旋前/旋前没有影响。将10个新鲜冷冻尸体标本安装在肘关节模拟器中，测量肌腱偏移、肘关节屈伸（FE）和前臂旋前（PS）角度。在多个、恒定的PS角下，计算整个PS偏移过程中的FE力臂，在多个、恒定的FE角下，测量整个PS偏移过程中的PS力臂。测试包括完整的裂口肌、切开的浅表裂口肌、切开的整个裂口肌以及与周围组织的连接。完整的撕裂肌在肘关节屈曲小于40°时增加了肱二头肌的FE力臂，在肘关节屈曲大于80°时降低了肱二头肌的FE力臂，根据屈曲角度的不同，其降低幅度可超过50%。完整的撕裂肌在所有屈曲角度均使PS旋后力矩臂减小；完整的撕裂肌甚至使二头肌在肘关节完全伸展时起到旋前肌的作用。完整的裂口肌有助于早期肘关节屈曲，而当肘关节屈曲超过80°时，裂口肌会阻碍肘关节屈曲。撕裂肌妨碍二头肌旋后的功能，特别是在旋后的位置。没有直接二头肌肌腱损伤的撕裂肌损伤可以在屈曲ROM的末端和较高的旋后角度进行最好的测试。撕裂肌综合征可以通过分离撕裂肌功能的刺激试验更快地诊断出来。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Journal of biomechanics 生物-工程：生物医学

CiteScore

5.10

自引率

4.20%

发文量

345

审稿时长

1 months

期刊介绍： The Journal of Biomechanics publishes reports of original and substantial findings using the principles of mechanics to explore biological problems. Analytical, as well as experimental papers may be submitted, and the journal accepts original articles, surveys and perspective articles (usually by Editorial invitation only), book reviews and letters to the Editor. The criteria for acceptance of manuscripts include excellence, novelty, significance, clarity, conciseness and interest to the readership. Papers published in the journal may cover a wide range of topics in biomechanics, including, but not limited to: -Fundamental Topics - Biomechanics of the musculoskeletal, cardiovascular, and respiratory systems, mechanics of hard and soft tissues, biofluid mechanics, mechanics of prostheses and implant-tissue interfaces, mechanics of cells. -Cardiovascular and Respiratory Biomechanics - Mechanics of blood-flow, air-flow, mechanics of the soft tissues, flow-tissue or flow-prosthesis interactions. -Cell Biomechanics - Biomechanic analyses of cells, membranes and sub-cellular structures; the relationship of the mechanical environment to cell and tissue response. -Dental Biomechanics - Design and analysis of dental tissues and prostheses, mechanics of chewing. -Functional Tissue Engineering - The role of biomechanical factors in engineered tissue replacements and regenerative medicine. -Injury Biomechanics - Mechanics of impact and trauma, dynamics of man-machine interaction. -Molecular Biomechanics - Mechanical analyses of biomolecules. -Orthopedic Biomechanics - Mechanics of fracture and fracture fixation, mechanics of implants and implant fixation, mechanics of bones and joints, wear of natural and artificial joints. -Rehabilitation Biomechanics - Analyses of gait, mechanics of prosthetics and orthotics. -Sports Biomechanics - Mechanical analyses of sports performance.