Residency · Residency · Plastic Surgery

Breast Anatomy and Assessment for Reconstruction

Introduction

Detailed knowledge of breast anatomy is the foundation for oncologic and reconstructive breast surgery. Reconstructive planning begins preoperatively in coordination with the surgical oncologist. The goal is to restore breast form, symmetry, and patient quality of life after mastectomy or lumpectomy. Options include implant-based, autologous, and combined approaches; selection is patient- and defect-specific.

Surface Anatomy and Landmarks

Breast boundaries: 2nd rib superiorly, 6th-7th rib inferiorly, sternal border medially, midaxillary line laterally. Tail of Spence: extension into the axilla. Nipple-areolar complex (NAC): typically at the 4th intercostal space or level of the inframammary fold (IMF). Inframammary fold: critical landmark for breast reconstruction; defined by superficial fascial system and ligamentous attachments to the chest wall (Würinger's septum).

Breast Parenchyma and Fascial Relationships

Breast tissue lies between the superficial and deep layers of the superficial fascia. Anterior (superficial) layer: lies just deep to the skin; contains Cooper's ligaments (suspensory ligaments connecting skin to pectoralis fascia). Posterior (deep) layer: lies on the pectoralis fascia. Retromammary bursa: potential space between the deep layer of superficial fascia and the pectoralis major fascia; plane of dissection in mastectomy. Cooper's ligaments: fibrous septa providing breast shape and support; involvement by tumor causes skin dimpling.

Vascular Anatomy

Arterial Supply (Four Sources)

Internal mammary artery (IMA) perforators: dominant blood supply (~60%); perforators emerge through intercostal spaces 1-5. Largest perforators typically at 2nd and 3rd intercostal spaces. Critical recipient vessels for free flap breast reconstruction. Lateral thoracic artery: courses along the lateral border of pectoralis minor.

Thoracoacromial artery: pectoral branch supplies upper breast through pectoralis major. Intercostal artery perforators: lateral and anterior branches of posterior intercostal arteries.

Venous Drainage

Mirrors arterial supply. Internal mammary veins: primary recipient veins for microsurgical breast reconstruction. Superficial venous drainage through subdermal plexus.

Lymphatic Drainage

Axillary nodes: drain 75% of the breast (lateral and central portions). Level I: lateral to pectoralis minor. Level II: deep to pectoralis minor. Level III: medial to pectoralis minor (infraclavicular/apical).

Internal mammary nodes: drain 25% (medial and central portions). Sentinel lymph node biopsy: standard staging procedure for clinically node-negative breast cancer.

Innervation

Lateral cutaneous branches of intercostal nerves (T3-T6). Anterior cutaneous branches of intercostal nerves. 4th lateral intercostal nerve: primary sensory supply to the NAC. Supraclavicular nerves (C3-C4): superior breast skin. Preservation of the 4th intercostal nerve branch during mastectomy may improve postoperative sensation.

Musculature

Pectoralis major: deep to breast tissue; origin from clavicle, sternum, ribs 1-6, external oblique aponeurosis; dual nerve supply (medial and lateral pectoral nerves). Pectoralis minor: deep to pectoralis major; origin from ribs 3-5, insertion at coracoid process. Serratus anterior: lateral chest wall; long thoracic nerve (damage → winged scapula). Rectus abdominis: relevant for TRAM/DIEP flap harvest. Latissimus dorsi: relevant for LD flap reconstruction.

Breast Measurements for Reconstruction

Key Measurements

Sternal notch to nipple (SN-N): 19-21 cm average. Nipple to inframammary fold (N-IMF): 7-9 cm. Base width (BW): horizontal diameter at the chest wall. Breast projection: distance from chest wall to most projecting point.

Inter-nipple distance: 20-22 cm average. Nipple position: relative to the meridian of the breast mound. Skin envelope: assessment of skin quantity and quality.

Assessment Tools

Clinical photography (standardized views). 3D surface imaging. Tissue-based measurements guide implant selection (base width determines implant diameter).

<image>Illustration of standardized breast measurements for reconstructive planning, showing an anterior view of the female chest with measurement lines overlaid. Lines indicate: sternal notch to nipple distance (SN-N), nipple to inframammary fold distance (N-IMF), breast base width (BW), inter-nipple distance, and breast meridian. A lateral view inset shows breast projection measured as the perpendicular distance from the chest wall to the most anterior point of the breast. All measurements are labeled with typical normal values. The inframammary fold is highlighted as a critical landmark.</image>

Classification of Breast Deformities (Post-Mastectomy)

Mastectomy Types

Simple (total) mastectomy: all breast tissue removed; skin and NAC removed. Skin-sparing mastectomy (SSM): breast tissue and NAC removed; skin envelope preserved. Nipple-sparing mastectomy (NSM): breast tissue removed; skin envelope AND NAC preserved. Modified radical mastectomy: total mastectomy + axillary lymph node dissection.

Post-Mastectomy Defect Classification

Skin deficiency: amount of skin available affects reconstruction options. Muscle coverage: pectoralis major intact vs. sacrificed. Radiation status: prior/planned radiation significantly impacts reconstruction options and outcomes. Chest wall defect: rare; after radical mastectomy or chest wall resection. Contralateral breast: shape, size, and ptosis determine symmetry procedure needs.

Reconstructive Planning

Timing

Immediate reconstruction: at the time of mastectomy. Advantages: single anesthesia, preserved skin envelope, psychological benefit. Considerations: potential delay of adjuvant therapy if complications arise. Delayed reconstruction: weeks to months after mastectomy (after completion of adjuvant therapy).

Advantages: cancer treatment not delayed, scar maturation, final radiation dose known. Disadvantages: additional surgery, tissue contraction, psychological impact of mastectomy deformity. Delayed-immediate: tissue expander placed at mastectomy; definitive reconstruction after adjuvant treatment is determined.

Patient Factors

Body habitus: BMI, available donor tissue. Smoking status (relative contraindication to autologous reconstruction; absolute for microsurgical flaps if active). Comorbidities: diabetes, connective tissue disease, anticoagulation. Prior abdominal surgery (affects DIEP/TRAM eligibility).

Radiation: prior or planned; significantly increases implant complication rates. Patient preference and goals. Oncologic treatment plan.

Reconstruction Options Algorithm

No radiation, thin patient, small breast: direct-to-implant or tissue expander/implant. No radiation, adequate donor tissue: implant-based or autologous. Prior/planned radiation: autologous reconstruction preferred (DIEP, LD + implant, other flaps). Post-radiation with implant failure: conversion to autologous (DIEP, LD flap).

Partial mastectomy defect: oncoplastic reduction, local tissue rearrangement, or volume replacement (LD miniflap, fat grafting).

Coordination with Oncologic Surgery

Oncoplastic Surgery

Combined oncologic resection and plastic surgical reconstruction in a single operation. Level I: tissue rearrangement and volume displacement techniques. Level II: volume replacement (flaps, fat grafting) and bilateral reduction/mastopexy. Allows wider oncologic margins with better aesthetic outcomes.

Mastectomy Technique Considerations

Skin flap thickness: preserve subdermal plexus to ensure flap viability. IMF preservation: critical for reconstructive outcome. NAC preservation criteria: tumor >2 cm from the nipple, no Paget's disease, negative retroareolar margin. Sentinel node biopsy timing: coordinate with reconstruction plan.

<image>Flowchart illustration showing the breast reconstruction decision algorithm. Starting with the mastectomy type (skin-sparing vs. non-skin-sparing), the chart branches based on radiation status (no radiation, planned radiation, prior radiation). Each branch leads to recommended reconstruction options: implant-based (tissue expander/implant or direct-to-implant), autologous (DIEP, TRAM, LD, SGAP, PAP), or combined approaches. Patient factors (BMI, donor tissue availability, comorbidities, smoking) are shown as modifying inputs at each decision point. The chart also shows the distinction between immediate, delayed, and delayed-immediate timing options with brief rationale for each.</image>

Clinical Pearls

The internal mammary vessels are the workhorse recipient vessels for free flap breast reconstruction; confirm their patency preoperatively with CTA if prior radiation or surgery in the area. The 4th intercostal nerve lateral cutaneous branch supplies the NAC; when possible, identify and preserve this during mastectomy to improve postoperative sensation (neurotization techniques for flap reconstruction are emerging). The inframammary fold is the single most important landmark for breast aesthetics; it must be precisely recreated in reconstruction — malposition (too high, too low, too lateral) is a common cause of poor outcomes.

In nipple-sparing mastectomy, retroareolar frozen section should confirm negative margins before proceeding with reconstruction. Radiation is the most important factor affecting reconstruction choice; implant-based reconstruction after radiation has capsular contracture rates of 30-50%, making autologous reconstruction the preferred approach in irradiated fields. Always assess and plan for contralateral symmetry; many patients require contralateral augmentation, reduction, or mastopexy to achieve symmetric results.

References

• Nahabedian MY, Neligan PC. Plastic Surgery. Vol 5: Breast. 4th ed. Elsevier; 2018.
• Würinger E, Mader N, Posch E, Holle J. Nerve and vessel supplying ligamentous suspension of the mammary gland. Plast Reconstr Surg. 1998;101(6):1486-1493.
• Hamdi M, Wuringer E, Schlenz I, Kuzbari R. Anatomy of the breast: a clinical application. In: Breast Surgery. Springer; 2006.
• Cordeiro PG. Breast reconstruction after surgery for breast cancer. N Engl J Med. 2008;359(15):1590-1601.
• Kronowitz SJ, Robb GL. Radiation therapy and breast reconstruction: a critical review of the literature. Plast Reconstr Surg. 2009;124(2):395-408.
• Colwell AS, Tessler O, Lin AM, et al. Breast reconstruction following nipple-sparing mastectomy: predictors of complications, reconstruction outcomes, and 5-year trends. Plast Reconstr Surg. 2014;133(3):496-506.

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