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Evaluation of entheses should include the bone surface as well as the tendon or ligament at and adjacent to its attachment. A straight, on incident image of the soft tissue structure in question as it attaches to the bone surface optimizes identification of disruption in the bone surface, particularly if the avulsion fragment is small or the avulsion fracture is partial.

The suspensory apparatus entheses are frequently affected by fractures that include a mixture of avulsion and fatigue injuries. Unicortical proximal palmar metacarpal (fatigue) fractures, or proximal third metacarpal or metatarsal avulsion fractures, usually involve only part of the enthesis. Ultrasonographic features of the former include accumulation of hypoechoic tissue between the fracture and the dorsal aspect of the suspensory ligament with or without subtle changes to the osseous reflection of the third metacarpal bone. Avulsions of the suspensory ligament origin are demonstrated well ultrasonographically. This can also assess the amount of enthesis affected, degree of fragment displacement and quantify accompanying desmitis.

The suspensory ligament branches are also affected by acute injuries including avulsion fractures or become compromised by fractures of the proximal sesamoid bones. Ultrasound can assess the amount of enthesis involved, the degree of associated desmopathy and consequent athletic potential (Figure 5.6). Utilization of colour flow doppler is useful to assess potential vascular compromise prior to considering arthrodesis in biaxial mid‐body fractures of the proximal sesamoid bones.

Similar principles apply to fractures and fragmentation of the bases of the proximal sesamoid bones and associated distal sesamoidean ligament entheses which can also be impacted by fragmentation associated with chronic enthesopathy (Chapter 20).