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# Breast region (male)

The male breast region is the area around the nipple on the [chest](https://durgical.com/en/anatomy/region/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 points

- In men the [nipple](https://durgical.com/en/anatomy/nipple/) is a reliable landmark for the 4th intercostal space and the T4 dermatome; in women its position varies too much to count on
- Gynecomastia is a firm, rubbery disc of gland centred under the [areola](https://durgical.com/en/anatomy/areola/); pseudogynecomastia is fat only, soft and without a disc
- Male breast cancer is rare but real: typically a firm, painless lump under or just off the areola, with [skin](https://durgical.com/en/anatomy/skin/) or nipple involvement early because there is little tissue

## 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](https://durgical.com/en/anatomy/pectoralis-major-muscle/) and its fascia, then [pectoralis minor](https://durgical.com/en/anatomy/pectoralis-minor-muscle/) and the 3rd to 5th [ribs](https://durgical.com/en/anatomy/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](https://durgical.com/en/anatomy/sternum/) and the [parasternal lymph nodes](https://durgical.com/en/anatomy/parasternal-nodes/) along the [internal thoracic artery](https://durgical.com/en/anatomy/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](https://durgical.com/en/anatomy/testis/), [liver](https://durgical.com/en/anatomy/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

- [Gynaecomastia](https://durgical.com/en/conditions/gynaecomastia/)

## 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.

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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](https://decs.bvsalud.org/es/ths/resource/?id=1965); [Anatomy, Thorax, Breast](https://www.ncbi.nlm.nih.gov/books/NBK519575/).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/anatomy/mammary-region/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/mammary-region/