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The New England Journal of Medicine Jan 2018
Topics: Aged, 80 and over; Fingers; Humans; Male; Muscular Diseases; Pectoralis Muscles; Poland Syndrome
PubMed: 29298145
DOI: 10.1056/nejmicm1709713 -
International Journal of Environmental... Oct 2020The bench press exercise is one of the most used for training and for evaluating upper-body strength. The aim of the current study was to evaluate the electromyographic...
The bench press exercise is one of the most used for training and for evaluating upper-body strength. The aim of the current study was to evaluate the electromyographic (EMG) activity levels of the pectoralis major (PM) in its three portions (upper portion, PMUP, middle portion, PMMP, and lower portion, PMLP), the anterior deltoid (AD), and the triceps brachii (TB) medial head during the bench press exercise at five bench angles (0°, 15°, 30°, 45°, and 60°). Thirty trained adults participated in the study. The EMG activity of the muscles was recorded at the aforementioned inclinations at 60% of one-repetition maximum (1RM). The results showed that the maximal EMG activity for PMUP occurred at a bench inclination of 30°. PMMP and PMLP showed higher EMG activity at a 0° bench inclination. AD had the highest EMG activity at 60°. TB showed similar EMG activities at all bench inclinations. In conclusion, the horizontal bench press produces similar electromyographic activities for the pectoralis major and the anterior deltoid. An inclination of 30° produces greater activation of the upper portion of the pectoralis major. Inclinations greater than 45° produce significantly higher activation of the anterior deltoid and decrease the muscular performance of the pectoralis major.
Topics: Adult; Arm; Electromyography; Humans; Muscle Strength; Muscle, Skeletal; Pectoralis Muscles; Weight Lifting
PubMed: 33049982
DOI: 10.3390/ijerph17197339 -
European Journal of Sport Science 2016This study compared the muscular activation of the pectoralis major, anterior deltoid and triceps brachii during a free-weight barbell bench press performed at 0°,... (Comparative Study)
Comparative Study
This study compared the muscular activation of the pectoralis major, anterior deltoid and triceps brachii during a free-weight barbell bench press performed at 0°, 30°, 45° and -15° bench angles. Fourteen healthy resistance trained males (age 21.4 ± 0.4 years) participated in this study. One set of six repetitions for each bench press conditions at 65% one repetition maximum were performed. Surface electromyography (sEMG) was utilised to examine the muscular activation of the selected muscles during the eccentric and concentric phases. In addition, each phase was subdivided into 25% contraction durations, resulting in four separate time points for comparison between bench conditions. The sEMG of upper pectoralis displayed no difference during any of the bench conditions when examining the complete concentric contraction, however differences during 26-50% contraction duration were found for both the 30° [122.5 ± 10.1% maximal voluntary isometric contraction (MVIC)] and 45° (124 ± 9.1% MVIC) bench condition, resulting in greater sEMG compared to horizontal (98.2 ± 5.4% MVIC) and -15 (96.1 ± 5.5% MVIC). The sEMG of lower pectoralis was greater during -15° (100.4 ± 5.7% MVIC), 30° (86.6 ± 4.8% MVIC) and horizontal (100.1 ± 5.2% MVIC) bench conditions compared to the 45° (71.9 ± 4.5% MVIC) for the whole concentric contraction. The results of this study support the use of a horizontal bench to achieve muscular activation of both the upper and lower heads of the pectoralis. However, a bench incline angle of 30° or 45° resulted in greater muscular activation during certain time points, suggesting that it is important to consider how muscular activation is affected at various time points when selecting bench press exercises.
Topics: Biomechanical Phenomena; Deltoid Muscle; Electromyography; Humans; Isometric Contraction; Male; Muscle, Skeletal; Pectoralis Muscles; Upper Extremity; Weight Lifting; Young Adult
PubMed: 25799093
DOI: 10.1080/17461391.2015.1022605 -
Hand (New York, N.Y.) Dec 2016Poland anomaly is a sporadic, phenotypically variable congenital condition usually characterized by unilateral pectoral muscle agenesis and ipsilateral hand deformity.... (Review)
Review
Poland anomaly is a sporadic, phenotypically variable congenital condition usually characterized by unilateral pectoral muscle agenesis and ipsilateral hand deformity. A comprehensive review of the medical literature on Poland anomaly was performed using a Medline search. Poland anomaly is a sporadic, phenotypically variable congenital condition usually characterized by unilateral, simple syndactyly with ipsilateral limb hypoplasia and pectoralis muscle agenesis. Operative management of syndactyly in Poland anomaly is determined by the severity of hand involvement and the resulting anatomical dysfunction. Syndactyly reconstruction is recommended in all but the mildest cases because most patients with Poland anomaly have notable brachydactyly, and digital separation can improve functional length. Improved understanding the etiology and presentation of Poland anomaly can improve clinician recognition and management of this rare congenital condition.
Topics: Brachydactyly; Hand Deformities, Congenital; Humans; Pectoralis Muscles; Phenotype; Poland Syndrome; Syndactyly
PubMed: 28149203
DOI: 10.1177/1558944716647355 -
CMAJ : Canadian Medical Association... Apr 2021
Topics: Adult; Allografts; Humans; Magnetic Resonance Imaging; Male; Military Personnel; Pectoralis Muscles; Plastic Surgery Procedures; Rupture; Tendons; Treatment Outcome; Weight Lifting
PubMed: 33875470
DOI: 10.1503/cmaj.201248-f -
Surgical and Radiologic Anatomy : SRA Oct 2022The thoracoacromial trunk (TAT) originates from the second part of the axillary artery and curls around the superomedial border of the pectoralis minor, subsequently...
PURPOSE
The thoracoacromial trunk (TAT) originates from the second part of the axillary artery and curls around the superomedial border of the pectoralis minor, subsequently piercing the costocoracoid membrane. Knowledge about the location, morphology, and variations of the TAT and its branches is of great surgical importance due to its frequent use in various reconstructive flaps.
METHODS
A retrospective study was conducted to establish anatomical variations, their prevalence, and morphometric data on TAT and its branches. The results of 55 consecutive patients who underwent neck and thoracic computed tomography angiography were analyzed. A qualitative evaluation of each TAT was performed.
RESULTS
A total of 15 morphologically different TAT variants were initially established. The median length of the TAT was set at 7.74 mm (LQ 3.50; HQ 13.65). The median maximum diameter of the TAT was established at 4.19 mm (LQ 3.86; HQ 4.90). The median TAT ostial area was set to 13.97 mm (LQ 11.70; HQ 18.86). To create a heat map of the most frequent location of the TAT, measurements of the relating structures were made.
CONCLUSION
In this study, the morphology and variations of the branching pattern of the TAT were presented, proposing a new classification system based on the four most commonly prevalent types. The prevalence of each branch arising directly from the TAT was also analyzed. It is hoped that the results of the present anatomical analysis can help to minimize potential complications when performing plastic or reconstructive procedures associated with TAT.
Topics: Humans; Retrospective Studies; Surgical Flaps; Plastic Surgery Procedures; Pectoralis Muscles; Axillary Artery
PubMed: 36094609
DOI: 10.1007/s00276-022-03016-4 -
Journal of Shoulder and Elbow Surgery Aug 2020This study evaluates the pectoralis major (PM) tendon humeral insertion, using imaging and histologic assessment in cadaveric specimens. Current descriptions of the...
BACKGROUND
This study evaluates the pectoralis major (PM) tendon humeral insertion, using imaging and histologic assessment in cadaveric specimens. Current descriptions of the pectoralis major tendon depict a bilaminar enthesis, and clarification of the anatomy is important for diagnostic and surgical considerations.
MATERIALS AND METHODS
Fourteen fresh-frozen whole upper extremity specimens were used in this study. Magnetic resonance (MRI) and ultrasonographic (US) imaging of the PM muscles, tendons, and entheses were performed, followed by anatomic dissection and inspection. Morphology of the lateral tendon and entheses were evaluated, focused on the presence of layers. In 11 specimens, the lateral 3 cm of the PM tendon was carefully dissected from the footprint, whereas in 3 specimens, the tendon and humeral insertion were preserved and removed en bloc. Histology was performed in axial slabs along the medial-lateral length of the tendon and also evaluated for the presence of layers.
RESULTS
The superior-inferior and medial-lateral lengths of the PM footprint were 75 ± 9 mm and 7 ± 1 mm respectively. In all specimens, the clavicular and sternal head muscles and tendons were identified, with the clavicular head tendon generally being shorter. The medial-lateral length of the clavicular head tendon measured 19 ± 8 mm superiorly and 9 ± 3 mm inferiorly. The medial-lateral length of the sternal head tendon measured 38 ± 8 superiorly and 41 ± 18 mm inferiorly. All specimens demonstrated a unilaminar, not bilaminar, enthesis with abundant fibrocartilage on histology. Three specimens demonstrated interspersed entheseal fat and loose connective tissue at the enthesis on MRI and histology.
CONCLUSION
The PM tendon humeral insertion consists of a unilaminar fibrocartilaginous enthesis. US, MRI, and histology failed to identify true tendon layers at the enthesis. Delaminating injuries reported in the literature may originate from a location other than the enthesis.
Topics: Adult; Aged; Cadaver; Clavicle; Female; Fibrocartilage; Humans; Humerus; Magnetic Resonance Imaging; Male; Middle Aged; Pectoralis Muscles; Sternum; Tendons; Ultrasonography; Young Adult
PubMed: 32169467
DOI: 10.1016/j.jse.2019.12.020 -
Ear, Nose, & Throat Journal Aug 2019Large and deep defects resulting from lateral skull base surgery represent a challenge to the head and neck surgeon. Different microvascular free flaps have specific...
Large and deep defects resulting from lateral skull base surgery represent a challenge to the head and neck surgeon. Different microvascular free flaps have specific advantages and disadvantages. While the pedicled pectoralis major flap is considered a "work horse," it comes with a rather short pedicle. The aim of this study was to analyze the vascular anatomy of the pectoralis major flap and assess its suitability for microvascular transfer. Anatomical studies have been performed on 6 Thiel-fixed cadavers allowing a harvest of 12 flaps by the same surgeon. Measurements of the pedicle's length and vessel diameters have been taken with a ruler and caliper. The mean pedicle length and mean diameters (Ø) of the thoracoacromial artery and concomitant vein were found to be 9.8 cm, Ø 4.2 mm, and Ø 4.9 mm, respectively. These results suggest the potential utility of a free pectoralis major flap with microvascular anastomosis.
Topics: Cadaver; Free Tissue Flaps; Humans; Microvessels; Pectoralis Muscles; Plastic Surgery Procedures; Skull Base
PubMed: 31018692
DOI: 10.1177/0145561319840821 -
Poultry Science Oct 2019The glycolytic capacity in the "white muscle fibers" found predominantly in broiler and turkey breast muscle have long been recognized as being key components... (Review)
Review
The glycolytic capacity in the "white muscle fibers" found predominantly in broiler and turkey breast muscle have long been recognized as being key components contributing to optimal pH changes post-harvest and the quality of breast muscle products. The pectoralis major (PMAJ) is the predominant breast muscle and is almost exclusively comprised of fast-twitch glycolytic (anaerobic) type IIb muscle fibers (white). In nature, the pectoralis muscles are designed to meet the intense, periodic energy demands of flight in contrast to the continual, oxidative metabolism (aerobic) inherent to the type I slow twitch fibers (red) in the thigh and drum. Within the past decade, it has been recognized that increased breast muscle yield in modern broiler strains may have contributed to muscle myopathies characterized by visible white striations (white striping; WS) often accompanied by surface hemorrhages and areas of extreme firmness (woody breast; WB). The research to date has primarily addressed differences in muscle physiology and processing characteristics in "normal" and "abnormal" muscle samples from older broilers. One hypothesis is that the extensive accretion of protein in a poorly vascularized breast muscle overwhelms the capacity for coping with excessive production of reactive oxygen species and the term "oxidative stress" has been used to describe this condition. There are few recent reports in poultry, however, which have addressed the potential negative physiological effects imposed by multiple layers of fascia surrounding individual muscle fibers, fiber bundles, and intact muscles on circulation and oxidative stability. The objective of this review is to support our hypothesis that the extensive accretion of breast muscle in a poorly vascularized and tightly bound PMAJ could be creating a "compartment syndrome" like condition leading to the development of the WS and WB anomalies in heavy, high yielding birds. Recent gene expression data support this hypothesis.
Topics: Animals; Chickens; Muscular Diseases; Oxidative Stress; Pectoralis Muscles; Poultry Diseases
PubMed: 30371852
DOI: 10.3382/ps/pey409 -
Brazilian Journal of Physical Therapy 2017Pectoralis minor muscle length is believed to play an important role in shoulder pain and dysfunction. Current clinical procedures for assessing pectoralis minor muscle...
BACKGROUND
Pectoralis minor muscle length is believed to play an important role in shoulder pain and dysfunction. Current clinical procedures for assessing pectoralis minor muscle length may not provide the most useful information for clinical decision making.
OBJECTIVE
To establish the reliability and construct validity of a novel technique to measure pectoralis minor muscle length under actively and passively lengthened conditions.
DESIGN
Cross-sectional repeated measures.
METHODS
Thirty-four healthy adults (age: 23.9, SD=1.6 years; 18 females) participated in this study. Pectoralis minor muscle length was measured on the dominant arm in three length conditions: resting, actively lengthened, and passively lengthened. Based upon availability, two raters, out of a pool of five, used a caliper to measure the distance between the coracoid process and the 4th rib. The average of two pectoralis minor muscle length measures was used for all muscle length conditions and analyses. Intraclass correlation coefficients determined intra-and inter-rater reliability, and measurement error was determined via standard error of measurement and minimal detectable change. Construct validity was assessed by ANOVA to determine differences in muscle length across the three conditions.
RESULTS
Our intra- and inter-rater reliability values across all three conditions ranged from 0.84 to 0.92 and from 0.80 to 0.90, respectively. Significant differences (p<0.001) in muscle length were found among all three conditions: rest-active (3.66; SD=1.36cm), rest-passive (4.72, SD=1.41cm), and active-passive (1.06, SD=0.47cm).
CONCLUSIONS
The techniques described in this study for measuring pectoralis minor muscle length under resting and actively and passively lengthened conditions have acceptable reliability for clinical decision making.
Topics: Cross-Sectional Studies; Humans; Pectoralis Muscles; Physical Examination; Reproducibility of Results; Shoulder Pain
PubMed: 28454725
DOI: 10.1016/j.bjpt.2017.04.004