Assessment of the Passive Tension of the First Dorsal Interosseous and First Lumbrical Muscles Using Shear Wave Elastography

Applications of ultrasound elastography to hand and upper limb disorders

Ultrasound elastography is a recently developed method for accurate measurement of soft tissue stiffness in addition to the clinician's subjective evaluation. The present review briefly describes the ultrasound elastography techniques and outlines clinical applications for tendon, muscle, nerve, skin and other soft tissues of the hand and upper limb. Strain elastography provides a qualitative evaluation of the stiffness, and shear-wave elastography generates quantitative elastograms superimposed on a B-mode image. The stiffness in degenerative tendinopathy and/or tendon injury was significantly lower than in a normal tendon in several studies. Elastography is also a reliable method to evaluate functional muscle activity, compared to conventional surface electromyography. The median nerve is consistently stiffer in patients with carpal tunnel syndrome than in healthy subjects, on whatever ultrasound elastography technique. Elastography distinguishes normal skin from scars and can be used to evaluate scar severity and treatment. Elastography has huge clinical applications in musculoskeletal tissues. Continued development of systems and increased training of clinicians will expand our knowledge of elastography and its clinical applications in the future.

Effects of metacarpophalangeal joint position and finger joint movement speed on lumbrical muscle activity

OBJECTIVES

The effect of metacarpophalangeal joint position and finger joint movement speed on lumbrical muscle activity remains unproven and was examined in this study.

MATERIAL AND METHODS

Twenty-four healthy adults performed flexion-extension movements of the index finger in different metacarpophalangeal joint positions (extension or flexion) and movement speeds (60, 120, 240, and 360 beats per minute). The activities of the first lumbrical, first dorsal interosseous, and extensor digitorum muscles were evaluated using surface electromyography, and compared with those during finger joint extension.

RESULTS

The metacarpophalangeal joint positions affected only lumbrical muscle activity, which was greater during extension. Further, finger movement speed affected the lumbrical and extensor digitorum muscle activities, which increased with increasing movement speeds.

CONCLUSION

The present study suggests that position and movement speed can influence the lumbrical muscle activity during metacarpophalangeal joint extension. These findings may help expound lumbrical function and develop suitable strategies for inducing lumbrical muscle activity.

Measurement of the lumbrical muscle activity of the hand using electromyography supported by the ultrasound imaging technique with string navigation

Although placing surface electrodes on small muscles by palpation is difficult, ultrasound guidance may enable electrode placement on the small muscles. This study aimed to examine whether ultrasound guidance is helpful for placement of electrodes on a small muscle, such as the hand lumbrical muscle. Twelve dominant hands of 12 healthy right-handed adults were included in this study. The first lumbrical muscle belly of the hands was identified using ultrasound guidance with a string navigation technique for placing surface electrodes. This technique was designed to identify the location of the center of the muscle belly under ultrasound imaging using a string. After the electrodes were placed on the muscle belly using this technique, the surface electromyographic signals of the first lumbrical, first dorsal interosseous, and adductor pollicis muscles were recorded. The activity of the lumbrical muscle could be separately measured of the first dorsal interosseous and adductor pollicis muscles. This technique has the potential to enable surface electromyography of small muscles for which placement of surface electrodes by palpation is challenging.

Ultrasound Elastography for Hand Soft Tissue Assessment

Over the past decade, ultrasound elastography has emerged as a new technique for measuring soft tissue properties. Real-time, noninvasive, and quantitative evaluations of tissue stiffness have improved and aid in the assessment of normal and pathological conditions. Specifically, its use has substantially increased in the evaluation of muscle, tendon, and ligament properties. In this review, the authors describe the principles of elastography and present different techniques including strain elastography and shear-wave elastography; discuss their applications for assessing soft tissues in the hand before, during, and postsurgeries; present the strengths and limitations of their measurement capabilities; and describe directions for future research.

Intrinsic plus hand: Painful Finger flexion and extension

Intrinsic plus hand describes a rare and painful contracture of the intrinsic hand muscles with excessive flexion at the metacarpophalangeal joints and extension at the interphalangeal joints. Resulting from many causes to include trauma and neurologic injury, intrinsic plus hand can involve any number of fingers. Emergency department (ED) assessment should include evaluation for cerebrovascular injury, infection, compartment syndrome, and deep vein thrombosis (DVT). Conservative splinting is generally unsuccessful and ultimately requires operative intervention. We highlight the case of a 61-year-old otherwise healthy male who awoke to a painful and mildly swollen left hand with his fingers held in a contracted position. Evaluation in the ED found no active range of motion in the digits, severe pain with any passive motion, and a negative upper extremity ultrasound for DVT. Ultimately, orthopedic and neurology consults in the ED agreed upon a diagnosis of intrinsic plus hand.