The lateral root of the ulnar nerve

In 158 brachial plexuses the origin of the fibers of the ulnar nerve-whether only from the medial or also from the lateral fascicle-was investigated. A lateral root was found in 56%. This lateral root may either be accompanied by fibers of the median nerve (type 1) or may run separately (type 2). Where this root crosses the medial root of the median nerve, either a small minority of fibers of the latter nerve may run behind the ulnar fibers (type a), or all median fibers are in front of them (type b). Considering the relation 56:44% between ulnar nerves with and without a lateral root both possibilities have to be considered as normal variations, none as a variety. In analogy to the term 'median loop' the term 'ulnaris loop' is suggested for specimens with a lateral root.     

Design and implementation of an instrumented ulnar head prosthesis to measure loads in vitro

The development of a novel instrumented implant for ulnar head replacement is presented in this study. This implant was instrumented with strain gauges to quantify bending moments about the anatomic axes of the distal ulna, and subsequently the distal radioulnar joint (DRUJ) reaction force magnitude. The implant was surgically inserted in seven cadaveric upper extremities, which were subsequently mounted in a custom joint simulator. Simulated active unresisted pronation and supination motion trials were conducted using computer-controlled pneumatic actuators to simulate forearm musculature. Passive (unloaded) trials were also conducted. The reaction force across the DRUJ ranged from 2 to 10 N in magnitude during this unresisted motion. Increased bending moment magnitudes were measured when the forearm was positioned in supination compared to pronation. The magnitude of joint bending moments showed a consistent pattern with forearm position, regardless of simulated active or passive rotation, or supination and pronation motion trials. This result illustrates that the primary influence on joint load is likely the position and contact with the radial articulation. This study of DRUJ loading should be useful for biomechanical modeling, implant design considerations and improved knowledge of articular mechanics.     

Island flap supplied by the dorsal branch of the ulnar artery

Two cases are reported in which a fasciocutaneous island flap was employed supplied by the ulnaris dorsalis artery after the method proposed by Becker and Gilbert. The original technique has been modified by the authors, and this produces a better venous outflow. The vascular pedicle includes, besides the ascending branch of the artery and the venae comitantes, one of the superficial veins together with its respective subdermal band. A technique is also described that provides an optimal length for the vascular pedicle.     

Recurrent anterior dislocation of the ulnar nerve at the cubital tunnel

Recurrent anterior dislocation of the ulnar nerve at the cubital tunnel is reported in two patients. This was due to traumatic attenuation of the flexor carpi ulnaris retinaculum. The mechanism of injury in both patients was a fall with the shoulder abducted and the elbow acutely flexed. Both patients had relief of their neurologic symptoms following anterior submuscular transposition of the ulnar nerve.     

Parameters of the ulnar medullary canal for locked intramedullary nailing

The development of a ‘one shot’ locked intramedullary device for rapid stabilization of adult ulnar fractures would benefit surgeon and patient alike, but, before a prototype device can be manufactured, basic internal measurements of the ulnar medullary canal are needed. Various sections and measurements of 142 adult human cadaver ulnas were performed to determine the calibre, length and curvature of the medullary canal. These measurements revealed that the device can be of one calibre but will need to be manufactured in three different lengths. Because of the minimal curvature of the ulnar medullary canal and the ability to lock the nail both proximally and distally, the nail can be straight and inserted loosely. A prototype design is described.     

A surgical approach to the motor branch of the ulnar nerve

Isolated injury to the motor branch of the ulnar nerve is a relatively rare injury, often initially misdiagnosed. If repair is attempted through the original laceration without complete motor branch exposure, results can be less than satisfactory. A recent case illustrates this injury and provides us with an opportunity to review the surgical anatomy of the motor branch of the ulnar nerve. The surgical approach to the motor branch has been detailed and specifically emphasizes complete motor branch exposure from the main ulnar nerve trunk to the most distal motor branch entry into the adductor pollicis muscle. This approach permits definition of the exact level of the nerve injury, preservation of any intact proximal fine motor branches, and facilitates the mechanics of nerve repair.     

Use of an adipofascial flap based on the proximal perforators of the ulnar artery to correct contracture of elbow burn scars: an anatomic and clinical approach.

Different techniques can be used to repair contracture of burn scars on the elbow, including local or distant pedicle flaps, muscle or myocutaneous flaps, free flaps, and tissue expanders. Among these, a pedicled adipofascial flap based on the most proximal two to four perforators of the ulnar artery (located 1 to 5 cm from the origin of the artery) can be anastomosed to form a sort of axially patterned blood supply within the fascia and subcutaneous fat. Therefore, no major vessel in the forearm need ever be severed. In addition, use of this type of flap preserves muscle function. The pedicled adipofascial flap described in this article allows for early rehabilitation because the flap is thin and pliable. Additional advantages are the easy and quick dissection and completion of the procedure in one stage. A detailed anatomic dissection of the flap was performed on 16 upper extremities from fresh cadavers; an injection study was also performed to determine the location and dimensions of the pedicle flap and its area of reach around the elbow. In the past 3 years, 14 flaps were used in 13 patients to repair elbow defects after release of burn scar contractures. Flap dimensions ranged from 4 x 7 cm to 6 x 14 cm (mean flap size, 74 cm). The results were very satisfactory.