Page 2 - MSK assignment

2 F. Elahi

Introduction to Elbow Ultrasound
Ultrasound utilizes high-frequency waves to create diagnostic images. The demand for
musculoskeletal ultrasounds has increased exponentially. Elbow ultrasounds allow for the
sonographer to view the anatomy, as well as perform dynamic assessments to assess the
tendons, joints, and ligaments (Berkoff, 2018). The superficial position of the elbow allows for
easy ultrasound assessment. The anatomy, pathologies, and protocol of the elbow will be
further discussed.

Chapter 1: Anatomy
Bones and Joints
Within the elbow joint there are three main
bones that include the proximal radius and
ulna and the distal portion of the humerus.
The small hollow area that gives room for
the ulna during flexion is the coronoid fossa
(O’Neill., 2008). Olecranon fossa is a larger
hollow area in which the olecranon process
goes during elbow extension. Capitellum
articulates with the head of the radius, with
the rounded shape of the lateral humeral
condyle (O’Neill., 2008). The semi circle shaped
capitellum articulates with the convex shape radial head. In complete flexion of the elbow, the
radial fossa accommodates the radial head. Figure 1 highlights some of the important bony
landmarks used in ultrasound.

Joints
There are three articulations allowing the elbow to be classified as a trochoginglymus joint (Alcid
et. al, 2004). The first one is the radiocapitellar joint, which has a pivotal articulation between the
radial head and the humeral capitellum. The second articulation is the radio-ulnar which is
between the radius and ulna. This articulation is with the
radial head and the sigmoid notch of the ulna. Both
radiocapitellar and radio-ulnar joints enable pronation and
supination. Finally, the trochlea-ulna articulation which is
where the humeral trochlea and ulna articulates in a hinge
motion (O’Neill, 2008). Figure 1 highlights the three joints
with their bones. These articulations are the reason why
the elbow joint is able to perform movements such as
flexion, extension, and rotations. The elbow’s range of
motion is from 0 degrees to 150 degrees in flexion. In
pronation the elbow is able to go to 75 degrees. In
supination it is able to go to 85 degrees. A big reason
for the wide range of motion is due to the 2 mm