Dissertation Research: The effect of exercise on the morphology of muscle attachment scars

肌肉插入疤痕，或称关节窝，是很容易观察到的，但对骨骼和化石的特征却知之甚少。在古生物学领域有一个长期存在的假设，即大的或明显的肌肉疤痕表明大量的肌肉使用。然而，这一假设从未被彻底验证过。这项研究将是第一个直接检查已知水平的肌肉力量和肠末形态的许多方面之间的关系。这项研究的目的是检查肌肉的使用是否以及如何影响端骨形态，以便古生物学家可以更自信地解释骨骼或化石上的这些特征。本研究将比较久坐和运动的成年羊（Ovis aries）的各种特征。初步研究表明，适度运动对肠末形态的某些方面没有影响。因此，在本研究中，被锻炼的羊将以较快的速度奔跑，同时背上负重适中。这种运动方案被设计为相对剧烈的，因为研究的一个目标是确定剧烈的肌肉使用是否确实与大的或明显的插入标记有关。各种特征将被测量在七个肌肉插入疤痕。其中6个疤痕是肢体肌肉的疤痕，将在跑步周期中使用。第七个是在下颌骨上的咬肌止点。这块肌肉在两组中负荷不应该不同，因此它的插入将作为一种内部控制来研究。每块肌肉产生的力将通过力扣和声压测量法进行量化。因此，这项研究将是第一个检查已经受到已知水平的肌肉力量在体内的形态学。本研究将开发第一个客观的定量方法，用于描述通常用于描述论文的各种特征。这些方法将用于测试增加肌肉使用显着影响插入疤痕的大小和粗糙度的假设。第一种方法是先前测试过的用于测量插入标记的三维表面积的乳胶成型方法。第二种方法将在本研究中得到大力发展，它将测量骨骼和化石上经常观察到的一种特征，但很少量化。将使用3d激光扫描仪扫描插入疤痕，并使用地理信息系统（GIS）软件包ArcView GIS 3.2分析其拓扑结构。在两个治疗组中，将使用荧光标记定期给药来测量插入物下的骨沉积率。这一信息将有助于深入了解由于肌肉力量的变化而在肌肉插入处的骨骼中发生的一些生理反应。它还将作为纵向测量既存的这些反应,从而帮助控制个人enthesis形态学的变化。总之，提出的研究将提供急需的洞察肌肉使用和端窝形态之间的关系。这是第一个测试肌肉使用影响插入疤痕形态假设的研究，并将证明这种形态的哪些方面受到如此影响。它也将提供第一种客观量化实体特征的方法。这项研究的结果应该允许古生物学家更自信地解释肌肉插入疤痕的功能形态。

uscle insertion scars, or entheses, are easily observable but poorly understood features of bones and fossils. There is a long-standing assumption in the field of paleontology that large or obvious muscle scars are indicative of heavy muscle use. However, this assumption has never been thoroughly tested. This study will be the first to directly examine the relationship between known levels of muscle force and numerous aspects of enthesis morphology. The goal of this study is to examine if and how muscle use influences enthesis morphology so paleontologists may more confidently interpret these features on bones or fossils. This study will compare a variety of features of the entheses of sedentary and exercised adult sheep (Ovis aries). Preliminary work has indicated that moderate exercise induces no change in some aspects of enthesis morphology. Therefore the exercised sheep in this study will be run at a fast pace while carrying moderately heavy loads on their backs. This exercise regime is by design relatively intense, as one goal of the study is to determine whether intense muscle use is indeed related to large or obvious insertion marks. A variety of features will be measured on seven muscle insertion scars. Six of the scars are those of limb muscles that will be used in the running cycle. The seventh is that of the masseter muscle insertion on the mandible. This muscle should not be loaded differently in the two groups and thus its insertion will be studied as an internal control. The forces produced by each of the muscles will be quantified using force buckles and sonomicrometry. Thus this study will be the first to examine the morphology of entheses that had been subjected to known levels of muscle force in vivo. This study will develop the first objective, quantitative methods for describing the various features that are typically used to describe entheses. These methods will be used to test the hypotheses that increased muscle use significantly affects the size and rugosity of insertion scars. The first method is a previously tested latex molding method for measuring the three-dimensional surface area of insertion marks. The second method, to be heavily developed in this study, will measure enthesis rugosity, a feature that is often observed on bones and fossils but rarely quantified. The insertion scars will be scanned using a 3D-laser scanner and their topology will be analyzed using ArcView GIS 3.2, a Geographic Information System (GIS) software package. The rate of bone deposition under the insertions in both treatment groups will be measured using periodic administrations of fluorochrome labels. This information will provide insight into some of the physiological responses that occur in the bone beneath muscle insertions due to variations in muscle forces. It will also serve as a longitudinal measure of these responses and thus help control for pre-existing individual variation in enthesis morphology. In sum, the proposed study will provide much-needed insight into the relationship between muscle use and enthesis morphology. It is the first study to test the assumption that muscle use affects insertion scar morphology, and will demonstrate which aspects of this morphology are so affected. It will also provide the first method to objectively quantify the features of entheses. The results of this study should allow paleontologists to more confidently interpret the functional morphology of muscle insertion scars.