As an imaging modality, ultrasound has enjoyed fantastic advances in the past 15 years meaning that many of the large peripheral nerves (and even their smaller branches) can be reviewed in fantastic detail.
We will follow the peripheral nerves of the upper limb down from the brachial plexus and consider the common points of nerve entrapment, the effect this entrapment has on the limb and what role ultrasound has to play in the workup of these conditions. A constant theme of the presentation will be to answer the question; when should I look for that?
Understanding nerve entrapment syndromes is important! Carpal Tunnel Syndrome and Cubital Tunnel Syndrome are common clinical entities and as such all musculoskeletal sonologists and sonographers should have a sound knowledge of these conditions and their ultrasound appearance.
In addition to these common conditions we will review the less common nerves entrapment syndromes of the upper limb such as Radial and Ulnar Tunnel Syndromes.

References
Duncan I, Sullivan P, Lomas F. Sonography in the diagnosis of Carpal Tunnel Syndrome. AJR 1999; 173:681-684.
Gassner E et al. Persistent Median Artery in the Carpal Tunnel. Colour Doppler Ultrasonographic Findings. J Ultrasound Med 21:455-461, 2002.
Tayfun Altinok M et al. Sonographic Evaluation of the Carpal Tunnel after Provocative Exercises. J Ultrasound Med 2004; 23: 1301-1306.
Beekman R, Visser LH. Sonography in the Diagnosis of Carpal Tunnel Syndrome: A critical review of the Literature. Muscle Nerve 2003; 27: 26-33.
Bodner G et al. Ultrasonographic Appearance of Supinator Syndrome. J Ultrasound Med 21: 1289-1293.
Beltran J, Rosenberg Z. Nerve Entrapment. Musculoskeletal Radiology. 1998; 2:175-84.
Cross-Sectional Imaging of Peripheral Nerve Sheath Tumors:Characteristic Signs on CT, MR Imaging, and Sonography. John Lin. AJR:176, January 2001

Sonography and MR Imaging of Posterior Interosseous Nerve Syndrome with Surgical Correlation. Alexander J. Chien et al AJR:181, July 2003

Sonographic Evaluation of the Median Nerve at the Wrist. David A. Jamadar. J Ultrasound Med 20:1011-1014, 2001.