perature measurement [3]. Patients with imper­forate anus without a stula (~5% of malformations), have a blind end of rectum, which is generally located within 2 cm of the perineum. There appears to be an association between this particular malformation (5–10% of anorectal malformations overall) and trisomy 21—although 2% of patients with anorectal mal­formations have trisomy 21, 95% of them have an imperforate anus without a stula [7, 8]. Finally, perineal stulas are usually thought to be an anteriorly-displaced anus. On examina­tion, there is a small perineal opening that is ste­notic and appears to be anterior to the center of the sphincter. Because these openings are obstructively small and are not centered within the sphincteric complex, these are best thought of as a stula to the perineum rather than a true displacement of the anus itself.

Anorectal malformations are part of the range of anomalies associated with the VACTERL sequence (vertebral, anorectal, cardiac, tracheo­esophageal, renal, limb anomalies). The evalua­tion for these involves sacral x-rays to evaluate for sacral and spinal defects such as spina bida, and an eventual sacral ultrasound or MRI (if older than 3months of age) to rule out the pres­ence of a tethered cord, which can be found in 24% of these patients (11% of those with rec­tovestibular stula and 29% of those with clo­aca), depending on the severity of their defect [12]. Smaller ratios of the coccygeal-sacroiliac distance to the sacroiliac-iliac crest distance are predictive of the severity of the malformation and presence of tethered cord [3, 12]. Sacral ultra­sound has been reported to be 80% sensitive and 89% specic for the presence of tethered cord, and can be conrmed with MRI [13]. Cardiac defects should be evaluated with an echocardio­gram. Tracheoesophageal stula is generally clinically apparent at birth if esophageal atresia is present, but may be challenging to identify until later in life if it involves an H-type defect with an intact esophagus. Renal or genitourinary malfor­mations are comprised primarily of renal agene­sis and vesicoureteral reux that do not generally necessitate immediate intervention at birth. Limb anomalies can be evaluated and treated on an elective basis by a pediatric orthopedist.