European Journal of Anatomy

Official Journal of The Spanish Society of Anatomy
Cover Volume 24 - Number 6
Eur J Anat, 24 (6): 491-499 (2020)

The architecture of the 6-month-old gastrocnemius: a 3D volumetric study

Luke R. Bradshaw1, Ethan M. Breinhorst1, Ngaire S. Stott2, Anne M.R. Agur3, Seyed A. Mirjalili1

1Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand2Department of Surgery, School of Medicine, University of Auckland, Auckland, New Zealand3Division of Anatomy, Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, Canada

ABSTRACT Gastrocnemius is essential in normal gait, con-tributing to the control of ankle plantarflexion and knee flexion. However, there is a paucity of litera-ture on the architecture of the infant gastrocnemius muscle prior to the onset of weight-bearing and gait. This study investigates the three-dimensional (3D) musculoaponeurotic architecture of the gas-trocnemius in a six-month-old infant. One six-month-old cadaver was used in this study (The University of Toronto Health Sciences Research Ethics Board, #32679, and The University of Auck-land Human Participants Ethics Committee, #016164). Medial (MG) and lateral (LG) heads of the gastrocnemius were serially dissected and a Microscribe G2X™ digitizer used to digitize fiber bundles, aponeuroses and tendons. Data were then exported to Autodesk® Maya® to create 3D models. Custom software quantified architectural parameters, including fiber bundle length, penna-tion angle, physiological cross-sectional area, and muscle volume. The intramuscular architecture was assessed to determine whether musculoapo-neurotic partitions were present. Muscle volume was <1cm3 for both MG and LG. Three architec-tural partitions, proximal, middle, and distal, were identified for both MG and LG. Notably, the proxi-mal partitions of both MG and LG had mean fiber bundle length at 2.21 ± 0.41 cm and 2.22 ± 0.27 cm, significantly greater (p<0.05) than the middle and the distal partitions. The results of this study suggest that both MG and LG have architectural partitions before the commencement of gait. Fur-ther longitudinal studies with larger sample sizes are needed to confirm the presence of these archi-tectural partitions, as well as to investigate their growth across the developmental spectrum.

Keywords: Gastrocnemius – Infant – Muscle architecture – Skeletal muscle – Digitization – Growth – Development

European Journal of anatomy
ISSN 2340-311X (Online)