Sacroiliac Ligament

This is the most severe type and results in total sacroiliac joint disruption. Features of the Type 1 and 2 pattern may be present. There is widening of the sacroiliac joint and there is diastasis both posteriorly as well as anteriorly due to the posterior sacroiliac ligament rupture. On clinical examination, the hemi-pelvis is unstable in all directions of force and typically requires operative stabilisation. It is possible for the sacroiliac joint to remain intact but there is fracture of the sacroiliac bone. Complications include bladder rupture, and vascular injury (Figs. 12.8,12.9). 

The lateral force has a more anterior orientation which will cause oblique pubic rami fractures, disruption of the posterior sacroiliac ligaments and fractures of the ileum (Figs. 12.12,12.13). 

Anteriorly the sacroiliac, sacro-spinous and sym-physeal ligaments are transversely orientated to support the pelvic floor and resist external rotation. There are superior symphyseal ligaments which support the pubic symphysis. 

There are a number of anatomical differences between children and adults. The paediatric skeleton is more elastic than in adults, particularly around the sacroiliac joints and pubic symphysis which allows greater absorption of energy before the joint and ligaments become disrupted. A high energy impact may cause deformity of the bones rather than the fractures and joint disruption that occurs in adulthood. 

There maybe fractures of the pubic rami as in Type I. There is further diastasis of the anterior aspect of the sacroiliac joints and these are classically referred to as the open book or spun pelvis type injuries. Sacroiliac diastasis is best assessed by CT. There may be some partial instability on AP compression. In children, there may be fracturing of the adjacent bone rather than ligament rupture. This is a reflection of the relative strength of the ligaments compared with bone in the growing skeleton (Figs. 12.6,12.7). 

This is usually the result of forces transmitted through the axial skeleton from an impact into the head and shoulders through to the lower limbs. There may be symphyseal diastasis, anterior arch fractures or posterior disruption of the sacroiliac joints with cephalic displacement. Vertical injuries are often severe with disruption of all the ligaments plus associated pelvic instability. Radiographs demonstrate ipsilateral or contralateral pubic rami fractures, with disruption of the sacroiliac joint. The major differentiating feature from compression injuries is the cephalic displacement of the pelvis on the side of the impact (Fig. 12.14). 

These relate to fractures or disruption of the pubic symphysis and are associated with anterior sacroiliac joint disruption. The posterior iliac ligament complex is unaffected and pelvic stability is maintained. In the older child, widening of the pubic symphysis beyond 2.5 cm is associated with disrup-... 

Technic In all spinal technic It Is my custom to have the patient exercise his own natural forces rather than the application of mine. There are no thrusts, no jerks nor the application of another or distal end of the anatomy as a lever. The principle Is that used and taught by Dr. Still, namely, exaggeration of the lesion to the degree of release and then allowing the ligaments to draw the articulations back Into normal relationship. This same method Is applied In sacroiliac technic. 

The iliacus muscle originates from the superior two thirds of the concavity of the iliac fossa, from the inner lip of the iliac crest, from the ventral sacroiliac and iliolumbar ligaments, and from the upper, lateral surface of the sacrum. In front, it reaches as far as the anterosuperior and anteroinferior iliac spines, and receives some fibers from the upper part of the capsule of the hip joint. It inserts into the lateral side of the tendon of the psoas major, which inserts into the lesser trochanter of the femur. 

The multiple forms and contours found at any sacroiliac articulation account for the diversity of motions of this joint. Its ligaments hold the joint together. There are no direct muscular attachments from the sacrum to the ilium. 

The patient s position and the stress involved, when added to the laxity of the ligaments at delivery, can create sacroiliac dysfunctions. These dysfunctions worsen and are locked into malposition as the ligaments regain their normal tensile strength postpostum. Dysfunction can be prevented after deliver] by holding the hip in internal rotation as each leg is removed from the lithotomy position and extended onto the table. 

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