Breast region (male) !
The male breast region is the area around the nipple on the chest; in men the nipple marks the 4th rib space, a landmark for the heart and lungs.
Official name: Mammary region
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What it is
The chest surface over the pectoralis major, with the nipple at about the 4th rib space in men (male base model).
What it does
A surface landmark for the heart and lungs. A female breast variant is planned.
Key facts
- Where
- Male nipple at about 4th intercostal space, midclavicular line (T4 dermatome); overlies pectoralis major
- Function
- Surface landmark; rudimentary ducts without developed gland
- Drains
- Lymph mainly to axillary nodes; medial part to parasternal nodes
Relations
- Deep
- Pectoralis major and its fascia, then pectoralis minor and the 3rd to 5th ribs with their intercostal spaces
- Lateral
- Anterior axillary fold, formed by the lower border of the pectoralis major, and the axilla with its lymph nodes
- Medial
- Sternum and the parasternal lymph nodes along the internal thoracic artery
- Below
- The 5th intercostal space, where the apex beat is usually felt a little medial to the midclavicular line
How to find it
The nipple lies about on the midclavicular line. Counting from the sternal angle (2nd rib) confirms the space; the apex beat is then looked for one space lower and slightly medial.
Examination
- Pinch test: tissue is gathered from both sides toward the nipple; a firm disc beneath the areola indicates true gynecomastia, while soft fat without a disc suggests pseudogynecomastia
- Examination of a breast lump in a man includes the axillary and supraclavicular nodes and, when gynecomastia is found, the testes, liver and thyroid as possible hormonal sources
On imaging
Ultrasound and mammography separate gynecomastia (gland centred behind the nipple) from fat and from cancer, which is usually an irregular mass off-centre to the nipple.
Common problems
- Gynecomastia (enlarged breast tissue in males) from hormones or medicines.
- Breast cancer also occurs in men, although rarely.
Clinical notes
- Gynecomastia is physiological in newborns, at puberty and in older age; other causes are hormonal imbalance, liver disease, hypogonadism, some testicular tumours and several medicines
- Risk factors for male breast cancer include BRCA2 mutations and Klinefelter syndrome
- The lower border of the triangle of safety for chest drains is a line at nipple level in men
Anatomical variants
- Accessory nipples occur in about 1–4% of people of both sexes, usually along the milk line below the normal nipple
Development
The nipple forms on the mammary ridge (milk line) that runs from the axilla to the groin in the embryo; the rest of the ridge normally regresses.
Related conditions
Test yourself
Think of the answer, then tap the question to see it.
Which intercostal space and dermatome does the male nipple mark?
The 4th intercostal space, on about the midclavicular line, and the T4 dermatome.
How does the pinch test tell gynecomastia from pseudogynecomastia?
A firm, rubbery disc beneath the areola means true gynecomastia; soft fat without a disc suggests pseudogynecomastia.
How does male breast cancer typically present?
A firm, painless lump under or just off the areola, with early skin or nipple involvement because there is little tissue.
What are risk factors for male breast cancer?
BRCA2 mutations and Klinefelter syndrome.
Where are accessory nipples usually found, and why?
Along the milk line below the normal nipple, because the embryonic mammary ridge runs from axilla to groin and normally regresses.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- regio mammaria; mamma; papilla mammaria TA2 252
- Official Spanish (DeCS)
- Región mamaria DeCS D001940
- English (TA2)
- Mammary region
- Also called
- regio mammalis
Sources: Terminologia Anatomica (TA2); DeCS; Anatomy, Thorax, Breast.
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Representative model, for educational purposes only.
