ABSTRACT Despite lack of consensus in clinical criteria, frozen shoulder is a condition that is primarily diagnosed clinically. Thickening of the inferior glenohumeral capsule has been proposed as one of the many ultrasound features for the diagnosis of frozen shoulder. However, due to inconsistencies in methods used to assess and measure this structure, variable normal and abnormal values of thickness have been reported. This makes the clinical use of this ultrasound measurement questionable. A standardised technique is required to reduce operator variability and ensure the use of evidence‐based measurements in clinical practice. This paper describes a simple clinical assessment and an ultrasound technique that were used in recent research studies to assess the inferior glenohumeral capsule. The objective is to promote standardisation of ultrasound assessment to aid in the diagnosis of frozen shoulder.