Apophyseal Injury

Type II Apophyseal injury including a portion of overlying cartilage of the annulus fibrosus. 

Type 2 and 3 apophyseal injuries as described by Takata et al. (1988) may be associated with avulsion of the posterior longitudinal ligament. 

Lazar RD, Waters PM, Jaramillo D (1998) The use of ultrasonography in the diagnosis of occult fracture of the radial neck. J Bone Joint Surg 80 1361-1364 Lazovic D, Wegner U, Peters G et al (1996) Ultrasound for diagnosis of apophyseal injuries. Knee Surg Sports Traumatol Arthrosc 3 234-237... 

The force generated by muscle contraction is transmitted to bone by tendons, with the muscle-tendon-bone combination forming a functional unit which can be referred to as the musculoskeletal chain. There are important differences between the child, the young adult and the mature adult which account for the different injury patterns that are encountered (Harris 1981). In children, the weak links in the musculoskeletal chain are at the bone-tendon interface and at the growth plate, which accounts for the high occurrence of apophyseal avulsion injuries... 

Various secondary ossification centres develop in the pelvis at different ages. Accessory ossification centres may develop at the tip of the ischial spine and the rim of the acetabulum between 14 and 18 years of age (Fig. 7.26). The normal apophyseal centres on the inferior border of the ischium (Fig. 7.27) should not be mistaken for avulsion injuries, although they may be separated by violent hamstring contraction. The fusing ischiopubic synchondroses maybe mistaken for healing fractures, particularly... 

Anterior wedging of the upper cervical bodies particularly C3 (Fig. 7.62) is a normal developmental variant and should not be confused with a compression injury. It may be the result of relative hypermobility of the spine during childhood and resolves with increasing maturity (Swischuk et al. 1993). Secondary ossification centres ( ring epiphyses or apophyses) appear at the superior and inferior aspects of all vertebral bodies and do not fuse with the vertebral body until early adulthood (Figs. 7.63, 7.64). These should not be mistaken for fractures, although they can be avulsed as a result of trauma (JOHNSSON et al. 1991). 

At the site of many of the muscle attachments are a number of apophyses which are separated from the bone by growth cartilage. An apophysis is essentially a centre of ossification which does not lead to longitudinal growth. In children, avulsion injuries are more common at these sites, which is a reflection of the presence of the relatively weaker cartilage in these regions. 

Apophyseal avulsion injuries are common around the hip and pelvis, with about 90% occurring in boys whilst playing sport. The apophysis is avulsed by strong muscle contraction. Once avulsed, the... 

The lesion occurs when the tibial tubercle is in the apophyseal stage and the secondary ossification centre has appeared. The tibial tubercle apophysis appears between 7-9 years of age, and repeated traction injuries cause microfractures in the apophysis (Lazerte 1958). 

Physeal fractures are Salter-Harris type I and II. They are avulsion type injuries. Younger children tend to sustain type I apophyseal avulsions where the fracture line may extend to the coronoid process almost like a sleeve fracture and not therefore break the articular surface (Fig. 18.19). Older children are more likely to sustain Salter-Harris type II equivalent injuries. A small metaphyseal flake of bone may be apparent on radiographs. 

In more subtle cases of apophyseal irritation with little displacement, US may demonstrate a double cortical sign as a result of subtle elevation of the most superficial layers of the bony cortex, a different appearance from that observed in Osgood-Schlatter disease (Fig. 19.28). In other instances, the injury causes stripping of the most external layers of cartilage or fibrocartilage that are superficial to... 

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