Quantitative and Neurovascular Anatomy of the Growing Gracilis Muscle in the Human Fetuses.

This study is intended to obtain the algebraic growth dynamics of the gracilis in fetuses and determine the variations of neurovascular pedicle(s) of the gracilis, to aid infant surgeries. Forty fetuses (19 males and 21 females) were included in the study. Gestational mean age of the fetuses was 22.40 ±â€Š2.67 (range, 18-28) weeks. Numerical values were obtained using a digital caliper and a digital image analysis software. Linear functions for the surface area, width, anterior, and posterior margin lengths of the gracilis were calculated, respectively, as: y = -289.307 + 20.501 × age (weeks), y = -7.113 + 0.622 × age (weeks), y = -24.421 + 3.434 × age (weeks), and y = -24.397 + 3.314 × age (weeks). In addition, length and width of the gracilis tendon were calculated as y = -6.676 + 0.934 × age (weeks) and y = -0.732 + 0.074 × age (weeks), respectively. Parameters of the gracilis had no statistically significant difference regarding side and sex (P > 0.05). In all the specimens, the gracilis was innervated by the anterior branch of the obturator nerve. Blood supply of the gracilis was identified to be derived from 1 single artery in 38 sides of total 80 (47.5%), from 2 arteries in 36 (45%) and from 3 arteries in 6 (7.5%). In 74 sides (92.5%), the nerve was superficial to the main artery, whereas in 6 sides (7.5%), it was deeper. The data of the present study could be beneficial for surgeons in infant surgeries to treat conditions such as obstetrical brachial plexus paralysis, facial palsy, or anal incontinence. Linear functions can be utilized to better evaluate the growth course of the gracilis in fetuses and to predict the dimensions thereof. Additionally, comprehending the structure and recognizing the variations of the gracilis nerves and arteries can help to protect the neurovascular pedicle(s) of the gracilis during the operations.

Anatomy and morphometry of the distal gracilis muscle tendon in adults and foetuses.

Ten human gracilis muscles obtained from adults and ten gracilis muscles collected from human foetuses between the 15th and 21st week of gestation were examined. The results of this preparatory study show that the gracilis muscle in adults is narrow and long - 482 mm on average. The distal tendon of gracilis muscle is long, 294 mm on average. It can be divided into two sections - external part, outside the muscle belly, and internal, intramuscular, part. The latter one is partially covered by muscle fibres and some of it is completely hidden inside the muscle belly, which is on average 76 mm long. Presence of an intramuscular part of the distal tendon was also demonstrated in the foetal material. Moreover, very strong correlations between particular muscle lengths were noted in foetuses. (Folia Morphol 2018; 77, 1: 138-143).