OBJECTIVE: The relationship of Gantzer muscle to the median and anterior interosseous nerve is debated. METHODS: Ìn an anatomical study with 80 limbs from 40 cadavers the incidence, origin, insertion, nerve supply and relations of Gantzer muscle have been documented. RESULTS: The muscle was found in 54 forearms (68% of limbs) and was supplied by the anterior interosseous nerve. It arose from the deep surface of the flexor digitorum superficialis muscle, (42 limbs), coronoid process (eight limbs) and medial epicondyle (seven limbs). Its insertion was to the ulnar part of flexor pollicis longus muscle. The Gantzer muscle always lay posterior to both the median and anterior interosseous nerve. CONCLUSION: The Gantzer muscle may contribute to the median nerve and anterior interosseous nerve compression. The muscle was found in 68% of limbs and should be considered a normal anatomical pattern rather than an anatomical variation. Level of Evidence IV, Case Series.

BackgroundIntervertebral disc degeneration (DD) is an important cause of low back pain and its precise aetiology is not fully understood, being attributed to cumulative environmental, biomechanical and genetic effects. The vitamin D plays a key role in regulation of calcium homeostasis and bone mineralization, exerting its biological activities by binding to a high-affinity receptor (VDR). Polymorphisms in VDR gene were previously associated with DD process, however with conflicting results. Here, we aimed to investigate the influence of lifestyle characteristics and VDR TaqI, BsmI, ApaI and FokI polymorphisms as risk factors for DD process.MethodsRetrospective case–control study involving 231 participants: 119 with confirmed DD and 112 healthy controls. Genotyping of VDR polymorphisms was performed by PCR–RFLP and real-time PCR using TaqMan methodology. All patients answered a questionnaire regarding lifestyle characteristics, such as educational level, pain localization, smoking habits, engagement of physical activity, postural and load weight at work and familial history of disc degeneration. The variables were compared between groups and adjusted by age and gender.ResultsThe case group was composed by 52% female and 48% male and the mean age was 40.0 years old, while in the control group 79% was female and 21% male and the mean age was 32.0 years old. Although gender distribution and mean age were different between groups, in the control group all participants were less than 45 years old and there was a prevalence of women in both groups. The factors that could be possibly associated to DD in the Brazilian population studied included smoking habits (26% in cases and 9% in controls, p = 0.003), lack of engagement in physical activity (observed in 77% of cases and 62% of controls, p = 0.018), and loading weight during work routine (58% in cases and 24% in controls, p ≤ 0.001). However, after adjusting by age and gender, only smoking habits remained associated to disc degeneration (p = 0.027). Considering the educational level, 35.2% of cases and 15.6% of controls had only the Elementary School, and 5.5% of DD group and 28.6% of control group had completed College (p = 0.025). In addition, educational level was directly associated to load weight at work (p = 0.012). Regarding VDR polymorphisms, no significant difference in genotype and allele frequencies between groups was observed. The haplotype analysis revealed that the combined wild-type alleles of TaqI, ApaI and FokI polymorphisms—TGT—was observed in a higher frequency in control group (p = 0.039).ConclusionThe findings suggested that smoking habits was a risk factor for disc degeneration in the population studied. Single analysis revealed no significant effects of VDR polymorphisms in disc degeneration process, while the combination of wild-type alleles of TaqI, ApaI and FokI polymorphisms, TGT haplotype, decreased the risk of the disease.

The results showed a positive association between VDR FokI/T2C polymorphism and DD in Brazilian patients tested.

ObjectiveThe 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.MethodsThis 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.ResultsThe 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.ConclusionThe 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: This paper reports the incidence, origin, course and anatomical relationships of intramuscular Martin-Gruber anastomosis. Methods: Anatomical dissection of 100 limbs from 50 adults cadavers was performed. The intramuscular Martin-Gruber anastomosis was found in five forearms, three in the right and two in the left side, one was bilateral. All communication were located between the anterior interosseous nerve and the ulnar nerve. Conclusion: The purpose of intramuscular Martin-Gruber anastomosis, which we found in 5% of dissected limbs, is to supply the flexor digitorum profundus muscle and it is unlikely to have any influence on the innervation of the intrinsic muscles of the hand. Level of Evidence IV, Cases Series.