Transcript Lecture Two - Maryville University

Lecture Two
Pectoral Region
Landmarks
• Sternum
– Manubrium
– Sternal angle (T4 vertebra)
– Body
– Xiphoid process
Landmarks
• Clavicle
– Acromial end and sternal end
Landmarks
• Ribs
– Shaft
– Head – posterior end; articulates with
vertebrae
– Tubercle – articulates with vertebrae
– Costal cartilage – hyaline cartilage
Breast
• nipple: fourth intercostal space about 10 cm
lateral to the sternum
• areola: rounded, pigmented elevation of skin
(pink in nulliparous women - no child bearing
women, turn brown permanently in whites)
• Breast doesn't have a distinct connective tissue
capsule (because it is a modified sweat gland).
Embedded in the general subcutaneous fatty
tissue. Separated from deep muscle by
retromammary space.
Breast
• Breast is partitioned radically around the
nipple into 15-20 lobes by dense, fibrous
connective tissue septa. Each has a single
lactiferous duct, lactiferous sinus (dilation
of duct) near nipple.
Infections
Arterial supply of breast
• Breast has abundant blood supplies.
Arteries are mainly from internal thoracic
artery (branch from subclavian artery) via
its perforating branches, which pierce the
second to fourth intercostal spaces. The
breast also receives blood from branches
of axillary artery (lateral thoracic and
thoracoacromial branches) and lateral and
anterior cutaneous branches from the
intercostal arteries.
Veins
• Venous drainage of the breast
Veins from the breast drain into the
axillary, internal thoracic, lateral thoracic,
and intercostal veins
Lymphatic drainage
• Most (75%) of the lymphatic drainage is to
the axillary lymph nodes, mainly the
pectoral group), From deep surface of the
breast, the lymphatics pass through the
pectoralis major and drain into the apical
group of axillary lymph nodes. Lymph from
the medial part of the breast drains into
parasternal lymph nodes. Lymph from the
skin may pass to the abdominal wall and
the opposite breast.
Breast cancer
• Risk factors (according to American Cancer
Society)
– Uncontrollable
•
•
•
•
•
•
•
Age
Gender
Family history
Breast cancer genes?
Previous abnormal breast biopsy
Previous breast radiation
Early menstruation, late menopause
Risk factors
• Life style related factors
– No children
– Pills
– Hormone replacement therapy
– Not breast feeding (long period)
– Alcohol
– Obesity, high fat diet (especially after
menopause)
– Physical inactivity
Myth factors
•
•
•
•
•
•
•
•
Antiperspirant
Underwire bras
Induced abortion
Breast implants
Environmental pollutants
Smoking
Night work
antibiotics
Signs
• Early symptoms of breast cancer
– A lump
– A swell, unusual appearance
– Veins more prominent on one breast.
– nipple inverted, rash, changes texture, or has
a discharge.
– A depression on the breast surface (dimpling)
Treatment options
•
•
•
•
Surgery
Radiation
Chemotherapy
Combination of above
Mastectomy w Reconstruction
• This 42 yr old had a
small breast cancer
dx at the age of 29 She had a
reoccurence 5 years
ago and had a right
mastectomy with
reconstruction and
augmentation on the
left
Prophylactic
• This 46 year old had a
small lump biopsied in
'00. She has a strong
family history though
BRCA negative and
elected to have
prophylactic
mastectomies. It took her
over a year to feel
comfortable with implants
but now she does and will
talk and show them to
new patients. 12/03
PECTORALIS MAJOR
• ORIGIN
Upper fibers (clavicular portion):
anterior surface of sternal one half of
clavicle
Lower fibers (sterocostal portion):
anterior surface of sternum, cartilage
of first six or seven ribs, and
aponeurosis of the external oblique.
• INSERTION
Insertion (both upper and lower
fibers)
crest of greater tubercle of humerus.
Upper fibers are more anterior and
caudal than the lower fibers which
twists and more posterior and cranial
PECTORALIS MAJOR
• ACTION
– Action of whole muscle:
With origin fixed, it adducts and medially
rotates the humerus.
With insertion fixed, it assists in elevating
thorax. In crutch walking or in parallel bar,
it supports the body.: Action of upper
fibers:
Flex and medially rotate the shoulder joint,
and horizontally adduct the humerous
toward the opposite shoulder
– Action of lower fibers:
Depress the shoulder girdle by virtue of
attachment on the humerus
• NERVE
– Upper : Lateral Pectoral, C5, 6, 7
– Lower: Lateral and medial pectoral, C6, 7,
8, T1
PECTORALIS MINOR
• ORIGIN
Superior margins, outer surfaces of third,
fourth, and fifth ribs near cartilage, and from
fascia over corresponding intercostal muscles
• INSERTION
Medial, superior surface of coracoid process of
scapula
• ACTION
With origin fixed, tilts the scapula anteriorly, i.e.
rotates the scapula about a coronal axis so that
the coracoid process moves anteriorly and
caudally, while the inferior angle moves
posteriorly and medially
With the scapula stabilized to fix the insertion,
pectoralis minor assists in forced inspiration
• NERVE
medial pectoral nerve with fiber from a
communicating branch of the lateral pectoral,
C(6), 7, 8, T1