The aim of the study is to assess the accuracy of shear wave elastography in volunteers. Shear wave elastography is a non-invasive, non-painful measure of tissue stiffness obtained using an ultrasound machine. It may be easier to think of shear wave elastography as a special type of ultrasound imaging which gives doctors a colour picture of body structures based on their stiffness.

Shear wave elastography is a quantitative ultrasound modality increasingly used to differentiate between "hard" breast cancer masses and "soft" normal tissue. Unlike strain elastography, shear wave elastography applies a non-compressive longitudinal acoustic radiation force to underlying tissues, inducing transverse shear waves. Studies in Thiel embalmed human cadavers have shown significant differences in Young's modulus between intraneural and extraneural tissue, and ready colour differentiation between tissues.

Therefore, before clinical application, we wish to measure the repeatability and reproducibility of Young's modulus of intraneural and extraneural tissue in volunteers. For measurement, a region of interest (ROI) will be selected over the appropriate nerve and adjacent tissue. The ROI results will be regarded as paired data. Paired data will be measured over and adjacent to the interscalene C5 nerve root, infraclavicular lateral cord, musculocutaneous, median, femoral, saphenous and sciatic nerves.

Inclusion Criteria:

• Fit healthy male volunteers between 18 and 35 years of age.
• Participants with an ASA score of 1.
• Capacity to provide informed consent.

Exclusion Criteria:

• All females.
• Male participants aged <18 years and >35 years of age.
• ASA score 2 or above.

Study of 8 subjects - volunteer medical students. Recruitment: Male medical students at Ninewells Hospital & Medical School, Dundee.

Male medical students will be e-mailed by the chief investigator.