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Objective: The goal of this study was to describe anatomical variations and clinical implications of anterior interosseous nerve. In complete anterior interosseous nerve palsy, the patient is unable to flex the distal phalanx of the thumb and index finger; in incomplete anterior interosseous nerve palsy, there is less axonal damage, and either the thumb or the index finger are affected., Methods: This study was based on the dissection of 50 limbs of 25 cadavers, 22 were male and three, female. Age ranged from 28 to 77 years, 14 were white and 11 were non-white; 18 were prepared by intra-arterial injection of a solution of 10% glycerol and formaldehyde, and seven were freshly dissected cadavers., Results: The anterior interosseous nerve arose from the median nerve, an average of 5.2 cm distal to the intercondylar line. In 29 limbs, it originated from the nerve fascicles of the posterior region of the median nerve and in 21 limbs, of the posterolateral fascicles. In 41 limbs, the anterior interosseous nerve positioned between the humeral and ulnar head of the pronator teres muscle. In two limbs, anterior interosseous nerve duplication was observed. In all members, it was observed that the anterior interosseous nerve arose from the median nerve proximal to the arch of the flexor digitorum superficialis muscle. In 24 limbs, the branches of the anterior interosseous nerve occurred proximal to the arch and in 26, distal to it., Conclusion: The fibrous arches formed by the humeral and ulnar heads of the pronator teres muscle, the fibrous arch of the flexor digitorum superficialis muscle, and the Gantzer muscle (when hypertrophied and positioned anterior to the anterior interosseous nerve), can compress the nerve against deep structures, altering its normal course, by narrowing its space, causing alterations longus and flexor digitorum profundus muscles.

Objective: The aim of this study was to analyze the anatomic variations of the bicipital aponeurosis (BA) ( lacertus fibrosus ) and its implications for the compression of the median nerve, which is positioned medially to the brachial artery, passing under the bicipital aponeurosis., Methods: Sixty upper limbs of 30 cadavers were dissected, 26 of which were male and four, female; of the total, 15 had been previously preserved in formalin and glycerine and 15 were dissected fresh in the Laboratory of Anatomy., Results: In 55 limbs, short and long heads of the biceps muscle contributed to the formation of the BA, and the most significant contribution was always from the short head. In three limbs, only the short head contributed to the formation of the BA. In two limbs, the BA was absent. The length of the bicipital aponeurosis from its origin to its insertion ranged from 4.5 to 6.2 cm and its width, from 0.5 to 2.6 cm. In 42 limbs, the BA was thickened; of these, in 27 it was resting directly on the median nerve, and in 17 a high insertion of the humeral head of the pronator teres muscle was found, and the muscle was interposed between the BA and the median nerve., Conclusion: These results suggest that a thickened BA may be a potential factor for nerve compression, by narrowing the space through which the median nerve passes.

Objective: To determine the frequency and features of the arcade of Struthers, and to assess its clinical implication in ulnar nerve compression., Method: Forty arms from 26 cadaver specimens were dissected in the Anatomy Laboratory of this institution. The extension of the arcade, distance from the medial epicondyle, and relation with ulnar nerve were recorded., Results: The arcade of Struthers was identified in 40 dissected arms (100%). In 29 (72.5%) the ulnar nerve was covered by a muscular arcade, in nine (22.5%) by an aponeurotic arcade, and in two (5%) the arcade was beneath the ulnar nerve. The extension of the arcade ranged from 3.0 to 7.5 cm, and the distance from the medial epicondyle ranged from 2.5 to 7.0 cm., Conclusion: The arcade of Struthers is a musculoaponeurotic canal that represents an important site of entrapment or compression of the ulnar nerve. The arcade, the intermuscular septum, and the internal brachial ligament should be released in patients submitted to ulnar nerve anterior transposition surgery.

Objective: To assess the anatomical variations of the pronator teres muscle (PTM) and its implication in the compression of the median nerve, which passes through the humeral and ulnar heads of the PTM., Methods: For the present study, 100 upper limbs from human cadavers from the anatomy laboratory were dissected. Forty-six specimens were male and four, female, whose aged ranged from 28 to 77 years; 27 were white and 23, non-white. A pilot study consisting of six hands from three fresh cadaver dissections was conducted to familiarize the authors with the local anatomy; these were not included in the present study., Results: The humeral and ulnar heads of PTM were present in 86 limbs. In 72 out of the 86 limbs, the median nerve was positioned between the two heads of the PTM; in 11, it passed through the muscle belly of ulnar head of the PTM, and in three, posteriorly to both heads of the PTM. When both heads were present, the median nerve was not observed as passing through the muscle belly of the humeral head of PTM. In 14 out of the 100 dissected limbs, the ulnar head of the PTM was not observed; in this situation, the median nerve was positioned posteriorly to the humeral head in 11 limbs, and passed through the humeral head in three. In 17 limbs, the ulnar head of PTM was little developed, with a fibrous band originating from the ulnar coronoid process, associated with a distal muscle component near the union with the humeral head. In four limbs, the ulnar head of the MPR was represented by a fibrous band. In both limbs of one cadaver, a fibrous band was observed between the supinator muscle and the humeral head of the PTM, passing over median nerve., Conclusion: The results suggest that these anatomical variations in relationship median nerve and PTM are potential factors for median nerve compression, as they narrow the space through which the median nerve passes.

Objective: This experimental study aimed to evaluate the biological performance of poly (l-co-D, l-lactic acid)-co-trimetilene carbonate/poly (vinyl alcohol) (PLDLA-co TMC/PVA), hydrogel scaffolds, as an implant in the filling (and not in the repair) of osteochondral defects in New Zealand rabbits, assessing the influence of the material in tissue protection in vivo ., Methods: Twelve rabbits were divided into groups of nine and 16 weeks. In each animal, an osteochondral defect was created in both medial femoral condyles. In one knee, a hydrogel scaffold was implanted (pin group) and in the other, the defect was maintained (control group). A histological analysis of the material was performed after euthanasia., Results: The condyles of the pin group showed no inflammatory reaction and were surrounded by a fibrous capsule. The control group presented higher bone growth in the areas of the defect, but with disorganized articular cartilage, evident fibrosis, bone exposure, atrophy, and proliferation of synovial membrane., Conclusion: The hydrogel pins are promising in filling osteochondral defects, generally do not cause inflammatory reactions, and are not effective in the repair of osteochondral defects.

Objective: The main objective of this study was to describe Martin-Gruber anastomosis anatomically and to recognize its clinical repercussions., Method: 100 forearms of 50 adult cadavers were dissected in an anatomy laboratory. The dissection was performed by means of a midline incision along the entire forearm and the lower third of the upper arm. Two flaps including skin and subcutaneous tissue were folded back on the radial and ulnar sides, respectively., Results: Nerve communication between the median and ulnar nerves in the forearm (Martin-Gruber anastomosis) was found in 27 forearms. The anastomosis was classified into six types: type I: anastomosis between the anterior interosseous nerve and the ulnar nerve (n = 9); type II: anastomosis between the anterior interosseous nerve and the ulnar nerve at two points (double anastomosis) (n = 2); type III: anastomosis between the median nerve and the ulnar nerve (n = 4); type IV: anastomosis between branches of the median nerve and ulnar nerve heading toward the flexor digitorum profundus muscle of the fingers; these fascicles form a loop with distal convexity (n = 5); type V: intramuscular anastomosis (n = 5); and type VI: anastomosis between a branch of the median nerve to the flexor digitorum superficialis muscle and the ulnar nerve (n = 2)., Conclusion: Knowledge of the anatomical variations relating to the innervation of the hand has great importance, especially with regard to physical examination, diagnosis, prognosis and surgical treatment. If these variations are not given due regard, errors and other consequences will be inevitable.

Objective: The objective of our study was to evaluate the effect that knee flexion angle while femoral tunnels are being drilled may have on the length of these tunnels, in anatomical reconstruction of the anterior cruciate ligament., Methods: We measured the lengths of anteromedial and posterolateral tunnels for the anterior cruciate ligament in 20 unpaired anatomical knee specimens (10 right and 10 left knees), all with the cartilage and cruciate ligaments intact. Tunnels were drilled with the knees flexed at 90°, 110° and 130°, through the accessory anteromedial portal, with a 2.5 mm drill. The statistical analysis was done by means of Friedman's variance analysis and the Mann-Whitney U test., Results: The mean anteromedial femoral tunnel lengths measured with the knees flexed at 90°, 110° and 130° were 33.7 (± 3.72) mm, 37.4 (± 2.93) mm and 38.8 (± 3.31) mm, respectively. For the posterolateral femoral tunnel lengths, the results were 32.1 (± 4.24) mm, 37.3 (± 4.85) mm and 38.4 (± 2.51) mm, respectively. Friedman's variance analysis showed that there was a significant difference between the lengths of the tunnels drilled with 90° and 110° of flexion angle, but showed that there was no significant difference between the tunnels drilled with flexion of 110° and 130° (P < 0.05)., Conclusions: It is possible to drill the femoral tunnels through the accessory anteromedial tunnel with the knee flexed at 110° in such a way as to produce a tunnel of sufficient length for a good bone-graft interface.

Objective: To induce growth of a neomeniscus into the pores of a prosthesis in order to protect the knee joint cartilage., Methods: 70 knees of 35 New Zealand rabbits were operated. The rabbits were five to seven months old, weighed 2 to 3.8 kilograms, and 22 were male and 13 were female. Each animal underwent medial meniscectomy in both knees during a single operation. A bioabsorbable polymeric meniscal prosthesis composed of 70% polydioxanone and 30% L-lactic acid polymer was implanted in one side. The animals were sacrificed after different postoperative time intervals. The femoral condyles and neomeniscus were subjected to histological analysis. Histograms were used to measure the degradation and absorption of the prosthesis, the growth of meniscal tissue in the prosthesis and the degree of degradation of the femoral condyle joint cartilage., Results: The data obtained showed that tissue growth histologically resembling a normal meniscus occurred, with gradual absorption of the prosthesis, and the percentages of chondrocytes on the control side and prosthesis side., Conclusion: Tissue growth into the prosthesis pores that histologically resembled the normal rabbit meniscus was observed. The joint cartilage of the femoral condyles on the prosthesis side presented greater numbers of chondrocytes in all its layers.

Objectives: To put forward an anatomical description of the innervation of the elbow capsule, illustrated through morphological analysis on dissections., Methods: Thirty elbows from fresh fixed adult cadavers aged 32-74 years, of both sexes, were dissected., Results: Among the dissected arms, we observed that the median nerve did not have any branches in two arms, while it had one branch in five arms, two branches in two arms, three branches in ten arms, four branches in nine arms and five branches in two arms. The radial nerve did not have any branches in two arms, while it had one branch in two arms, two branches in nine arms, three branches in ten arms, four branches in five arms and five branches in two arms. The ulnar nerve did not have any branches in three arms, while it had one branch in six arms, two branches in four arms, three branches in five arms, four branches in seven arms, five branches in four arms and six branches in one arm., Conclusions: We observed branches of the radial, ulnar and medial nerves in the elbow joint, and a close relationship between their capsular and motor branches.

Objective: To describe the path of the infrapatellar branch of the saphenous nerve (IBSN) using the medial joint line, anterior tibial tuberosity (ATT), tibial collateral ligament and a horizontal line parallel to the medial joint line that passes over the ATT, as reference points, in order to help surgeons to diminish the likelihood of injuring this nerve branch during reconstruction of the anterior cruciate ligament (ACL) using flexor tendons., Methods: Ten frozen knees that originated from amputations were examined. Through anatomical dissection performed with the specimens flexed, we sought to find the IBSN, from its most medial and proximal portion to its most lateral and distal portion. Following this, the anatomical specimens were photographed and, using the ImageJ software, we determined the distance from the IBSN to the medial joint line and to a lower horizontal line going through the ATT and parallel to the first line. We also measured the angle of the direction of the path of the nerve branch in relation to this lower line., Results: The mean angle of the path of the nerve branch in relation to the lower horizontal line was 17.50 ± 6.17°. The mean distance from the IBSN to the medial joint line was 2.61 ± 0.59 cm and from the IBSN to the lower horizontal line, 1.44 ± 0.51 cm., Conclusion: The IBSN was found in all the knees studied. In three knees, we found a second branch proximal to the first one. The direction of its path was always from proximal and medial to distal and lateral. The IBSN was always proximal and medial to the ATT and distal to the medial joint line. The medial angle between its direction and a horizontal line going through the ATT was 17.50 ± 6.17°.

Objective: To evaluate the frequency and morphometry of the Wrisberg's ligament and its relationships with the posterior cruciate ligament's femoral insertion., Study Design: Controlled laboratory study., Methods: 24 unpaired knee pieces, 12 right and 12 left were submitted to a deep dissection of the Wrisberg and posterior cruciate ligaments. The pieces were photographed with a digital camera and ruler; the Image J software was used to measure the ligaments' insertion areas, in square millimeters., Results: The Wrisberg ligament was present in 91.6% of the studied pieces. In those its shape was elliptical in 12 pieces (54.54%). In 68% of the knees, the WL insertion was proximal to the medial intercondilar ridge, close to the PCL posteromedial bundle. The average area for the WL was 20.46 ± 6.12 mm 2 . This number corresponded to 23.3% of the PCL's average area., Conclusions: WL ligament is a common structure in knees. There is a wide variation of its insertion area. Proportionally to the PCL's insertion area the WL ones suggests that it may contribute to the posterior stability of the knee joint.

Objective: To provide anatomical and morphometric basis of the posterior cruciate ligament's tibial insertions in order to assist the creation of anatomical tibial tunnels, in the ligament surgical reconstruction., Material and Methods: The topographic anatomy and morphometry of the posterior cruciate ligament's anterolateral and posteromedial bundles' tibial insertions were analyzed in 24 anatomical knee pieces. The pieces were photographed by a digital camera and the images obtained were studied by the software ImageJ, where the bundles' insertion areas were measured in square millimeters, and the length of structures and the distances between significant points were measured in millimeters., Results: In 54.2% of the knees the insertion' shape was concave; in most pieces (41.6%) the form of insertion was oval. The average posterior cruciate ligament's tibial insertion total area was 88.33 ± 21.66 mm 2 ; the average anterolateral bundle's tibial insertion area was 46.79 ± 14.10 mm 2 and it was 41.54 ± 9.75 mm 2 for the posteromedial bundle., Conclusions: The anterolateral bundle has a tibial insertion area larger than the posteromedial bundle; the insertion areas of those bundles in our study, were smaller than the ones found in the literature. The variations in the posterior cruciate ligament's tibial insertion area suggest that there should be an indication for anatomical reconstructions of this ligament using single or double tibial tunnels according to individual characteristics.

Purpose: To provide an anatomical and morphometric basis for the femoral insertions of the posterior cruciate ligament (PCL) in order to aid in the creation of anatomical femoral tunnels in ligament surgical reconstruction. Study design: laboratory controlled study., Material and Methods: The macroscopic details of the femoral insertions of the PCL's anterolateral (AL) and posteromedial (PM) bundles were analyzed in 24 cadaver knees. The specimens were photographed with a digital camera and the images obtained were studied using the software ImageJ. The bundles' insertion areas were measured in square millimeters, and the length of the structures and the distances between significant points were measured in millimeters., Results: The PCL's femoral insertion average total area was 87.29 ± 31.42 mm 2 . The mean insertion's areas of the AL and PM bundles were, respectively, 47.13 ± 19.14 and 40.67 ± 16.19 mm 2 . In 95.8% of the examined knees was verified the presence of the medial intercondylar ridge and in 83.3% of the knees was noted the medial bifurcated ridge. The average length of the medial intercondylar ridge was 20.54 ± 2.26 mm and the medial bifurcated ridge's average length was 7.62 ± 2.35 mm., Conclusions: The AL had a femoral insertion area larger than the PM bundle; these bundles' insertion areas were lower than those previously described in the literature. There were important individual variations related to the area of the bundles in the samples, suggesting that there should be an individual recommendation for anatomical reconstructions of the PCL with single or double femoral tunnels.