Anatomic and Biomechanical Study of the Forearm Interosseous Membrane, Distal Oblique Bundle, and Triangular Fibrocartilage Complex: Role in Galeazzi Fracture Dislocation.

Purpose: The purpose of this study was to measure distal radioulnar joint (DRUJ) dislocation and radioulnar displacement associated with sequential sectioning of the different bands of the interosseous membrane and triangular fibrocartilage complex in the simulation of a Galeazzi fracture dislocation. Methods: Twelve fresh-frozen cadaver forearms were dissected. We examined the anatomy and function of the forearm interosseous membrane. Each forearm was then mounted onto a biomechanical wrist and forearm device. In the control group, radial osteotomy was performed and the degree of DRUJ displacement with progressive loads was measured. In addition to radial osteotomy, in group 1, the central band (CB) was sectioned; in group 2, the CB, distal membranous portion of the interosseous membrane, and distal oblique bundle were sectioned; and in group 3, the CB, distal membranous portion of the interosseous membrane, distal oblique bundle, and triangular fibrocartilage complex were sectioned. Results: The radioulnar displacement (mm) at 25 N, 50 N, and 75 N was recorded. In group 1, applying progressive loads resulted in an average DRUJ displacement of 4.3, 5.9, and 7.9 mm, respectively. In group 2, the displacement was 5.2, 5.7, and 6.9 mm, respectively. In group 3, the displacement was 6.2, 8.1, and 9.9 mm, respectively. Our study showed a correlation between increase in the load applied to the same injury and the degree of displacement (P = .001). In group 3, the degree of DRUJ displacement was statistically increased compared to the other groups (P = .04). Conclusions: Migration of the radius under loads implies disruption of both the CB and triangular fibrocartilage complex. The distal oblique bundle by itself does not seem to have a relevant role in radioulnar displacement at the DRUJ. Clinical relevance: This study provides insights into the interosseous membrane and stability of the DRUJ, which can contribute to a better understanding of Galeazzi fracture-dislocations.

Ultrasound-anatomic correlation of the peripheral nerves of the upper limb.

BACKGROUND: Sonography allows good visualization of the peripheral nerves and the vascular and muscular structures that surround them. Our goals are to provide an easy-to-use atlas that gives accurate information about the locations and relations among the nerves in the different parts of the arm and to correlate it with the probe position and the ultrasound images. MATERIALS AND METHODS: A cadaver right arm was used for the present study. The arterial and venous vessels were injected with red and blue-colored latex to obtain a better correlation with ultrasound slices from two healthy volunteers. The specimen was frozen and then cut into slices with an average thickness of 2 cm, starting from the lower part of the axilla. RESULTS: Close correlation was present between the ultrasound and anatomic slices identifying the main muscular, vascular and nervous structures. In the arm, median, ulnar and radial nerves were easily seen because of the proximity to vascular landmark and their size. In the forearm, the ulnar nerve was also easy to identify because of the factors previously mentioned; the median nerve was easy to locate between the flexor digitorum superficialis and profundus muscles. The superficial branch of the radial arm was seen in most cases, although some skill was required. CONCLUSION: Ultrasound is a useful tool to identify the main nerves of the upper arm. This atlas indicates the locations and relations among the nerves, correlating with the ultrasound appearance.

Arteries of the scrotum: a microvascular study and its application to urethral reconstruction with scrotal flaps.

OBJECTIVE: To study scrotal microvascularization and apply the findings to the design of reliable skin flaps for reconstructive surgery of complex urethral or panurethral stenoses. MATERIALS AND METHODS: In 15 cryopreserved male cadavers, scrotal skin vascularization was explored using macro- and microdissections, and the scrotal sac made transparent using the Spalteholtz method. A meticulous descriptive analysis of the arterial network was conducted out in all cases to evaluate the number, distribution and anastomosis of the cutaneous arteries of the scrotum. RESULTS: Scrotal skin is irrigated by two main vascular systems, through the inferior external pudendal arteries and the perineal arteries, which branch into multiple scrotal arteries. These arteries are distributed in three cutaneous territories, two lateral and one central, which are widely inter-anastomosed. Each lateral territory receives an inferior external pudendal artery which accesses at the midpoint of the scrotal root and fans out to cover the entire corresponding hemiscrotum. The central cutaneous territory is vascularized through the branches of two main scrotal arteries which are a continuation of the perineal arteries and which access via the posterior face, running deeply on both sides of the septum. CONCLUSIONS: The special anatomical distribution of scrotal branches stemming from perineal arteries enables the construction of adequate reliable longitudinal median island scrotal flaps for the reconstructive surgery of panurethral stenosis, as profuse axial vascularization is ensured.