The clinical breast examination (CBE) is a systematic physical assessment of the breast performed by a trained clinician to detect breast abnormalities, complementing mammographic screening. Breast tissue is composed of 15-20 lobes of glandular tissue arranged radially around the nipple, with each lobe containing lobules (milk-producing units) and lactiferous ducts that converge at the nipple. The upper outer quadrant and axillary tail of Spence contain the greatest concentration of glandular tissue and are the most common site for breast malignancies (~50% of cancers). The CBE involves two phases: visual inspection and palpation. Visual inspection is performed with the patient in upright position with arms at sides, arms raised overhead, and hands pressed on hips (pectoralis contraction) — the clinician looks for asymmetry, skin retraction, dimpling, peau d'orange (dermal lymphatic obstruction), erythema, nipple inversion or deviation, and spontaneous nipple discharge. Palpation is performed with the patient supine, ipsilateral arm raised behind the head to flatten the breast against the chest wall. The clinician uses the pads of the three middle fingers in a vertical strip pattern (shown to be more thorough...