Thorax 6b: Anatomy of the Breast Flashcards
Anatomy of the Breast
Female breast base extends from the ….nd - ….th rib in the …………………. line
It overlies the …………………. ………………….
Laterally, it extends to lie on …………………. …………………. and …………………. …………………. muscles
An axillary tail of breast tissue sometimes extends into the medial wall of the ……………. and lies in the ……………. fat
The medial and lateral extents depending on the size of the breast from the midline (medially) to the axillary line (laterally)
Anatomy of the Breast
Female breast base extends from the 2nd - 6th rib in the midclavicular line
It overlies the pectoralis major
Laterally, it extends to lie on serratus anterior and external oblique muscles
An axillary tail of breast tissue sometimes extends into the medial wall of the axilla and lies in the subcutaneous fat
The medial and lateral extents depending on the size of the breast from the midline (medially) to the axillary line (laterally)
The breast is a ………………. ……………… ………………
Under hormonal influence it can produce milk post-partum
It is made up of: ……………….. …………….., ………. and ………………… ………………
Radiology Terminology:
Black = ……………………
White = ……………………
The breast is a MODIFIED SWEAT GLAND
Under hormonal influence it can produce milk post-partum
It is made up of: glandular tissue, fat and fibrous tissue
Radiology Terminology:
Black = Radiolucent
White = Radioopaque
The breast consists of 15-20 …………… ……………. ……………. each draining into a main duct
There is a complex network behind the nipple
There are between 4-18 …………. …………. open on the summit of the nipple or on the areola
…………… lies interspersed between the ductal lobular units
The organ is divided by fibrous septae that radiate from the centre outwards (……………………. ……………………. ……. …………………..)
The breast consists of 15-20 ductal lobular units each draining into a main duct
There is a complex network behind the nipple
There are between 4-18 milk ducts open on the summit of the nipple or on the areola
FAT lies interspersed between the ductal lobular units
The organ is divided by fibrous septae that radiate from the centre outwards (suspensory ligaments of Cooper)
Mammography
Young women have more dense breasts so it is more radioopaque on a mammogram and hence it is more difficult to identify breast tumours
The breasts are put side by side so you can look for asymmetry
You look at the breast in TWO views:
…………… ………………
…………… ………………. …………..
Mammography
Young women have more dense breasts so it is more radioopaque on a mammogram and hence it is more difficult to identify breast tumours
The breasts are put side by side so you can look for asymmetry
You look at the breast in TWO views:
Cranio-Caudal
Medial-Lateral-Oblique (MLO)
This is an MLO view
In a fatty breast it is easier to see a difference
Breast cancer causes …………………. - it tethers and draws in tissue
This is a tumour in the …………….. ………….. quadrant of the breast
This is an MLO view
In a fatty breast it is easier to see a difference
Breast cancer causes spiculation - it tethers and draws in tissue
This is a tumour in the upper outer quadrant of the breast
Cranio-Caudal View
You sometimes have to do an extended lateral view because you might miss some of it
……………… SIDE IS AT THE TOP
…………….. side is at the bottom
With MALES:
If they have …………………… then you may be able to see some glandular tissue
You tend to do …………………… scans first with males
It is difficult to get much breast tissue between the plates in males
Cranio-Caudal View
You sometimes have to do an extended lateral view because you might miss some of it
LATERAL SIDE IS AT THE TOP
Medial side is at the bottom
With MALES:
If they have gynaecomastia then you may be able to see some glandular tissue
You tend to do ultrasound scans first with males
It is difficult to get much breast tissue between the plates in males
Breast cancer can cause tethering and it looks spiculated in a mammogram
Breast cancer causes ………………………
This abnormal calcification is linear and follows the milk ducts to the nipple
All the bits in white are the areas of microcalcification
Breast cancer can cause tethering and it looks spiculated in a mammogram
Breast cancer causes microcalcification
This abnormal calcification is linear and follows the milk ducts to the nipple
All the bits in white are the areas of microcalcification
Sometimes you can get indrawing of the skin (tethering) due to the ligaments of Cooper being involved in the tumour process
If the tumour is tethered to the pectoralis you examine them with their arms up
You also get them to tense their pectoralis major
Blood Supply to the Breast
The blood supply is derived from branches of the:
Lateral thoracic artery
Internal thoracic artery
Thoraco-acromial artery
Thoraco-dorsal artery
Intercostal arteries
The skin is supplied by the ………………. plexus which communicates with the deep parenchymal vessels
The nipple receives a branch from the ………………….. ……………….. artery
Venous return follows the arteries
There is a rich supply of blood to the breast which is why you can do skin-sparing mastectomy
Blood Supply to the Breast
The blood supply is derived from branches of the:
Lateral thoracic artery
Internal thoracic artery
Thoraco-acromial artery
Thoraco-dorsal artery
Intercostal arteries
The skin is supplied by the subdermal plexus which communicates with the deep parenchymal vessels
The nipple receives a branch from the internal thoracic artery
Venous return follows the arteries
There is a rich supply of blood to the breast which is why you can do skin-sparing mastectomy
Sensory Innervation of the Breast
Sensory innervation is ……………………., mainly from the anterolateral and anteromedial branches of THORACIC INTERCOSTAL NERVES T…-T…
There is also innervation from the ………………………. nerves to the upper and lateral parts of the breast
The nipple has a dominant supply from the lateral cutaneous branch of T…
Sensory Innervation of the Breast
Sensory innervation is dermatomal, mainly from the anterolateral and anteromedial branches of THORACIC INTERCOSTAL NERVES T3-T5
There is also innervation from the supraclavicular nerves to the upper and lateral parts of the breast
The nipple has a dominant supply from the lateral cutaneous branch of T4
Breast Ultrasound
Ultrasound can be used to help biopsy breasts
A benign lump is smooth and longer than it is tall in the longitudinal plane - cancers tend to be the opposite
This is a fibroadenoma
Ultrasound can be used to guide a wire into a tumour
Dense tissue is very BLACK
Glandular tissue is WHITE
Imaging can show you a breast cancer while its in situ
Breast MRI
This is quite a large cancer showing tethering and spiculation
TUMOUR is WHITE
Everything else is BLACK
This is the opposite of ultrasound in terms of colour
Breast MRI isn’t offered to many people because it takes a long time, is a little distressing and is expensive
Lymphatics
The lymphatic and venous channels play an important role in the spread of breast cancer
Lymphatic drainage from the breast is mostly towards the …………………..
If you remove too many lymph nodes in breast surgery, you get oedema in your …….
You usually just remove the …………………. lymph node - axillary clearance is only performed if absolutely necessary
Before breast surgery, a dye is inserted into the breast and it is observed to see which lymph nodes it spread to
You can identify the sentinal lymph node and perform a biopsy
Lymphatics
The lymphatic and venous channels play an important role in the spread of breast cancer
Lymphatic drainage from the breast is mostly towards the axilla
If you remove too many lymph nodes in breast surgery, you get oedema in your arm
You usually just remove the sentinal lymph node - axillary clearance is only performed if absolutely necessary
Before breast surgery, a dye is inserted into the breast and it is observed to see which lymph nodes it spread to
You can identify the sentinal lymph node and perform a biopsy
Lymph Glands
From the submammary and subareolar plexuses, lymph from most of the breast drains to the:
Pectoral group of axillary nodes
But there is drainage of adjacent parts of the breast to:
The infraclavicular group
Parasternal nodes
Mediastinal nodes (inferiorly through the abdominal wall, and diaphragm)
To the opposite breast
Because there is rich anastomoses, there are other routes of drainage other than to the axillary nodes
If there is tumour blocking one of the routes or one of the routes has been removed in surgery, you need to know where else it can drain
There is free communication between the nodes above and below the clavicle and between the cervical and axillary nodes
Lymphoedema
Lymphoedema of the arm can occur after surgery (axillary clearance) or radiotherapy to the axilla due to blockage of the lymphatics or as a result of impairment of venous drainage
Lymphoedema is associated with a higher risk of infection
Polands syndrome
Congenital Abnormalities
Accessory nipples
Accessory breast tissue
Underdevelopment or absence of one breast (may coexist with muscle/rib cage anomaly)
Poland Syndrome (underdevelopment or absence of the chest muscle (pectoralis) on one side of the body)
Scars
Relaxed skin tension lines
Langer’s lines
Axilla contractures
