Find information on thousands of medical conditions and prescription drugs.

Imperforate anus

An imperforate anus or anal atresia is a birth defect in which the rectum is malformed. Its cause is unknown. more...

ICF syndrome
Ichthyosis vulgaris
Imperforate anus
Inborn error of metabolism
Incontinentia pigmenti
Infant respiratory...
Infantile spinal muscular...
Infective endocarditis
Inflammatory breast cancer
Inguinal hernia
Interstitial cystitis
Iodine deficiency
Irritable bowel syndrome


There are several forms of imperforate anus:

  • A low lesion, in which the colon remains close to the skin. In this case, there may be a stenosis (narrowing) of the anus, or the anus may be missing altogether, with the rectum ending in a blind pouch.
  • A high lesion, in which the colon is higher up in the pelvis and there is a fistula connecting the rectum and the bladder, urethra or the vagina.
  • A cloaca (named after the analogous orifice in amphibians), where the rectum, vagina and colon are joined into a single opening.

Imperforate anus usually presents along with other birth defects—spinal problems, anal atresia, heart problems, tracheoesophageal fistula, esophageal atresia, renal anomalies, and limb anomalies.


Imperforate anus usually requires immediate surgery to open a passage for faeces. Depending on the severity of the imperforate, it is either treated with a perineal anoplasty or colostomy.


With a high lesion, many children have problems controlling bowel function and most also become constipated. With a low lesion, children generally have good bowel control, but they may still become constipated.


Imperforate anus has an estimated incidence of 1 in 5,000 live births. It is more common in boys than in girls.


[List your site here Free!]

The Newborn Examination: Part II : Emergencies and Common Abnormalities Involving the Abdomen, Pelvis, Extremities, Genitalia, and Spine
From American Family Physician, 1/15/02 by Mamta Fuloria

Careful examination of the neonate at delivery can detect anomalies, birth injuries, and disorders that may compromise successful adaptation to extrauterine life. A newborn with one anatomic malformation should be evaluated for associated anomalies. If a newborn is found to have an abdominal wall defect, management includes the application of a warm, moist, and sterile dressing over the defect, decompression of the gastrointestinal tract, aggressive fluid resuscitation, antibiotic therapy, and prompt surgical consultation. Hydroceles are managed conservatively, but inguinal hernias require surgical repair. A newborn with developmental hip dysplasia should be evaluated by an orthopedist, and treatment may require use of a Pavlik harness. The presence of ambiguous genitalia is a medical emergency, and pituitary and adrenal integrity must be established. Early diagnosis of spinal lesions is imperative because surgical correction can prevent irreversible neurologic damage. (Am Fam Physician 2002;65:265-70. Copyright[C] 2002 American Academy of Family Physicians.)

The newborn examination facilitates the early identification of anomalies and health problems that require immediate intervention. A careful examination is also appropriate after a newborn has completed the transition from fetal to neonatal life. If one anatomic malformation is found, the newborn should be evaluated for associated anomalies. Part II of this two-part article reviews anomalies and disorders of the abdomen, pelvis, extremities, genitalia, and spine.


A scaphoid abdomen suggests the presence of a diaphragmatic hernia. In newborns with abdominal distension, it is important to determine whether the condition is secondary to excess air inside or outside the bowel, fluid in the peritoneal cavity, an enlarged viscus, or a tumor in the abdomen (Table 1).(1) A general approach to newborns who have an abdominal mass is provided in Figure 1,2 and approaches to newborns who have hepatomegaly with or without hyperbilirubinemia are presented in Figure 2.3

The umbilicus should be inspected for signs of bleeding, infection, granuloma, or abnormal communication with the intra-abdominal organs. A single umbilical artery is present in 0.2 to 1 percent of newborns(4) and may be associated with asymptomatic renal anomalies in 7 percent of these infants.(5)

Abdominal wall defects, including gastroschisis and omphalocele, are usually diagnosed prenatally. Features and management of these defects are summarized in Table 2.(6,7)

Anal patency is assessed by inspection or by probing with a small finger. Anterior displacement of the anus should be noted.

Pelvis and Extremities

Excessive traction of the spinal nerve roots C5-T3 results in brachial plexus injury (Table 3).(8, 9) Treatment, directed at preventing contractures, involves partial immobilization of the affected arm for one to two weeks, followed by active physiotherapy.(8)

Developmental hip dysplasia may be unilateral or bilateral and includes subluxated or dislocated hips and malformed acetabula. Soft tissue hip clicks may be confused with Ortolani and Barlow clunks. According to guidelines established by the American Academy of Pediatrics,(10) an examination that is positive for developmental hip dysplasia should lead to an orthopedic referral. If the results are inconclusive, the examination should be repeated in two weeks. If the follow-up examination is positive or inconclusive, orthopedic referral is indicated. Although triple diapering is common, no data on its effectiveness are available, and use of this measure may delay initiation of appropriate treatment (e.g., Pavlik harness).(10)

Metatarsus adductus is identified by the C curve of the lateral border of the foot(11) (Figure 3). This defect is commonly associated with a fixed intrauterine position and may be associated with developmental hip dysplasia. When the defect is marked and relatively rigid, it cannot be distinguished from talipes equinovarus, a condition characterized by adduction or inversion of the forefoot, inversion at the ankle, and equinus posturing (toes down, heel up, and malrotation of the calcaneus). Referral to an orthopedist is indicated.

Supernumerary digits occur more often in black infants. This anomaly tends to be hereditary and is frequently lateral to the fifth digit on the hands or feet. The extra digits may have a nail and are attached by a small pedicle, which differentiates the defect from true polydactyly. If bony tissue is not palpable, the application of a ligature around the pedicle allows the digit to fall off.

True polydactyly more commonly occurs on the feet and may be present with malformation syndromes. Syndactyly may involve soft tissue (simple synostosis) or fusion of bone (complex synostosis). Radiographs are necessary to determine the degree of fusion, and affected newborns should be referred to an orthopedic surgeon.


An abnormally small penis (normal values in term newborns: 3.5 [+ or -] 0.7 cm in length and 1.1 [+ or -] 0.2 cm in diameter) indicates reduced androgen effect or reduced growth hormone action during the second and third trimesters.

Hypospadias (proximally displaced urethral meatus) can vary from a mild glanular form to a more severe perineal form. Chordee (ventral curvature of the penis) without hypospadias occurs less frequently and may be due to skin tethering or a short urethra. Circumcision should be delayed in these newborns. Other anomalies associated with hypospadias include cryptorchidism and inguinal hernia, which are more likely to occur with proximal hypospadias.

The clinical features and management of inguinal hernia and hydrocele are described in Table 4.(12,13)

If a testis is not palpable, it is important to determine if it is retractile, ectopic, or cryptorchid. Cryptorchidism can be unilateral (66 percent of cases) or bilateral (10 percent of cases).14 Cryptorchidism occurs in 2.7 to 5.9 percent of term newborns, but its incidence is 10 times higher in premature infants.14 The scrotum of a neonate with undescended testis is often underdeveloped. The management of infants with this anomaly is described in Figure 4.15

In female newborns, the clitoris can have a relatively prominent appearance, especially if the labia are underdeveloped or the infant is premature. Clitoromegaly may be a sign of masculinization or a virilizing tumor. It may also be caused by increased maternal androgen production or maternal drug use.

Withdrawal of maternal hormones in normal newborns may cause a milky, sometimes bloody secretion from the vagina. The secretion may persist for several days but requires no treatment.

The presence of ambiguous genitalia is a medical emergency. Adrenal and pituitary integrity must be established.


Malformations affecting the spine are often diagnosed prenatally or are apparent in the delivery room. These defects require neurosurgical intervention. Occult lesions of the spine may be subtle and asymptomatic at birth. Early diagnosis is imperative because surgical correction can prevent irreversible neurologic damage. When neurologic signs or symptoms become apparent, most are irreversible (Table 5).(16)

Overlying cutaneous markers are found in 50 to 90 percent of newborns with spinal malformation and may be the only indication of a tethered cord.(17) Cutaneous manifestations associated with occult spinal lesions include hypertrichosis, lipomas and lipomyelomeningocele, large hemangiomas overlapping the midline, and large dimples above the gluteal crease and anal verge. Healthy newborns often have smaller dimples within the gluteal crease. Dimples should never be probed and should be evaluated with magnetic resonance imaging before neurosurgical intervention.(17)

The authors indicate that they do not have any conflicts of interest. Sources of funding: none reported.


(1.) Disease based on age: etiology of neonates (birth to 1 month). In: Kao SC, ed. Pediatric abdominal mass imaging: imaging a child with an abdominal mass. Retrieved October 2001, from: http://www. Imaging/KaosMenu.html.

(2.) Korones SB. Abdominal masses. In: Korones SB, Bada-Ellzey HS, eds. Neonatal decision making. St. Louis: Mosby-Year Book, 1993:90-1.

(3.) Wolf AD, Lavine JE. Hepatomegaly in neonates and children. Pediatr Rev 2000;21:303-10.

(4.) Allcott SW. Physical examination and care of the newborn. In: Fanaroff AA, Martin RJ, eds. Neonatal-perinatal medicine. 6th ed. St. Louis: Mosby-Year Book, 1997:403-24.

(5.) Bourke WG, Clarke TA, Mathews TG, O'Halpin D, Donoghue VB. Isolated single umbilical artery--the case for routine screening. Arch Dis Child 1993; 68(5 spec no):600-1.

(6.) Nakayama DK. Omphalocele. In: Nakayama DK, Bose CL, Chescheir NC, Valley RD, eds. Critical care of the surgical newborn. Armonk, N.Y.: Futura, 1997:277-88.

(7.) Nakayama DK. Gastroschisis. In: Nakayama DK, Bose CL, Chescheir NC, Valley RD, eds. Critical care of the surgical newborn. Armonk, N.Y.: Futura, 1997: 261-76.

(8.) Mangurten HH. Birth injuries. In: Fanaroff AA, Martin RJ, eds. Neonatal-perinatal medicine: diseases of the fetus and infant. 6th ed. St. Louis: Mosby-Year Book, 1997:425-54.

(9.) Fletcher MA. Physical diagnosis in neonatology. Philadelphia: Lippincott-Raven, 1998:441-504.

(10.) Clinical practice guideline: early detection of developmental dysplasia of the hip. Committee on Quality Improvement, Subcommittee on Developmental Dysplasia of the Hip. American Academy of Pediatrics. Pediatrics 2000;105(4 pt 1):896-905.

(11.) Ward WT, Davis HW, Hanley EN Jr. Orthopedics. In: Zitelli BJ, Davis HW, eds. Atlas of pediatric physical diagnosis. 2d ed. London: Mosby-Wolfe, 1992:21-43.

(12.) Nakayama DK. Inguinal hernia and hydrocele. In: Nakayama DK, Bose CL, Chescheir NC, Valley RD, eds. Critical care of the surgical newborn. Armonk, N.Y.: Futura, 1997:289-303.

(13.) Wiener ES, Touloukian RJ, Rodgers BM, Grosfeld JL, Smith EI, Ziegler MM, et al. Hernia survey of the Section on Surgery of the American Academy of Pediatrics. J Pediatr Surg 1996;31:1166-9.

(14.) Pillai SB, Besner GE. Pediatric testicular problems. Pediatr Clin North Am 1998;45:813-30.

(15.) Ferrer FA, McKenna PH. Current approaches to the undescended testicle. Contemp Pediatr 2000;17: 106-11.

(16.) Vannucci RC, Yager JY. Newborn neurologic assessment. In: Fanaroff AA, Martin RJ, eds. Neonatal-perinatal medicine: diseases of the fetus and infant. 6th ed. St. Louis: Mosby-Year Book, 1997:812-26.

(17.) Drolet BA. Cutaneous signs of neural tube dysraphism. Pediatr Clin North Am 2000;47:813-23.

This is part II of a two-part article on the newborn examination. Part I, "Emergencies and Common Abnormalities Involving the Skin, Head, Neck, Chest, and Respiratory and Cardiovascular Systems" appeared in the previous issue (Am Fam Physician 2002;65:000-00).

COPYRIGHT 2002 American Academy of Family Physicians
COPYRIGHT 2002 Gale Group

Return to Imperforate anus
Home Contact Resources Exchange Links ebay