Harrison’s sulcus is a horizontal groove that appears along the lower border of the chest. It is not a disease, but a clinical sign that can point to an underlying medical condition. This indentation develops at the costal margin, where the lower ribs meet the cartilage connecting them to the sternum. The appearance of this groove is often related to conditions from infancy or early childhood. While it can be concerning to notice a change in a child’s chest, the sulcus itself is harmless.
Physical Characteristics of Harrison’s Sulcus
This horizontal groove is located along the line of attachment for the diaphragm, a major muscle involved in breathing. The depth of the groove can differ among individuals but is often most pronounced over the sixth rib. It can appear on one or both sides of the chest.
The indentation may become more noticeable during inhalation because the diaphragm contracts and pulls downward on the ribcage. In some cases, the lower edge of the ribs may appear to flare outwards below the groove. The sulcus starts near the breastbone and becomes less deep as it extends towards the sides of the body.
Underlying Medical Causes
The formation of Harrison’s sulcus is linked to the persistent pulling action of the diaphragm on the ribcage during a child’s formative years. This action can lead to an indentation if the bones are softened or if respiratory effort is significantly increased for a prolonged period. The causes can be separated into nutritional deficiencies and chronic respiratory problems.
A primary cause is rickets, a condition resulting from a severe deficiency in vitamin D. Vitamin D is necessary for the body to absorb calcium and build strong bones. Without it, the ribs can become soft and pliable, making them susceptible to being misshapen by the diaphragm’s movement.
Chronic respiratory conditions that lead to labored breathing are another major cause. Severe and poorly controlled asthma, for example, forces a child to use their diaphragm more forcefully to breathe. This increased, repetitive strain can pull on the lower ribs, creating the groove over time, especially in young children whose skeletons are still developing. Other conditions like recurrent pneumonia can have a similar effect.
Diagnosis and When to Consult a Doctor
A diagnosis of Harrison’s sulcus is made during a physical examination by a healthcare provider. The doctor will observe the chest to identify the characteristic horizontal groove. The focus shifts to determining the underlying reason for its development.
The diagnostic process will involve a detailed medical history. A doctor may ask questions about the child’s breathing patterns, any history of respiratory illnesses like asthma, and their diet to assess for potential nutritional deficiencies. Based on this initial evaluation, further tests might be recommended to pinpoint the cause.
To check for bone-softening conditions like rickets, blood tests may be ordered to measure levels of vitamin D and calcium. If a respiratory issue is suspected, a chest X-ray might be used to get a clearer view of the lungs and rib structure. The appearance of a Harrison’s sulcus should prompt a visit to a doctor for a thorough evaluation.
Management and Prognosis
Treatment for Harrison’s sulcus is directed at the underlying medical condition that caused it. If rickets is diagnosed, management involves supplementing with vitamin D and calcium to restore normal bone mineralization and strength. For respiratory causes, the focus is on managing the specific condition, such as using medications and action plans to control severe asthma.
The prognosis for the sulcus is positive. In many children, as the underlying condition is effectively treated and as they grow, the indentation can become less noticeable or may resolve completely. The skeletal structure remodels and strengthens throughout childhood, which can diminish the appearance of the groove. The sulcus itself does not cause any functional problems with breathing or lung capacity.