Musculoskeletal Development

Understanding Mechanobiological Effects of Peripheral Nerve Injury on Developing Bone and Muscle

Collaboration with Dr. Katherine Saul, Mechanical & Aerospace Engineering, NC State

Brachial Plexus Birth Injury (BPBI), a peripheral nerve injury that affects 1-3 in 1,000 births annually, causes impaired function of the neonatal upper limb. Despite physical therapy and surgical interventions, the resulting denervation of muscle following injury often causes gross morphological changes in the glenohumeral joint, presenting as osseous (e.g. glenoid retroversion, humeral head subluxation) and postural deformities (e.g. internal shoulder rotation contracture).

[Image copyright ©2008 Children’s Healthcare of Atlanta Inc.,Illustration by Bernie Kida]

Effects to bone due to altered musculoskeletal loading following nerve injury requires an in-depth understanding of changes in bone mineralization and microstructure in developing joints, which is currently not well understood. We use a rat model to determine BPBI-related changes in bone structure and metabolism in the proximal humerus and distal scapula during development using micro-computed tomography and histology. While the etiology of osseous deformity in BPBI remains unclear, understanding changes in bone microstructure and metabolism resulting from injury may present a foundation for understanding the progression of deformity and offer targets for interventions and treatments.


Selected Publications and Presentations:

  • Fawcett EB*, McCormick CM*, Murray AF, Crouch DL, Saul KR, Cole JH. Characterizing trabecular bone properties near the glenohumeral joint following brachial plexus birth injury. bioRxiv preprint. [DOI: 10.1101/967224]. Under Review. * co-first authors
  • Tushak SK*, Tamburro MK*, Fawcett EB, Merritt LE, Saul KR, Cole JH. Forelimb disuse impairs glenohumeral muscle development in growing rats. bioRxiv preprint. [DOI: 10.1101/967273].  Under Review. * co-first authors
  • Merritt LE, Tamburro MK, Tushak SK, Fawcett EB, Cole JH, Saul KR. Forelimb unloading impairs glenohumeral bone development in growing rats. Under Review.
  • Dixit NN, McCormick CM, Cole JH, Saul KR. Influence of brachial plexus birth injury location on morphology of the glenohumeral joint. Under Review.
  • Dixit NN, McCormick CM, Warren E, Cole JH, Saul KR. Preganglionic and postganglionic brachial plexus birth injury effects on shoulder muscle growth. Under Review.
  • Fawcett EB, Merritt LE, Dixit NN, Saul KR, Cole JH (2020) Adaptations in trabecular bone microstructure following brachial plexus birth injury are not due solely to limb disuse. American Society of Biomechanics Annual Meeting, Atlanta, GA, Aug 4-7, Accepted for poster presentation.
  • Fawcett EB, Lo KE, Merritt LE, Dixit NN, Cole JH, Saul KR (2020) Macrostructural bone deformity following brachial plexus birth injury cannot be explained solely by limb disuse. American Society of Biomechanics Annual Meeting, Atlanta, GA, Aug 4-7, Accepted for poster presentation.
  • Dixit NN, McFarland DC, Fisher MB, Cole JH, Saul KR (2020). Integrated iterative musculoskeletal modeling predicts bone morphology following brachial plexus birth injury (BPBI). Journal of Biomechanics 103:109658. DOI: 10.1016/j.jbiomech.2020.109658. PMID: 32089271.


This work was funded by the National Institutes of Health (R21 HD088893) and the NC State Office of Undergraduate Research.