Variaciones anatómicas del nervio musculocutáneo en una muestra de población colombiana. Estudio en cadaver / Anatomic variations of the musculocutaneous nerve in a colombian population sample. Cadaveric study

Introducción y objetivo: El nervio musculocutáneo (NMC) inerva a los músculos bíceps, coracobraquial y braquial, que tienen como función principal contribuir con la flexión de la articulación del codo. El conocimiento de la anatomía y las variantes de sus ramas motoras permite transferencias nerviosas para recuperar la flexión del codo cuando se lesiona.El objetivo de este estudio es describir la distribución anatómica y biométrica de las principales ramas motoras y sensitivas terminales del NMC en su recorrido en el miembro superior en cadáveres de una población local de población colombiana.Material y método.Estudio descriptivo anatómico de miembros superiores en cadáveres mediante disecciones para determinar el origen de las ramas motoras y sensitivas del NMC en relación a estructuras anatómicas constantes, y su número de ramas terminales al llegar a los vientres musculares respectivos.Resultados.Disecamos 30 extremidades superiores. El NMC atraviesa el músculo coracobraquial (MCB) a 56 mm (DE 17 mm) de la apófisis coracoides; la rama motora del bíceps sale del tronco del NMC a 142 mm (DE 44); el 80% se localizan en el tercio medio, 14% en tercio proximal y 6% en tercio distal; existe 1 rama motora para el bíceps en el 57% de los casos, 2 en el 27% y 3 o más en el 16%; la longitud de las ramas es de 34 mm (DE 17). Para el músculo braquial, la rama motora sale del tronco del NMC a 181 mm (DE 28) de la apófisis coracoides; existe 1 rama motora para el braquial en el 70% de los casos, 2 en el 20% y 3 o más en el 10%; el 88% se localizan en el tercio medio y el 12% en tercio distal; la longitud es de 44 mm (DE 17); encontramos unión con el nervio mediano en el tercio medio del brazo en el 10%. (AU)

Background and objective: The musculocutaneous nerve (NMC) innervates biceps, coracobrachialis and brachialis muscle, whose main function is to flex the elbow. Knowledge of the anatomy and variations in motor branches allow to carry out nerve transfer surgery to recover the functionality of elbow flexion when the musculocutaneous nerve is injured.Our aim is to describe the anatomical and biometric distribution of the main terminal motor and sensitive branches of the MCN during its course in the upper limb in bodies of a local Colombian population.Methods.Descriptive anatomical study in corpses of upper limbs using dissections to find the origin site of the NMC motor and sensitives branches in relation to constant anatomical structures and their number of terminal branches when they reach the respective muscle bellies.Results.Dissections were performed on 30 upper extremities. MCN crosses the coracobrachialis muscle 56 mm (SD 17) from the coracoid process; the motor branch of the biceps leaves de NMC trunk at 142 mm (SD 44); 80% of the branches are located in the middle third, 14% in the proximal third and 6% in the distal third; there is 1 motor branch for biceps in 57% of cases, 2 in 27% and 3 or more in 16%; the length of the motor branches is 34 mm (SD 17). For brachialis muscle, the motor branch leaves de NMC trunk at 181 mm (SD 28) from the coracoid process; there is 1 motor branch for brachialis muscle in 70% of cases, 2 in 20% and 3 or more in 10%; 88% of the branches are located in the middle third and 12% in the distal third; the length of the motor branches of the BR is 44 mm (DS 17). Union with the median nerve was found in the middle third of the arm in 10%. (AU)

Eye Refraction in Doubly Exchanged Monozygotic Twins.

This case study examined the hypothesis that longer outdoor time results in normal vision and refractive status, using unique genetically informative kinships. The participants were the members of 29-year-old doubly exchanged monozygotic male twin pairs from Bogotá, Colombia, in South America. Comprehensive ophthalmological examinations, including uncorrected and corrected visual acuity, refraction and keratometry, and visual life history interviews were undertaken; all examinations were conducted by two ophthalmologists blind to the hypothesis, relatedness, and rearing status of the four participants. Normal uncorrected vision and refractive status were present in the two rural-raised, unrelated brothers, relative to their urban-raised counterparts. Uncorrected visual acuities were 20/160 and 20/200 for the city-raised twins and 20/20 and 20/30 for the country-raised twins. Premature birth, low birth weight, computer use, and reading time could not explain these differences. It was concluded that time spent outdoors appears to be a significant factor in the development of myopia, reinforcing extant findings via a novel experimental approach.

Self-medication in ophthalmology: a questionnaire-based study in an Argentinean population.

PURPOSE: The aim of this study was to identify practices of self-medication in the treatment of ocular conditions and to identify a profile of patients who self-medicate. METHODS: We conducted a cross-sectional descriptive survey of patients, over the age of 17 years seen in our ophthalmology practice in Cordoba, Argentina. Self-medication was defined as the use of ophthalmic medicines which had not been prescribed by a health care specialist in the previous year. RESULTS: The sample included 379 subjects, 162 males (43%) and 217 females (57%); mean age 46.8 years. Prior to looking for medical attention in our institution, 97 patients (25.6%) reported self-medicating. The most frequently employed products included non-steroidal anti-inflammatory drops in combination with a vasoconstrictive agent (32%) followed by a combination of antibiotics and steroids (9%), however, 14% of patients did not remember the name or type of medication applied. A total of 31% of patients used drugs recommended by a pharmacist; 25% used drugs of their own choosing and 24% followed suggestions from a friend or family member. Only 12% of patients knew the drug's components and only 3% were aware of any possible side effects. There was no difference in behavior patterns related to educational level or age, however, there was a significant difference related to gender, with males misusing ophthalmic drops more frequently than women (P = 0.004). CONCLUSIONS: Patients commonly attempt to treat conditions that require ophthalmologic care by self-medicating with over-the-counter eye drops. Educational efforts to inform patients of the consequences of self-medication are necessary.

Characteristics of the corneal endothelium and pseudoexfoliation syndrome in patients with senile cataract.

BACKGROUND: The characteristics of the corneal endothelium in patients with/without pseudoexfoliation syndrome (PEX) with senile cataract in Paraguay are unknown. METHODS: Endothelial density, mean coefficient of variation (%) in cell size and mean cell hexagonality (%) were measured using automated specular microscopy. Multivariate general linear model analysis was used to determine the effect of age, gender and PEX on endothelial characteristics. Analysis of variance tests analysed the effect of age on endothelial variables without regard to PEX status. Categories of <2000 and > or =2000 cells/mm(2) were compared in the presence/absence of PEX using age as covariate to calculate odds ratios for corneal decompensation. RESULTS: Out of 468 eligible patients, 51 were excluded. Sixty-one patients had PEX. Unadjusted mean endothelial cell density was 2451 cells/mm(2); cell size coefficient of variation was 34.3; and the mean percentage of hexagonal cells was 57.7. Adjusting for age, only the mean difference between the groups with and without PEX for endothelial cell density was significant (PEX = 2315, no PEX = 2482, P = 0.002). Of the total study population, at-risk endothelial cell densities were found in 46 eyes (11%); and 13 (28%) of those were found to have PEX. When PEX was present, the calculated odds ratio for corneal decompensation following surgery was 1.90 after adjustment for age. CONCLUSIONS: Endothelial cell density data were consistent with published literature. Because Paraguay has a high prevalent of PEX, it is suggested that specular microscopy screening be carried out for all patients scheduled for intraocular surgery where feasible.

Biologic risk factors associated with diabetic retinopathy: the Los Angeles Latino Eye Study.

OBJECTIVE: To identify biologic risk factors associated with having diabetic retinopathy (DR) in Latinos with type 2 diabetes mellitus (T2DM). DESIGN: Population-based cross-sectional study. PARTICIPANTS: Six thousand three hundred fifty-seven Latinos ages > or =40 years from 6 census tracts in Los Angeles, California. METHODS: An in-home interview was administered to all participants in the Los Angeles Latino Eye Study (LALES). All participants diagnosed with T2DM underwent a complete ophthalmologic examination including stereoscopic fundus photography (7 standard Early Treatment Diabetic Retinopathy Study fields). Photographs were graded in a masked manner using a modified Airlie House grading system to assess presence and severity of DR. Univariate and stepwise logistic regression analyses were used to identify independent risk factors. MAIN OUTCOME MEASURES: Biologic risk factors associated with any DR and proliferative DR (PDR). RESULTS: Of the 7789 eligible individuals in LALES, 6357 (82%) had a clinical examination. One thousand two hundred sixty-three participants had definite diabetes and 1187 Latinos had T2DM. Of those with T2DM, 46% (544) had DR. Stepwise logistic regression analyses revealed that compared with females, males had a 50% higher risk of having any DR (OR = 1.50; P = 0.006). Factors independently associated with a greater risk of having any DR were longer duration of known diabetes (per year, OR = 1.08, P<0.0001), higher glycosylated hemoglobin levels (per 1%, OR = 1.22, P<0.0001); higher systolic blood pressure (per 20 mmHg, OR = 1.26, P = 0.002); and insulin treatment (OR = 1.60, P = 0.01). Factors independently associated with PDR included longer duration of known diabetes (per year, OR = 1.06, P<0.0001); being on insulin treatment (OR = 3.2, P<0.0001); and a higher systolic blood pressure (per 20 mmHg, OR = 1.44, P = 0.01). The relationship of these variables to the risk of having DR or PDR is not a constant linear function in all cases and varies depending on the variable. CONCLUSIONS: Our study showed that the high risk of DR in adult Latinos is independently associated with both nonmodifiable and modifiable risk factors. These findings suggest that controlling hyperglycemia and hypertension in this ethnic group may reduce the high risk of having DR associated with T2DM.