Wasting of the hand associated with a cervical rib or band

Abstract

SUMMARY Nine patients are described with unilateral wasting of the hand muscles associated with elongated C7 transverse processes or with rudimentary cervical ribs. In three patients there was selective wasting of the lateral part of the thenar pad, accompanied by mild weakness of the other hand muscles. In four patients all the hand muscles were wasted, but this was more marked in the lateral part of the thenar pad than elsewhere. In two patients wasting was uniformly distributed throughout the hand. Weakness and wasting in the forearm was only present in four patients and was relatively mild. Sensory loss, when present, affected mainly the inner side of the forearm. Nerve conduction studies revealed no abnormality in the distal part of the median nerve, but some patients had reduced or absent sensory action potentials when the fifth finger was stimulated. In all nine patients a sharp fibrous band was found at operation, which extended from an elongated C7 transverse process or from a rudimentary cervical rib to the region of the scalene tubercle on the first rib. The fibrous band caused angulation of the C8 and TI roots in five patients, and of the lower trunk of the brachial plexus in three. Pathological changes were frequently visible in affected nerves at the site of angulation. Division of the fibrous band relieved pain and paraesthesiae in eight patients and atrested muscle wasting and weakness in nine patients. There was, however, only slight recovery of power in affected muscles; wasting in the hand appeared to be unchanged after periods of up to eight years.

Ultrasonographic Identification of Fibromuscular Bands Associated with Neurogenic Thoracic Outlet Syndrome: The “Wedge-Sickle” Sign

“…In neurogenic 6 TOS, the brachial plexus is typically compressed in the scalenic triangle at the level of the lower trunk 7 or the distal portion of its constituents, the C8 and Th1 anterior primary rami ('roots'). This gives rise 8 to a characteristic clinical syndrome with the selective wasting of the thenar and the first dorsal 9 interosseous muscle (Gilliatt et al 1970), and sensory disturbance on the medial aspect of the forearm, 10 with or without pain in the affected arm. The electrophysiological hallmark of neurogenic TOS is the 11 demonstration of postganglionic sensorimotor C8-Th1 axon loss, with Th1 being affected more and 12 earlier (Tsao et al 2014).…”

“…However, given that the estimated prevalence of cervical ribs in the general 19 population is 0.5-2% (Ferrante 2012;Viertel et al 2012) and that of neurogenic TOS is 1 per million 20 (Gilliatt et al 1970), statistically the presence of a cervical rib is in itself not diagnostic for neurogenic 21 TOS (Ferrante 2012;Weber and Criado 2014). Its relevance appears to be higher for arterial vascular 22 TOS (Weber and Criado 2014).…”

Cervical Radiculopathy vs Parsonage–Turner Syndrome: A Case Report

“…Thoracic outlet syndrome predominantly affects the lower trunk or medial cord of the brachial plexus. Physical examination is significant for Tinel_s sign in the supraclavicular fossa, sensory deficits on the medial forearm and ulnar side of hand (without ring finger splitting), weakness of hand intrinsics, and atrophy of thenar and hypothenar eminences [16,18]. EMG studies on these patient will usually demonstrate abnormalities in muscles innervated by the lower brachial plexus, such as the abductor pollicis brevis and flexor digitorum indicis.…”

“…Thoracic outlet syndrome (TOS) is another source of unilateral upper extremity pain and sensory changes; the true or Bclassic^type is caused by compression of the lower trunk of the brachial plexus by a cervical rib or fibrous band from an elongated C7 transverse process [25,26]. Clinical presentation is not of neck pain, but of mild, deep, aching upper extremity pain, hand weakness and clumsiness, and atrophy of thenar eminence (abductor pollicis brevis) called the Bguttering sign^ [16]. Thoracic outlet syndrome predominantly affects the lower trunk or medial cord of the brachial plexus.…”

True neurogenic thoracic outlet syndrome in a competitive swimmer: a case report of this rare association

“…They result in ischemia of the digits and hand or swelling of the arm and represent only 5% of the patients with TOS 4 . The neurogenic TOS represent the rest 95% and can be subdivided in true and disputed.Following the ongoing debate in regard to the entity of TOS over the past two decades, a consensus has emerged that classic (true) neurogenic TOS is uncommon and is usually caused by compression of the lower trunk of the brachial plexus due to a cervical rib or band and enlarged scalenus muscles [5][6][7] . This compression results in arm pain, numbness of the inner surface of the hand and forearm, and characteristic wasting and weakness of the thenar and intrinsic hand muscles.…”