scholarly journals Activation of individual extrinsic thumb muscles and compartments of extrinsic finger muscles

2013 ◽  
Vol 110 (6) ◽  
pp. 1385-1392 ◽  
Author(s):  
J. Alexander Birdwell ◽  
Levi J. Hargrove ◽  
Todd A. Kuiken ◽  
Richard F. ff. Weir
Keyword(s):  
Neural Control ◽  
Muscular Activity ◽  
Middle Finger ◽  
The Other ◽  
Flexor Digitorum Profundus ◽  
Human Hand ◽  
Activity Levels ◽  
Extensor Pollicis Longus ◽  
Flexor Digitorum ◽  
Different Levels

Mechanical and neurological couplings exist between musculotendon units of the human hand and digits. Studies have begun to understand how these muscles interact when accomplishing everyday tasks, but there are still unanswered questions regarding the control limitations of individual muscles. Using intramuscular electromyographic (EMG) electrodes, this study examined subjects' ability to individually initiate and sustain three levels of normalized muscular activity in the index and middle finger muscle compartments of extensor digitorum communis (EDC), flexor digitorum profundus (FDP), and flexor digitorum superficialis (FDS), as well as the extrinsic thumb muscles abductor pollicis longus (APL), extensor pollicis brevis (EPB), extensor pollicis longus (EPL), and flexor pollicis longus (FPL). The index and middle finger compartments each sustained activations with significantly different levels of coactivity from the other finger muscle compartments. The middle finger compartment of EDC was the exception. Only two extrinsic thumb muscles, EPL and FPL, were capable of sustaining individual activations from the other thumb muscles, at all tested activity levels. Activation of APL was achieved at 20 and 30% MVC activity levels with significantly different levels of coactivity. Activation of EPB elicited coactivity levels from EPL and APL that were not significantly different. These results suggest that most finger muscle compartments receive unique motor commands, but of the four thumb muscles, only EPL and FPL were capable of individually activating. This work is encouraging for the neural control of prosthetic limbs because these muscles and compartments may potentially serve as additional user inputs to command prostheses.

scholarly journals MRI Study on the Distance between the Distal Radius and the Flexor and Extensor Tendons: Is There Any Room for Error/Hardware?

2019 ◽  
Vol 08 (06) ◽  
pp. 470-476
Author(s):  
Minke Bergsma ◽  
Jemara Board ◽  
Job N. Doornberg ◽  
Inger Sierevelt ◽  
Mark Rickman ◽  
...  
Keyword(s):  
Distal Radius ◽  
Magnetic Resonance Images ◽  
Dorsal Side ◽  
Flexor Digitorum Profundus ◽  
Dorsal Cortex ◽  
Level Of Evidence ◽  
Extensor Pollicis Longus ◽  
Extensor Tendons ◽  
Flexor Digitorum ◽  
Extensor Carpi Radialis

Abstract Purpose This study aims to quantify the distances between the cortex of the distal radius and flexor and extensor tendons. Methods We analyzed 50 magnetic resonance images (MRI) of intact wrist without pathology. The distances between the volar cortex and the flexor pollicis longs (FPL), index flexor digitorum profunduns (FDPi), flexor digitorum profundus (FDP), and flexor digitorum superficialis (FDS) were measured at the level of the watershed line and 3- and 6-mm proximal to this level. The distances between the dorsal cortex and the extensor carpi radialis longus (ECRL), extensor carpi radialis brevis (ECRB), extensor pollicis longus (EPL), extensor indicis proprius (EIP), and the extensor digitorum communis (EDC) were measured at the level of Lister's tubercle and 5-mm distal to this level. Analysis was descriptive. Results At the watershed line, the FPL, FDPi, FDP, and FDS were located at an average of 3.1, 2.4, 3.6, and 5.1 mm, respectively, volar to the volar cortex. The distances of the FDP and FDS increased at 3-mm proximal to the watershed line and increased for all four tendons at 6-mm proximal to the watershed line. Dorsally, at Listers' tubercle the ECRL, ECRB, EPL, EIP, and EDC were identified at an average of 0.7, 0.5, 0.5, 2.6, and 3.2 mm, respectively, dorsal to the dorsal cortex of the distal radius. At 5-mm more distal, these tendons were located on average 1.2, 1.0, 0.7, 1.9, and 1.8 mm, respectively, dorsal to the dorsal cortex. Conclusion On the volar side, on average there is enough room for a volar plate when staying proximal to the watershed line. On the dorsal side, there is virtually no room for protruding screws as physical anatomical space is limited to a maximum of 0.7 mm from cortex to the closest tendon (the FDP), with screw increments being 2 mm. Level of Evidence This is a Level II Study.

scholarly journals Bilateral Variation of Forearm Flexor Muscles - A Case Report and Clinical Significance

2012 ◽  
Vol 01 (01) ◽  
pp. 040-043
Author(s):  
D. Malar ◽  
Keyword(s):  
Middle Finger ◽  
Flexor Digitorum Profundus ◽  
Flexor Digitorum Superficialis ◽  
Flexor Carpi Ulnaris ◽  
Close Proximity ◽  
Flexor Muscles ◽  
Male Cadaver ◽  
Forearm Flexor Muscles ◽  
Flexor Digitorum ◽  
Forearm Flexor

AbstractDuring routine dissection, bilateral multiple variations of forearm flexor muscles were observed in a male cadaver. The variations were a) an additional belly arising from the coronoid process of ulna, distal to the origin of ulnar head of flexor digitorum superficialis, passing deep to flexor digitorum superficialis and joining the tendon of flexor digitorum profundus to the middle finger; b) an additional belly arising from the distal part of flexor carpi ulnaris and passing superficial to ulnar nerve and ulnar vessels in the Guyon's canal and c) the origin of second lumbricals from the profundus tendon in the carpal tunnel. An aberrant muscle may stimulate a ganglion or a soft tissue tumor or if in close proximity to a nerve, it may cause pressure neuritis. Identification of these variations is important in defining the anatomical features for clinical diagnosis and surgical procedures.

Avulsion Of The Ring Finger Flexor Digitorum Profundus Tendon: An Experimental Study

HAND ◽  
1978 ◽  
Vol os-10 (1) ◽  
pp. 52-55 ◽  
Author(s):  
Paul R. Manske ◽  
Peggy A. Lesker
Keyword(s):  
Experimental Study ◽  
Breaking Strength ◽  
Ring Finger ◽  
Middle Finger ◽  
Frequent Occurrence ◽  
Flexor Digitorum Profundus ◽  
Flexor Digitorum ◽  
Flexor Digitorum Profundus Tendon

Summary The results of an experimental study of the breaking strength of the tendon-bone junction of the flexor digitorum profundus tendon in cadaver specimens indicates a significantly weaker insertion of the ring finger compared to the middle finger. This explains in part the more frequent occurrence of avulsion of the ring finger profundus tendon as observed clinically.

Changes in Tendon Strength After Partial Cut and Effects of Running Peripheral Sutures

2003 ◽  
Vol 28 (5) ◽  
pp. 478-482 ◽  
Author(s):  
J. TAN ◽  
B. WANG ◽  
B. TAN ◽  
Y. XU ◽  
J. B. TANG
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Ultimate Strength ◽  
The Other ◽  
Flexor Digitorum Profundus ◽  
Gap Formation ◽  
Load To Failure ◽  
Flexor Digitorum ◽  
Lower Tensile Strength

We performed a study to evaluate the tensile properties of partial tendon lacerations and the effects of peripheral sutures on the tendon strength. Seventy-two fresh pig flexor digitorum profundus tendons were divided equally into eight groups. Tendons in four of the groups were subjected to partial lacerations (60%, 70%, 80%, and 90%) and were not repaired. In the other four similar groups partial lacerations were repaired with running peripheral sutures. The tendons were subjected to load-to-failure tests in an Instron tensile machine to determine the initial, 1 mm, 2 mm gap formation forces and the ultimate strength. The tendons with lacerations of 80% and 90% had a remarkably lower tensile strength than those 60% and 70% lacerations. Running peripheral sutures increased the gap formation forces and the ultimate strength of all the tendons, though particularly those with 80% and 90% lacerations.

Motor-Unit Synchrony Within and Across Compartments of the Human Flexor Digitorum Superficialis

2007 ◽  
Vol 97 (1) ◽  
pp. 550-556 ◽  
Author(s):  
Tara L. McIsaac ◽  
Andrew J. Fuglevand
Keyword(s):  
Motor Unit ◽  
Motor Neurons ◽  
Motor Units ◽  
Flexor Digitorum Profundus ◽  
Human Hand ◽  
Flexor Digitorum Superficialis ◽  
Short Term ◽  
Synaptic Inputs ◽  
Muscles Of The Hand ◽  
Flexor Digitorum

An interesting feature of the muscular organization of the human hand is that the main flexors and extensors of the fingers are compartmentalized and give rise to multiple parallel tendons that insert onto all the fingers. Previous studies of motor-unit synchrony in extensor digitorum and flexor digitorum profundus indicated that synaptic input to motor neurons supplying these multitendoned muscles is not uniformly distributed across the entire pool of motor neurons but instead appears to be partially segregated to supply subsets of motor neurons that innervate different muscular compartments. Little is known, however, about the organization of the synaptic inputs to the motor neurons supplying another multitendoned finger muscle, the flexor digitorum superficialis (FDS). Therefore in this study, we estimated the extent of divergence of last-order inputs to FDS motor neurons by measuring the degree of short-term synchrony among motor units within and across compartments of FDS. The degree of synchrony for motor-unit pairs within the same digit compartment was nearly twofold that of pairs of motor units in adjacent compartments and more than fourfold that of pairs in nonadjacent compartments. Therefore like other multitendoned muscles of the hand, last-order synaptic inputs to motor neurons supplying the FDS appear to primarily supply subsets of motor neurons innervating specific finger compartments. Such an organization presumably enables differential activation of separate compartments to facilitate independent movements of the fingers.

POST-TRAUMATIC COMBINED FLEXION OF THE THUMB, INDEX AND MIDDLE FINGER AFTER INTRINSIC MUSCLES RECONSTRUCTION OF THE HAND: A CASE REPORT

Hand Surgery ◽  
2011 ◽  
Vol 16 (02) ◽  
pp. 189-191 ◽  
Author(s):  
Stefano Lucchina ◽  
Alexandru Nistor ◽  
Cesare Fusetti
Keyword(s):  
Middle Finger ◽  
Surgical Reconstruction ◽  
Flexor Digitorum Profundus ◽  
Resonance Imaging ◽  
Flexor Pollicis Longus ◽  
Post Traumatic ◽  
Magnetic Resonance Imaging Mri ◽  
Flexor Digitorum ◽  
Intrinsic Muscles ◽  
Early Functional Recovery

We report a case in which simultaneous flexion of the thumb, index and middle finger occurred 6 months after the surgical reconstruction of the adductor (AM) and first dorsal interosseous (IO) muscles. An anomalous connection in the form of tendon slip associated to fibrous adhesions between the flexor pollicis longus (FPL) tendon, flexor digitorum profundus indicis (FDPI) and middle finger (FDPM) tendons were found. Either ultrasound (US) examination or magnetic resonance imaging (MRI) were unable to detect the site of adhesion. Excision of the slip and radical tenosynoviectomy led to early functional recovery.

Flexor Digitorum Tendon Transection As A Complication of Endoscopic Carpal Tunnel Release

1997 ◽  
Vol 22 (4) ◽  
pp. 508-509
Author(s):  
N. A. S. POSCH ◽  
K. E. BOS
Keyword(s):  
Carpal Tunnel ◽  
Carpal Tunnel Release ◽  
Middle Finger ◽  
Cadaver Study ◽  
Flexor Digitorum Profundus ◽  
Endoscopic Carpal Tunnel Release ◽  
Flexor Digitorum ◽  
Flexor Digitorum Profundus Tendon

A complete laceration of the flexor digitorum profundus tendon of the middle finger following endoscopic carpal tunnel release is reported. In a cadaver study the mechanism that could have led to this complication was investigated.

Comparison of modified Kessler tendon suture at different levels in the human flexor digitorum profundus tendon and porcine flexors and porcine extensors: an experimental biomechanical study

2011 ◽  
Vol 36 (8) ◽  
pp. 670-676 ◽  
Author(s):  
J. Havulinna ◽  
O. V. Leppänen ◽  
T. L. N. Järvinen ◽  
H. Göransson
Keyword(s):  
Tensile Testing ◽  
Flexor Tendon ◽  
Biomechanical Study ◽  
Flexor Digitorum Profundus ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Testing ◽  
Polyester Suture ◽  
Flexor Digitorum ◽  
Flexor Digitorum Profundus Tendon ◽  
Different Levels

This study compared the biomechanical behaviour of repairs in the human flexor digitorum profundus tendon in zones I, II and III with repairs of different segments of the porcine flexor tendon of the second digit and the extensor digiti quarti proprius tendon, in order to assess the validity of porcine tendons as models for human flexor tendon repairs. These porcine tendons were selected after comparing their size with the human flexor digitorum profundus tendon. The tendon repairs were done in three segments of each porcine tendon and repairs in the human tendons were done in zones I,II and III. Ten tendons in each group yielded a total of 90 specimens. A modified Kessler repair was done with 3-0 coated braided polyester suture and subjected to uniaxial tensile testing. In human flexor tendons, the ultimate force was higher in zones I and II than in zone III. The porcine flexor digitorum profundus tendon from the second digit and the proximal segment of the extensor digiti quarti proprius tendon behaved similarly to the human flexor tendon in zone III and can be considered as surrogates for the human flexor tendon.

Voluntary Activation of the Different Compartments of the Flexor Digitorum Profundus

2010 ◽  
Vol 104 (6) ◽  
pp. 3213-3221 ◽  
Author(s):  
Hiske van Duinen ◽  
Simon C. Gandevia ◽  
Janet L. Taylor
Keyword(s):  
Force Production ◽  
Voluntary Contraction ◽  
The Other ◽  
Voluntary Activation ◽  
Flexor Digitorum Profundus ◽  
Force Output ◽  
Neural Drive ◽  
Linear Relationships ◽  
Full Flexion ◽  
Flexor Digitorum

Flexor digitorum profundus (FDP), the sole flexor of the fingertips, is critical for tasks such as grasping. It is a compartmentalized multitendoned muscle with both neural and mechanical links between the fingers. We determined whether voluntary activation (VA), the level of neural drive to muscle, could be measured separately in its four compartments, whether VA differed between the fingers, and whether maximal voluntary contraction (MVC) force and VA changed when the non-test fingers were extended from full flexion to 90° flexion to partially “disengage” the test finger. Transcranial magnetic stimulation (TMS) of the motor cortex was used to measure VA, in a position in which only FDP generated force at the fingertip. Despite differences among the fingers in MVCs, VA for each finger was ∼92% ( n = 8), with no differences between fingers. When the test finger was partially disengaged by extending the other fingers to 90° flexion, performance was more variable both within and between subjects. MVCs decreased significantly by about 25–40% for the four fingers. However, VA was not significantly changed ( n = 6) and was similar for the four fingers. In both positions, there were strong linear relationships between the voluntary forces and the superimposed twitch sizes, indicating that the method to measure VA was very reliable. Our results indicate that maximal VA is similar for all four compartments of FDP when force production by the other fingers is unconstrained. When altered mechanical connections between the compartments decrease voluntary force output there is little difference in neural drive.

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