Inervación del músculo flexor superficial de los dedos / Innervation of the superficial flexor digitorum muscle

La inervación del músculo flexor superficial de los dedos (FSD) es controversial. Diversos autores describen que los ramos de este músculo surgen independiente o desde un tronco común que proviene desde el nervio mediano, dentro de la región cubital. Otras descripciones señalan la presencia de ramos adicionales en los tercios medio y distal del antebrazo. Estas diferencias también se reflejan al describir los puntos motores. El objetivo fue determinar el número, ubicación y patrones de distribución de los ramos para el FSD. Se utilizaron 30 antebrazos de cadáveres adultos brasileños formolizados. En relación al número de ramos, el 26 % presentó un solo ramo (R1). El 57 % presentó dos ramos (R1 y R2) y el 17 % presentó 3 ramos (R1, R2 y R3). Respecto al formato de origen, el 87 % de los R1 surgieron independiente, mientras que el 13 % surgió desde un tronco común. En el caso de los R2 y R3, el 100 % surgió independiente. En relación a los puntos de origen, el 90 % de los R1 se originó en el tercio proximal del antebrazo, en tanto, el 60 % de los R2 surgieron en el tercio medio, y de los 5 R3, el 60 % se originó en el tercio medio y los dos restantes surgieron en el tercio distal. Esta misma variabilidad se presentó en la distribución de los puntos motores. Respecto a los patrones de distribución de estos ramos motores se identificaron de dos tipos. El patrón I se presentó en el 85 % y se caracterizó por que todos sus ramos surgieron en un punto distal al origen del nervio interóseo anterior (NIA), en cambio, en el patrón tipo II (15 % de la muestra), el primer ramo se originó proximal al origen del NIA.

Innervation of the flexor digitorum superficialis muscle (FDS) is controversial. Several authors describe that the branches of this muscle arise independently or from a common trunk that comes from the median nerve, within the ulnar region. Other descriptions indicate the presence of additional branches in the middle and distal third of the forearm. These differences are also reflected when describing the motor points. The aim was to determine the number, location and distribution patterns of the branches for the FDS. 30 forearms of Brazilian adults were used. About the number of branches, 26 % presented a single branch (R1). 57 % presented two branches (R1 and R2) and 17 % presented 3 branches (R1, R2 and R3). Regarding the format of origin, 87 % of the R1 emerged independently, while 13 % emerged from a common trunk. In the case of R2 and R3, 100 % emerged independently. About the points of origin, 90 % of the R1 were originated in the proximal third of the forearm, while 60 % of the R2 emerged from the middle third, and of the 5 R3, 60 % were originated in the middle third and the remaining two emerged in the distal third. This same variability was present in the motor points distribution. Regarding the distribution patterns of these motor branches, two types were identified. Pattern I was present in 85 % and was characterized by all branches arising at a point distal to the origin of the anterior interosseous nerve (AIN), however, in the type II pattern (15 % of the sample), the first branch was originated proximal to the origin of the AIN.

Concomitant Variations in Flexor Digitorum Superficialis: A Case Report / 체질인류학회지

The flexor digitorum superficialis (FDS) muscle is located in the intermediate layer of the muscles in the anterior compartment of the forearm. Variable but individual variations have been reported in the FDS regarding the number of head and the origin, distribution and interconnections of muscle slip and insertion to finger. In this case, we report a concomitant complex variation in FDS which was observed in a cadaver during a routine dissection classes for the undergraduate medical students. It includes the variation which is the separation of the tendon of FDS into the superficial and deep layers, the structural variations in muscle slips and associated tendon variations, the finding of Gantzer' muscle leading to flexor pollicis longus muscle. These complex variations in FDS are very rare case and this report summarizes the related phylogenetic and embryological significance.

Flexor Digitorum Superficialis and Flexor Digitorum Profundus with separated sheaths, a new normal variation in human / Flexor superficial de la y Flexor profundo de los con vainas separadas, una nueva variación normal en humanos

Case description: A 25 years old man presented with a laceration on radial side of proximal phalanx of 4th finger (zone II flexor) which was due to cut with glass. Clinical findings: The sheaths of Tendons of flexor digitorum sperficialis and profundus were not the same and each tendon had a separate sheath. Treatment and outcome: The tendons were reconstructed by modified Kessler sutures, after 15 months the patient had a 30 degrees of extension lag even after physiotherapy courses. Clinical relevance: This is the first reported of such normal variation in human hand tendon anatomy.

Descripción del caso: Se presentó un hombre de 25 años con una laceración en la parte radial de la falange proximal del cuarto dedo de la mano (zona flexor II) causada por el corte con un vidrio. Hallazgos clínicos: Las cubiertas de los tendones del flexor digitorum sperficialis y profundus estaban separadas en diferentes cubiertas. Tratamiento y resultado: Los tendones se reconstruyeron por la suturas modificadas de Kessler. Después de 15 meses el paciente presentó una pérdida del 30% en la extensión , aun después de la fisioterapia. Relevancia clínica: Es el primer reporte de la variación en la anatomía de la mano.

Accessory belly of flexor digitorum superficialis - case report of a rare variant.

Variations of the muscles pose a challenge to diagnosis and knowledge about them is important during surgeries and other interventions. At times these variations may cause symptoms per se. Variations of the Flexor digitorum superficialis: a muscle of the anterior compartment of forearm, are not very common. We present a rare variation of this muscle in the right upper limb of a male cadaver. The variant was an accessory belly arising from and under the Flexor digitorum superficialis and inserting into the base of proximal phalanx of the index finger. We also review the evolutionary and embryological concepts of such variations.

Numbers Matter: Clinical Significance of Additional Belly of First And Second Lumbrical Muscles of the Hand.

In a routine dissection conducted in the Department of Anatomy, Amrita School of Medicine Kochi, additional origins of the first and second lumbricals were observed on the right hand of a male cadaver. The additional belly originated from the radial side of the tendon of flexor digitorum superficialis (FDS) of the index finger, deep to the flexor retinaculum. Distally the tendon of both bellies united and inserted to the dorsal digital expansion of the index finger. In the case of the second lumbrical the additional belly arose from the ulnar side of the tendon of Flexor digitorum profundus (FDP) of the index finger and inserted into the dorsal digital expansion of middle finger. Knowledge of possible variations helps the clinician find aetiology for various compressive syndromes so that treatment modality can be tailored and customised. This presentation will add to the compendium of information.

Impact of index finger force on motor unit recruitment pattern in flexor digitorum superficialis / 医用生物力学

Objective To detect the recruitment pattern of motor unit in human flexor digitorum superficialis (FDS) at different force levels produced by the index finger. Methods Eight subjects were recruited to produce a certain force level with the index finger to match the ordered force level (20%, 40%, 60% maximum voluntary contraction). During the force tracking task, the multi-channel surface electromyography (sEMG) signals were recorded on FDS using 8×1 (row×column) electrode-array. The motor unit action potential (MUAP) information was extracted by Fast Independent Component Analysis (FastICA), and then the correlation between MUAP pattern and force level was analyzed. Results Four different types of MUAP were extracted successfully by FastICA from original sEMG signals and the total number of MUAP showed an increasing trend with the force level increasing. At different force levels, the proportion of different types of MUAP was different, showing different trends with change of the force level. ConclusionsAt different levels of the finger force, the recruitment pattern of motor unit in FDS will be changed so as to produce the force accordingly.

A Case of Trigger Finger Following Longitudinal Tear of Flexor Digitorum Superficialis after Repeated Closed Injury

PURPOSE: Many causes for triggering or locking of the fingers have been discussed in other literatures. The most common one is known stenosing tenosynovitis, which causes, a mismatch between the volume of the flexor tendon sheath and its contents. However, repeated trauma to the hand is uncommon cause of trigger finger. Therefore, we present a case of a rare condition of stenosing tenosynovitis which developed from a repeated relatively weak superficial flexor tendon injury. METHODS: The patient was a 62-year-old woman who showed a painless, fixed and round mass on her right hand with no particular cause. Active and passive range of motion of the metacarpophalangeal joint of long finger was limited in flexion and extension. Ultrasonographic finding showed injured flexor digitorum superficialis tendon had fibrillar architecture with swelling between hyperechoic synovial membrane and hypoechoic surrounding area. Surgical exploration revealed that a bunched portion of the flexor digitorum superficialis and A1 pulley cause triggering during operation after adhesiolysis of scar tissue. RESULTS: After releasing the A1 pulley, the range of motion of the metacarpophalangeal joint of long finger showed no limitation and histological examination of the subcutaneous tissue revealed fibrous fatty degeneration. In this case, releasing the A1 pulley with adhesiolysis of the subcutaneous scar tissue was successful and we obtained good functional outcome. CONCLUSION: We examined a patient in whom a repetitive impact forces to the palm caused longitudinal tear of the flexor tendon, leading to trigger finger. We experienced a rare case of stenosing tenosynovitis and trigger finger caused after close injury to flexor digitorum superficialis and its degenerative changes that caused mass like effect. To the best of authors' knowledge, our case of close injury to the flexor digitorum superficialis and unique morphologic change before rupture of tendon is rarely to be reported.

Topographic Anatomy of the Median Nerve and the Pronator Teres and the Flexor Digitorum Superficialis Muscles / 대한해부학회지

The pronator teres syndrome can occur when the median nerve is compressed by the adjacent structures in the proximal forearm. The pronator teres and the flexor digitorum superficialis muscles have been suggested to contribute to this syndrome. This study was performed to clarify the topographical relationship among the median nerve, the pronator teres muscle and the flexor digitorum superficialis muscle in 55 Korean adult cadavers (100 sides of arms). The two heads of the pronator teres muscle met at the point of 61.3 mm distal to the biepicondylar line and inserted to the radius at the point of 141.5 mm distal to the line. The ulnar side of its ulnar head was muscular in 8%, tendinous in 70%, and mixed in 20%. The radial side of its humeral head was muscular in 53%, tendinous in 14%, and mixed in 33%. The median nerve was completely covered by the pronator muscle within 26.5 mm from the biepicondylar line and entered between the two heads of the pronator muscle at 54.2 mm from the line and exited it after running 25.5 mm. The most distal part of the musculotendinous arch of the flexor digitorum superficialis muscle was located at the average 80.9 mm from the biepicondylar line. The distalmost radial head of the flexor digitorum superficialis muscle originated from the distal point of the pronator teres insertion in 28.6%, distal to that point in 54.3%, and proximal to that point in 14.3%.

The Proximal and Distal Interphalangeal Flexion Dysfunction, Opposition Palm Ratio and Thumb Index Ratio in the Korean Adults

OBJECTIVE: The purpose of this study was to evaluate the incidence of inability to flex proximal interphalangeal (PIP) and distal interphalangeal (DIP) joint in normal Koreans. The opposition palm ratio and thumb index ratio was also of interest. METHOD: Randomly selected eighty nine normal Korean adults of 48 men and 41 women, with ages 20 to 79 years. The finger flexion was measured using the standard flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) screening tests. Thumb index ratio and opposition palm ratio was also assessed additionally. RESULTS: In the sample population, 2 subjects (2.2%) were unable to bilaterally flex their fifth PIP joints independently. Four subjects (4.4%) were unable to flex one or both of their fourth or fifth DIP joints. These results show far less incidence of FDS dysfunction comparing with 52% of FDS dysfunction rate in Americans. The opposition palm ratio in men were 63.6% and in women 69.9%, indicating lower ratio in men. The thumb index ratio was not different statistically between the men and women. CONCLUSION: These data suggest that the different incidences of FDS and FDP dysfunction should be considered in interpretation. The opposition palm ratio and thumb index ratio might be useful in the hand rehabilitation.