Biometry of thenar muscle origins on the flexor retinaculum

2020 ◽  
Vol 33 (8) ◽  
pp. 1176-1180
Author(s):  
Jeremy Loss ◽  
Zong‐Ming Li
2021 ◽  
Vol 46 (4) ◽  
pp. 352-359
Author(s):  
Susumu Saito ◽  
Itaru Tsuge ◽  
Hiroki Yamanaka ◽  
Naoki Morimoto

Wassel VI radial polydactyly is associated with metacarpal adduction and radial deviation of the metacarpophalangeal joint of the ulnar duplicate. The soft tissue abnormalities responsible for these deformities were characterized using preoperative multi-planar three-dimensional ultrasound and intraoperative observation in four patients. In all patients, the abductor pollicis brevis and superficial head of the flexor pollicis brevis inserted into the radial first metacarpal, whereas the adductor pollicis and deep head of the flexor pollicis brevis inserted into the ulnar thumb. Aberrant location of the flexor pollicis longus and absence of the A1 pulley system was associated with severe radial deviation. An additional superficial thenar muscle along the ulnar metacarpal was associated with minimal metacarpal adduction. Uneven forces on the ulnar duplicate could be associated with these characteristic deformities and joint instability. Knowledge of these abnormalities allows better planning of surgery and further insight into this rare radial polydactyly configuration. Level of evidence: II


Hand ◽  
2021 ◽  
pp. 155894472199973
Author(s):  
Shruthi Deivasigamani ◽  
Ali Azad ◽  
S. Steven Yang

Background The abductor pollicis longus (APL) is classically described as inserting on the base of the first metacarpal. This study analyzed APL insertional anatomy and quantified the size of various elements of the extensor side of the thumb to determine associations with size and function. Methods Twenty-four formalin-preserved upper limbs were dissected. The insertional anatomy of the APL, extensor pollicis brevis, and extensor pollicis longus were characterized, and the capacity of APL tendon slips to perform palmar abduction of the first digit was quantified based on slip size and insertion. Results The mean number of APL tendon slips observed was 2.3. Abductor pollicis longus insertion sites included the base of the first metacarpal, trapezium, abductor pollicis brevis, and opponens pollicis. Only 4 specimens had a solitary metacarpal slip, while 83% of specimens had insertions onto at least 1 thenar muscle. A total of 62.5% of APL tendons exhibited some form of branching that we categorized into “Y” and “Z” patterns. In assessing palmar abduction capacity, we found that APL tendon slips inserting into the base of the first metacarpal were larger in cross-sectional area than nonmetacarpal slips and reproduced complete palmar abduction of the digit in the absence of nonmetacarpal slips. The abduction capacity of APL tendon slips was not correlated to the cross-sectional area. Conclusions There is significant variability in APL tendon slips, branching patterns, and insertional anatomy. These findings provide further understanding of the function of the APL and its surgical implications.


2021 ◽  
Vol 29 (1) ◽  
pp. 230949902199340
Author(s):  
Kotaro Sato ◽  
Kenya Murakami ◽  
Yoshikuni Mimata ◽  
Gaku Takahashi ◽  
Minoru Doita

Purpose: Supraretinacular endoscopic carpal tunnel release (SRECTR) is a technique in which an endoscope is inserted superficial to the flexor retinaculum through a subcutaneous tunnel. The benefits of this method include a clear view for the surgeon and absence of median nerve compression. Surgeons can operate with a familiar view of the flexor retinaculum and median nerve downward, similar to open surgery. This study aimed to investigate the learning curve for SRECTR, an alternate method for carpal tunnel release, and evaluate its complications and the functional outcomes using a disposable commercial kit. Methods: We examined the open conversion rates and complications associated with SRECTR in 200 consecutive patients performed by two surgeons. We compared the operative time operated by a single surgeon. We evaluated outcomes in 191 patients according to Kelly’s grading system. Patients’ mean follow-up period was 12.7 months. Results: Nine patients required conversion to open surgery. There were no injuries to the nerves and tendons and no hematoma or incomplete dissection of the flexor retinaculum. The operative times varied between 11 and 34 minutes. We obtained the following results based on Kelly’s grading of outcomes: excellent in 116, good in 59, fair in 13, and poor in 3 patients. Conclusions: We found no patients with neurapraxia, major nerve injury, flexor tendon injury, superficial palmar arch injury, and hematoma. Although there was a learning curve associated with SRECTR, we performed 200 consecutive cases without neurovascular complications. This method may be a safe alternative to minimally invasive carpal tunnel surgery.


1988 ◽  
Vol 13 (1) ◽  
pp. 100-101
Author(s):  
N. R. CLAY ◽  
S. AUSTIN

Two patients are described with idiopathic hypertrophy of the first dorsal interosseous and thenar muscles. CT scans have proved helpful in defining the abnormality.


2021 ◽  
Vol 67 (4) ◽  
pp. 518-525
Author(s):  
Zuhal Özişler ◽  
Müfit Akyüz

Objectives: This study aims to evaluate the predictors of standard nerve conduction study (NCS) parameters in determining the presence of axonal loss by means of spontaneous activity in patients with mild and moderate carpal tunnel syndrome (CTS). Patients and methods: Between May 2015 and April 2018, a total of 118 patients (11 males, 107 females; mean age: 52.3±10.6 years; range, 27 to 79 years) who underwent electrophysiological studies and were diagnosed with CTS were included. Demographic data of the patients including age, sex, and symptom duration were recorded. Electrodiagnostic studies were performed in all patients. All the needle electromyography (EMG) findings were recorded, but only the presence or absence of spontaneous EMG activities was used as the indicator of axonal injury. Results: In 37 (31.4%) of the patients, spontaneous activity was detected at the thenar muscle needle EMG. No spontaneous activity was observed in any of 43 (36.4%) patients with normal distal motor latency (DML). There were significant differences in DMLs, compound muscle action potential (CMAP) amplitudes, sensory nerve action potentials amplitudes, and sensory nerve conduction velocities between the groups with and without spontaneous activity (p<0.05). The multiple logistic regression analysis revealed that DML was a significant independent risk variable in determining presence of spontaneous activity. The most optimal cut-off value for median DML was calculated as 4.9 ms. If the median DML was >4.9 ms, the relative risk of finding spontaneous activity on thenar muscle needle EMG was 13.5 (95% CI: 3.6-51.2). Conclusion: Distal motor latency is the main parameter for predicting the presence of spontaneous activity in mild and moderate CTS patients with normal CMAP. Performing needle EMG of the thenar muscle in CTS patients with a DML of >4.9 ms may be beneficial to detect axonal degeneration in early stages.


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