OBJECTIVE: The authors report a case of a foreign body in the nasal septum resulting from external trauma, the treatment used, and a literature review. CASE REPORT: W. P. A., a 9-year-old boy who is a student and residing in Santa Ines-MA, visited the ENT Clinic of the Municipal Hospital Tomaz Martins presenting with signs of inflammation in the left nasal cavity for 3 months due to trauma of the nasal pyramid from a tree branch after diving into a river, which caused nasal obstruction and occasional nosebleeds. Computed tomography (CT) of the paranasal sinuses showed a foreign body in the nasal septum. After the trauma, he was first treated only with external sutures. Later, he underwent excision of the foreign body (a piece of wood) under general anesthesia, and suturing of the nasal septum. There was no septal perforation. CONCLUSION: Foreign bodies in the nasal cavities are common, especially in children under 4 years, corresponding to 11% of otorhinolaryngology emergencies. Complications occur in 22% of the cases, resulting from removal attempts by non-qualified people, inexperience in the management of foreign bodies, lack of infrastructure in emergency departments of public hospitals, and presence of the foreign body for a long duration. The most common complication is septal perforation. In the case presented, there was mismanagement in the initial care, with only external suturing of the nasal pyramid and monitoring of symptoms after the trauma. Regardless of age, but especially in children, a complete history and physical examination should be performed in patients with unilateral nasal obstruction, and this is very important for early diagnosis and treatment as well as for the prevention of complications.