Effect of adduction during glenohumeral external rotation exercises in the scapulohumeral muscles / Efecto de la adducción durante ejercicios de rotación externa glenohumeral en los músculos escapulohumerales

SUMMARY: The effect of adduction during glenohumeral external rotation (ER) exercises on the scapulohumeral muscles is controversial. The aim of this study was to evaluate the effect of carrying out adduction during external rotation exercises in low and high shoulder positions on the electromyographic (EMG) activity of the infraspinatus (IS), middle deltoid (MD), and posterior deltoid (PD) muscles. EMG activity of the IS, MD, and PD muscles of 20 healthy participants was evaluated. Subjects performed 6 ER exercises that combined two factors: i) different adduction pressures according to biofeedback unit (0, 5 and 10 mmHg), and ii) low and high shoulder position. The pressure was controlled using a biofeedback unit. The low and high shoulder positions were 20? and 90? of abduction. In the low shoulder position, the activity of the IS muscle increased as the pressure on the biofeedback unit increased and the MD and PD muscles presented the highest activity at 10 mmHg. In the high shoulder position, the activity of the IS muscle was higher at 0 and 10 mmHg, the MD muscle presented higher activity at 5 mmHg, and PD muscle activity did not vary with the pressure. The addition of adduction at a pressure of 5 mmHg in the low shoulder position promotes is activity. Likewise, adduction at a pressure of 10 mmHg will promote activity of the IS, MD, and PD.

RESUMEN: El efecto de la aducción durante los ejercicios de rotación externa (RE) glenohumeral sobre los músculos escapulohumerales es controversial. El objetivo de este estudio fue evaluar el efecto de la realización de la aducción durante los ejercicios de rotación externa en posiciones bajas y altas del hombro sobre la actividad electromiográfica (EMG) delos músculos infraespinoso (IS), deltoides medio (DM) y deltoides posterior (DP). Se evaluó la actividad EMG de los músculos IS, MD y PD de 20 participantes sanos. Los sujetos realizaron 6 ejercicios de RE que combinaron dos factores: i) diferentes presiones de aducción de acuerdo con la unidad de biorretroalimentación (0, 5 y 10 mmHg), y ii) posición del hombro baja y alta. La presión se controló mediante una unidad de biorretroalimentación. Las posiciones del hombro baja y alta fueron de 20? y 90? de abducción. En la posición del hombro bajo, la actividad del músculo IS aumentó a medida que aumentaba la presión sobre la unidad de biorretroalimentación y los músculos MD y PD presentaron la actividad más alta a 10 mmHg. En la posición del hombro alto, la actividad del músculo IS fue mayor a 0 y 10 mmHg, el músculo MD presentó mayor actividad a 5 mmHg y la actividad del músculo PD no varió con la presión. La adición de aducción a una presión de 5 mmHg en la posición baja del hombro promueve la actividad del músculo IS. Asimismo, la aducción a una presión de 10 mmHg promoverá la actividad del IS, MD y PD.

Abnormal origin of posterior circumflex humeral artery and subscapular artery: case report and review of the literature / Origem anômala das artérias circunflexa posterior do úmero e subescapular: relato de caso e revisão de literatura

The subscapular, anterior circumflex, and posterior circumflex arteries arise from the third part of the axillary artery. During dissection of the right upper limb of the cadaver of a 70-year-old male, a common trunk was observed arising from the third part of the axillary artery which, after traveling for 0.5 cm, bifurcated into subscapular and posterior circumflex humeral arteries. The common trunk was crossed anteriorly by the radial nerve. The medial nerve was formed by medial and lateral roots on the medial side of the third part of the axillary artery, remaining medial to the brachial artery up to the cubital fossa and then following its usual course thereafter. Awareness of the vascular variations observed in the present case is important when conducting surgical procedures in the axilla, for radiologists interpreting angiographs, and for anatomy-pathologists studying rare findings

As artérias subescapular, circunflexa anterior e circunflexa posterior se originam da terceira parte da artéria axilar. Durante a dissecção de membro superior direito de um cadáver humano com 70 anos de idade, do sexo masculino, um tronco comum foi observado originando-se da terceira parte da artéria axilar, após um percurso de 0,5 cm, bifurcando-se em artéria subescapular e artéria circunflexa posterior do húmero. O tronco comum era cruzado anteriormente pelo nervo radial. O nervo medial era formado por raízes medial e lateral, no lado medial da terceira parte da artéria axilar, permanecendo em posição medial à artéria braquial até a fossa cubital e seguindo seu curso usual a partir de então. Conhecimento das variações vasculares observadas neste caso é importante ao executar procedimentos cirúrgicos na axila, para radiologistas que interpretam radiografias, e também para anatomo-patologistas que estudam achados raros

Biomechanical Comparison of the Latarjet Procedure with and without Capsular Repair

BACKGROUND: The purpose of this study was to determine if capsular repair used in conjunction with the Latarjet procedure results in significant alterations in glenohumeral rotational range of motion and translation. METHODS: Glenohumeral rotational range of motion and translation were measured in eight cadaveric shoulders in 90degrees of abduction in both the scapular and coronal planes under the following four conditions: intact glenoid, 20% bony Bankart lesion, modified Latarjet without capsular repair, and modified Latarjet with capsular repair. RESULTS: Creation of a 20% bony Bankart lesion led to significant increases in anterior and inferior glenohumeral translation and rotational range of motion (p < 0.005). The Latarjet procedure restored anterior and inferior stability compared to the bony Bankart condition. It also led to significant increases in glenohumeral internal and external rotational range of motion relative to both the intact and bony Bankart conditions (p < 0.05). The capsular repair from the coracoacromial ligament stump to the native capsule did not significantly affect translations relative to the Latarjet condition; however it did cause a significant decrease in external rotation in both the scapular and coronal planes (p < 0.005). CONCLUSIONS: The Latarjet procedure is effective in restoring anteroinferior glenohumeral stability. The addition of a capsular repair does not result in significant added stability; however, it does appear to have the effect of restricting glenohumeral external rotational range of motion relative to the Latarjet procedure performed without capsular repair.

Reconstruction of humeral length from measurements of its proximal and distal fragments

The aim of the present study was to estimate the length of humeri from measurements of their proximal and distal fragments. This information is important in archaeological studies and forensic investigations, particularly when fragmented material is examined. Forty humerus of adults individuals, sex-aggregated, of the Departamento de Anatomia/UFRJ collection were selected to analysis (right = 20; left = 20). Maximum length and measures of 12 fragments of the humerus (proximal = 7; distal = 5), named P1-P7 and D1-D5, were obtained by means an osteometrical board and an analogical caliper. Simples and multiple linear regressions (p < 0.01) were made to correlate each fragment with total length of the humerus. In right humeri, best estimates were observed with P1, P4, P6, P7 (proximal fragments) and D1, D2, D3, and D4 (distal fragments). In left side, P1, P6 (proximal fragments) and D1, D2, D3 (distal fragments) showed best results. Multiple regressions did not show significant increase in estimates of the humeral length. Regressions formulae were obtained to define these estimative. In conclusion, our study demonstrated that length of the humerus can be estimated from measures of proximal or distal fragments.

Biomechanical properties of the biceps-labral complex submitted to mechanical stress

OBJETIVO: Determinar as propriedades biomecânicas do complexo labrum-glenóide bicipital superior submetido ao estresse mecânico contínuo ou repetitivo (repentino).