The Architecture Of Intramuscular Nerve And Blood Branches In Forearm Muscles: An Anatomical Study

Objective To study on the neurovascular distribution of forearm muscles to reveal anatomical features of muscular branches of forearm nerves and categorize them according to their shapes and distribution; To evaluate whether the muscle in the foream could be split into several functional units for transplant. Methods Five forearm were dissected from 10% formaldehyde-fixed adult cadavers to observe the extramuscular distribution of nerve and blood vessels. Ten forearm muscles were dissected from 4 fresh cadavers and stained with the standard method of Sihler's nerve staining. Eight forearm muscles from four fresh cadavers were studied blood vessels with a mixture of 30% barium sulfate and gelatin from brachial artery and then X-photographed. The resulting pictures were compared to study the intramuscular distribution of nerve and blood vessels. Results The intramuscular nerve branches were clearly visualized after being stained purple-black. The muscles were classified into three classes according to common shapes and intramuscular neurovascular distribution. Class I were controlled by single nerve trunk. Pattern Ia muscles in trapezoidal-shaped were supplied by predominant pedicles with major intramuscular nerves lying perpendicular to muscle fibers and similar orientation and distribution of intramuscular nerve and artery branches. Pattern Ib muscles were spindle-shaped and supplied by segmental pedicle with abundant anastomotic network. Pattern II muscles were all spindle-shaped and supplied by several nerves pertaining to the same trunk. Pattern IIa muscles were unipennates that were supplied by segmental pedicle which were of abundant anastomotic network.. Pattern IIb muscles were split into two parts by their tendons, each with separate innervation and abundant anastomosis. The distribution maps of the intramuscular nerves and the accompanying artery were grossly consistent. Pattern III muscles had multiple heads of origin and multiple tendons of insertion. Pattern IIIa muscles had more than one head of origin, such as pronator teres, which each head receive with separate innervation and were supplied by segmental pedicl combining abundant anastomosis. Pattern IIIb muscles had multiple tendons of insertion, and the intramuscular nerves lying parallel or vertical to muscle fibers. They were generally supplied by segmental or segmental plus dominant pedicles stemming from one single neurovascular bundle before entry into the muscles. Among them, some had one additional recurrent branch at the entry site to the proximal one third of muscle belly, and some were supplied by...