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Our next topic is breast anatomy.

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I want you to review some

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basic anatomy of the breast.

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In a few different projections, this

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is a sagittal image through the center

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of the breast, and just showing that,

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uh, we have a nipple at the center,

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multiple ducts going up to the nipple.

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And as we go back into the breast tissue,

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the ducts branch and then end in the

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terminal duct lobular unit, which would

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be the functional part of the breast,

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which produces milk during lactation.

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The breast tissue forms.

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It's somewhat of a cone shape, and

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then is surrounded by fatty tissue,

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both subcutaneous and retro-glandular.

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And the fatty tissue is linked to

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the skin by the Cooper's ligaments.

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So these bands of fibrous tissue at the

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back of the breast, we have the pectoralis

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major and pectoralis minor muscle.

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And then we have the chest wall, which

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includes the ribs and the intercostal muscles.

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We do our breast MRIs in the axial plane.

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That's how we review them.

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And the images will look a

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little bit like this image.

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And on this image, we have skin.

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We have the nipple-areolar complex.

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We have ducts going backward into

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the breast and then branching.

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You can see that they form these kinds of

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segments, which would include one duct and

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all of its branches and lobules that are

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kind of triangular shaped with the broad base

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toward the posterior aspect of the breast.

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Again, the breast tissue forms a cone shape.

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There is subcutaneous fat

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and retro-glandular fat.

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And those fat lobules are linked to the

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skin and underlying structures by the

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fibrous bands called Cooper's ligaments.

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And then, um, we have pectoralis muscle

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at the posterior aspect of the breast.

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Lymph nodes are very important.

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And, uh, this is a diagram

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showing lymph node anatomy.

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The majority of the lymph nodes are going

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to be found in the axilla, although lymph

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nodes can be seen in any part of the breast.

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But the majority of intramammary lymph nodes

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are going to be upper outer quadrant and kind

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of along the lateral aspect of the breast.

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As far as the levels of lymph nodes, level

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one lymph nodes are going to be considered

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lateral to the pectoralis minor muscle.

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Level two are going to be

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posterior to the pectoralis muscle.

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And level three are going to be

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medial to the pectoralis muscle.

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And then, as we get closer to the

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clavicle, we have infraclavicular lymph

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nodes and then supraclavicular lymph nodes.

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On breast MRI, we can also see the

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internal mammary lymph nodes, and

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those are important to look at.

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They're going to be medial

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and actually inside the chest.

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So we'll look at them here in a minute.