Distal part

Figure 1. Ventral view, transverse plane. b: distal tendon of m. biceps brachii, m: n. medianus, r: n. radialis, a: a. brachialis, c: humeral cartilage

Transverse ultrasound section through the anterior portion of the distal arm shows the distal tendon of m. biceps brachii (b) in cross-section as a superficially located hyperechoic oval structure. Immediately beneath it, the m. brachialis is visible, which has a more homogeneous and less echogenic appearance. Laterally the m. brachioradialis is located, medially the m. pronator teres. In this area, the n. medianus (m) located medially to the tendon and the n. radialis (r) running laterally along the m. brachioradialis are also well identifiable; the a. brachialis (a) is also visible in close proximity. This projection is important for anatomical orientation, nerve mapping and for safe planning of interventional procedures in the cubital fossa region.

Figure 12. Ventral view, longitudinal oblique plane. biceps: distal tendon of m. biceps brachii

The longitudinal oblique ultrasound section follows the natural course of the distal tendon of m. biceps brachii to its insertion on the tuberositas radii. The tendon appears as a hyperechoic fibrillar structure with parallel linear architecture that narrows distally. The probe orientation corresponds to the oblique course of the tendon. Deep to the tendon, the m. brachialis is visible, with the cortex of the radius forming the bottom of the image. This projection is essential for assessing the continuity of the distal biceps tendon and for demonstrating partial or complete ruptures.

Figure 3. Ventral view, transverse plane – pronator window. b: distal tendon of biceps brachii muscle, a: brachialis artery

Transverse ultrasound section in the pronator window area shows the distal tendon of biceps brachii muscle (b) in cross-section during its course to insertion on the tuberositas radii. The tendon appears as an oval hyperechoic fibrillar structure. Deep beneath the tendon, the radius is visible as a hyperechoic cortical line with dorsal acoustic shadowing. Superficially, the pronator teres muscle is located, which creates a suitable acoustic window for imaging this area. This projection is particularly useful for evaluating distal biceps tendon pathology, especially partial ruptures and enthesopathy.

Figure 4. Ventral view, longitudinal plane. biceps: distal tendon of m. biceps brachii

The longitudinal ultrasound section displays the distal tendon of m. biceps brachii in its oblique course from the distal myotendinous junction to its insertion on the tuberositas radii. The tendon appears as a linear hyperechoic fibrillary structure running beneath the m. pronator teres. The tuberositas radii is visible as a bright continuous cortical line where the tendon inserts. This projection allows for assessment of tendon continuity, dynamic examination and evaluation of tendinopathy or partial and complete ruptures.

Figure 5. Lateral roll position, longitudinal plane. biceps: distal tendon of m. biceps brachii

Longitudinal ultrasound section in lateral roll position shows the distal tendon of m. biceps brachii as a hyperechoic fibrillar structure running obliquely from the myotendinous junction to its insertion on the tuberositas radii. In this projection, the tendon is located beneath m. brachioradialis. This view is suitable for dynamic examination, assessment of distal tendon continuity and evaluation of the myotendinous junction area.

Figure 6. Cobra position, transverse plane. b: distal tendon of biceps brachii muscle

Transverse ultrasound section in cobra position (elbow flexion and forearm pronation with hand placed palm down at the shoulder) shows the distal tendon of biceps brachii muscle (b) during its curved course to insertion on the tuberositas radii. The tendon is visible between the radius and ulna, which allows clearer visualization of its distal portion and relationship to the insertion site. This projection is particularly useful for assessing continuity of the distal biceps tendon and in diagnosing partial or complete ruptures.

Figure 7. Cubitum, transverse plane. A: a. brachialis, M: n. medianus.

Transverse ultrasound section in the cubital fossa region. The image shows the a. brachialis (A) and n. medianus (M), which is positioned medially to the a. brachialis in this projection. The n. medianus further runs beneath the lacertus fibrosus and is located in the space between the m. brachialis and m. pronator teres. The image also captures the m. biceps brachii, m. brachialis, m. pronator teres and the contour of the humerus.