Elbow - Posterior View
How to perform the examination
Patient Positioning
Primary position (recommended): the patient is seated with the upper limb flexed forward and the elbow flexed at 90–120 degrees to fully expose the posterior surface. The arm may rest on a table with the forearm hanging freely to allow complete relaxation of the posterior muscles and facilitate access to deep structures.
Alternative position: the patient may be placed in the prone position with the upper limb abducted and the elbow flexed. This position optimizes visualization of the olecranon and the cubital tunnel, allowing dynamic examination of the ulnar nerve during flexion-extension movements of the elbow.
Anatomy to Identify
- Olecranon (fractures, bursitis, calcifications, osteophytes)
- Olecranon fossa (loose bodies, osteophytes, bone alterations)
- Olecranon bursa (inflammation, effusion, thickening)
- Ulnar nerve (compression, subluxation, morphological alterations)
- Triceps tendon (tendinopathies, calcifications, tears)
- Posterior ligaments (thickening, calcifications)
Probe
High-frequency linear transducer (7–12 MHz) essential for imaging superficial posterior structures. Adequate penetration is required to visualize the deep bony structures of the olecranon fossa. Doppler is useful for assessing vascularization in bursitis and identifying active inflammatory processes. Compound imaging techniques improve the resolution of posterior bony interfaces.
Anatomical Zones
Olecranon
The olecranon represents the posterior prominence of the proximal ulna and serves as the insertion point for the triceps brachii tendon. In hemophilic arthropathy, this bony structure may show significant alterations due to both intra-articular processes and chronic mechanical stress on periarticular tissues.
Characteristic: Posterior bony prominence, triceps insertion, part of the ulno-trochlear joint
Findings:
- Olecranon osteophytes: Osteophytic formations at the tip of the olecranon due to chronic mechanical stress
- Articular erosions: Loss of bony substance of the olecranon’s articular surface that articulates with the olecranon fossa
- Triceps enthesopathy: Alterations at the triceps tendon insertion with possible calcifications
- Profile irregularity: Bony remodeling of the olecranon due to chronic inflammatory processes
Probe Positioning
Place the probe longitudinally on the posterior surface of the proximal ulna, centered over the olecranon. The marker should be oriented proximally. It is important to use a generous amount of ultrasound gel to optimize acoustic contact over the bony surface.
Olecranon fossa
The olecranon fossa is a bony depression located on the posterior surface of the distal humerus that accommodates the olecranon during full elbow extension. In hemophilic arthropathy, this structure may exhibit bony alterations and accumulation of articular debris that compromise full range of motion.
Characteristic: Triangular depression, receives the olecranon in extension, variable depth
Findings:
- Loose bodies: Osteochondral fragments within the fossa resulting from articular erosive processes
- Marginal osteophytes: Osteophytic formations along the edges of the fossa that limit full extension
- Fossa floor sclerosis: Increased echogenicity of the fossa floor due to chronic mechanical stress
- Morphological irregularities: Changes in the shape and size of the fossa due to bone remodeling
Probe Positioning
Perform longitudinal scans on the posterior surface of the distal humerus, visualizing the olecranon fossa and its relationship with the olecranon during extension movements. The probe should be positioned centrally over the elbow.
Clinical Cases by Severity grade
The clinical cases are organized according to the HEAD-US protocol (Head-to-Head Assessment of Ultrasound Score), which classifies the severity of hemophilic arthropathy into four levels. Click on each level to explore the available cases for that specific joint–projection combination.