China
Africa
Explore chapters and articles related to this topic
Peripheral Nerve Examination
Published in J. Terrence Jose Jerome, Clinical Examination of the Hand, 2022
J Terrence Jose Jerome, Dafang Zhang
The thenar muscles are comprised of the abductor pollicis brevis, the flexor pollicis brevis and the opponens pollicis, which together contribute more than 30% of grip strength and 60% of pinch strength in a normal hand [3]. The thenar muscles allow for opposition of the thumb, which is the placement of the thumb in a plane opposite the lesser digits [9]. Opposition is a composite motion that combines flexion, pronation and palmar abduction at the thumb trapeziometacarpal joint and flexion at the thumb metacarpophalangeal joint [9,10]. The abductor pollicis brevis has the greatest contribution to thumb opposition due to its superficial position and resultant mechanical advantage. The flexor pollicis brevis frequently has redundant innervation from the ulnar nerve, particularly its deep head which has supply from the ulnar nerve in nearly 80% of patients [9].
Neurology, ophthalmology and psychiatry
Published in Shibley Rahman, Avinash Sharma, MRCP Part 2 Best of Five Practice Questions, 2018
Shibley Rahman, Avinash Sharma
A 46-year-old woman has had nocturnal pain and paraesthesiae in the right forearm and hand for six months. The symptoms typically wake her and she shakes the hand to relieve them. For several years, she had complained of neck pain, exacerbated by movement. She had smoked around 10 cigarettes a week for the previous two years. Examination demonstrated subtle thenar wasting, and very mild weakness of right abductor pollicis brevis.
Upper limb
Published in Aida Lai, Essential Concepts in Anatomy and Pathology for Undergraduate Revision, 2018
Attachments of abductor pollicis brevis– origin: tubercle of scaphoid and trapezium– insertion: proximal phalanx of thumb– nerve SS: recurrent branch of median n. (C8, T1)– function: abduct metacarpophalangeal joint of thumb
Visual attention affects late somatosensory processing in autism spectrum disorder
Published in International Journal of Neuroscience, 2022
Haruka Noda, Akiko Tokunaga, Akira Imamura, Goro Tanaka, Ryoichiro Iwanaga
Electroencephalogram (EEG) data were obtained using Neuropack μ MEB-9100 (Nihon Kohden Corp., Tokyo, Japan) and analyzed with LabChart (Bio Research Center Co, Ltd., Nagoya, Japan). The EEG responses from C3′ and C4′ (2 cm posterior to C3 and C4) were obtained, according to the International 10–20 System, using Ag-AgCl scalp electrodes. Reference electrodes were attached to the earlobes. Electrode impedance was kept below 5 kΩ during the course of the experiment. Simultaneously, electromyograph (EMG) data were recorded in the right abductor pollicis brevis muscle. Electrical stimulation was delivered at a frequency of 1 Hz to the right median nerve at the wrist, using a square-wave pulse (0.2 ms duration). The motor threshold of the abductor pollicis brevis muscle was identified from the amplitude of m-wave, and the electrical stimulus intensity was set at 1.3 times the motor threshold [21].
Impact of occupational lead exposure on nerve conduction study data
Published in International Journal of Neuroscience, 2022
Tülin Aktürk, Gülay Çeliker, Hikmet Saçmacı
Motor nerve conduction studies included median, ulnar, peroneal and tibial nerve studies. The median motor nerve was stimulated from the distal (wrist) and proximal (elbow) areas and recording was obtained from the abductor pollicis brevis muscle. The ulnar motor nerve conduction study was stimulated in the distal (wrist) and proximal (under elbow) areas and recording was obtained from the abductor digiti minimi muscle. The peroneal motor nerve was stimulated in distal (ankle) or proximal (knee) areas, respectively, and recording was made from the extensor digitorium brevis muscle. The tibial motor nerve was stimulated in distal (ankle) or proximal (popliteal fossa) areas, respectively, and a record was obtained from the abductor hallucis muscle. The distal motor latency was calculated as the time from stimulus to the initial compound muscle action potential (CMAP) deflection from baseline, and the amplitude of CMAP was measured from baseline to the negative peak.
Split phenomenon of antagonistic muscle groups in amyotrophic lateral sclerosis: relative preservation of flexor muscles
Published in Neurological Research, 2021
Jingwen Liu, Zhili Wang, Dongchao Shen, Xunzhe Yang, Mingsheng Liu, Liying Cui
Muscle wasting is an active process controlled by specific signalling pathways and transcriptional programs. This process involves alterations in ubiquitin-proteasome and autophagy-lysosome, leading to protein breakdown and muscle atrophy [2]. For patients with ALS, muscle weakness in adjacent muscle groups for the same limb does not develop in a synchronized pattern. The earliest report of this phenomenon stems from a description of the split-hand, which refers to preferential wasting of the abductor pollicis brevis (APB), as well as the first dorsal interosseous (FDI), with relative sparing of the abductor digiti minimi (ADM), which was first described by Wilbourn [3]. The split-hand phenomenon rarely occurs in other neuromuscular diseases [4]. It seems to be a highly specific clinical manifestation that is seen in the early stages of ALS and is considered a useful clinical marker and helpful for the diagnosis of ALS [5].