Typical m. triceps surae morphology and architecture measurement from 0 to 18 years: A narrative review.

The aim of this review was to report on the imaging modalities used to assess morphological and architectural properties of the m. triceps surae muscle in typically developing children, and the available reliability analyses. Scopus and MEDLINE (Pubmed) were searched systematically for all original articles published up to September 2020 measuring morphological and architectural properties of the m. triceps surae in typically developing children (18 years or under). Thirty eligible studies were included in this analysis, measuring fibre bundle length (FBL) (n = 11), pennation angle (PA) (n = 10), muscle volume (MV) (n = 16) and physiological cross-sectional area (PCSA) (n = 4). Three primary imaging modalities were utilised to assess these architectural parameters in vivo: two-dimensional ultrasound (2DUS; n = 12), three-dimensional ultrasound (3DUS; n = 9) and magnetic resonance imaging (MRI; n = 6). The mean age of participants ranged from 1.4 years to 18 years old. There was an apparent increase in m. gastrocnemius medialis MV and pCSA with age; however, no trend was evident with FBL or PA. Analysis of correlations of muscle variables with age was limited by a lack of longitudinal data and methodological variations between studies affecting outcomes. Only five studies evaluated the reliability of the methods. Imaging methodologies such as MRI and US may provide valuable insight into the development of skeletal muscle from childhood to adulthood; however, variations in methodological approaches can significantly influence outcomes. Researchers wishing to develop a model of typical muscle development should carry out longitudinal architectural assessment of all muscles comprising the m. triceps surae utilising a consistent approach that minimises confounding errors

Architecture of the human soleus muscle, three-dimensional computer modelling of cadaveric muscle and ultrasonographic documentation in vivo

grantor: University of TorontoThe purpose of this study was to visualize and document the architecture of the human soleus muscle throughout its entire volume. The architecture was visualized by creating a three-dimensional manipulatable computer model of an entire cadaveric soleus, 'in situ', using B-spline solids to display muscle fiber bundles that had been serially dissected, pinned and digitized. A database of fiber bundle length and angle of pennation throughout the marginal, posterior and anterior soleus was compiled from three sources: the computer model, manually measured cadaveric specimens and from ultrasonographic scans of relaxed and contracted muscle of living subjects. The computer model allowed documentation of the architectural parameters in three-dimensional space, with the angle of pennation being measured relative to the tangent plane of the point of attachment of a fiber bundle. The architectural parameters recorded to date have been two-dimensional, like those obtained from the scans and manually measured cadaveric specimens in this study. Three-dimensional reconstruction is an exciting innovation since it provides not only an architectural database but also allows visualization of each fiber bundle 'in situ ' from any perspective. It was concluded that the architecture is non-uniform throughout the volume of soleus, the percentage change of the architectural parameters on contraction varies by muscle part and the soleus of females has significantly longer fiber bundles, smaller angles of pennation and is not as thick as the soleus of males. The techniques developed in this thesis provide a novel approach to the study of muscle architecture. Detailed architectural studies may lead to the development of muscle models that can more accurately predict interaction between muscle parts, the effect of pathologic states on muscle function and force generation.Ph.D

Distribution, course, and spatial relationships of the saphenous nerve: A 3D neuroanatomical map for nerve stimulation.

The overall objective of this study was to construct a 3D neuroanatomical map of the saphenous nerve based on cartesian coordinate data to define its course in 3D space relative to bony and soft tissue landmarks. Ten lower limb embalmed specimens were meticulously dissected, digitized, laser scanned, and modelled in 3D. The course of the main branches, number of collateral branches, and relationship of saphenous nerve to the great saphenous vein were defined and quantified using the high-fidelity 3D models. In 60% of specimens, the saphenous nerve was found to have three branches in the leg, infrapatellar, anterior, and posterior. In 40% of specimens, the posterior branch was absent. Three landmarks were found to consistently localize the anterior branch: the medial border of tibia at the level of the tibial tuberosity, the medial border of tibia at the level of the mid-point of leg, and the mid-point of the anterior border of the medial malleolus. The posterior branch, when present, had variable branching patterns but did not extend as far distally as the medial malleolus in any specimen. Anatomically, the anterior and posterior branches at the level of the tibial tuberosity could be most advantageous for nerve stimulation due to their close proximity to the bifurcation of the saphenous nerve where the branches are larger and more readily localizable than distally. Additionally, the tibial tuberosity is a prominent landmark that can be easily identified in most individuals and could be used to localize the anterior and posterior branch using ultrasound or other imaging modalities. These findings will enable implementation of highly realistic computational models that can be used to simulate saphenous nerve stimulation using percutaneous and implanted devices

Automatic three-dimensional reconstruction of fascicles in peripheral nerves from histological images.

Computational studies can be used to support the development of peripheral nerve interfaces, but currently use simplified models of nerve anatomy, which may impact the applicability of simulation results. To better quantify and model neural anatomy across the population, we have developed an algorithm to automatically reconstruct accurate peripheral nerve models from histological cross-sections. We acquired serial median nerve cross-sections from human cadaveric samples, staining one set with hematoxylin and eosin (H&E) and the other using immunohistochemistry (IHC) with anti-neurofilament antibody. We developed a four-step processing pipeline involving registration, fascicle detection, segmentation, and reconstruction. We compared the output of each step to manual ground truths, and additionally compared the final models to commonly used extrusions, via intersection-over-union (IOU). Fascicle detection and segmentation required the use of a neural network and active contours in H&E-stained images, but only simple image processing methods for IHC-stained images. Reconstruction achieved an IOU of 0.42±0.07 for H&E and 0.37±0.16 for IHC images, with errors partially attributable to global misalignment at the registration step, rather than poor reconstruction. This work provides a quantitative baseline for fully automatic construction of peripheral nerve models. Our models provided fascicular shape and branching information that would be lost via extrusion

Naming the Soft Tissue Layers of the Temporoparietal Region: Unifying Anatomic Terminology Across Surgical Disciplines

BACKGROUND: The complexity of temporoparietal anatomy is compounded by inconsistent nomenclature. OBJECTIVE: To provide a comprehensive review of the variations in terminology and anatomic descriptions of the temporoparietal soft tissue layers, with the aim of improving learning and communication across surgical disciplines. METHODS: MEDLINE (1950-2009) searches were conducted for anatomic studies of the temporoparietal region, and for studies describing temporoparietal anatomy in the context of surgical techniques. RESULTS: Sixty-nine articles were included in the review. Naming of the soft tissue layers of the temporoparietal region was inconsistent both within and across surgical disciplines, with several terms utilized for the same layer and occasionally the same term applied to different layers. Studies also varied in their description of the vascular, neural, and soft tissue architecture of the temporoparietal region. CONCLUSION: A uniform, descriptive nomenclature is paramount to facilitating surgical education and interpreting future studies. A naming system based on the Terminologica Anatomica is proposed in this review. From superficial to deep, the proposed terms for the soft tissue layers of the temporoparietal region include: temporoparietal fascia, loose areolar tissue plane, superficial leaflet of temporal fascia, fat pad of temporal fascia, deep leaflet of temporal fascia, fat pad deep to temporal fascia, temporalis or temporal muscle, and pericraniu

Dissections and 3D models of the branching pattern of the saphenous nerve, medial views.

(A) and (B) 3D model and dissection of the same specimen with a long posterior branch. (C) and (D) 3D model and dissection of the same specimen with a short posterior branch. (E) 3D model of specimen with no posterior branch. MM, medial malleolus; MT, medial surface of tibia; P, patella; PL, patellar ligament; TT, tibial tuberosity.</p

Relative position of SN to GSV in the proximal, middle, and distal thirds of the leg.

Relative position of SN to GSV in the proximal, middle, and distal thirds of the leg.</p