Thorax Anatomy · Surgery

Bronchopulmonary Segments

Bronchopulmonary segments are the functional lung units — each with an independent bronchus, artery, and connective tissue boundary. They are the units of surgical resection.

✦ The Mnemonic

"Apes Produce Art; Lateral Medics; Super Medical Artists Love Posterity"

Right lung: RUL=APA; RML=LM; RLL=S+4basal(MALP)

RUL-A Right Upper: Apical Superior pole; most common TB reactivation site
RUL-P Right Upper: Posterior TB target when leaning forward
RUL-An Right Upper: Anterior Largest of the upper lobe segments
RML-L Right Middle: Lateral Lateral face of middle lobe
RML-M Right Middle: Medial Compressible by hilar nodes → middle lobe syndrome
RLL-S Right Lower: Superior Most superior; supine aspiration target
RLL-Bas Right Lower: 4 Basal Medial, Anterior, Lateral, Posterior basal
Left Left lung: 8–10 segs LUL: Apicoposterior, Anterior, Sup/Inf Lingular; LLL: Superior+3–4 basal

📚 Clinical Breakdown

The left upper lobe has the apicoposterior segment — a fusion of what would be apical and posterior segments in the right lung. Most common site of postprimary (reactivation) TB in both lungs.

Middle lobe syndrome: recurrent RML collapse from extrinsic compression of the medial segment bronchus by enlarged hilar lymph nodes. The RML has poor collateral ventilation — making it prone to collapse.

Each segment can be resected individually (segmentectomy). Intersegmental veins form the surgical plane; the bronchus and artery run centrally. VATS segmentectomy is standard for small peripheral lung cancers.

Right segments 10 total: 3+2+5
Left segments 8–10 (fused variants)
TB reactivation Apical/posterior segments of upper lobes
Middle lobe syndrome Hilar node compression of medial segment bronchus

⭐ Clinical Pearl

Aspiration by position: Upright → right lower lobe basal segments. Supine → right upper lobe posterior segment or left lower lobe superior segment. Knowing the patient's position guides bronchoscopy and chest physiotherapy.

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