Pectoral Region & Breast and anatomy of upper limb

Pectoralis major innervation

1. Pectoral Region & Breast

2. Attachments, innervation & actions of
pectoralis major/minor
Clavipectoral fascia layers &
costocoracoid membrane
Surface landmarks of pectoral region
& breast (mid-clavicular line, anterior
axillary fold, inframammary crease,
nipple line)
Cutaneous nerves & superficial
lymphatics of chest wall
Axillary tail of Spence, retromammary
space, Cooper’s ligaments
Breast anatomy: lobes, ducts, stroma,
vascular & lymphatic supply, micro-
anatomy
Breast development, hormonal
variations, age-related involution,
congenital anomalies
Surgical anatomy: sentinel-node
biopsy, mastectomy planes,
implant/expander pockets
1.AN9.1 Describe attachment, nerve supply & action of pectoralis major
and pectoralis minor and describe clavipectoralfascia.
2.AN9.2 Describe the location, extent, deep relations, structure, blood
supply, lymphatic drainage, microanatomy and applied anatomy of
breast.
3.AN9.3 Describe development of breast, associated age changes and
congenital anomalies.
4.Describe the layers and attachments of clavipectoralfascia, including the
costocoracoidmembrane and suspensory ligament of axilla, and relate
them to surgical “safe planes”.
5.Identify, describe and demonstrate the surface landmarks of the pectoral
region and breast (mid-clavicular line, anterior axillary fold,
inframammary crease, nipple line, axillary tail) and correlate with
common clinical procedures and imaging.
6.Enumerate the cutaneous nerves (supraclavicular, intercostobrachial,
lateral cutaneous branches of intercostals) and outline the superficial
lymphatic drainage of the pectoral region and breast; explain their
relevance to regional anaesthesia, pain pathways and metastatic spread.
7.Describe the axillary tail of Spence, suspensory (Cooper’s) ligaments and
retromammaryspace, and explain their significance in breast mobility,
imaging signs (e.g., peaud’orange) and surgical clearance.
8.Describe the surgical anatomy relevant to breast-conserving surgery,
sentinel-lymph-node biopsy, modified radical mastectomy and the
creation of implant or tissue-expander pockets, including neurovascular
and fascial considerations.

4. Topography of the Pectoral Region
•Boundaries:
–Superior: clavicle
–Inferior: costal margin
–Lateral: anterior axillary line
–Medial: midline of sternum
•Layers (superficial → deep):
•Skin (with hair follicles, sweat and sebaceous glands).
•Superficial fascia (contains superficial veins,
lymphatics, cutaneous nerves, breast tissue in
females).
•Deep fascia (pectoral fascia, clavipectoralfascia).
•Muscles: pectoralis major → pectoralis minor →
subclavius.
•Ribs and intercostal muscles.
•Pleura and thoracic cavity contents.

9. Pectoralis Major & Minor
•Pectoralis major:
–Attachments: medial clavicle, sternum, costal
cartilages (1–6), aponeurosis of external oblique
→ lateral lip of bicipital groove (humerus).
–Innervation: medial and lateral pectoral nerves.
–Actions: adduction, medial rotation, flexion of
arm.
–Landmark: forms anterior axillary fold.
•Pectoralis minor:
–Attachments: ribs 3–5 → coracoid process.
–Innervation: medial pectoral nerve.
–Clinical: landmark for axillary vessels;
retraction of scapula.

13. •Strong sheet of
connective tissue deep
to pectoralis major,
enclosing subclavius
and pectoralis minor.
•Costocoracoid
membrane: thickened
part between clavicle
and coracoid process.
•Structures piercing
fascia: cephalic vein,
thoracoacromialartery
branches, lateral
pectoral nerve,
lymphatics.
•Surgical importance:
defines safe planes for
axillary dissection,
barrier against infection
spread.
ClavipectoralFascia

16. Costocoracoidmembrane

17. Surface Landmarks (Topographic Orientation)
•Mid-clavicular line–vertical reference through clavicle
midpoint.
•Anterior axillary fold–lateral border of pectoralis
major.
•Inframammary crease–fold under the breast
(important in surgery).
•Nipple line–typically 4th intercostal space in males.
•Axillary tail of Spence–breast extension into axilla,
palpable in exams.
•Clinical use: palpation of cardiac apex beat, lung
auscultation points, breast exam.

22. Breast Anatomy –Topographic Relations
•Position: 2nd → 6th ribs, sternum → mid-axillary line.
•Layers:
–Skin (nipple, areola with sebaceous glands).
–Superficial fascia (fatty + glandular tissue).
–Retromammaryspace (loose connective tissue over
pectoral fascia).
•Relations: rests on pectoralis major (2/3) and serratus
anterior (1/3).
•Clinical: tumors may fix breast to pectoral fascia (loss of
mobility).

25. Microanatomy & Functional Units
•15–20 lobes → lobules → alveoli → lactiferous
ducts → lactiferous sinus → nipple.
•Stroma: fat + fibrous septa (Cooper’s
ligaments).
•Clinical: most carcinomas start in terminal duct
lobular units (TDLU).

27. Vascular Supply & Lymphatics
(Topographic Focus)
•Arteries: internal thoracic (medial breast),
lateral thoracic (lateral breast), intercostal
arteries.
•Veins: axillary → subclavian → SVC.
•Lymphatic drainage:
–75% → axillary nodes (pectoral, central,
apical).
–20% → parasternal (along internal thoracic).
–Few → posterior intercostal nodes.
•Clinical: explains patterns of metastatic
spreadand surgical clearance strategy.

31. Breast Development & Anomalies
•Embryology: mammary ridge → buds → ducts;
canalization at puberty.
•Hormonal variations: enlargement at puberty,
hypertrophy in pregnancy, involution with age.
•Anomalies: polymastia, polythelia, amastia.
•Clinical: polytheliacan mimic pigmented skin
lesions; important in differential diagnosis.

33. Suspensory & Fascial Structures
•Retromammaryspace: mobility of breast,
invaded in advanced cancer.
•Cooper’s ligaments: suspensory bands to skin
–cause skin dimplingin carcinoma.
•Clavipectoralfascia & axillary tail: define
surgical planes, relevant in mastectomy.

38. Surgical Anatomy & Applied Aspects
•Sentinel-node biopsy–identifies first draining
node (usually axillary).
•Mastectomy planes–superficial fascia (skin
flaps) and pectoral fascia.
•Implant/expander pockets: subglandular
(above pectoralis major) vs subpectoral.
•Structures to avoid: long thoracic nerve
(winged scapula), thoracodorsal nerve
(latissimus paralysis), intercostobrachial
nerve (sensation loss).

39. TASKS