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At least 19 recordsLinked to original sources
PubMed1994

[A biomechanical analysis of pronation-supination of the forearm using magnetic resonance imaging: dynamic changes of the interosseous membrane of the forearm during pronation-supination].

A magnetic resonance (MR) study was performed using a 0.5 tesla system to investigate the behavior of the interosseous membrane of the forearm during pronation-supination and to evaluate the influence of pronation-supination loading in the neutral position. The right forearm was examined in twenty volunteers at the proximal fourth part, middle part and distal fourth part of the forearm. Slices were examined at maximum pronation, 45 degrees pronation, neutral, 45 degrees supination and at maximum supination. A 0.1 Nm torque in both rotational directions was added in the neutral position. The MR image of the interosseous membrane of the forearm was a thin line with low contrast in the neutral position. The tendinous portion and membranous portions of the interosseous membrane could be differentiated. At maximum pronation and at maximum supination, the interosseous membrane was flexed, caused mainly by the relaxation in the membranous portion. The radius shifted slightly volarly to the ulna at maximum pronation, caused by the incongruity of the distal radioulnar joint. The radius shifted dorsally with pronation loading, and shifted volarly with supination loading. The inelasticity of the membranous portion of the interosseous membrane may be responsible for pronation-supination contracture, while rotational loading may be a cause of the distal radioulnar joint dislocation. These studies suggest that this technique is useful for further in vivo studies of kinesiology.

Adult↗
PubMed1988

Comparison of pronator tenotomy and pronator rerouting in children with spastic cerebral palsy.

Forty-one patients with cerebral palsy and pronation contracture of the forearm were treated with pronator teres rerouting compared with 16 patients who were treated with pronator teres tenotomy. The mean age of patients with pronator tenotomy was 4 years 3 months compared with 7 years 3 months for patients with rerouting. Follow-up averaged 94 months for tenotomy and 21 months for rerouting. Average gain in supination was 78 degrees for rerouting and 54 degrees for tenotomy. No patient lost active range of motion during follow-up. Although pronator teres tenotomy increased active supination of the forearm, greater active supination of the forearm was afforded patients treated with pronator teres rerouting.

Adolescent↗
PubMed1981

Treatment of pronation contractures of the forearm in cerebral palsy by changing the insertion of the pronator radii teres.

In twenty-two patients with cerebral palsy and a pronation contracture of the forearm, transfer of the pronator radii teres posteriorly to the anterolateral border of the radius converted it from a pronator to a supinator. Of the twenty-two patients so treated and followed for two to six years, 82 per cent were judged to have a good to excellent result since they had gained an average of 46 degrees of active supination compared with their preoperative status. There was no loss of motion with the passage of time and, determined by palpation, active contract of the transferred pronator teres was evident during voluntary supination. The procedure allowed the patients to improve function significantly by giving them the ability to supinate the forearm during activities requiring axial rotation of the forearm.

Adolescent↗
PubMed1978

[Contribution of the biceps brachii and pronator teres muscles to the efforts of pronation or supination. I. Statistical work (author's transl)].

The electrical activity of the biceps brachii and pronator teres muscles is studied through the prono-supination of the forearm in some isometrical conditions (static work) with different loads and joint positions. If the pronator teres is always being active in pronation, this activity is a function of the load and of the wrist and elbow positions. The same phenomena can be observed for the biceps brachii but when in supination. From the curvilinear relationships between the integrated electrical activity and the load--observed on both muscles--some torque-angle relationships can be established for the biceps brachii which show that a bifunctional muscle seems to be characterized by a very and unique force-length relationship.

Arm↗
PubMed1978

[Contribution of the biceps brachii and pronator teres muscles to the efforts of pronation or supination. II. dynamic work (author's transl)].

The electrical activity of the biceps brachii and pronator teres muscles is studied through the prono-supination of the forearm in some anisometrical conditions (dynamic work) when the inertia of the mobile system and the elbow position are being varied. The subjects are required to perform pronation, supination and flexion movements, either isolated or combined. From the findings obtained when the integrated electrical activity (Q) is related to the mechanical work (W), one can conclude that a. the Q-W linear relationship seems to characterize the chief function of a muscle, b. the slope of the Q-W relationship depends on the elbow position, c. the pronator muscles do not inhibit in a selective manner the biceps supinating function. So a bifunctional muscle seems to act as a whole.

Biomechanical Phenomena↗
PubMed2004

Electromyographic activity and strength during maximum isometric pronation and supination efforts in healthy adults.

There exists a lack of quantitative data in the literature related to the torque produced during axial forearm rotation and the electromyographic (EMG) activity of the muscles involved. Therefore, the purpose of this study was to compare the relative EMG activity of four forearm muscles during resisted forearm rotation. A custom-built device capable of measuring torque in the absence of grip was employed. Fourteen healthy volunteers performed maximum isometric voluntary contractions in five positions of axial forearm rotation for both pronation and supination. EMG data were collected simultaneously from the supinator, biceps, pronator quadratus (deep and superficial heads), and pronator teres muscles using fine-wire bipolar electrodes. Data were analyzed to determine the contributions of each muscle to pronation and supination torque over five positions of forearm rotation. In the absence of grip no significant difference was found between supination and pronation torque in neutral position. Supination torque generation was greater in the pronated forearm positions, and pronation torque was greater in the supinated positions (p<0.05). A root-mean-square EMG analysis verified the major contributions of the pronator teres and both heads of the pronator quadratus muscle to pronation torque, and supinator and biceps to supination torque. The deep head of the pronator quadratus was active during both pronation and supination, lending support to the theory that it may act primarily as a dynamic distal radioulnar joint stabilizer. This information may be helpful in upper extremity modeling, surgical treatments, and rehabilitation strategies.

Adult↗
PubMed2001

What happens to the triangular fibrocartilage complex during pronation and supination of the forearm? Analysis of its morphology and diagnostic assessment with MR arthrography.

OBJECTIVE: To evaluate the dynamic morphologic changes of the triangular fibrocartilage complex (TFCC) during pronation and supination of the forearm using high-resolution MR arthrography in cadavers and to evaluate the impact of these changes on the diagnostic assessment of the normal and abnormal TFCC. DESIGN AND SPECIMENS: High-resolution MR arthrography of 10 wrists of cadaveric specimens was obtained in maximum pronation, in the neutral position, and in maximum supination of the forearm. The structures of the TFCC were evaluated by two musculoskeletal radiologists and correlated with anatomic sections. The position of the forearm that allowed the best visualization of normal structures and lesions of the TFCC was determined. RESULTS: The shape and extent of the articular disc as well as the radial portions of the radioulnar ligaments did not change with pronation and supination. The articular disc was horizontal in the neutral position and tilted more distally to align with the proximal carpal row in pronation and supination. The fibers of the ulnar part of the radioulnar ligaments (ulnar attachment of the articular disc) revealed the most significant changes: their orientation was coronal in the neutral position and sagittal in positions of pronation and supination. The ulnomeniscal homologue was largest in the neutral position and was reduced in size during pronation and supination. The extensor carpi ulnaris tendon was centered in its groove in the neutral position and pronation. In supination this tendon revealed subluxation from this groove. The dorsal capsule of the distal radioulnar joint was taut in pronation, and the palmar capsule was taut in supination. The preferred forearm position for analysis of most of the structures of the TFCC was the neutral position, followed by the pronated position. The neutral position was rated best for the detection of ulnar and radial detachments of the TFCC, followed by the pronated position, except for two central perforations of the TFCC which were best seen with supination. CONCLUSION: The articular disc and the surrounding radial portions of the radioulnar ligaments form a rigid, unified complex with the radius without change in their shape in positions of pronation and supination of the forearm, while the ulnar attachment of the TFCC shows important dynamic changes. The neutral forearm position is the best position to analyze both the normal and the abnormal TFCC.

Arthrography↗
PubMed1983

Pronation injuries of the ankle in children. Retrospective study of radiographical classification and treatment.

In a retrospective study in children aged 0-18 years, 457 ankle fractures in children were classified traumatologically according to Gerner-Smidt or Lauge-Hansen. Anatomically, ankle fractures with open growth plates were classified according to the Salter-Harris classification. Pronation injuries constituted 18% of the ankle injuries and showed different fracture patterns. In total 83 pronation injuries were found. Of these, 52 showed open growth plates: 25 pronation-abduction, 23 pronation-eversion, and 4 pronation-dorsal flexion injuries. The pronation-abduction injuries were classified into two groups. In 15, a detachment of the deltoid ligament at the medial malleolus, visible on radiographs as a minimal fragment or transverse fracture of the medial malleolus, was found; seven showed in addition a fracture through the growth plate (Salter-Harris type I or II) or a metaphyseal fracture of the distal fibula. In 10, a physeal fracture through the distal tibia (Salter-Harris type I) was found. Of these, seven had in addition a metaphyseal fibular fracture. Pronation-eversion injuries showed in 21 cases a physeal-metaphyseal fracture (Salter-Harris type II) with an antero-lateral metaphyseal fragment (Stage I-II); 17 had in addition a metaphyseal fibular fracture (Stage III). A minimal posterolateral metaphyseal fragment of the distal tibia represents the fourth stage but could not adequately be separated from the third, so Stages III and IV were combined. Pronation-dorsal flexion showed a physeal-metaphyseal fracture in four cases with an anteriorly situated metaphyseal fragment (Stages I-II); one case also had a metaphyseal fracture of the distal fibula (Stage III). Pronation-eversion injuries showed frequently displacement and were more commonly treated by reduction than pronation-abduction and supination injuries including supination-eversion injuries of intra-articular type. However, complete reduction of pronation-eversion injuries with closed methods often proved difficult.

Adolescent↗
PubMed2002

Upper-limb surface electro-myography at maximum supination and pronation torques: the effect of elbow and forearm angle.

Forearm pronation and supination, and increased muscular activity in the wrist extensors have been both linked separately to work-related injuries of the upper limb, especially humeral epicondylitis. However, there is a lack of information on forearm torque strength at ranges of elbow and forearm angles typical of industrial tasks. There is a need for strength data on forearm torques at different upper limb angles to be investigated. Such a study should also include the measurement of muscular activity for the prime torque muscles and also other muscles at possible risk of injury due to high exertion levels during tasks requiring forearm torques.Twenty-four male subjects participated in the study that involved maximum forearm torque exertions for the right arm, in the pronation and supination directions, and at four elbow and three forearm rotation angles. Surface EMG (SEMG) was used to evaluate the muscular activity of the pronator teres (PT), pronator quadratus (PQ), biceps brachi (BB), brachioradialis (BR), mid deltoid (DT) and the extensor carpi radialis brevis (ECRB) during maximum torque exertions. Repeated measures ANOVA indicated that both direction and forearm angle had a significant effect on the maximum torques (p<0.05) while elbow angle and the interactions were highly significant (p<0.001). The results revealed that supination torques were stronger overall with a mean maximum value of 16.2 Nm recorded for the forearm 75% prone. Mean maximum pronation torque was recorded as 13.1 Nm for a neutral forearm with the elbow flexed at 45 degrees. The data also indicated that forearm angle had a greater effect on supination torque than pronation torque. Supination torques were stronger for the mid-range of elbow flexion, but pronation torques increased with increasing elbow extension. The strength profiles for the maximum torque exertions were reflected in the EMG changes in the prime supinators and pronators. In addition, the EMG data expressed as the percentage of Maximum Voluntary Electrical activity (MVE), revealed high muscular activity in the ECRB for both supination (26-43% MVE) and pronation torques (17-55% MVE). The results suggest that the ECRB acts as a stabiliser to the forearm flexors for gripping during pronation torques depending on forearm angle, but acts as a prime mover in wrist extension for supination torques with little effect of elbow and forearm angle. This indicates a direct link between forearm rotations against resistance and high muscular activity in the wrist extensors, thereby increasing stress on the forearm musculo-skeletal system, especially the lateral epicondyle.

Adult↗
PubMed1992

Electromyography of pronators and supinators in great apes.

We obtained electromyographic recordings from the supinator, biceps brachii, pronator quadratus, and pronator teres muscles of a chimpanzee and a gorilla and from the supinator, pronator quadratus, and biceps brachii muscles of an orangutan as they stood and walked quadrupedally on horizontal and inclined surfaces, engaged in suspensory behavior, reached overhead, and manipulated a variety of foods and artifacts. In Pan troglodytes and Pan gorilla, as in Homo sapiens, the supinator muscle is the prime supinator, with the biceps brachii muscle serving to augment speed or force of supination. Primary of the pronator quadratus muscle over the pronator teres muscle during pronation is less clear in the African apes than in humans. Possibly, pongid radial curvature or forelimb elongation or both factors are related to the somewhat different patterns of activity that we observed in the pronator muscles of Pan versus those reported for Homo sapiens. In Pongo pygmaeus, as in P. troglodytes and P. gorilla, the pronator quadratus muscle acts as a pronator and the supinator muscle acts to supinate the hand at the radioulnar joints. The biceps brachii muscle is active at low levels as the orangutan supinates its hand with the elbow flexed.

Animals↗
PubMed2004

Mechanical evaluation of the Pronator Teres rerouting tendon transfer.

We simulated pronator teres rerouting using a three-dimensional biomechanical model of the arm. Simulations comprised the evaluation of changes in muscle length and the moment arm of pronator teres with changes in forearm axial rotation and elbow flexion. The rerouting of Pronator Teres was simulated by defining a path for it through the interosseous membrane with re-attachment to its original insertion. However the effect of moving the insertion to new positions, 2 cm below and above, the original position was also assessed. The effect on total internal rotation and external rotation capacity was determined by calculating the potential moments for pronator teres, supinator, pronator quadratus, biceps brachii and brachioradialis. Pronator teres was found to be a weak internal rotator in extreme pronation, but a strong internal rotator in neutral rotation and in supination. After rerouting pronator teres was only a strong external rotator in full pronation and not at other forearm positions, where the effect of rerouting was comparable to a release procedure.

Biomechanical Phenomena↗