[Granular cells tumour (Abrikossof) of the ulnar nerve at the arm. A case report and literature review]. / Tumeur d'Abrikossof (tumeur à cellules granuleuses) du nerf ulnaire au bras. À propos d'un cas et revue de la littérature des tumeurs à cellules granuleuses du nerf ulnaire.

INTRODUCTION: Granular cell tumours are extremely rare on peripheral nerves, with an incidence of 0.029% of pathologic samples. In a literature review, we found only 5 cases involving the ulnar nerve, although considered the most frequently involvement nerve. CASE REPORT: A 32 year-old female from the French West Indies presented a severe arm pain with deficit of interosseous hand muscles. Imaging studies were in favour of a Schwanoma, but during surgery, we found an unremovable intra-neural tumour. Nerve biopsy revealed a granular cell tumour. Initial decision was observation only. However, within two years, tumour increased in size, along with pain aggravation and functional deficit. We performed a nerve resection (with adequate margins) with reconstruction using sural nerve graft associated with a neurotisation of the motor branch with the anterior interosseus nerve. At two years follow-up, no recurrence was observed. The scar is hypersensitive with moderate neuropathic pain. There is a sensory reinnervation of the fourth finger, with no motor recovery of the hand. We observed a slight recovery of flexor profundus tendons, which, in turn increased the claw hand. DISCUSSION: The five cases described in the literature were managed differently (biopsy only, excision, excision with reconstruction), with modest results. There is no recommended treatment. Our case is the first at arm level. We were able to perform complete resection, but functional result is poor. CONCLUSION: Granular cell tumours require treatment if symptomatic (pain, function loss), but, at the moment, there is no recommended treatment.

[Two anomalous muscles of a forearm revealed by ulnar nerve compressions, a Double Crush syndrome]. / Malformation musculaire associée à une variation anatomique de l'avant-bras révélées par des compressions étagées du nerf ulnaire (Double Crush syndrome).

This article describes the concomitant presence of two anomalous muscles on a left forearm in a 40-year-old man. The anconeus epitrochlearis muscle was responsible for a cubital tunnel syndrome and the unusual origin of the flexor digiti minimi brevis muscle was responsible for a compartment syndrome with ulnar nerve compression at the level of Guyon's canal during effort diagnosed by MRI. Resection of these muscles relieved the symptoms and allowed the patient to return to work.

Ulnar nerve dislocation in ulnar nerve entrapment at the elbow. Influence on surgical outcome.

Our aim was to assess the incidence of symptomatic ulnar nerve dislocation and its influence on surgical outcome after primary and revision surgeries in ulnar nerve entrapment at the elbow (ulnar neuropathy at the elbow (UNE) or cubital tunnel syndrome). The influence of pre- or intra-operative ulnar nerve dislocation on postoperative outcome was assessed in 548 surgically treated cases (548 nerves) from two hand surgery departments reporting to the Swedish National Quality Registry for Hand Surgery, using QuickDASH, a patient-reported outcome measure (PROM), before surgery and at 3 and 12 months postoperatively, and a doctor-reported outcome measure (DROM), grading as "cured-improved "or "unchanged-worsened," at a median follow-up of 3.0 months [IQR, 1.5-6.0]. 109 of the 548 cases (20%) showed documented pre- or intra-operative ulnar nerve dislocation; more often found at revision (35/75, 47%) than at primary surgery (74/473, 16%) (p < 0.0001). Cases with dislocation presented higher QuickDASH scores at 12 months (p = 0.026). A linear regression model, adjusted for age and gender, predicted higher QuickDASH scores at 12 months postoperatively for cases with dislocation (unstandardized B 11.3 [95% CI 0.4-22.2], p = 0.043). DROM grading as unchanged-worsened at a median 3 months predicted worse QuickDASH scores (p < 0.0001) than in cured-improved cases at 3 (unstandardized B, 18.4 [95% CI 9.4-27.3]) and 12 months (unstandardized B, 18.1 [9.1-27.0]). Primary surgeries had better DROM grading than revision surgeries (p = 0.033; cured-improved, 75% and 63%, respectively), but QuickDASH scores did not differ. Presence of a clinically relevant ulnar nerve dislocation resulted in worse outcome, perhaps due to more extensive surgery with transposition. Nerve dislocation needs attention when treating UNE patients.

Palliative surgery for thumb involvement in ulnar paralysis.

Ulnar paralysis has multiple clinical presentations, which are due to partial recovery or to anatomical variations between the ulnar and median nerves. The main sequelae of ulnar nerve paralysis are the loss of hand strength with impairment of all intrinsic functions of the fingers and some of the thumb's functions. Weakness of the adductor pollicis and flexor pollicis brevis muscles may manifest as weak key pinch with automatic flexion of the thumb interphalangeal joint when gripping. Indications for palliative surgery have decreased due to advances in peripheral nerve surgery. However, palliative surgery still has a significant role to play when nerve repair techniques are not indicated or do not provide satisfactory results. The principle is to reinforce metacarpophalangeal flexion while stabilizing the thumb's interphalangeal joint, thus supplementing the action of the flexor pollicis brevis. This is generally done by transferring the flexor digitorum superficialis tendon of the fourth finger to the distal insertion of the superficial thenar muscles and the extensor pollicis longus. Restoration of the first dorsal interosseous is more rarely indicated.

Evaluation of functional recovery in the intrinsic and flexor muscles after nerve transfer for ulnar nerve lesion. A new measurement method: The Cha method.

"Supercharge" end-to-side (SETS) nerve transfer for lesions of the proximal ulnar nerve is a recognized novel option, but improvement in motor function after surgery has not been properly evaluated. We therefore propose a modified method for quantitative evaluation of improvement in the intrinsic hand strength. We screened 216 patients with proximal ulnar nerve lesions who presented to our outpatient department from 2012 to 2020. Of these, 101 met our inclusion/exclusion criteria and were evaluated just before surgery. We used a novel method to measure finger abduction ("2nd-abd"), adduction ("5th-add"), and ring and little finger flexion strength ("4,5 grip"), and analyzed correlations with established pinch strength data. The male:female sex ratio was 86:15, and the ratio dominant to nondominant arm involvement was 68:33. All strength measurements were analyzed as percentage affected to contralateral normal side. On Pearson correlation analysis, the strength ratios for "4,5 grip", "2nd-abd", and "5th-add", but not "5 fingers (total) grip", showed significant positive correlation with key and oppositional pinch strength (all p < 0.001). Additionally, linear regression analysis showed identical results for each strength correlation with key/oppositional pinch, except for "5 fingers total) grip" (all, p < 0.001). SETS is a reasonable alternative for lesions of the proximal ulnar nerve. The measurement method we propose is feasible for specific assessment of intrinsic muscle strength, which improves after surgery. LEVEL OF EVIDENCE: Diagnostic, level IV.

Restoration of the first dorsal interosseous muscle.

Motor dysfunction of the 1st dorsal interosseous (DIO) muscle is typically observed in low and high ulnar nerve palsy. This causes weak thumb-index pinch, which can be disabling for the patient. Various reconstructive techniques have been described; however, the choice often depends on the surgeon's experience, the presence of associated neurovascular and musculotendinous injuries, as well as the requirements of the palliative surgery schedule. Nerve transfers can be proposed when patients present early in the course of the disease. Tendon transfers are often a last resort when late presentation occurs. Tendon transfers must follow general principles: the insertion is made on the 1st DIO terminal tendon; the tension must be adjusted in a neutral position to avoid excessive tension, and immobilization is maintained for 4 weeks. Although many transfers are possible, the extensor pollicis brevis transfer is our preferred option. This donor does not require additional tendon grafting, has a direct line of pull close to that of the 1st DIO and is not often used for other reconstructive purposes.

Ulnar nerve morphology on magnetic resonance imaging predicts nerve recovery after surgery for cubital tunnel syndrome.

Magnetic resonance imaging (MRI) can evaluate nerve morphology in cubital tunnel syndrome (CuTS), but its value in predicting surgical outcome is unclear. The purpose of this study was to determine whether ulnar nerve morphology on MRI correlated with outcome after CuTS surgery. We reviewed 40 patients who had preoperative MRI and electrodiagnostic (EDX) examinations for CuTS and outcome evaluation 6 months and 2 years postoperatively. Using MRI, ulnar nerve cross-sectional area (UNCSA), changes in signal intensity, and any space-occupying lesion were evaluated. Other factors assessed were age, symptom duration and severity, type-2 diabetes and EDX parameters. Factors associated with unfavorable surgical outcome were identified. At 6 months postoperatively, 12 patients (30%) had excellent, 19 (47.5%) good, 8 (20%) fair and 1 (2.5%) poor results on modified Wilson-Krout criteria. On univariate analysis, unfavorable outcomes were associated with increased UNCSA, space-occupying lesion, and decreased motor nerve conduction velocity (mNCV), and on multivariate analysis with increased UNCSA 1 cm distal from the epicondyle only (model 1) or increased UNCSA 1 cm proximal from the epicondyle and decreased mNCV (model 2). At 2 years, 15 patients (37.5%) had excellent, 21 (52.5%) good, 3 (7.5%) fair and 1 (2.5%) poor results, and no factors correlated with unfavorable outcome. Increased UNCSA on MRI was associated with unfavorable outcome at 6 months but not at 2 years. This study suggests that morphologic ulnar nerve changes can predict delayed nerve recovery after surgery for CuTS.

Reliability of deep branch of ulnar nerve identification in interosseous-to-ulnar motor nerve transfer: A cadaver study of 20 wrists.

Reinnervation of the intrinsic hand muscles after proximal ulnar nerve repair is often unsatisfactory. Promising results have nevertheless been reported recently for supercharged end-to-side anterior interosseous to deep branch of the ulnar nerve (DBUN) transfer. The aim of this study was to determine whether the DBUN can be reliably identified without retrograde intraneural dissection from Guyon's canal. Twenty cadaveric wrists were dissected. In a first stage, nerve transfer was performed through a limited 4 cm incision without releasing Guyon's canal. In a second stage, correct identification of the DBUN was assessed by retrograde intraneural dissection from its point of exit from Guyon's canal. The DBUN was correctly identified in 18 of the 20 wrists (90%). Although anatomical landmarks provide valuable clues, identifying the DBUN by neurolysis is technically challenging. All the elements required for nerve transfer can be exposed through a 4 cm incision, but the DBUN was nevertheless incorrectly identified in 10% of cases. Guyon canal release seems advisable to guarantee correct DBUN identification.

A case of ulnar nerve section at the elbow alleviated by Martin-Gruber communicating branch. Diagnostic characterization.

Martin-Gruber communicating branch may be a confounding factor in the diagnosis of ulnar neuropathy at the elbow. It may also lead to a surprising level of motor function conservation despite evident neuropathy. We present a patient with ulnar nerve section at the elbow who underwent early treatment by nerve suture. At 7 months, function was good, despite sonographic findings of neurotmesis at the elbow. Electroneurography revealed Martin-Gruber communicating branch. This type of communicating branch can be associated with functional conservation despite ulnar nerve section. Electrophysiological and ultrasound findings can be highly contributive in defining these conditions.

The Gantzer transfer - Assessment of the feasibility of using the nerve supplying the Gantzer muscle for end-to-side supercharging of the ulnar nerve.

Our study aimed at assessing the anatomical feasibility of using the nerve supplying the Gantzer muscle (GM) to supercharge the ulnar nerve following injury. The GM nerve was dissected and measured in 36 forearms. The distance between its origin and the lateral epicondyle of humerus and between the GM nerve and the ulnar nerve was measured. The GM was present in 15 forearms (47%). The average distance between the origin of the GM nerve and the lateral epicondyle was 7.34 cm (range 3.3-9.1 cm). The average length of the GM nerve was 3.05 cm (range 1.6-4.5 cm) from origin to neuromuscular junction. The average distance from the ulnar nerve was 2.56 cm (range 1.8-13 3.4 cm). The length of the GM nerve was significantly greater (p < 0.05) than the perpendicular distance between its origin and the ulnar nerve, allowing ample margin for side-to-side or end-to-side supercharging of the ulnar nerve with minimal or no need for further translocation or dissection. The use of the GM nerve as donor following ulnar nerve injury may provide an alternative to the pronator quadratus nerve for supercharged end-to-side transfer, or as an addition, thus supercharging the ulnar nerve twice.

Clinical efficacy of decompression and anterior transposition of the ulnar nerve in osteoarthritis-induced cubital tunnel syndrome and influencing factors.

We aimed to explore the clinical efficacy of decompression and anterior transposition of the ulnar nerve in osteoarthritis-induced cubital tunnel syndrome (CTS). 109 patients with moderate-to-severe CTS treated from July 2015 to March 2019 were selected. Upper-limb function was scored. After ultrasound examination, decompression and anterior transposition of the ulnar nerve were performed; then ulnar nerve motor nerve conduction velocity (MNCV) was assessed. Patients were followed up every 3 months for 18 months and their prognosis was assessed. Upper-limb function examination results were compared according to disease severity. Univariate and multivariate regression analyses were conducted, and a nomogram prediction model was established. After treatment, the number of patients with intrinsic contracture of the hand, Tinel sign (+), clipping paper test (+) and Froment's sign (+) significantly declined; hand grip strength, ulnar nerve MNCV, latency, amplitude, 2-point discrimination (2-PD) and Disabilities of the Arm, Shoulder and Hand (DASH) score were improved (p < 0.05). Age, gender, course of disease, long-term elbow bend work (LTEBW), ulnar nerve MNCV, 2-PD and DASH score were independent risk factors for poor prognosis (p < 0.05). The calibration curve confirmed that prognosis results after treatment were highly consistent with actual outcomes. Decompression and anterior transposition of the ulnar nerve exerted significant therapeutic effects on moderate-to-severe osteoarthritis-induced CTS. The nomogram prediction model established by age, gender, course of disease, LTEBW, ulnar nerve MNCV, 2-PD and DASH score can be used to effectively evaluate prognosis.

Benefits of a collagen membrane for recurrent ulnar nerve entrapment at the elbow: A series of 40 cases.

The rate of failure or recurrence after ulnar nerve release at the elbow is up to 25%. Various biomaterials have been developed to protect nerves from postoperative adhesions. The aim of this study was to review a case series of 40 surgical revision procedures of the ulnar nerve at the elbow, protected by a collagen membrane (Cova™ ORTHO). Forty patients who had this revision surgery between January 2013 and December 2017 were reviewed: 34 were evaluated in person, 6 were evaluated over the phone. The operation consisted in release of the ulnar nerve, anterior subcutaneous transposition and nerve protection using a collagen membrane. We assessed the following parameters with an average follow-up of 4 years and 3 months: paresthesia, night awakening, quality of life (QuickDASH score) and neuropathic pain (DN4 questionnaire). The outcome was determined with the Gabel & Amadio score. The patients' satisfaction was evaluated. A significant decrease in paresthesia and night awakening was found (p < 0.05). The average Gabel & Amadio score improved from 4.4 to 6.7 with 5 excellent, 19 good, 9 fair, and 1 poor result. The average DN4 was 5/10 and the QuickDASH score was 40.1. Eighty percent of patients were satisfied or very satisfied with the outcome. Surgical revision of the ulnar nerve at the elbow remains a delicate operation without a gold standard. This case series found good or excellent results in 70% of patients. Surgical revision of the ulnar nerve with a collagen membrane is a reliable alternative among other possibilities for ulnar nerve release at the elbow.

A novel local adipofascial flap for the management of recalcitrant ulnar tunnel syndrome.

Ulnar tunnel syndrome is the second most common upper-limb peripheral nerve compression syndrome. Recurrence or persistence of symptoms after primary surgery is found in 9.9%-21% of cases. The main cause of failure is peri- and endo-neural fibrosis, and management is difficult and controversial. Revision of nerve neurolysis combined with freestyle adipofascial flap provides nerve decompression and coverage with vascularized tissue, which prevents scar tissue formation around the nerve and restores glide. We performed a preliminary vessel-injected cadaver study. The perforating vessels from the posterior recurrent ulnar artery vascularize the medial adipose and fascial tissues of the elbow, allowing elevation of an adipofascial flap which is able to reach the ulnar nerve. Eight patients with neuropathic ulnar nerve pain in recalcitrant ulnar tunnel syndrome due to peri- and/or endo-neural fibrosis were treated by neurolysis, and the nerve was covered with an ulnar adipofascial flap. All patients were evaluated by percussion test, visual analog scale for pain, electromyography, electroneurography and ultrasound, and were classified according to the McGowan classification as modified by Goldberg. The study was approved by the review board. All patients had good 4-year outcome, with complete return to daily activity, work and sports 4 months after surgery. The results of this novel surgical technique were encouraging, without complications or donor site morbidity. Adipofascial flap combined with neurolysis could be a valid solution in the treatment of recalcitrant ulnar tunnel syndrome.

Clinical outcomes of combined surgical treatment of medial epicondylitis and cubital tunnel syndrome.

Surgical results for treatment of medial epicondylitis and cubital tunnel syndrome are generally satisfactory when performed alone. However, our experience suggests a combined procedure is associated with inferior outcomes. A retrospective review was conducted of consecutive surgical cases of medial epicondylectomy/debridement and ulnar nerve decompression during a single operation at our institution from March 2008 to February 2017 using CPT codes. Thirty combined procedures were identified in 29 patients. Fourteen patients and 15 elbows returned to clinic for evaluation at average 4.3 years after surgery (8 men, 6 women, mean age 45.1 years). A Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, visual analogue pain scale (VAS), and physical examination were performed. The data was stratified by type of ulnar nerve procedure and analyzed. Three of fifteen elbows underwent in situ ulnar nerve decompression, and twelve of 15 had transposition, five subcutaneous and seven submuscular. The mean DASH score for in situ decompression was significantly higher than that of transposition (68.2 vs. 13.1). The average visual pain score for patients whom underwent in situ decompression was significantly higher than that of those with ulnar nerve transposition (8.0 vs. 1.2). All other physical exam measures demonstrated no significant difference between the two groups. In situ ulnar nerve decompression in the setting of medial epicondylectomy/debridement may be associated with inferior clinical outcomes in comparison to ulnar nerve transposition. Further studies are needed to validate the results of our study and inform management.

Designing a 20 mm incision to protect the dorsal branch of the ulnar nerve during arthroscopic repair of triangular fibrocartilage complex injuries: Cadaver study and preliminary clinical results.

The ulnar-sided approach for arthroscopic peripheral triangular fibrocartilage complex (TFCC) repair may be associated with injury to the dorsal branch of the ulnar nerve (DBUN). The goal of this study was to develop a small incision to help minimize DBUN injury. Ten cadaveric upper limbs were used to measure the anatomic parameters of the DBUN. Based on these measured anatomical relationships, a 20 mm longitudinal incision with the ulnar styloid process as the midpoint was designed to explore and protect the DBUN. Three additional cadaveric upper limbs were used to test the feasibility of this method. Then this method was applied in 15 patients with TFCC injury (IB type). In 10 cadavers, the DBUN was located volar to the ulnar styloid process. The mean linear distance between the DBUN and the ulnar styloid process was 8.04 mm (range: 7.02-8.82mm) in the transverse-volar direction and 13.78 mm (range: 11.06-16.02mm) in the longitudinal-distal volar direction. In three additional cadavers, the DBUN was successfully explored and retracted with this incision, creating a safer space for passing sutures and tying knots. This modified method was used successfully in 15 patients, and the DBUN was protected during surgery. There were no complications, and most importantly, no injuries to the DBUN at the 6-month follow-up visit. Therefore, we recommend that a 20 mm longitudinal incision with the ulnar styloid process as the midpoint be made prior to passing sutures during the arthroscopic repair of TFCC tears to avoid injuring the various branches of the DBUN.

"Snapping triceps": A rare and misleading condition - a clinical case report.

Snapping triceps corresponds to subluxation of the medial head of the triceps brachii over the medial epicondyle during active elbow flexion. It is a rare and misleading condition that is often associated with ulnar nerve instability. The latter can result in the snapping triceps being missed. Diagnosis requires a detailed clinical examination. Surgical treatment consists of anterior translocation of the nerve with an adipose flap to stabilize it and transfer of the distal attachment of the medial head of triceps brachii.

Hypothenar hammer syndrome: A case of a late complication after surgery.

Hypothenar hammer syndrome is a rare condition secondary to ulnar artery damage in Guyon's canal, affecting mainly those exposed to repeated palm trauma. Surgery is discussed in cases of severe symptoms that are resistant to conservative treatment, and/or when anatomical lesions with high embolism potential are discovered during imaging exams. Resection of the pathological zone with revascularization by autologous vein graft is the best option. We report the case of a 60-year-old patient who had a recurrence of symptoms more than 10 years after this type of surgical treatment was performed. There was an aneurysmal thrombosed vein graft with extensive thrombus from the ulnar artery upstream to Guyon's canal to the superficial palmar arch. Finger revascularization was provided by the superficial branch of the radial artery and the presence of a collateral vascular supply. This late complication was responsible for compression of the ulnar nerve in Guyon's canal. A new surgery was performed to resect the thrombosed zone, including the vein graft, without vascular reconstruction due to the good vascularization of all the fingers, and to release the ulnar nerve at the wrist. The postoperative course was uneventful with the disappearance of pain and sensory-motor deficits. Good finger vascularization was confirmed by imaging at 3 months postoperative; nerve conduction was normal at 6 months on electroneuromyography.

[Hypothenar hammer syndrome: A recurrent case report after surgery]. / Syndrome du marteau hypothénarien : à propos d'un cas de récidive après traitement chirurgical.

Hypothenar hammer syndrome is a rare entity secondary to ulnar artery damage in the wrist, affecting mainly those exposed to repeated hand-palm trauma. Surgery is discussed in case of severe symptoms, resistant to medical treatment, and/or when anatomical lesions with emboligenic potential are demonstrated in the radiological exams. In this case, resection of the pathological zone with revascularization by autologous vein graft is the best option. We report the case of a 60-year-old patient who had a recurrence of symptoms more than 10 years after the completion of a surgical treatment. There was an aneurysmal thrombosed vein graft with extensive thrombus extending from the ulnar artery upstream of the Guyon's canal to the superficial palmar arch. The digital revascularization was provided by the radial superficial palmar arch and the presence of a collateral vascular supply. This late complication was responsible for compression of the ulnar nerve in Guyon's canal. A new surgery was performed consisting of the resection of the thrombosed zone, including the vein graft, without vascular reconstruction given the good vascularization of all the fingers, and release of the ulnar nerve to the wrist. The operative follow-up was uneventful with the disappearance of pain and sensory-motor deficits. Good digital vascularization was confirmed by imaging at 3 months postoperatively; nerve recovery by electromyogram at 6 months with normal conduction.

Little finger abduction and adduction testing in ulnar nerve lesions.

We aimed to evaluate the abduction and adduction of the little finger based on a new clinical test in the context of ulnar nerve lesions. We tested little finger abduction and adduction in 34 patients with an isolated ulnar nerve injury and 20 patients with cubital tunnel syndrome. With their forearms supinated, patients were asked to fully abduct their little finger. Then, the examiner held the patients' index, middle, and ring fingers in extension and maximal radial deviation, and then asked the patients to touch their little finger to their radially deviated ring finger. In patients with ulnar nerve injuries, either above or below the elbow, little finger abduction and adduction were impossible. In the patients with cubital tunnel syndrome, 19 had partial paralysis of little finger adduction and one patient had complete paralysis. Abduction and adduction of the little finger is not possible when the ulnar nerve is transected. In cubital tunnel syndrome, this little finger adduction test was able to identify decreased range of motion, possibly indicating muscle weakness.

Change in the temporal coordination of the finger joints with ulnar nerve block during different power grips analyzed with a sensor glove.

Ulnar nerve injuries can cause deficient hand movement patterns. Their assessment is important for diagnosis and rehabilitation in hand surgery cases. The purpose of this study was to quantify the changes in temporal coordination of the finger joints during different power grips with an ulnar nerve block by means of a sensor glove. In 21 healthy subjects, the onset and end of the active flexion of the 14 finger joints when gripping objects of different diameters was recorded by a sensor glove. The measurement was repeated after an ulnar nerve block was applied in a standardized setting. The change in the temporal coordination of the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints with and without the nerve block was calculated within the same subject. In healthy subjects, the MCP joints started their movement prior to the PIP joints in the middle and ring finger, whereas this occurred in the reverse order at the index and little finger. The DIP joint onset was significantly delayed (P<0.01). With the ulnar nerve block, this coordination shifted towards simultaneous onset of all joints, independent of the grip diameter. The thumb and index finger were affected the least. With an ulnar nerve block, the PIP joints completed their movement prior to the MCP joints when gripping small objects (G1 and G2), whereas the order was reversed with larger objects (G3 and G4). The alterations with ulnar nerve block affected mainly the little finger when gripping small objects. With larger diameter objects, all fingers had a significant delay at the end of the PIP joint movement relative to the MCP and DIP joints, and the PIP and DIP joint sequence was reversed (P<0.01). Based on the significant changes in temporal coordination of finger flexion during different power grips, there are biomechanical effects of loss of function of the intrinsic muscles caused by an ulnar nerve block on the fine motor skills of the hand. This can be important for the diagnosis and rehabilitation of ulnar nerve lesions of the hand.