Brachial plexus variations during the fetal period

Abstract

The brachial plexus is an important nervous system structure. It can be injured during the perinatal period and by postnatal damage. The goal of this study was to assess human fetal brachial plexus variability. A total of 220 brachial plexuses were surgically prepared from 110 human fetuses aged 14-32 weeks of fetal life (50 females and 60 males) ranging in CRL from 80 to 233 mm. The study incorporated the following methods: dissectional and anthropological, digital image acquisition, digital image processing using Image J and GIMP software, and statistical methods (Statistica 9.0). Symmetry and sexual dimorphism were examined. Anomalies of the brachial plexuses were observed in 117 (53.18 %) cases. No sexual dimorphism was found. It was observed that cord variations occurred more often on the left side. Division variants (33.64 %) occurred most often, but also cords (18.18 %) as well as root nerves and terminal ramifications (15.90 %) were found. Trunk anomalies were rare and occurred in only 5.45 % of plexuses. Three height types of median nerve roots in combination with the nerve were distinguished. In one-third of cases, median nerve root connections were found below the axillary fossa and even half in the proximal part of the humerus. In conclusion, the brachial plexus was characterized for anatomical structural variability. Most often division and cord variations were observed. Anomalies occurred regardless of sex or body side except for cord variants. Brachial plexus variation recognition is significant from the neurosurgical and traumatological point of view.

Anatomical variations of brachial plexus in fetal cadavers

“…In another study conducted by Wozniak et al, distal nerve variations were observed in 35 cases (15.90%) (27). Uysal et al reported terminal branch variations in 8.5% of the cases they observed where the roots of the nervus medianus joined in the distal part of the arm; in 2.5% of the cases, the axillary nerve was separate from the posterior division of the TS.…”

“…On the other hand, postfixed BPs were reported by Singhal et al and Matejcik et al with a frequency of 5% and 2%, respectively (14,23). In general, variations are not limited to the origin of the BP, although division, cord and distal ramification anomalies have been also reported (27).…”

“…It has been demonstrated in studies that extensive variations may accompany BP in the formation of roots, trunks, divisions and cords. For instance, a C4 nerve supernumerary root was found or the T2 nerve root formed the BP (27). Studies conducted by Singhal et al, Matejcik, and Fazan et al, reported an incidence of prefixed BP at a proportion of 24%, 21.7% and 48%, respectively (4,14,23).…”

Prevalence of musculocutaneous nerve variations: Systematic review and meta‐analysis

“…All included studies were performed on cadavers. Among 20 studies that specified the age of cadavers (fetus or adult), five studies (Uysal et al, ; Kervancioglu et al, ; Woźniak et al, ; Reis et al, ; Caetano et al, ) dissected fetuses, one study (Guerri‐Guttenberg and Ingolotti, ) included both fetuses and adults, while 14 studies dissected only adult cadavers (Chiarapattanakom et al, ; Aktan et al, ; Choi et al, ; Beheiry, ; Loukas and Aqueelah, ; Pacha Vicente et al, ; Maheswari and Sadanandam, ; Pozo Kreilinger et al, ; Budhiraja et al, ; Sawant et al, ; Chaudhary et al, ; Ballesteros et al, ; Cambon‐Binder and Leclercq, ; Leng et al, ). Only in eight studies, the variations were described together with information about the sex of individual cadavers in whom they were encountered.…”

Bilateral anatomic variation in the relation of the upper trunk of the brachial plexus to the anterior scalene muscle

“…Variations in the formation of the BP's trunks [4,7,[23][24][25], as well as in their relation to the scalene muscles [5,18], have been described in the literature. Certain variations are linked to the neurogenic thoracic outlet syndrome (TOS) [9], due to the proximity of the muscle fibres and the nerves.…”