SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Authors report in connection with two cases, operated on with an operative procedure rather rare in the practice in this country. The deltoid paralysis, developed following the injury of the axillary nerve, was successfully treated with the transposition of the bony insertion of the trapezius muscle to the proximal part of the humerus.
The present study was specifically aimed at evaluating if the structure of the deltoid muscles is modified in patients with chronic obstructive pulmonary disease (COPD). Twenty-eight male volunteers (61+/-13 yr) were assigned, according to pulmonary function, to either the COPD (n=14, FEV(1)=22-74%pred) or control group (n=14, FEV(1)=83-121%pred). Biopsies from non-dominant deltoid muscle were obtained and processed for morphometric analysis of the fibre types. Both type I and type II muscle fibres were distributed in the typical mosaic pattern. The mean value of the fibre size was within the normal range. However, three differentiated modes were observed in the deltoid from COPD patients: a central mode of normal sized fibres, a mode of atrophic fibres and a mode of hypertrophic fibres. This observation was evident even within single fascicles and especially prevalent in the most severe COPD patients. We conclude that factors with opposite effect (promotion of either atrophy or hypertrophy) exert relevant roles in the histomorphometrical characteristics of the deltoid muscles in COPD patients.
The action potential level for shoulder muscles deltoid-anterior portion (DA) and pectoralis major-clavicular portion (PMC) determined by four different modalities of execution of rowing exercises, each one with two different grips, was recorded. These were compared with the action potential level determined for the same muscles by four different modalities of execution of the frontal-lateral cross, dumbbells exercises. Twenty-four male volunteers were examined using a 2 channel TECA TE4 electromyograph and Hewlett Packard surface electrodes. The statistic analysis showed significant (p < 0.05) superiority for all the frontal-lateral cross, dumbbells exercises in comparison to all rowing exercises for the PMC, for the DA this generalized supremacy was not observed.
A balance exists between the deltoid and rotator cuff contribution to arm elevation. Both cadaver and computer models have predicted an increase in deltoid muscle force with dysfunction of the rotator cuff. The goal of the present study was to verify this phenomenon in vivo by examining the effects of paralysis of the supraspinatus and infraspinatus muscles with a suprascapular nerve block on the electrical activity of seven shoulder muscles. Electromyographic data were collected before and after the administration of the block. The block resulted in a significant increase in muscle activity for all heads of the deltoid, with a higher percentage increase noted at lower elevation angles. Although the deltoid activity was reduced as the subjects recovered from the block, even low levels of cuff dysfunction were found to result in increased deltoid activity. These results suggest that even small disruptions in the normal function of some rotator cuff muscles (e.g., due to fatigue or impingement syndrome), may result in an increase in deltoid activity. It is possible that such compensation may result in higher superior loads at the glenohumeral joint, possibly increasing the risk of tendon damage.
The electromyographic activity of the shoulder muscles deltoid-anterior portion (DA) and pectoralis major-clavicular portion (PMC) was tested on 24 male volunteers using a 2 channel TECA TE4 electromyograph and Hewlett Packard surface electrodes during the execution of three different modalities of rowing exercises with closed grip. All rowing exercises were inefficient to determine action potential levels in the PMC but two of them were extremely efficient to the DA: the upright rowing exercise and the sitting rowing exercise. Some suggestions to the use of the tested exercises are presented by the authors.
Recurrent traumatic anterior shoulder dislocation results in soft tissues lesions around the glenohumeral joint. The subscapularis muscle is a major active stabilizer of the shoulder and the hypothesis of the current study is that one would expect pathologic changes within its substance secondary to the trauma. A histomorphometric study of the subscapularis muscle was done of 52 patients operated on for recurrent traumatic anterior shoulder dislocation. At the time of surgery biopsy specimens were taken of the subscapularis muscle and the ipsilateral deltoid muscle as a comparison and to see if any changes were present. The results revealed interstitial fibrosis within the subscapularis muscle compatible with muscle scarring, and modifications in the ratio of fiber types as usually is seen with disuse atrophy. Both of these findings may alter strength and stability and therefore the function of the glenohumeral joint. The histologic findings were not compatible with a denervation pattern. After traumatic anterior shoulder dislocation rehabilitation of the subscapularis muscle is recommended.
Anatomical studies of the deltoid muscle were performed on 16 cadaver shoulders. The anatomy of the axillary nerve, the vascular pedicles, and the musculocutaneous perforators was assessed. These studies confirmed that part of the deltoid muscle can be used as a vascularised flap to cover defects of the shoulder while leaving some viable functioning muscle intact. We report the use of hemideltoid flaps to treat chronic radionecrotic ulcers involving the shoulders of two patients. In the first, the posterior part of the muscle was used as a local muscle flap. In the second, the anterior part of the muscle was raised with overlying skin to form a musculocutaneous flap. The flaps remained healed at one year follow-up. These soft tissue radionecrotic defects over the shoulder are an uncommon late complication of radiotherapy for breast cancer. Pedicled or free flaps are now recognised as the preferred methods of treatment.
Deltoid contracture is usually congenital and affects the intermediate part of the muscle. Fibrosis occurring in these fibres produces the contracture. Six patients are reported. Recovery occurred after resection of the fibrotic band.
OBJECTIVE: To investigate muscle tissue in patients with polymyalgia rheumatica (PMR). METHODS: Deltoid muscle biopsies obtained from 10 female patients with PMR before corticosteroid therapy and from 5 healthy female controls of similar age were studied using light microscopy. Serial cryosections were stained for the activity of myofibrillar ATPases at various pH and for oxidative and glycolytic enzymes. Sections were also incubated with antibodies against different myosin heavy chain (MyHC) isoforms, and the laminin alpha1 chain, identifying capillaries and cell borders, and against ligands for selected adhesion molecules. RESULTS: The muscle fibers in patients and controls were mainly of type I containing slow MyHC, or type II AB containing both fast A and fast B MyHC isoforms. The oxidative capacity of the muscle fibers was in general low. In the patients with PMR the numbers of capillaries per unit area of type I and type II fibers were higher than in controls (p = 0.05 and p < 0.5, respectively). No accumulation of inflammatory cells or increased expression of adhesion molecules in the muscle sections from patients with PMR was found. CONCLUSION: There is increased microvascularization of the deltoid muscle fibers in patients with PMR. Whether this is directly associated with the systemic inflammation and the musculoskeletal symptoms or is mainly due to muscle fiber atrophy could not be determined.
A quantitative analysis of deltoid muscle biopsy specimens was performed by light microscopy in 26 males and 25 females aged 50-79 years without known neuromuscular disease. Muscle fibre size, fibre type distribution and increase in mitochondrial content in muscle fibres were examined using a semi-automatic image analysis system. This study showed significant age- and gender-related differences. In females, there was marked atrophy of type II fibres with increasing age, specially of type IIb fibres, but no significant change in muscle fibre type distribution. In males, there was diminution in the relative proportion of type IIb fibres with increasing age but no significant muscle fibre atrophy. Mitochondrial aggregates increased with age, and this increase was observed earlier in females than in males. The gender-related morphological changes observed in the present study differ somewhat from those reported in the literature. The differences between males and females may be partially related to gender differences in muscular activity and may reflect an earlier decline in deltoid muscle strength in females. The existence of these age and gender changes should be taken into account in the interpretation of muscle biopsies of aged individuals.
The objective of this investigation was to study the effects of androgenic-anabolic steroid (AAS) misuse on deltoid muscle fiber characteristics in experienced, male strength-trained athletes. In a double-blind study, 15 volunteers were administered nandrolone decanoate (ND) for 8 weeks (200 mg/week, intramuscularly). In an additional study, 12 subjects self-administered various AASs at supratherapeutic dosages (AAS group), while 7 non-users served as controls. In all subjects, a percutaneous needle biopsy sample of the deltoid muscle was obtained at baseline and after 8 weeks. Muscle sections were pre-incubated at pH 4.4, stained with adenosine triphosphatase and analyzed morphometrically. In each biopsy sample, at least 150 fibers were classified for "gray level" and "lesser fiber diameter" to determine the mean fiber size, the sizes of type I and type II fibers, and the fiber type distribution. ND administration did not seem to affect any of those parameters. In the AAS group, mean muscle fiber size (+ 12.6%), and the size of type I (+ 10.8%) and type II (+ 14.6%) muscle fibers increased. The fiber type distribution remained unaltered. We conclude that polydrug regimens of AAS misuse at supratherapeutic dosages increased the size of deltoid muscle fibers (especially type II fibers) in experienced strength-trained athletes, while ND at a therapeutic intramuscular dose of 200 mg did not exert any effect.
The relationship of the anterior branch of the axillary nerve to the deltoid muscle was studied on both sides in 66 adult cadavers. The nerve runs a course on the deep surface of the deltoid muscle about 2.2 cm above the midpoint on the vertical plane of the muscle.
A child with an abduction contracture of the left shoulder secondary to diffuse fibrosis of the deltoid muscle was successfully treated by recession of the inserting muscle fibers proximally. Previously reported cases of deltoid muscle contracture were secondary to fibrous cords or nodules within the muscle. This patient's contracture may be related to either a brachial plexus birth injury or may be similar to the idiopathic fibrosis seen in the quadriceps muscle.
BACKGROUND: Less invasive procedures have recently been introduced to facilitate an earlier return to sports or work activities after rotator cuff repair. Few reports, however, have verified whether such procedures are really less invasive than conventional open repair. The purpose of this study was to compare the postoperative thickness of the deltoid muscle in patients treated with either conventional or mini-open rotator cuff repair. METHODS: Conventional open repair was performed from 1994 through 1997 in forty-three patients with rotator cuff tears. The mini-open deltoid-splitting approach was introduced in 1997, and the cases of thirty-five patients who underwent that procedure were reviewed. The two groups were compared with respect to the thickness of the anterior fibers of the deltoid muscle measured on the transverse magnetic resonance images, the degree of active forward flexion, and the times required for return to work and sports activities. RESULTS: The thickness of the anterior deltoid fibers did not change significantly after surgery in the mini-open repair group, whereas it was significantly decreased in the open repair group at six months as well as at twelve months postoperatively (p < 0.05). At three months postoperatively, the mean University of California at Los Angeles score for active forward flexion in the patients treated with the mini-open repair (4.9 points) was significantly greater than that in the patients in the conventional open repair group (4.6 points) (p < 0.05). In addition, the mean time-period required for return to work in the mini-open repair group (2.4 months) was significantly shorter than that required in the control group (3.4 months) (p < 0.05). CONCLUSIONS: The mini-open repair appeared to cause less postoperative atrophy of the deltoid muscle than did the conventional open rotator cuff repair, and patients treated with the mini-open repair recovered more quickly.
The behavior of the moment arms of the rotator cuff and deltoid muscles was studied during simple and combine movements of abduction and rotation about the glenohumeral joint. This was done by experimental measurement of excursions of the muscles in an in vitro cadaver model and by use of a multiple-regression analysis to delineate the changes in the moment arms as a function of abduction and rotation. The results demonstrated the potential of some rotator cuff muscles to contribute to both abduction and rotation, the sensitivity of the abductor moment-arm lengths to internal and external rotation and of the rotator moment-arm lengths to the degree of abduction, and the capacity of the abductor moment-arm lengths of the deltoid to increase with increasing abduction. Characterization of this behavior resulted in an increased understanding of the complex role of the rotator cuff and deltoid muscles about the gleno-humeral joint and provided quantitative descriptions of functional relationships. This study demonstrates the capacity of the infraspinatus and subscapularis muscles to contribute not only to external and internal rotation, respectively, but also to elevation of the arm in the plane of the scapula, a role for which these muscles have been given little or no consideration. Furthermore, it demonstrates that the contribution of the infraspinatus to abduction is enhanced with internal rotation while that of the subscapularis is enhanced with external rotation. Thus, dysfunction of the supraspinatus muscle need not preclude good elevation of the arm, and rehabilitation to reprogram and strengthen the remaining muscles becomes an important consideration.
Electromyograms (EMGs) were recorded from both deltoid muscles (DMs) when subjects were sitting, standing, and bending the head laterally at different cold sensations to clarify the role of head and body positions in the thermoregulatory tonus. At room temperature (22 degrees C), neither EMG related to thermoregulatory muscle tonus (TMT) nor were changes in EMG intensity observed during changes in posture. At a cold temperature (5 degrees C), when the subjects felt slightly cold or cold, the averaged surface EMG intensity of TMT was approximately 2-3 microV during sitting with the head held upright. The EMG of TMT was 7.23 +/- 2.99 microV in subjects sitting with the head upright when feeling cold and extremely cold and increased to 14.75 +/- 5.15 microV (P < 0.01) when the subjects stood at ease and to 19.96 +/- 11.01 microV (P < 0.01) when the subjects stood on tiptoes. Lateral head bending in subjects standing at ease and feeling extremely cold increased the EMG 40-60% (P < 0.01) in the contralateral DM without any significant effect on the ipsilateral DM. The results suggest that in humans TMT is influenced by tonic postural reflexes.
A bilateral anomaly of deltoid muscles was found in cadaver dissection of a middle aged male. Posterior part of the muscle was enclosed with a separate fascial sheath. There was no concomitant muscular anomaly in any part of the body.
The purpose of the study was to analyse the influence of the precision of a task on tension and fatigue of the trapezius and deltoid muscles. Ten young men took part in experiments. Different levels of force and different frequencies of pressing a button defined the precision of the task. Surface electromyography (EMG) was used. Muscle tension and fatigue were reflected by 2 parameters of the EMG signal: the Root Mean Square amplitude related to the maximum value and changes in the Median Power Frequency. The results showed that hand activities influence the descending part of the trapezius muscle and do not influence the deltoid muscle, and that the precision of work can influence the examined muscles of the arm and shoulder even during work in which only the hand is involved in a performed task.