The Sectional Anatomy And 3-D Reconstruction Of The Cubital Tunnel And Relevant Structure

Objective To demonstrate the precise anatomy of the cubital tunnel and epitrochleo-anconeus (EA) by successive celloidin-embedded slices and three-dimensional reconstruction technique may be required for elucidating the potential pathogenesis of the cubital tunnel syndrome. This study also provides the anatomical data for the simple decompression procedure, to treat the cubital tunnel syndrome more efficaciously.Materials and methodsâ‘ 14 elbows were obtained from 7 formalin-fixed adult cadavers.11 elbows dissected to reveal the anatomy of the cubital tunnel.3 extended elbows were decalcified with 8% hydrochloric acid for 70 days, then were embedded in celloidin, cut into successive horizontal,coronal and sagittal slices with an immersing-alcohol microtome (L-type, R. Jung AG, Heidelberg, Germany). The slices explored with anatomic microscopy. All slices were read blindly by 2 readers. 67 images of the successive horizontal sections were imported into 3D-doctor 3.5 (Able Software Corp. Lexington, MA) from inferior to superior. The bone, capsule, triceps brachii muscle, EA, ulnar nerve and the FCU were marked with a different color, and then complete the reconstruction.â‘¡We collected 13 patients' MRI images which took during the period from July to September in Tianjin First Center Hospital. All the 13 patients were without the disease of abdominal to compare with the slices.Resultâ‘ The cubital tunnel is an ellipse tunnel. It is formed by the floor and the roof. The content in it is ulnar nerve, the inferior ulnar collateral artery and vein and posterior ulnar recurrent artery and vein supplying the ulnar nerve.The floor of cubital tunnel is formed by the elbow capsule and the anterior bundle, posterior bundle and the transverse bundle of ulnar collateral ligament(UCL). The roof of cubital tunnel is formed by the cubital tunnel retinaculum or EA and the fascia between the two heads of FCU. The EA muscle origin from the medial epicondyle and the upper 1/3 portion of this muscle inserted to the medial margin of the olecranon through a long fascia while the lower 2/3 portion directly to it. A fascial pedicle connected the ulnar nerve to the posterolateral portion of the floor at the level of the retrocondylar groove.â‘¡Each structure of elbow joint is showed well on the slices, boundary obviously, easy to recognized. The elbow joint is showed well on the MRI. Small structures can also be displayed with MRI, though their borders are not clear. The display of the elbow joint by MRI is basically consistent to that of the slices. So the MRI is an ideal method to display the elbow joint.Conclusionsâ‘ The floor of cubital tunnel is formed by the elbow capsule and the anterior bundle, posterior bundle and the transverse bundle of ulnar collateral ligament (UCL). The roof of cubital tunnel is formed by the cubital tunnel retinaculum or EA and the fascia between the two heads of FCU.â‘¡With the accurate anatomic knowledge of EA, it could be precisely and reasonably excised for treatment of cubital tunnel syndrome.â‘¢The fascial pedicle may have the function to prevent the ulnar nerve from hypermobile or subluxation. Base on the different aetiology (compression or stretch), management of the fascial pedicle in simple decompression should be different.â‘£Comparing the slices and the MRI is useful for the doctor to speculate the more precise anatomy of the eblow and obtain precise diagnosis by the MRI.