1. A Brief Orientation to Ultrasound Imaging of the Musculoskeletal System

1. For most musculoskeletal examinations, the linear probe and a musculoskeletal preset should be selected.
2. The probe indicator, in most instances, is oriented proximally or medially.
3. Common structures that are visualized using ultrasound include bones, tendons, ligaments, and muscles.
4. Bones are hyperechoic and create shadow artifacts posteriorly.
5. Tendons and ligaments are hyperechoic and have a fibrillar appearance.
6. Muscle appears relatively hypoechoic and striated.

2. Examination of the Knee

1. Review the examination of the knee here: JoVE Video 10203: Knee Exam 
2. Select the linear probe and the musculoskeletal preset on the ultrasound machine.
3. Have the patient in the supine position.
4. Begin by identifying the quadriceps tendon in sagittal view. Correlate this with the location of clinically palpable knee effusions in the suprapatellar bursa.
5. Slide the probe inferiorly over the patella to the patellar tendon with its insertion on the tibial tuberosity. This is the area to inspect and palpate to identify prepatellar and infrapatellar bursitis and Osgood Schlatter's disease.
6. Move the probe to the medial knee with the indicator pointing proximally. Identify the medial joint line, medial collateral ligament (MCL), and medial meniscus. Correlate this with the joint line tenderness to palpation associated with osteoarthritis and a meniscal tear. Highlight the effect of applying valgus strain on the knee if the MCL is strained or torn.
7. Slide the transducer distally and rotate obliquely to find the insertion of sartorius, gracilis, and semitendinosis on the tibia, which is the area of the anserine bursa. Correlate this with the identification of anserine bursitis with palpation.
8. Move the probe to the lateral side of the knee with the probe indicator pointing proximally. Identify the lateral joint line, lateral femoral epicondyle, lateral collateral ligament (LCL), lateral meniscus, and the head of the fibula. Correlate this with the joint line tenderness to palpation associated with osteoarthritis and a meniscal tear. Highlight the effect of applying varus strain on the knee if the LCL is strained or torn.
9. Slide the probe distally and more anterior to identify Gerdy's tubercle and the iliotibial (IT) band. Note the IT band running over the lateral femoral epicondyle when the knee is in full extension. Correlate this with pain elicited at Gerdy's tubercle and with palpation of the lateral epicondyle with active flexion and extension of the knee to diagnose IT band syndrome.

3. Examination of the Shoulder

1. Review the examination of the shoulder here: JoVE Video 10173: Shoulder Exam I, and  JoVE Video 10185: Shoulder Exam II.  
2. Select the linear probe and the musculoskeletal preset on the ultrasound machine.
3. Have the patient in the seated position with the elbow flexed, hand supinated and resting on the thigh.
4. Place the probe in a transverse plane over the anterior aspect of the proximal humerus and identify the long head of the biceps brachii tendon. Correlate this location with tenderness elicited with the Speed's and Yergason's tests.
5. Slide the probe medial while externally rotating the shoulder to identify the subscapularis tendon and muscle. Correlate the dynamic motion under ultrasound with the function of the muscle and testing by resisted internal rotation.
6. Slide the probe laterally when internally rotating the shoulder to identify the teres minor and infraspinatus tendon and muscle. Correlate the dynamic motion under ultrasound with the function of the muscle and testing by resisted external rotation.
7. Rotate the probe, so the indicator is directed proximally and positioned over the lateral aspect of the shoulder. Identify the acromion process and supraspinatus tendon. Additionally, observe the movement of the supraspinatus tendon under the acromion process with the abduction of the shoulder. In the shoulder impingement syndrome, the pain is generated from the impingement of structures between the acromion process and the head of the humerus.
8. Position the probe along the superior aspect of the clavicle and identify the acromioclavicular joint. Correlate this with the tenderness to palpation over this location in patients with acromioclavicular arthritis.