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Concept: Flexor pollicis longus muscle


A previous ultrasound study showed inflammation around the extensor pollicis longus tendon and surrounding structures at 6 weeks after manipulation, with or without pin fixation, and immobilization for distal radius fracture. Ultrasound examination after plating of distal radius fracture followed by early active mobilization of the wrist showed a short-lived inflammatory response, evident at 2 weeks but not at 6 weeks, around the extensor pollicis longus tendon (26 wrists examined) and flexor pollicis longus tendon (18 wrists examined). Early active mobilization of the wrist appears to limit the duration of inflammation around these tendons.

Concepts: Flexor digitorum profundus muscle, Wrist, Distal radius fracture, Flexor pollicis longus muscle, Extensor pollicis brevis muscle, Carpal tunnel, Flexor pollicis brevis muscle, Extensor pollicis longus muscle



Strong evidence indicates that highly repetitive manual work is associated with the development of upper extremity musculoskeletal disorders (MSDs). One of the occupational activities that involves highly repetitive and forceful hand work is manual pipetting in chemical or biological laboratories. In the current study, we quantified tendon displacement as a parameter to assess the cumulative loading exposure of the musculoskeletal system in the thumb during pipetting. The maximal tendon displacement was found in the flexor pollicis longus (FPL) tendon. Assuming that subjects' pipetting rates were maintained constant during a period of 1h, the average accumulated tendon displacement in the FPL reached 29m, which is in the lower range of those observed in other occupational activities, such as typing and nail gun operations. Our results showed that tendon displacement data contain relatively small standard deviations, despite high variances in thumb kinematics, suggesting that the tendon displacements may be useful in evaluating the musculoskeletal loading profile.

Concepts: Variance, Standard deviation, Flexor pollicis longus muscle, Extensor pollicis brevis muscle, Michigan, Musculoskeletal system


We investigated the flexor pollicis longus (FPL) tendon and median nerve in smartphone users by ultrasonography to assess the effects of smartphone addiction on the clinical and functional status of the hands.

Concepts: Ulnar nerve, Flexor pollicis longus muscle, Extensor pollicis brevis muscle, Carpal tunnel, Hand strength


In hemiplegic patients with a spastic clenched fist deformity, one of the goals of surgery is to address the hygiene, nursing and appearance problems. Transfer of the flexor digitorum superficialis (FDS) to the flexor digitorum profundus (FDP), initially described by Braun and colleagues, opens the non-functional hand in these patients. The primary objective of our study was to confirm the effectiveness of this technique for correcting these deformities. The secondary objectives were to demonstrate potential functional gains and to identify potential complications.

Concepts: Varus deformity, Object, Flexor digitorum profundus muscle, Flexor pollicis longus muscle, Deformity, Flexor digitorum superficialis muscle, Raised Fist


Pediatric trigger thumb is regarded as an acquired condition characterized by flexion deformity of the interphalangeal joint of the thumb. However, the exact etiology and pathoanatomy of this condition remain unknown. The purpose of this study was to evaluate cross-sectional configurations of the flexor pollicis longus (FPL) tendon and the area under the A1 pulley quantitatively using ultrasonography.

Concepts: Knee, Flexor pollicis longus muscle, Extensor pollicis brevis muscle, Fingers


Volar plates positioned at, or distal to, the watershed line have been shown to have a higher incidence of attritional rupture of the flexor pollicis longus (FPL). In this study, we aimed to evaluate the effect of wrist extension and volar tilt on the contact between the plate and the FPL tendon in a cadaver model. We hypothesized that, following volar plate application, loss of native volar tilt increases the contact between the FPL and the plate at lower degrees of wrist extension.

Concepts: Effect, Model theory, Flexor digitorum profundus muscle, Tendon, Flexor pollicis longus muscle, Extensor pollicis brevis muscle, Carpal tunnel, Extensor pollicis longus muscle


Muscles of flexor compartment of forearm have a common origin from medial epicondyle of humerus. Additional bellies of flexor muscles are commonly reported but presence of supernumerary muscles is an infrequent phenomenon. The present study describes an unusual muscle mass in flexor compartment of forearm simulating pronator teres. During routine dissection the upper limb of a 50 years old male cadaver, a supernumerary muscle was found on left side of the upper limb in the flexor compartment. The origin of the muscle was 2cm wide and aponeurotic in nature and attached to an oblique line extending from the inferior surface of the medial epicondyle and the medial surface of the trochlea. It was inserted on an oblique line 2.5cm wide on the radius in area between supinator superiorly and flexor digitorum profundus inferiorly. Existence of accessory muscles, which connect flexor muscles, could be explained embryologically by incomplete cleavage of flexor mass during development. The flexor muscles of the forearm develop from the flexor mass which subsequently divides into two layers: superficial and deep. The deep layer gives rise to flexor digitorum superficialis, flexor digitorum profundus and flexor pollicis longus. These supernumerary muscles are extremely rare entities and probably represent deranged embryological development or the process of atavism in which the anomalous part persist for a longer time in the tree of evolution.

Concepts: Muscle, Ulna, Flexor digitorum profundus muscle, Forearm, Upper limb, Flexor pollicis longus muscle, Muscles of the upper limb


The short-term joint immobilization induces a decrease of corticospinal excitability; however, detailed time course of the immobilization-induced central nervous system changes and their extent have not yet been clarified. To evaluate the time course of changes in corticospinal excitability during forearm/hand immobilization for 24 h and investigate the effect on muscle strength, adhesive casting tape was used to immobilize the nondominant forearm/hand. The amplitude of the motor-evoked potential of the flexor pollicis brevis muscle induced by transcranial magnetic stimulation was measured during immobilization and after cast removal. The muscle strength was evaluated after the termination of immobilization. The resting motor-evoked potential recorded from flexor pollicis brevis muscle showed a significant decrease 3 h after initiation of immobilization and gradually declined further until the end of immobilization. It then increased over 2 h after cast removal, but was still significantly below baseline. However, no significant difference from baseline was observed at 3 h. Both pinch power and integrated electromyogram were significantly reduced by immobilization, and then gradually returned to baseline after the cast was removed. These results indicate that short-term forearm/hand immobilization rapidly reduces corticospinal excitability, and this change is rapidly reversed after resumption of movement.

Concepts: Central nervous system, Nervous system, Spinal cord, Brain, Transcranial magnetic stimulation, Nerve, Flexor pollicis longus muscle, Extensor pollicis brevis muscle


Injury to the flexor pollicis longus (FPL) tendon is one of the most frequent complications when fixing distal radius fractures with the volar locking plates. The author proposed a simple surgical technique providing a reliable soft tissue protection to prevent friction on the FPL with the volar locking plate, using a flap of the FCR sheath sutured to attachments of the volar capsule on the lunate buttress facet of the distal radius.

Concepts: Extracellular matrix, Surgery, Tissues, Injury, Gemstone, Distal radius fracture, Flexor pollicis longus muscle, Extensor pollicis brevis muscle