Lung fissures !
The lung fissures are deep grooves that divide each lung into lobes: two on the right, one on the left; they let the lobes move separately.
Official name: Oblique fissure of right lung
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What it is
Deep grooves dividing the lungs into lobes: the oblique fissure in both lungs and the horizontal fissure in the right.
What it does
Let the lobes move separately; surgeons follow them to remove a lobe.
Key facts
- Where
- Oblique (both lungs): from about T2–T3 spinous process back to 6th costal cartilage front; horizontal (right): along 4th rib to midaxillary line
- Function
- Divide lungs into lobes (right 3, left 2); horizontal fissure often incomplete (varies)
Relations
- Course
- Oblique fissure: from about T3 behind, down and forward around the side of the chest to the 6th costal cartilage; horizontal fissure: from the oblique fissure in the midaxillary line forward along the 4th costal cartilage to the sternum
- Contents
- Two layers of visceral pleura covering the facing lobes, reaching almost to the hilum, with a film of pleural fluid between them
How to find it
With the arm raised fully overhead, the medial border of the scapula lies roughly along the oblique fissure. In front, the oblique fissure meets the 6th costal cartilage near the midclavicular line; the horizontal fissure runs along the 4th costal cartilage from the sternum to meet it in the midaxillary line.
On imaging
On a frontal film usually only the horizontal fissure is seen, as a fine line near the 4th rib; both oblique fissures appear on the lateral view. Fissures move toward a collapsed lobe and bulge away from an expanded one. CT shows how complete each fissure is before surgery.
Common problems
- Pneumonia (infection), asthma and COPD (narrowed airways).
- Lung cancer, often linked to smoking.
- Pulmonary embolism: a clot blocks an artery in the lung.
How it is diagnosed
Listening to the chest, chest X-ray, CT, breathing tests (spirometry), blood oxygen.
Treatment
- Depends on the cause: antibiotics, inhalers, oxygen; surgery removes a lobe or segment for some cancers.
Clinical notes
- In lobectomy the pulmonary artery branches are found in the depths of the oblique fissure; an incomplete fissure has to be divided to reach them
- Consolidation that stops sharply at a fissure is lobar; spread across a fissure suggests an incomplete fissure or another process
- One-way endobronchial valves for severe emphysema only shrink a lobe when its fissures are complete; CT assessment of fissure integrity is part of patient selection
Anatomical variants
- Incomplete or absent horizontal fissure is common, so the middle lobe may merge with the upper lobe
- Accessory fissures: the azygos fissure at the right apex, the inferior accessory fissure around the medial basal segment and a left horizontal fissure that separates the lingula
Development
The lobar buds of the embryonic lung mark out the future lobes; the fissures are the clefts left between them. Where neighbouring lobes stay joined by lung tissue, the fissure is incomplete.
Test yourself
Think of the answer, then tap the question to see it.
What is the surface course of the oblique fissure of the lung?
From about T3 behind, down and forward around the side of the chest to the 6th costal cartilage in front.
Where does the horizontal fissure of the right lung run?
Along the 4th costal cartilage from the sternum to meet the oblique fissure in the midaxillary line.
What is a vanishing tumour (pseudotumour) on a chest X-ray?
Fluid trapped inside a lung fissure that looks like a mass and clears when heart failure is treated.
Why does an incomplete lung fissure matter in lobectomy?
The pulmonary artery branches lie in the depths of the oblique fissure, so an incomplete fissure has to be divided to reach them.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- fissura obliqua pulmonis dextri; fissura horizontalis pulmonis dextri; fissura obliqua pulmonis sinistri TA2 3292
- Official Spanish (DeCS)
- Cisuras oblicua y horizontal DeCS D008168
- English (TA2)
- Oblique fissure of right lung
Sources: Terminologia Anatomica (TA2); DeCS; Anatomy, Thorax, Lungs; Anatomy of the Human Body (20th ed.): The Respiratory Apparatus (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain.
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Representative model, for educational purposes only.
