# Ultrasound-Guided Procedures in Common Tendinopathies at the Elbow: From Image to Needle
## 3 Common Elbow Pathologies
### Tennis Elbow
#### 3.1.2 US scanning and Guided Injection  
For US scanning of the CET, the patient may be positioned supine on the examination bed while the patient's forearm rests on the stomach in mild supination. For the contralateral elbow, the US practitioner can easily scan the lateral compartment from his seat. Alternatively, the patient may sit opposite to the sonographer with the elbow flexed and with the shoulder internally rotated and the forearm semi-supinated. The probe is placed at the LE along the forearm's long axis to visualize the CET in the long axis (Figure 3). The underlying bony landmarks are the LE and the radial head. The hyperechoic fibrillar layer between bone and subcutaneous tissue represents the CET (superficial) and the lateral collateral ligament (deep), which is difficult to distinguish from the CET due to the similar fibrillar eductexture. Similarly, distinguishing between individual tendons of the CET can also be challenging. To identify an individual tendon, one can use distal to proximal muscle tracking. The ECRB and EDC tendons are predominantly affected [34]. Notably, identifying the specific tendon affected by inflammation might help tailor the rehabilitation  
Figure 1: Common extensor origin. The cadaveric specimen shows the location of muscular origin on the posterolateral aspect of the right elbow joint. BrR: brachioradialis muscle, CET: common extensor tendon, ECRB: extensor carpi radialis brevis muscle, ECRL: extensor carpi radialis longus muscle, ECU: extensor carpi ulnaris muscle, EDC: extensor digitorum communis muscle. program [35] and determine a convenient target for interventions (e.g., dry-needling or regenerative medicine injections). When intact, the CET is noncompressible, homogenous, and hyperechoic with a fibrillar tendons pattern (Figure 4a). In pathologic cases, the examiner can observe cortical irregularities (e.g., bony spurs or erosions), tendon thickening with a loss of normal fibrillar pattern, focal or diffuse hypoechogenicity, calcifications, tears, and hypervasularity (Figure 4b-e) [36]. Furthermore, the examiner can use sonopalpation to correlate the abnormal findings with local tenderness [37]. Figure 3: Ultrasound-guided injection for tennis elbow: (**a**) position of the patient (supine, elbow flexed to 90\({}^{\circ}\), internal rotation of the shoulder, thumb extension); (**b**) position of the probe on the lateral epicondyle perpendicular to the long axis of the forearm. Figure 2: Location of muscular and ligamentous attachments on distal humerus: (**a**) anterior, (**b**) medial, (**c**) posterior, and (**d**) lateral aspect of the right distal humerus. Light blue: articular surfaces. An: anconeus, Br: brachialis, BrR: brachioradialis muscle, CET: common extensor tendon, CFT: common flexor tendon, ECRB: extensor carpi radialis brevis muscle, ECRL: extensor carpi radialis longus muscle, JC: joint capsule, LCL: lateral collateral ligament, MCL: medial collateral ligament, PT: pronator teres, Tri: triceps brachii, TriMe: triceps brachii, medial head. Even though tennis elbow is, to a certain point, a self-limited disease, approximately 80% of patients get better after a year. Notably, some methods can enhance the healing process [38]. [PERSON] et al. [39] reported a lack of clinical benefit comparing nonsurgical treatment to observation/placebo in intermediate to long-term clinical benefits. Nevertheless, in some patients who suffered from recalcitrant pain, despite the initial conservative therapy (physiotherapy, local/oral nonsteroidal anti-inflammatory drugs, orthotics), injection therapy can be considered. One promising option is dry-needling therapy, which, compared to ibuprofen, showed a better effect at six months follow up [40]. In clinical trials, various injectates are commonly compared to placebo, which is typically represented by saline solution (SS). A recent meta-analysis reported that SS might have some therapeutic effect itself. [PERSON] et al.