However, variant anatomy of the brachial plexus is present in approximately 50% of the population ( 1). These ventral rami are the roots of the brachial plexus. Various muscles, vessels, and osseous structures can be used as landmarks for identifying the various subdivisions of the brachial plexus on imaging studies.Ĭlassically, the brachial plexus is formed from the ventral rami of the C5–T1 spinal nerves. This article is intended to serve as an image-rich review of the brachial plexus, with emphasis on multimodality comparison of US, CT, and MRI techniques and findings. It is critical to review the clinical data in each case to understand how imaging may affect patient care. A structured report template used to report brachial plexus imaging findings is available at. Effective reporting of brachial plexus imaging findings requires familiarity with the brachial plexus anatomy and relevant landmarks, the spectrum and categories of brachial plexopathies, and the associated clinically relevant terminology. Even with use of dedicated advanced imaging, the findings can be difficult to correlate to traditional anatomic and diagrammatic representations. In many cases, imaging has an important role in lesion localization and characterization and affects the management of traumatic and nontraumatic brachial plexopathies.Īlthough the brachial plexus is commonly included in the field of view at nondedicated imaging, it can be challenging for the radiologist to assess owing to its convoluted course, portions of which can be obscured. Evaluation of brachial plexus disease typically begins with obtaining the patient history and performing a physical examination and electrophysiologic testing. The brachial plexus is an intricate neural network that provides motor and somatosensory innervation of the arm, shoulder, and upper chest. Although diagnosing a brachial plexus anomaly is potentially perplexing, it can be straightforward if it is based on foundational knowledge of anatomy, imaging findings, and pathologic features. Direct extension and metastasis from primary malignancies such as breast and lung cancer can occur. Primary and secondary tumors of the brachial plexus are not uncommon, with the most common primary tumors being peripheral nerve sheath tumors. In acute brachial neuritis, antecedent stressors occur within a specific time frame. Knowledge of the timing of radiation therapy is critical to diagnosing post–radiation therapy brachial plexopathy. For nontraumatic plexopathies, having access to an accurate patient history is often crucial. In the traumatic plexopathy group, there are distinct imaging findings and management methods for pre- versus postganglionic injuries. Brachial plexopathies can be divided into two broad categories that are based on disease origin: traumatic and nontraumatic. Applying this anatomic knowledge, a radiologist should then be able to identify pathologic appearances of the brachial plexus by using imaging modalities such as MRI, CT, and US. The components of the brachial plexus can be determined by using key anatomic landmarks.

Owing to its complex form and longitudinal course, the brachial plexus can be challenging to conceptualize in three dimensions, which complicates evaluations in standard orthogonal imaging planes. The brachial plexus is an intricate anatomic structure with an important function: providing innervation to the upper extremity, shoulder, and upper chest.

Complete anatomy brachial plexus