Research Article|Articles in Press

The consequences of a thoracic outlet syndrome's entrapment model on the biomechanics of the ulnar nerve - Cadaveric study

Published:October 23, 2022DOI:


      • A nerve fixation at the thoracic outlet induced traumatic conditions on the ulnar nerve, which were non-existent in the normal “control” anatomical situation and could favour the development of neuropathies.
      • The results of this study invite surgeons to consider nerve mobility as an essential parameter in decompression surgeries for entrapment syndromes.
      • For a physiotherapist, it seems crucial to treat the peripheral nerve in its entire path, and to assess its mobility with specific neurodynamic tests like ULNT to guide the rehabilitation.


      Study Design

      A cross sectional cadaveric measurement study.


      The etiology of entrapment neuropathies, such as carpal tunnel syndromes or thoracic outlet syndromes (TOS), is usually not only linked with the compressive lesion of the nerve but can also be associated with fibrosis and traction neuropathy.

      Purpose of the Study

      This work studies the biomechanics of the ulnar nerve in a cadaveric model of thoracic outlet syndrome (TOS). We explored the biomechanical impact of a restriction of mobility of the ulnar nerve. We measured if it could significantly affect the deformation undergone by the nerve on the rest of its path.


      We studied 14 ulnar nerves from 7 embalmed cadavers. We opened three 6.5cm windows (at the wrist, forearm, and arm), and two optical markers 2cm apart were sutured to the ulnar nerve. We then studied the deformation of the ulnar nerve in three successive tensioning positions inspired by the ULNT3 manoeuvre (Upper Limb Neural Test 3). We then fixed the brachial plexus to the clavicle to mimic a nerve adhesion at the thoracic outlet.


      Fixing the brachial plexus to the clavicle bone had significant effects on ulnar nerve mobility. In the position of intermediate tension, the nerve deformation increased by +0.68% / +1.43% compared to the control measure. In the position of maximum tension, it increased by +1.16% / +1.94%, pushing the nerve beyond the traumatic threshold of 8% of deformation causing reversible damage to axonal transport and vascularization.


      Our nerve adhesion at the thoracic outlet showed significant effects on the mobility of the ulnar nerve compared to the control situation, by significantly increasing the deformation undergone throughout the rest of the nerve's course, and by taking it over the 8% of physiological traumatic deformation.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Hand Therapy
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Citisli V.
        Assessment of Diagnosis and Treatment of Thoracic Outlet Syndrome, An Important Reason of Pain in Upper Extremity.
        Based on Literature. 2015; (Published online)
        • Freischlag J
        • Orion K.
        Understanding thoracic outlet syndrome.
        Scientifica (Cairo). 2014. 2014; 248163
        • Sanders RJ
        • Hammond SL
        • Rao NM
        Diagnosis of thoracic outlet syndrome.
        J Vasc Surg. 2007; 46: 601-604
        • Laulan J
        • Fouquet B
        • Rodaix C
        • Jauffret P
        • Roquelaure Y
        • Descatha A.
        Thoracic outlet syndrome: definition, aetiological factors, diagnosis, management and occupational impact.
        J Occup Rehabil. 2011; 21: 366-373
        • Stewman C
        • Vitanzo PC
        • Harwood MI
        Neurologic thoracic outlet syndrome: summarizing a complex history and evolution.
        Curr Sports Med Rep. 2014; 13: 100-106
        • Brantigan CO
        • Roos DB
        Etiology of neurogenic thoracic outlet syndrome.
        Hand Clin. 2004; 20: 17-22
        • Crotti FM
        • Carai A
        • Carai M
        • et al.
        TOS pathophysiology and clinical features.
        Acta Neurochir Suppl. 2005; 92: 7-12
        • Crotti FM
        • Carai A
        • Carai M
        • Sgaramella E
        • Sias W.
        Post-traumatic thoracic outlet syndrome (TOS).
        Acta Neurochir Suppl. 2005; 92: 13-15
        • Grewal R
        • Xu J
        • Sotereanos DG
        • Woo SL.
        Biomechanical properties of peripheral nerves.
        Hand Clin. 1996; 12: 195-204
        • Kwan MK
        • Wall EJ
        • Massie J
        • Garfin SR.
        Strain, stress and stretch of peripheral nerve. Rabbit experiments in vitro and in vivo.
        Acta Orthop Scand. 1992; 63: 267-272
        • Topp KS
        • Boyd BS.
        Peripheral nerve: from the microscopic functional unit of the axon to the biomechanically loaded macroscopic structure.
        J Hand Ther. 2012; 25 (quiz 152): 142-151
        • Clark WL
        • Trumble TE
        • Swiontkowski MF
        • Tencer AF.
        Nerve tension and blood flow in a rat model of immediate and delayed repairs.
        J Hand Surg Am. 1992; 17: 677-687
        • Ogata K
        • Naito M.
        Blood flow of peripheral nerve effects of dissection, stretching and compression.
        J Hand Surg Br. 1986; 11: 10-14
        • Rydevik BL
        • Kwan MK
        • Myers RR
        • et al.
        An in vitro mechanical and histological study of acute stretching on rabbit tibial nerve.
        J Orthop Res. 1990; 8: 694-701
        • Tanoue M
        • Yamaga M
        • Ide J
        • Takagi K.
        Acute stretching of peripheral nerves inhibits retrograde axonal transport.
        The Journal of Hand Surgery: British & European Volume. 1996; 21: 358-363
        • Wall EJ
        • Massie JB
        • Kwan MK
        • Rydevik BL
        • Myers RR
        • Garfin SR.
        Experimental stretch neuropathy. Changes in nerve conduction under tension.
        J Bone Joint Surg Br. 1992; 74: 126-129
        • Floranda EE
        • Jacobs BC.
        Evaluation and Treatment of Upper Extremity Nerve Entrapment Syndromes.
        Primary Care: Clinics in Office Practice. 2013; 40: 925-943
        • Doughty CT
        • Bowley MP.
        Entrapment Neuropathies of the Upper Extremity.
        Medical Clinics of North America. 2019; 103: 357-370
        • Toby EB
        • Hanesworth D.
        Ulnar nerve strains at the elbow.
        Journal of Hand Surgery. 1998; 23: 992-997
        • Festen-Schrier VJMM
        • Amadio PC
        The biomechanics of subsynovial connective tissue in health and its role in carpal tunnel syndrome.
        Journal of Electromyography and Kinesiology. 2018; 38: 232-239
        • Grewal R
        • Varitimidis SE
        • Vardakas DG
        • Fu FH
        • Sotereanos DG
        Ulnar nerve elongation and excursion in the cubital tunnel after decompression and anterior transposition.
        J Hand Surg Br. 2000; 25: 457-460
        • Wright TW
        • Glowczewskie F
        • Cowin D
        • Wheeler DL
        Ulnar nerve excursion and strain at the elbow and wrist associated with upper extremity motion.
        J Hand Surg Am. 2001; 26: 655-662
        • Sakurai M
        • Miyasaka Y.
        Neural fibrosis and the effect of neurolysis.
        J Bone Joint Surg Br. 1986; 68: 483-488
        • Mahan MA
        • Vaz KM
        • Weingarten D
        • Brown JM
        • Shah SB
        Altered ulnar nerve kinematic behavior in a cadaver model of entrapment.
        Neurosurgery. 2015; 76: 747-755
        • Lloyd TE.
        Axonal transport disruption in peripheral nerve disease: From Jack's discoveries as a resident to recent contributions.
        J Peripher Nerv Syst. 2012; 17: 46-51
        • Millecamps S
        • Julien JP.
        Axonal transport deficits and neurodegenerative diseases.
        Nat Rev Neurosci. 2013; 14: 161-176
        • Upton AR
        • McComas AJ.
        The double crush in nerve entrapment syndromes.
        Lancet. 1973; 2: 359-362
        • Narakas AO.
        The role of thoracic outlet syndrome in the double crush syndrome.
        Ann Chir Main Memb Super. 1990; 9: 331-340
        • Leffert RD
        Anterior submuscular transposition of the ulnar nerves by the Learmonth technique.
        J Hand Surg Am. 1982; 7: 147-155
        • Rogers MR
        • Bergfield TG
        • Aulicino PL.
        The failed ulnar nerve transposition. Etiology and treatment.
        Clin Orthop Relat Res. 1991; Aug(269): 193-200
        • Mazal PR
        • Millesi H.
        Neurolysis: is it beneficial or harmful?.
        Acta Neurochir Suppl. 2005; 92: 3-6
        • Larsson C
        • Ekvall Hansson E
        • Sundquist K
        • Jakobsson U
        Impact of pain characteristics and fear-avoidance beliefs on physical activity levels among older adults with chronic pain: a population-based, longitudinal study.
        BMC Geriatrics. 2016; 16: 50
        • Pells J
        • Edwards CL
        • McDougald CS
        • et al.
        Fear of movement (kinesiophobia), pain, and psychopathology in patients with sickle cell disease.
        Clin J Pain. 2007; 23: 707-713
        • Basson A
        • Olivier B
        • Ellis R
        • Coppieters M
        • Stewart A
        • Mudzi W.
        The Effectiveness of Neural Mobilization for Neuromusculoskeletal Conditions: A Systematic Review and Meta-analysis.
        J Orthop Sports Phys Ther. 2017; 47: 593-615
        • Butler DS
        • Jones MA
        Mobilisation of the nervous system.
        Churchill Livingstone, 1991
        • Kleinrensink GJ
        • Stoeckart R
        • Vleeming A
        • Snijders CJ
        • Mulder PGH
        • van Wingerden JP
        Peripheral nerve tension due to joint motion. A comparison between embalmed and unembalmed human bodies.
        Clin Biomech (Bristol, Avon). 1995; 10: 235-239
        • Barberio CG
        • Chaudhry T
        • Power DM
        • et al.
        Towards viscoelastic characterisation of the human ulnar nerve: An early assessment using embalmed cadavers.
        Med Eng Phys. 2019; 64: 15-22
        • Coppieters MW
        • Alshami AM.
        Longitudinal excursion and strain in the median nerve during novel nerve gliding exercises for carpal tunnel syndrome.
        J Orthop Res. 2007; 25: 972-980
        • Gugliotti M
        • Futterman B
        • Ahrens T
        • et al.
        Impact of shoulder internal rotation on ulnar nerve excursion and strain in embalmed cadavers. A pilot study.
        J Man Manip Ther. 2016; 24: 111-116
        • Manvell N
        • Manvell JJ
        • Snodgrass SJ
        • Reid SA.
        Tension of the ulnar, median, and radial nerves during ulnar nerve neurodynamic testing: observational cadaveric study.
        Phys Ther. 2015; 95: 891-900
        • Manvell JJ
        • Manvell N
        • Snodgrass SJ
        • Reid SA.
        Improving the radial nerve neurodynamic test: An observation of tension of the radial, median and ulnar nerves during upper limb positioning.
        Man Ther. 2015; 20: 790-796
        • Pawlaczyk M
        • Lelonkiewicz M
        • Wieczorowski M.
        Age-dependent biomechanical properties of the skin.
        Postepy Dermatol Alergol. 2013; 30: 302-306
        • Agyapong-Badu S
        • Warner M
        • Samuel D
        • Stokes M.
        Measurement of ageing effects on muscle tone and mechanical properties of rectus femoris and biceps brachii in healthy males and females using a novel hand-held myometric device.
        Arch Gerontol Geriatr. 2016; 62: 59-67