midclavicular

Midclavicular is an anatomical term referring to the middle portion of the clavicle or to the vertical lines that pass through the midpoint of the clavicle, known as the midclavicular lines. The adjective midclavicular describes structures or locations related to this region or line.

In anatomy and clinical practice, the midclavicular line is a common reference landmark on the chest. It runs vertically from the midpoint of the clavicle and is used to describe locations of organs, sounds, and imaging findings. The left midclavicular line, in particular, serves as a standard reference in assessing the heart and lungs. For example, the apical impulse (the heart’s apex beat) is typically palpable at the left fifth intercostal space along the left midclavicular line in healthy adults. The same line helps guide examination and imaging of thoracic structures and is used in educational descriptions of chest anatomy.

In electrocardiography and radiology, the midclavicular line helps define lead placement and anatomical regions. The left fifth intercostal space at the left midclavicular line is a classic location associated with certain ECG lead placements (for instance, the V4 lead is placed at this position). Chest radiographs frequently reference the left midclavicular line when describing heart size, contour, and mediastinal position relative to thoracic landmarks.

Related anatomical lines include the anterior, midaxillary, and posterior axillary lines, which, alongside the midclavicular line, help delineate regions of the chest for examination and imaging. The term reflects its Latin roots: medius meaning middle and clavicula meaning collarbone.