Lecture 2: Thoracic Walls & Breast Flashcards
What is the role of the thoracic wall?
To protect viscera
Is the mechanical basis of breathing
What is the thoracic wall made up of?
The thoracic cage and coverings
What are the three types of ribs?
True (1-7)
False (8-10)
Floating (11 & 12)
Which ribs are atypical?
1 2 10 11 12
Which ribs are typical?
3-9
What is found in the intercostal space?
Muscle
Nerves
Vessels
What are the three layers of intercostal muscle?
External intercostal muscles (and membrane)
Internal intercostal muscles
Innermost intercostal muscles
What structures does the costal groove protect?
Intercostal vein
Intercostal artery
Intercostal nerve
What are the superficial muscles that cover the thoracic wall?
Pectoralis minor Pectoralis major Subclavius Serratus anterior Serratus posterior
What are the coverings of the thoracic cage?
Subcutaneous fat
Subcutaneous fascia
Skin
Where does the mammary gland sit and how is it attached?
Sits on fascia superficial to pectoralis major
Attached to skin and fascia by suspensory ligaments
How many lobules does the mammary gland have and what do they contain?
15-20 lobules Contain alveoli (milk secreting portion of the lobule)
What dermatome innervates the teets?
T4 teets
What dermatome innervates the belly button?
T10
What are the attachments and movements of pectoralis minor?
Coracoid process to ribs 3, 4, 5
Elevates ribes/stabilises scapula
What are the 3 attachments and movements of pectoralis major?
Clavicular head and sternal head to humerus (bicipital groove)
Adducts the arm
What are the attachments and movements of serratus anterior?
Lateral aspect of ribs 1-8 to the medial border of the anterior surface of scapula
Protracts the scapula
What are the attachments and movements of serratus posterior?
Spinous processes of C7-T3 to angle of ribs 2-5
Elevates the ribs
Spinous processes of T11-L2 to angle of ribs 9-12
Depresses the ribs
Where is the retomammary space and what can it be used for?
Between the pec major and breast tissue
Important in breast implants and mastectomy
What is the mammary gland drained by?
The lactiferous duct which opens independently on the nipple
What portion of breast sits on the serratus anterior and pectoralis major?
Serratus anterior: 1/3
Pectoralis major: 2/3
What ribs can the breast be found on?
Ribs 2-6
What is the areola?
The pigmented area around the nipple that has sebaceous glands for lubrication
At what level is the nipple found?
At the 4th intercostal space in the mid-clavicular line (nulliporous women)
What is the nipple?
The opening of the lactiferous ducts, smooth muscle, no fat/hair/sweat glands
What are the two types of mammograms and who are they used on?
Dense (connective tissue & glands) - younger women Low density (fatty) - older women
What is the blood supply to the breast?
Subclavian artery > axillary artery > lateral thoracic artery > lateral mammary branches
Internal thoracic artery (through intercostal space) > medial mammary branches
Lateral mammary branches of posterior intercostal arteries
What is the venous drainage of the breast?
Internal jugular vein > subclavian vein > axillary vein > lateral thoracic vein > lateral mammary vein
Internal thoracic vein > medial mammary vein
Where does 75% of lymph from the breast end up?
In the axillary nodes
