Anatomy and Physiology
Delivery: The clinician should be familiar with the events of the antecedent delivery.
General Appearance: A newborn exam should always start with a rapid visual assessment. The purpose of this is to observe the generalized state of the newborn regarding their level of activity and alertness, taking notice of poor tone, color, or respiratory status. Signs of respiratory distress include tachypnea, nasal flaring, grunting, retractions, and cyanosis. Any abnormalities in the above areas may indicate a need for urgent intervention.
If no significant abnormalities are noted, one can move on to the remainder of the physical exam. Most often, the infant is sleeping before starting the exam. In this case, it is best to perform the auscultatory portions of the exam first while taking care to minimize any manipulation of the infant to ensure that the infant remains quiet. After auscultation is complete, one should adopt a head-to-toe approach to ensure consistency and thoroughness. If the infant is crying initially and auscultation cannot be completed first, the head-to-toe approach can be used before auscultation.
Auscultation of the anterior fontanelle can be done to assess for a cranial bruit. If present, this could be due to referred sounds from the heart or due to an arteriovenous malformation in the brain. The next step would be cardiac auscultation, making a note of the rate, rhythm, and quality of sounds. Heart sounds should have a single first heart sound and a second split heart sound. Neonatal murmurs on the first day of life are common and are usually transient. All infants with a murmur should have blood pressure taken in the upper and lower extremities to assess for coarctation of the aorta. If there is an upper and lower pressure gradient difference greater than 20 mm Hg or abnormal femoral pulses, transthoracic echocardiography should be done to evaluate for coarctation of the aorta.[1] Congenital heart disease is screened with pulse oximetry prior to discharge.[2]
During respiratory auscultation, breath sounds should be clear and equal bilaterally. Diminished breath sounds on one side can signify pneumothorax, pleural effusion, or diaphragmatic hernia and should prompt for imaging with chest ultrasound.[3] Transient tachypnea of the newborn (TTN) occurs when fluid is retained in the lungs resulting in tachypnea and increased work of breathing. TTN may require supplemental oxygen therapy; however, it usually resolves within 48 hours.[4]
The last portion of auscultation involves the abdomen. Bowel sounds should be heard every 10 to 15 seconds. The size of the liver can also be estimated using auscultation by placing the stethoscope on the lower right ribs and softly scratching the abdomen from the lower to upper right quadrants. The lower edge of the liver can be determined when the scratching is easily audible through the stethoscope.
Once auscultation is complete, the head-to-toe portion of the exam can begin.
Skin: There are multiple skin findings in newborns that are common and typically benign. It is essential to examine the entire body surface and be able to distinguish abnormal lesions that require further workup or referral. Some common benign papular lesions that are normal include erythema toxicum, pustular melanosis, and milia. Erythema toxcium are flesh-colored papules on an erythematous base that resolve within the first week of life. Pustular melanosis consists of pustules without erythema that can spontaneously rupture and leave behind hyperpigmented macules that can last for months. Both erythema toxicum and pustular melanosis are diffusely distributed and found on the face and trunk, whereas milia are most commonly found on the nose.[5] Milia are white papules that can resolve within the first few weeks of life. Some common macular lesions include nevus simplex, nevus flammeus or port-wine stain, slate grey nevus (also known as "Mongolian spots"), and cafe au lait spots. Port-wine stains or nevus flammeus can be differentiated from nevus simplex in that the former are more sharply demarcated, usually unilateral and often do not fully blanch. If they occur on the eyelid, forehead, or temple, this warrants an ophthalmology referral and can be associated with Sturge-Weber syndrome. In Klippel-Trenaunay-Weber syndrome, port wine stains commonly occur on the lower limbs. Prominent nevus simplex lesions on the glabella are associated with Beckwith-Wiedemann syndrome, fetal alcohol syndrome and Nova syndrome.
Head: The exam of the head starts by looking at the appearance of the face for dysmorphic features that may suggest any underlying pathology. Ear size, shape, symmetry, and position are important to assess and may suggest a genetic disorder. For example, low-set ears can be a sign of Turner syndrome or trisomy 18 or 21. Asymmetric ear size consistent with hemihypertrophy can be seen in Beckwith-Wiedemann syndrome.[6] Some of the more common findings in newborns are preauricular skin tags and ear pits, which can indicate isolated hearing loss.[7][8] However, if they are seen in conjunction with other morphologic malformations, they can be a part of congenital anomaly syndromes.
As we start with the head and work down, the scalp should be examined for any trauma during delivery. The skull may be molded from a vaginal delivery; however, it should resolve within several days of birth. It is important to palpate the sutures of the head for craniosynostosis, or early fusion of sutures, which would require surgical intervention to allow for brain growth and development. Anterior and posterior fontanelles should also be open, soft, and flat. The visual exam of the scalp should also include evaluation for hematomas and subcutaneous swelling that can be due to caput succedaneum, cephalohematoma, or even a subgaleal hemorrhage. Caput succedaneum is subcutaneous swelling that occurs due to increased uterine pressure on the head during labor. This pitting edema can cross suture lines and typically resolves spontaneously within a week of birth. On the other hand, a cephalohematoma is subperiosteal bleeding that results from the injury of blood vessels. It is limited by suture lines and usually resolves after several weeks. Cephalohematoma increases the risk of jaundice and sepsis.[9][10] Therefore, identification and monitoring are important. It is most commonly seen in deliveries with forceps or vacuum extractor. Deliveries with vacuum extraction also have the potential to cause subgaleal hemorrhage, which is blood between the epicranial aponeurosis and periosteum. A subgaleal hemorrhage crosses suture lines, but it differs clinically from the others in that it is typically more diffuse, can enlarge, and may shift with movement. This requires close monitoring and following serial hematocrit and occipital-frontal circumference as it can quickly lead to hemorrhagic shock.[11]
Eyes: A thorough eye exam is next on the newborn screen. Edema of eyelids can be a normal finding and typically resolves after a couple of days. It is imperative to examine the eyes for a pupillary response to light. A red reflex can be elicited with an ophthalmoscope and is normal with light projecting onto eyes symmetrically without opacities or spots. Leukocoria, a white reflex, is an abnormal finding and may indicate the presence of cataracts, a tumor, or retinopathy of prematurity. Cataracts can also cause reduced or absent red reflex. A cornea size larger than 1 cm in diameter can be indicative of congenital glaucoma. Conjunctival hemorrhages are common and resolve with time.
Ears: Evaluation of patent ear canals and visualization of tympanic membranes can be done with an otoscope. Additional evaluation related to the ear exam was covered under the Head section above.
Nose: While still focusing on the head, nasal passages should be examined for patency or narrowing. If choanal atresia is suspected, it can be further assessed by passing a small catheter into the nasal passages.
Mouth: The mouth should be examined for neonatal teeth and clefts, which may require intervention. Neonatal teeth do not require removal unless they are loose with risk for aspiration. Clefts can be found in the submucosal, soft, and hard palate.[12] One should be able to visualize and palpate an intact palate. The gingiva should be examined for cysts. The tongue should extend beyond the lower gum. Tongue movement can be restricted with an anterior lingual frenulum and may require frenotomy if feeding is impaired.
Neck: The neck should be examined for symmetry and masses. Abnormalities can include congenital torticollis and masses. Congenital torticollis, contracted sternocleidomastoid muscle producing a head tilt, can be caused by trauma during delivery. Other abnormalities of the neck include goiters, thyroglossal duct cysts, branchial clefts, pits, masses, and webbing of the neck. The latter can indicate Turner syndrome.
Clavicles: Clavicles should be palpated for asymmetry, swelling, or crepitus as fractures can result from trauma during delivery.
Chest: As we transition from the neck, the next focus is the chest. The most important parts of the chest exam involve auscultation, which we have already reviewed. Another important part of the chest exam is evaluating chest wall shape, making a note of pectus excavatum or carinatum, or asymmetry. Asymmetry can be due to the absence of a pectoralis muscle.
Abdomen: The examination of the abdomen includes looking for distension and hernias. Auscultation of the abdomen should be done prior to palpation and is described above. The abdomen should be palpated for organomegaly or masses. The abdomen should be soft, and the liver is usually felt 1 to 2 cm below the right lower costal margin. Any abdominal masses that are palpated should be initially evaluated with ultrasound. The umbilical cord is clamped during delivery. An umbilical hernia is common as the fascia below the umbilicus is weak. The umbilical cord stump may take up to four weeks to separate. If there is a delay in separation, further evaluation is warranted. Omphalitis is an infection of the umbilical cord after birth that can present with surrounding erythema, induration, and tenderness. It is important to obtain blood and cerebrospinal fluid (CSF) cultures and start empiric antibiotics if the neonate presents with fever in the setting of omphalitis.
Hips: Assessment of the hips for congenital hip dysplasia should include examining gluteal/thigh fold symmetry, leg length, and performing Barlow and Ortolani maneuvers. A "clunk" (dislocation or relocation) or asymmetry in abduction are considered positive and require follow-up hip exams with outpatient ultrasound or referral to orthopedics.
Genitalia: Term females typically have a prominent labia majora. Labia minora can be spread apart to evaluate hymen patency. A hymenal tag, white discharge, or a small amount of blood is normal. In utero, maternal estrogen crosses the placenta. After delivery, a withdrawal from maternal hormones can cause vaginal bleeding.
In term males, both testes can be palpated in the scrotal sac. Testes may be palpated in the inguinal canal and do not require intervention if they can be pushed into the scrotal sac. Ambiguous genitalia in a female can be seen with clitoromegaly or fusion of labia, and in males, it can be seen with bilaterally undescended testes, small penis (less than 2.5 cm), or a bifid scrotum and should prompt endocrinology, genetics, and urology consult.[13]
The penis should be examined for hypospadias, urethral opening on the ventral side, which warrants deferral of circumcision and surgical correction by a urologist.[14] The scrotum should also be inspected for an inguinal hernia, hydrocele, or solid mass. Inguinal hernias can extend into the scrotum and can often be reduced with pressure. Inguinal hernias are often repaired surgically due to the increased risk of incarceration and strangulation. A hydrocele is fluid around a testicle and does not require intervention. Both hernias and hydroceles will transilluminate well, which can be done by covering the otoscope light with a glove and placing the light against the scrotum.
Extremities: The extremities should be assessed for symmetry, length, and presence of supernumerary digits, congenital bands, syndactyly, or clubfoot, which may require surgical intervention. Femoral and brachial pulses should be palpated and equal bilaterally.
Back: Examination of the spine should include palpation of the entire spine, looking for symmetry, sacral hair tufts, sinus tracts, or masses, which may suggest spinal abnormalities.
Sacral Dimple: On the lower posterior trunk, a single midline dimple can be found in the skin overlying the coccyx. It should have a visible intact base and a dimple that is less than 0.5 cm in diameter. A sacral dimple is a common finding, typically a two to five percent prevalence rate. The dimple is typically benign and without clinical significance. If a dimple is present, no additional investigation is needed.[15][16] However, if the sacral dimple is deep and large, greater than 0.5 cm, and falls within the superior portion or just above the gluteal cleft, and/or is associated with other cutaneous markers for neural tube defects, the infant is more likely to have an underlying neural tube defect.[17][18] If the infant has the anatomy mentioned above and characteristics, an ultrasound of the spinal canal or magnetic resonance imaging (MRI) of the lumbar spine should be completed to rule out neural tube defects.[19][20]
Anus: The anus should be examined for patency. The anus cannot be assumed patent until after the newborn infant passes meconium, which usually occurs within the first 48 hours of life. Meconium coming from a urethral opening is a sign of anorectal malformation—an imperforate rectum warrants immediate surgical intervention. An echocardiogram would also need to be obtained to evaluate for possible syndromes such as VACTERL (vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula, renal anomalies, and limb abnormalities).[21]
Neurologic Examination: A neurological exam should include a more thorough assessment of tone & level of alertness than the initial inspection. Tone can be assessed by holding up the newborn under the bilateral axilla. Additional portions of the exam include the evaluation of appropriate cranial nerves and reflexes such as sucking reflex, grasp reflex, rooting reflex, Moro reflex, and Babinski reflex. Hypotonia or abnormal primitive reflex should warrant further investigation and possible neurological consult.[22]
Neonatal Evaluation