The log roll test involves gently rotating the entire lower limb inwards and outwards with the patient on his back, to check when muscle guarding occurs. The unaffected hip and the knees, ankles, feet and spine are found to be normal. Complications
In the past, there have been speculations about possible complications after transient synovitis. The current consensus however is that there is no proof of an increased risk of complications after transient synovitis.One such previously suspected complication was coxa magna, which is an overgrowth of the femoral head and broadening of the femoral neck, accompanied by changes in the acetabulum, which may lead to subluxation of the femur. There was also some controversy about whether continuous high intra-articular pressure in transient synovitis could cause avascular necrosis of the femoral head (Legg-Calvé-Perthes disease), but further studies did not confirm any link between the two conditions. Diagnosis
There are no set standards for the diagnosis of suspected transient synovitis, so the amount of investigations will depend on the need to exclude other, more serious diseases. It is of great importance to exclude the diagnosis of septic arthritis. This is because if septic arthritis is missed in children, grave complications can occur. The exclusion of septic arthritis is mainly built upon the physicians clinical expertise and is supplemented by basic laboratory test and relevant imaging modalities.
Aplasia cutis congenita  is a rare disorder characterized by congenital absence of skin. Frieden classified ACC in 1986 into 9 groups on the basis of location of the lesions and associated congenital anomalies. The scalp is the most commonly involved area with lesser involvement of trunk and extremities. Frieden classified ACC with fetus papyraceus as type 5. This type presents as truncal ACC with symmetrical absence of skin in stellate or butterfly pattern with or without involvement of proximal limbs. It is the most common congenital cicatricial alopecia, and is a congenital focal absence of epidermis with or without evidence of other layers of the skin.The exact etiology of ACC is still unclear but intrauterine infection by varicella or herpes virus, drugs such as methimazole, misoprostol, valproate, cocaine, marijuana etc., fetus papyraceus, feto-fetal transfusion, vascular coagulation defects, amniotic membrane adherence, abnormal elastic fiber biomechanical forces and trauma are implicated. It can be associated with Johanson–Blizzard syndrome, Adams–Oliver syndrome, trisomy 13, and Wolf–Hirschhorn syndrome. It can also seen with exposure to methimazole and carbimazole in utero. This dermatological manifestation has been linked to Peptidase D haploinsufficiency and a deletion in Chromosome 19. Signs and symptoms
Genetics
This condition has been linked to mutations in the ribosomal GTPase BMS1 gene. Diagnosis
Treatment
Skin grafting is a solution to fix aplasia cutis congenita. See also
List of cutaneous conditions

References
External links
Aplasia cutis congenita (ACC) on emedicine