- Email: [email protected]
Spontaneous rupture of the flexor digitorum superficialis tendon of the index and middle fingers: “The pen sign”
Chirurgie de la main 28 (2009) 330–333
Clinical case
Spontaneous rupture of the flexor digitorum superficialis tendon of the index and middle fingers: ‘‘The pen sign’’ Rupture spontanée du fléchisseur superficiel de l’index et du majeur : « le signe du stylo » X. Martinache *, J.-M. Cognet, F. Schernberg SOS mains Champagne-Ardenne, polyclinique Saint-André, 5, boulevard de la Paix, 51100 Reims, France Received 11 November 2008; received in revised form 17 April 2009; accepted 27 May 2009
Abstract We report this case of a flexor digitorum superficialis (FDS) tendon rupture of the second and third fingers of the right hand in a 46-year-old patient. This rupture seems to occur under moderate stress. In this precise situation, the diagnosis was confirmed from the MRI data. Treatment was entirely conservative. However, the clinical presentation of the patient appeared quite original and so misleading to us that we reported this case here and developed the term ‘‘pen sign’’ to describe it. Considering this case, in order to reanimate thumb flexion transferring the fourth finger, FDS would appear to be entirely justified because of the lack of consequent difficulties on fine thumb index finger grasping used when holding pens or fine tweezers. It should also lead us in our everyday surgical practice to attempt to systematically repair the two index flexor tendons when they are damaged. # 2009 Elsevier Masson SAS. All rights reserved. Keywords: Rupture; Spontaneous; Flexor tendon; Pen sign
Résumé Nous rapportons ici le cas d’une rupture traumatique des fléchisseurs superficiels du deuxième et troisième rayon de la main droite chez un chef d’entreprise de 46 ans. Cette rupture est survenue au décours d’un effort modéré. Dans ce cas précis, le diagnostic a pu être confirmé secondairement par les données de l’imagerie (IRM). Une abstention thérapeutique pure et simple a été observée. Cependant, la présentation clinique du patient nous a semblée suffisamment originale, voire déroutante, pour être rapportée ici et commentée sous l’appellation de « signe du stylo ». À la lueur de ce cas, le choix du fléchisseur superficiel du quatrième doigt pour la réanimation de la flexion du pouce paraît pleinement justifiée car n’entraînant pas de gêne dans les prises pollicidigitales fines. À l’inverse, l’utilisation du fléchisseur superficiel de l’index est à déconseiller en raison de la gêne entraînée. # 2009 Elsevier Masson SAS. Tous droits réservés. Mots clés : Rupture ; Spontanée ; Tendon fléchisseur ; Signe du stylo
1. Introduction While traumatic subcutaneous avulsions of the flexor digitorum profondus (FDP) tendons are commonly described in sports and trauma medicine, all referred to as ‘‘Jersey’’ or ‘‘Rugby’’ finger, main body ruptures are less frequent and often located on the deep tendon of the little finger. Isolated
* Corresponding author. E-mail address: [email protected] (X. Martinache).
subcutaneous rupture of the flexor digitorum superficialis (FDS) tendons is very rare [1]. We report a case of FDS tendon rupture in the right index and middle fingers occurring in a 46-year-old company executive. The diagnosis was confirmed secondarily by the findings on imaging (MRI). Treatment was entirely conservative. However, the functional problem mentioned by the patient, particularly when writing, appeared sufficiently novel and so misleading to us that we coined the term ‘‘pen sign’’ to describe it.
1297-3203/$ – see front matter # 2009 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.main.2009.05.002
X. Martinache et al. / Chirurgie de la main 28 (2009) 330–333
2. Clinical case A 46-year-old, right-handed, male company executive presented with discomfort when using his pen for the previous few days. Such discomfort resulted in a modification of his signature. Initially, we were somewhat confused regarding his reason for presenting, until the patient showed us, by using his left hand, his usual manner of handling a pen. We helped him to reproduce his normal pen holding position with his right hand. For that purpose, counterpressure had to be placed on the distal interphalangeal (DIP) joint in order to create simultaneous flexion of the proximal interphalangeal (PIP) joint and the necessary slight hyperextension of the DIP joint. The patient was not able to maintain this position on his own (Fig. 1). Formal testing was very informative and confirmed the lack of normal function of the superficial flexor tendons (FDS) in his index and middle finger (Fig. 2). The patient, who had no history of rheumatoid or metabolic disease, was questioned to determine the cause of his injury. He revealed he had purchased a pair of climbing boots equipped with a loop through which the user passes his index to help to pull on the boots. Doing this had caused some pain a few days
331
before the patient noticed his writing difficulty, but he did not link the two events. He also described a very brief sensation of locking of his index finger PIP joint that was still present at the time of the consultation. From his answers and the clinical examination, we considered the possible diagnosis of a rupture of the superficial index and middle finger flexor tendons. It was our opinion that no treatment would be required unless the locking effect, which did not appear to trouble the patient, worsened. MRI confirmed the diagnosis of rupture of the superficial index and middle finger flexor tendons and showed the tendinous retraction and the location of the rupture in the area of the A1 pulley for both the tendons (Fig. 3). This explained the locking effect experienced by the patient and subsequently required a steroid infiltration. No surgical tendon repair was recommended, given the limited clinical repercussions. 3. Discussion Spontaneous rupture of a flexor tendon is rarely reported in the literature.
Fig. 1. A. Holding the pen with the right hand. B. Reproducing with the left hand the ‘‘usual’’ index position when holding a pen. C. Simulating with the examiner’s help the right position which the patient is now unable to achieve anymore on his own.
332
X. Martinache et al. / Chirurgie de la main 28 (2009) 330–333
axial traction forces, ruptures appear to occur preferentially at the distal point of insertion of the tendon (athlete’s jersey or rugby finger) or at the muscle–tendon junction (muscle elongation or tear) [3]. The tendon itself, however, is not prone to rupture. According to McMaster, at least half of the fibres in a tendon have to be damaged in order for a rupture to occur [3]. In the past, such ruptures within the tendon material itself have been described as associated with underlying diseases. These are secondary ruptures for which a precise cause is often found: repeated corticosteroid injections [4] or as resulting from a tenosynovitis consequent to an underlying disease such as rheumatoid arthritis or gout. Other cases of tendon attrition may be found at operation and include wear ruptures due to a bony irregularity or ruptures due to an anatomical abnormality (single tendon or attachment point proximal to the lumbrical for deep tendons of the ring and little fingers [5,6]. This anatomic abnormality has been long known and Testut himself cites earlier authors [7]. The causes of attrition rupture due to an anatomic abnormality have been described in many publications reporting small numbers of cases such as:
Fig. 2. A. Clinical evaluation of the flexor digitorum superficialis (FDS) of the index and the middle fingers neutralising the action of the flexor digitorum profondus (FDP). B. Comparison with the left side.
Most flexor tendon ruptures occur following avulsion of the FDP at its point of insertion [1]. The flexor tendon is considered to be the most resistant part of the muscle–tendon system [2]. When subjected to excessive
pseudarthroses or prominence of the hook of the Hamate. The first case was described by Boyes in 1960 et al. [8] and subsequently in many publications; calcifications of the triangular fibrocartilage [9]; pisotriquetral osteoarthritis [10]; aggressive callus of the radius [11]; retrolunar dislocation of the carpal bone or intracarpal abnormalities [12]; Kienböck’s disease or scaphoid pseudarthroses [13]. True spontaneous intratendoninous ruptures are uncommon, with fewer than 50 cases being reported in the literature. By the term ‘‘spontaneous’’, we refer to the criteria defined by Boyes et al. in 1960 which excludes any intrinsic or extrinsic pathological process to explain the rupture. Boyes et al. only
Fig. 3. MRI confirmation of the rupture which is located at the level of the A1 pulley for both flexor digitorum superficialis (FDS) tendons. The specificity of this investigation modality is about 95 to 100% [18].
X. Martinache et al. / Chirurgie de la main 28 (2009) 330–333
found only three cases that met these criteria in a series of 80 ruptures [8]. The largest series is that of the Naam [2] study in 1995 that included 13 cases of FDP rupture which met the criteria defined by Boyes et al. Most of the cases involved men between 30 and 60 years old performing repetitive work sometimes associated with trauma [1,14]. Rupture was located in the midpalmar region in the lumbrical or immediately distal to its distal insertion. In terms of site, the three ulnar fingers are involved most often with predominant involvement of the little finger in two third of the cases, the ring finger in 20% of cases and finally the middle finger marginally, in less than 10% of cases. The deep flexor is involved in 82% of cases; the superficial flexor in 12% and the thumb flexor in 6% of cases [8]. Combined tendon involvement is commonly seen with the little finger [15]. The predominant injury of the little finger FDP appears to be due to the peak force which is applied to the FDP because of the relatively common absence of FDS function in the fifth finger. Baker et al. [16] found FDS deficiency in 34% of cases out of a cohort of 263 adults tested. Other authors describe complete absence of FDS in the little finger in only 5% of cases [17]. The site of involvement in the case reported here is therefore atypical, both regarding the location of the superficial tendons rupture and the fingers involved (index and middle). The site of the ruptures (zone 3) is consistent however with published findings [18]. From the case series findings available, spontaneous flexor tendon ruptures present clinically, when they do occur, with an audible click in 70% of cases. In 28% of cases, the patients experience cramp or acute pain in the midpalmar region [1]. Apart from the functional defect, the clinical presentation is different in cases of tendon avulsion in which the features of rupture are rarely audible and are more often characterised by jamming or adherence effects in the digital canal [19]. Our patient was unaware of the rupture and the initiating mechanism of the lesion was only found after direct questioning about the injury. This ‘‘novel’’ reason for consultation (altered writing praxia) has not been reported yet and we consider that this was significantly misleading and original in its description. For synergistic reasons, some groups have proposed transferring the superficial index finger flexor tendon to reanimate thumb flexion as palliative surgery. On the basis of our case, we would not recommend such a transfer. On the other hand, transferring the ring finger FDS would appear to be entirely justified because of the lack of consequent difficulties on fine thumb and index finger pinch grip used when holding pens or fine tweezers. 4. Conclusion The ‘‘newspaper’’ sign has immortalised Jules Froment. The ‘‘pen’’ sign described here will certainly remain relatively unknown in view of the rarity of such disorder. We may assume
333
however that there are more actual cases than a literature review would suggest. Given the limited clinical repercussions, it is likely that only a small percentage of patients will present seeking treatment. Apart from its novel nature and the fact that to our knowledge this type of case has not been reported previously, our case clearly demonstrates the synergistic effect of deep and superficial index flexor tendons when writing. It should make us attempt, in our daily surgical practice, to systematically repair both flexor tendons when they are damaged. This should also encourage us to avoid sacrificing the superficial index finger tendon for secondary transfer surgery, unless it is absolutely necessary. References [1] Bois AJ, Johnston G, Classen D. Spontaneous flexor tendon ruptures of the hand: case series and review of the literature. J Hand Surg 2007;32(7): 1061–71. [2] Naam NH. Intratendinous rupture of the flexor digitorum profundus tendon in zones II and III. J Hand Surg 1995;20A:478–83. [3] McMaster PE. Tendon and muscle ruptures, clinical and experimental studies on the causes and location of subcutaneous ruptures. J Bone Joint Surg 1933;15:705–22. [4] Fitzgerald BT, Hofmeister EP, Fan AJ, Thompson M. delayed flexor digitorum superficialis and profundus ruptures in a trigger finger after a steroid injection: a case report. J Hand Surg 2005;30:479–82. [5] Davis C, Armstrong J. Spontaneous flexor tendon rupture in the palm: the role of a variation of tendon anatomy. J Hand Surg 2003;28A:149–52. [6] de Roos KW, Zeeman RJ. A flexor tendon rupture in the palm of the hand. J Hand Surg 1991;16A:663–5. [7] Testut L. Les anomalies musculaires chez l’homme. Paris: Masson; 1884. [8] Boyes JH, Wilson JN, Smith JW. Flexor tendon ruptures in the forearm and hand. J Bone Joint Surg 1960;42A:346–67. [9] Fukui A, Kido A, Inada Y, Mii Y, Tamai S. Closed rupture of the flexor digitorum profundus tendon of the little finger caused by calcification of the triangular-fibrocartilage. J Hand Surg 1996;21B(3):375–7. [10] Corten EML, van den Broecke DG, Kon M, Schuurman AH. Pisotriquetral instability causing an unusual flexor tendon rupture. J Hand Surg 2004;29A:236–9. [11] McMaster PE. Late ruptures of extensor and flexor pollicis longus tendons following Colles’ fractures. J Bone Joint Surg 1932;14:93–101. [12] Koizumi M, Kanda T, Satoh S, Yoshizu T, Maki Y, Tsubokawa N. Attritional rupture of the flexor digitorum profundus tendon to the index finger caused by accessory carpal bone in the carpal tunnel: a case report. J Hand Surg 2005;30A:142–6. [13] Yamazaki H, Kato H, Hata Y, Nakatsuchi Y, Tsuchikane A. Closed rupture of the flexor tendons caused by carpal bone and joint disorders. J Hand Surg Eur Vol 2007;32:649–53. [14] Imbriglia JE, Goldstein SA. Intratendinous ruptures of the flexor digitorum profundus tendon of the small finger. J Hand Surg 1987;12A:985–91. [15] Popov N, Escaré P, Allieu Y. Primary flexor tendon ruptures of the little finger within the carpal tunnel. Proposed classification based on six clinical cases and review of the literature. Chir Main 2007;26:35–9. [16] Baker DS, Gaul JS, Williams VK, Graves M. The little finger superficialis: clinical investigation of its anatomic and functional shortcomings. J Hand Surg 1981;6A:374–8. [17] Furnas DW. Muscle-tendon variations in the flexor compartment of the wrist. Plast Reconstr Surg 1965;36:320–4. [18] Drapé JL, Tardif-Chastenet De Gery S, Silbermann-Hoffman O, Chevrot A, Houvet P, Alnot JY, et al. Closed ruptures of the flexor digitorum tendons: MRI evaluation. Skeletal Radiol 1998;27(11):617–24. [19] Ferraro SP, Schenck RR. Isolated closed rupture of the bony insertion of the flexor digitorum superficialis tendon: an unusual case. J Hand Surg 1998;23:837–9.
Clinical case
Spontaneous rupture of the flexor digitorum superficialis tendon of the index and middle fingers: ‘‘The pen sign’’ Rupture spontanée du fléchisseur superficiel de l’index et du majeur : « le signe du stylo » X. Martinache *, J.-M. Cognet, F. Schernberg SOS mains Champagne-Ardenne, polyclinique Saint-André, 5, boulevard de la Paix, 51100 Reims, France Received 11 November 2008; received in revised form 17 April 2009; accepted 27 May 2009
Abstract We report this case of a flexor digitorum superficialis (FDS) tendon rupture of the second and third fingers of the right hand in a 46-year-old patient. This rupture seems to occur under moderate stress. In this precise situation, the diagnosis was confirmed from the MRI data. Treatment was entirely conservative. However, the clinical presentation of the patient appeared quite original and so misleading to us that we reported this case here and developed the term ‘‘pen sign’’ to describe it. Considering this case, in order to reanimate thumb flexion transferring the fourth finger, FDS would appear to be entirely justified because of the lack of consequent difficulties on fine thumb index finger grasping used when holding pens or fine tweezers. It should also lead us in our everyday surgical practice to attempt to systematically repair the two index flexor tendons when they are damaged. # 2009 Elsevier Masson SAS. All rights reserved. Keywords: Rupture; Spontaneous; Flexor tendon; Pen sign
Résumé Nous rapportons ici le cas d’une rupture traumatique des fléchisseurs superficiels du deuxième et troisième rayon de la main droite chez un chef d’entreprise de 46 ans. Cette rupture est survenue au décours d’un effort modéré. Dans ce cas précis, le diagnostic a pu être confirmé secondairement par les données de l’imagerie (IRM). Une abstention thérapeutique pure et simple a été observée. Cependant, la présentation clinique du patient nous a semblée suffisamment originale, voire déroutante, pour être rapportée ici et commentée sous l’appellation de « signe du stylo ». À la lueur de ce cas, le choix du fléchisseur superficiel du quatrième doigt pour la réanimation de la flexion du pouce paraît pleinement justifiée car n’entraînant pas de gêne dans les prises pollicidigitales fines. À l’inverse, l’utilisation du fléchisseur superficiel de l’index est à déconseiller en raison de la gêne entraînée. # 2009 Elsevier Masson SAS. Tous droits réservés. Mots clés : Rupture ; Spontanée ; Tendon fléchisseur ; Signe du stylo
1. Introduction While traumatic subcutaneous avulsions of the flexor digitorum profondus (FDP) tendons are commonly described in sports and trauma medicine, all referred to as ‘‘Jersey’’ or ‘‘Rugby’’ finger, main body ruptures are less frequent and often located on the deep tendon of the little finger. Isolated
* Corresponding author. E-mail address: [email protected] (X. Martinache).
subcutaneous rupture of the flexor digitorum superficialis (FDS) tendons is very rare [1]. We report a case of FDS tendon rupture in the right index and middle fingers occurring in a 46-year-old company executive. The diagnosis was confirmed secondarily by the findings on imaging (MRI). Treatment was entirely conservative. However, the functional problem mentioned by the patient, particularly when writing, appeared sufficiently novel and so misleading to us that we coined the term ‘‘pen sign’’ to describe it.
1297-3203/$ – see front matter # 2009 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.main.2009.05.002
X. Martinache et al. / Chirurgie de la main 28 (2009) 330–333
2. Clinical case A 46-year-old, right-handed, male company executive presented with discomfort when using his pen for the previous few days. Such discomfort resulted in a modification of his signature. Initially, we were somewhat confused regarding his reason for presenting, until the patient showed us, by using his left hand, his usual manner of handling a pen. We helped him to reproduce his normal pen holding position with his right hand. For that purpose, counterpressure had to be placed on the distal interphalangeal (DIP) joint in order to create simultaneous flexion of the proximal interphalangeal (PIP) joint and the necessary slight hyperextension of the DIP joint. The patient was not able to maintain this position on his own (Fig. 1). Formal testing was very informative and confirmed the lack of normal function of the superficial flexor tendons (FDS) in his index and middle finger (Fig. 2). The patient, who had no history of rheumatoid or metabolic disease, was questioned to determine the cause of his injury. He revealed he had purchased a pair of climbing boots equipped with a loop through which the user passes his index to help to pull on the boots. Doing this had caused some pain a few days
331
before the patient noticed his writing difficulty, but he did not link the two events. He also described a very brief sensation of locking of his index finger PIP joint that was still present at the time of the consultation. From his answers and the clinical examination, we considered the possible diagnosis of a rupture of the superficial index and middle finger flexor tendons. It was our opinion that no treatment would be required unless the locking effect, which did not appear to trouble the patient, worsened. MRI confirmed the diagnosis of rupture of the superficial index and middle finger flexor tendons and showed the tendinous retraction and the location of the rupture in the area of the A1 pulley for both the tendons (Fig. 3). This explained the locking effect experienced by the patient and subsequently required a steroid infiltration. No surgical tendon repair was recommended, given the limited clinical repercussions. 3. Discussion Spontaneous rupture of a flexor tendon is rarely reported in the literature.
Fig. 1. A. Holding the pen with the right hand. B. Reproducing with the left hand the ‘‘usual’’ index position when holding a pen. C. Simulating with the examiner’s help the right position which the patient is now unable to achieve anymore on his own.
332
X. Martinache et al. / Chirurgie de la main 28 (2009) 330–333
axial traction forces, ruptures appear to occur preferentially at the distal point of insertion of the tendon (athlete’s jersey or rugby finger) or at the muscle–tendon junction (muscle elongation or tear) [3]. The tendon itself, however, is not prone to rupture. According to McMaster, at least half of the fibres in a tendon have to be damaged in order for a rupture to occur [3]. In the past, such ruptures within the tendon material itself have been described as associated with underlying diseases. These are secondary ruptures for which a precise cause is often found: repeated corticosteroid injections [4] or as resulting from a tenosynovitis consequent to an underlying disease such as rheumatoid arthritis or gout. Other cases of tendon attrition may be found at operation and include wear ruptures due to a bony irregularity or ruptures due to an anatomical abnormality (single tendon or attachment point proximal to the lumbrical for deep tendons of the ring and little fingers [5,6]. This anatomic abnormality has been long known and Testut himself cites earlier authors [7]. The causes of attrition rupture due to an anatomic abnormality have been described in many publications reporting small numbers of cases such as:
Fig. 2. A. Clinical evaluation of the flexor digitorum superficialis (FDS) of the index and the middle fingers neutralising the action of the flexor digitorum profondus (FDP). B. Comparison with the left side.
Most flexor tendon ruptures occur following avulsion of the FDP at its point of insertion [1]. The flexor tendon is considered to be the most resistant part of the muscle–tendon system [2]. When subjected to excessive
pseudarthroses or prominence of the hook of the Hamate. The first case was described by Boyes in 1960 et al. [8] and subsequently in many publications; calcifications of the triangular fibrocartilage [9]; pisotriquetral osteoarthritis [10]; aggressive callus of the radius [11]; retrolunar dislocation of the carpal bone or intracarpal abnormalities [12]; Kienböck’s disease or scaphoid pseudarthroses [13]. True spontaneous intratendoninous ruptures are uncommon, with fewer than 50 cases being reported in the literature. By the term ‘‘spontaneous’’, we refer to the criteria defined by Boyes et al. in 1960 which excludes any intrinsic or extrinsic pathological process to explain the rupture. Boyes et al. only
Fig. 3. MRI confirmation of the rupture which is located at the level of the A1 pulley for both flexor digitorum superficialis (FDS) tendons. The specificity of this investigation modality is about 95 to 100% [18].
X. Martinache et al. / Chirurgie de la main 28 (2009) 330–333
found only three cases that met these criteria in a series of 80 ruptures [8]. The largest series is that of the Naam [2] study in 1995 that included 13 cases of FDP rupture which met the criteria defined by Boyes et al. Most of the cases involved men between 30 and 60 years old performing repetitive work sometimes associated with trauma [1,14]. Rupture was located in the midpalmar region in the lumbrical or immediately distal to its distal insertion. In terms of site, the three ulnar fingers are involved most often with predominant involvement of the little finger in two third of the cases, the ring finger in 20% of cases and finally the middle finger marginally, in less than 10% of cases. The deep flexor is involved in 82% of cases; the superficial flexor in 12% and the thumb flexor in 6% of cases [8]. Combined tendon involvement is commonly seen with the little finger [15]. The predominant injury of the little finger FDP appears to be due to the peak force which is applied to the FDP because of the relatively common absence of FDS function in the fifth finger. Baker et al. [16] found FDS deficiency in 34% of cases out of a cohort of 263 adults tested. Other authors describe complete absence of FDS in the little finger in only 5% of cases [17]. The site of involvement in the case reported here is therefore atypical, both regarding the location of the superficial tendons rupture and the fingers involved (index and middle). The site of the ruptures (zone 3) is consistent however with published findings [18]. From the case series findings available, spontaneous flexor tendon ruptures present clinically, when they do occur, with an audible click in 70% of cases. In 28% of cases, the patients experience cramp or acute pain in the midpalmar region [1]. Apart from the functional defect, the clinical presentation is different in cases of tendon avulsion in which the features of rupture are rarely audible and are more often characterised by jamming or adherence effects in the digital canal [19]. Our patient was unaware of the rupture and the initiating mechanism of the lesion was only found after direct questioning about the injury. This ‘‘novel’’ reason for consultation (altered writing praxia) has not been reported yet and we consider that this was significantly misleading and original in its description. For synergistic reasons, some groups have proposed transferring the superficial index finger flexor tendon to reanimate thumb flexion as palliative surgery. On the basis of our case, we would not recommend such a transfer. On the other hand, transferring the ring finger FDS would appear to be entirely justified because of the lack of consequent difficulties on fine thumb and index finger pinch grip used when holding pens or fine tweezers. 4. Conclusion The ‘‘newspaper’’ sign has immortalised Jules Froment. The ‘‘pen’’ sign described here will certainly remain relatively unknown in view of the rarity of such disorder. We may assume
333
however that there are more actual cases than a literature review would suggest. Given the limited clinical repercussions, it is likely that only a small percentage of patients will present seeking treatment. Apart from its novel nature and the fact that to our knowledge this type of case has not been reported previously, our case clearly demonstrates the synergistic effect of deep and superficial index flexor tendons when writing. It should make us attempt, in our daily surgical practice, to systematically repair both flexor tendons when they are damaged. This should also encourage us to avoid sacrificing the superficial index finger tendon for secondary transfer surgery, unless it is absolutely necessary. References [1] Bois AJ, Johnston G, Classen D. Spontaneous flexor tendon ruptures of the hand: case series and review of the literature. J Hand Surg 2007;32(7): 1061–71. [2] Naam NH. Intratendinous rupture of the flexor digitorum profundus tendon in zones II and III. J Hand Surg 1995;20A:478–83. [3] McMaster PE. Tendon and muscle ruptures, clinical and experimental studies on the causes and location of subcutaneous ruptures. J Bone Joint Surg 1933;15:705–22. [4] Fitzgerald BT, Hofmeister EP, Fan AJ, Thompson M. delayed flexor digitorum superficialis and profundus ruptures in a trigger finger after a steroid injection: a case report. J Hand Surg 2005;30:479–82. [5] Davis C, Armstrong J. Spontaneous flexor tendon rupture in the palm: the role of a variation of tendon anatomy. J Hand Surg 2003;28A:149–52. [6] de Roos KW, Zeeman RJ. A flexor tendon rupture in the palm of the hand. J Hand Surg 1991;16A:663–5. [7] Testut L. Les anomalies musculaires chez l’homme. Paris: Masson; 1884. [8] Boyes JH, Wilson JN, Smith JW. Flexor tendon ruptures in the forearm and hand. J Bone Joint Surg 1960;42A:346–67. [9] Fukui A, Kido A, Inada Y, Mii Y, Tamai S. Closed rupture of the flexor digitorum profundus tendon of the little finger caused by calcification of the triangular-fibrocartilage. J Hand Surg 1996;21B(3):375–7. [10] Corten EML, van den Broecke DG, Kon M, Schuurman AH. Pisotriquetral instability causing an unusual flexor tendon rupture. J Hand Surg 2004;29A:236–9. [11] McMaster PE. Late ruptures of extensor and flexor pollicis longus tendons following Colles’ fractures. J Bone Joint Surg 1932;14:93–101. [12] Koizumi M, Kanda T, Satoh S, Yoshizu T, Maki Y, Tsubokawa N. Attritional rupture of the flexor digitorum profundus tendon to the index finger caused by accessory carpal bone in the carpal tunnel: a case report. J Hand Surg 2005;30A:142–6. [13] Yamazaki H, Kato H, Hata Y, Nakatsuchi Y, Tsuchikane A. Closed rupture of the flexor tendons caused by carpal bone and joint disorders. J Hand Surg Eur Vol 2007;32:649–53. [14] Imbriglia JE, Goldstein SA. Intratendinous ruptures of the flexor digitorum profundus tendon of the small finger. J Hand Surg 1987;12A:985–91. [15] Popov N, Escaré P, Allieu Y. Primary flexor tendon ruptures of the little finger within the carpal tunnel. Proposed classification based on six clinical cases and review of the literature. Chir Main 2007;26:35–9. [16] Baker DS, Gaul JS, Williams VK, Graves M. The little finger superficialis: clinical investigation of its anatomic and functional shortcomings. J Hand Surg 1981;6A:374–8. [17] Furnas DW. Muscle-tendon variations in the flexor compartment of the wrist. Plast Reconstr Surg 1965;36:320–4. [18] Drapé JL, Tardif-Chastenet De Gery S, Silbermann-Hoffman O, Chevrot A, Houvet P, Alnot JY, et al. Closed ruptures of the flexor digitorum tendons: MRI evaluation. Skeletal Radiol 1998;27(11):617–24. [19] Ferraro SP, Schenck RR. Isolated closed rupture of the bony insertion of the flexor digitorum superficialis tendon: an unusual case. J Hand Surg 1998;23:837–9.