Innervation Patterns of the Lumbrical Muscles of the Foot in Human Fetuses

Background We sought to describe the innervation patterns of the foot lumbrical muscles and their morphological properties in human fetuses and to define the communicating branches between the medial (MPN) and lateral (LPN) plantar nerves, which play a part in the innervation of those muscles. Methods Thirty formalin-fixed fetuses (13 male and 17 female) with a mean ± SD gestational age of 25.5 ± 3.8 weeks (range, 18–36 weeks) from the inventory of the Mersin University Faculty of Medicine Anatomy Department were bilaterally dissected. Innervation patterns of the lumbrical muscles and the communicating branches between the MPN and the LPN were detected and photographed. Results No variations were seen in lumbrical muscle numbers. In the 60 feet, the first lumbrical muscle started directly from the flexor digitorum longus tendon in 48 and from the flexor hallucis longus slips in addition to the flexor digitorum longus tendon in 12. Fifty-five feet had the classic innervation pattern of the lumbrical muscles, and five had variations. No communicating branches were seen in 48 feet, whereas 12 had connections. Conclusions This study classified innervation patterns of the foot lumbrical muscles and defined two new innervation types. During surgeries on the foot and ankle in neonatal and early childhood terms, awareness of the communicating branches between the MPN and the LPN and innervation of the intrinsic muscles of the foot, such as the lumbrical muscles, might aid in preventing possible complications.

Morphological study of the hypoglossal and lingual nerves

Background and objectives: In treatment of dental conditions and dental anaesthesiology, a thorough understaoding of course, directions and distribution of nerves and blood vessels supplying the tongue is extremely important. However, the morphology of the nerves supplying the tongue has not yet been fully understood. We applied comparative anatomical approach in order to observe innervation of the tongue in detail, with the focus on the distribution of the lingual nerves and its communication with the hypoglossal nerve. Material and methods: Ten adult human tongues with no grossly detectable abnormalities that were resected from cadavers donated for anatomical study and five monkey tongues were used. Specimens were immersed in water and dissected under a stereomicroscope, and gross examination of the morphology and directions of branches of the hypoglossal and lingual nerves, communicating branches between these two nerves, and their connection status was done. Observations: All branches shared common morphological characteristics: branches near the root of the tongue were relatively straight, while they meandered and formed loops nearer to the apex of tongue. In addition to the branch on the anterior muscle bundle of the hyoglossus muscle, which could be easily observed, there were two more communicating points (total of three communicating branches in both humans and Japanese macaques: in the inner part of the genioglossus muscle and the apex of the tongue). Conclusions: The levels of communicating nerve complexity between the hypoglossal nerve and the lingual nerve and the thickness of nerve fibers varied among individual subjects, but there was a common three-site communication pattern.