Thoracic-Regional Anatomy Breast, Thoracic Muscles, Thoracic Circulation and Brachial Plexus

Question 1

The cylindrical thorax consists of:

Answer 1

1. Anterior Thoracic Wall
2. Two pleural cavities
   a. Two Lungs
3. Mediastinum
   a. Pericardial Cavity
   1. Heart
   b. Superior Mediastinum

Question 2

Function of the Thoracic area

Answer 2

The thorax :

Houses the heart and lungs

Acts as a conduit for structures passing between the neck and the abdomen

Plays a principal role in breathing.

Protects the heart and lungs and provides support for the upper limbs.

Muscles anchored to the anterior thoracic wall provide some of this support, and together with their associated connective tissues, nerves, and vessels, and the overlying skin and superficial fascia, define the pectoral region.

Question 3

is external to the anterior thoracic wall and anchors the upper limb to the trunk.
It consists of:
1. A superficial compartment containing skin, superficial fascia, and breasts. Nerves, vessels, and lymphatics emerge from the thoracic wall, the axilla, and the neck
2. Deep compartment containing muscles and associated structures.

Answer 3

PECTORAL REGION

Question 4

consist of mammary glands and associated skin and connective tissues. The mammary glands are modified sweat glands in the superficial fascia anterior to the pectoral muscles and the anterior thoracic wall.
The mammary glands consist of a series of ducts and associated secretory lobules. These converge to form 15 to 25 lactiferous ducts, which open independently onto the nipple. The nipple is surrounded by a circular pigmented area of skin termed the areola.
A well-developed, connective tissue stroma surrounds the ducts and lobules of the mammary gland. In certain regions, this condenses to form well-defined ligaments, the suspensory ligaments of breast, which are continuous with the dermis of the skin and support the breast.
Carcinoma of the breast creates tension on these ligaments, causing pitting of the skin.

Answer 4

Breast

Question 5

are modified sweat glands in the superficial fascia anterior to the pectoral muscles and the anterior thoracic wall.

Answer 5

mammary glands

Question 6

The mammary glands consist of a series of ducts and associated secretory lobules. These converge to form 15 to 25 lactiferous ducts, which open independently onto the nipple. The nipple is surrounded by a circular pigmented area of skin termed the

Answer 6

areola

Question 7

A well-developed, connective tissue stroma surrounds the ducts and lobules of the mammary gland. In certain regions, this condenses to form well-defined ligaments, which are continuous with the dermis of the skin and support the breast.

Answer 7

suspensory ligaments of breast

Question 8

creates tension on these ligaments, causing pitting of the skin.

Answer 8

Carcinoma of the breast

Question 9

Also known as acini or alveoli, these are the actual source of breast milk. They develop during puberty to a certain degree, and then complete their development during pregnancy. Lobular development causes the breasts to expand. The final development occurs during pregnancy, and allows the production of milk just before and after giving birth. Most breasts of the same cup size have the same average number of lobules, and they are grouped into 15 to 25 lobes. As a woman approaches menopause, the lobules start to atrophy, allowing a reduction in the density of the breasts. They may be replaced with fatty tissue, further softening the breast; a process called involution.

Answer 9

Gland Lobules of the Breast

Question 10

These gather the milk from the lobules and deliver it to the nipple. Each lobe usually has its own ductal system.

Answer 10

Lactiferous Ducts (milk ducts)

Question 11

This is an enlarged area in the Lactiferous Duct that maintains a small reserve of milk that will be immediately available to the infant that is placed at the breast. It will maintain his/her interest until the Lobules are able to produce and release more milk. Pressure is placed directly onto these to manually express milk from the breast, not on the nipple.

Answer 11

Ampulla (Lactiferous Sinus)

Question 12

The nipple contains an opening (pore or duct) that is the terminus of each Lactiferous Duct. There are actually 5 to 25 openings in the nipple, through which breast milk is expressed. The nipple might be prominent (sticks out away from the areola), flat (is flush with the areola), or inverted (actually folds inwardly, into the areola). Stimulation (cold, fear, sexual excitement, direct contact, etc.) usually causes the nipple to become erect.

Answer 12

Nipple (Papilla)

Question 13

This special skin is pigmented and surrounds the nipple. It contains the Areolar (Montgomery’s) Glands, hair follicles and the Nipple. It is often darker than the surrounding skin, but this varies over a large range of intensity depending upon the person’s genetic background. The areolae often get darker and larger in diameter during pregnancy and lactation, being one of the earliest indications of a pregnancy.

Answer 13

Areola (Areola Mammae) (Areola Papillaris)

Question 14

These are those small nodules that look and function like extra large “goose bumps”. They are sebaceous glands that secrete a waxy, lipoid fluid to lubricate, moisturize and protect the areola and the nipple. Stimulation causes them to become more prominent.

Answer 14

Montgomery’s Glands (Areolar Glands)

Question 15

One third of the average sized adult breast of a non-lactating woman consists of fatty tissue. Larger adult breasts usually only contain more fatty tissue. Smaller than average breasts still contain the same amount of Glandular (milk producing) tissue, but have less fatty tissue. Poor nutrition will prevent the storage of excess fat in the breasts, and may result in a sagging (pendulous) effect.

Answer 15

Fatty tissue of the Breast

Question 16

Located at the junction between the lower side of the breast and the chest wall, it is a more dense area that is easily felt when lying on your back. This will often thicken with age. It might be (and often is) confused with a mass or lump during a Breast Self-Examination.

Answer 16

Inframammary Ridge

Question 17

Suspensory ligaments of the thorax

Answer 17

1.Suspensory ligament of axilla, also known as Gerdy’s ligament
2.Suspensory ligaments of breast, also known as Cooper’s ligaments
3.Suspensory ligament of thyroid gland, also known as Berry’s ligament

Question 18

connects the clavipectoral fascia to the axillary fascia. This union shapes the axilla (underarm).
Suspensory ligament of axilla, also known as

Answer 18

Gerdy’s ligament

Question 19

Suspensory ligaments of breast, also known as

Answer 19

Cooper’s ligaments

Question 20

Suspensory ligament of thyroid gland, also known as

Answer 20

Berry’s ligament

Question 21

a french term that literally means “the skin of an orange.” It is often used in medical circles to describe skin that has become thick and pitted, just like that of an orange. There are many reasons why a person may develop peau d’orange. Some of the most common are inflammatory breast cancer, Grave’s disease and Grönblad–Strandberg syndrome, which is also known as pseudoxanthoma elasticum or PXE.
For a person suffering from breast cancer, peau d’orange is often a late sign of the disease. The skin of the breast will thicken and pit slowly, usually with noticeable lumps and pain. This condition happens during breast cancer because the breast has swollen to the point where the hair follicles resemble dimples. The swelling is caused by lymphatic endema, water build up in the lymphoid tissue of the breast. Peau d’orange can occur in the breast and not be a sign of breast cancer. Grave’s disease, which creates an overactive thyroid and an infection of the lymphatic system, can create similar symptoms.

Answer 21

Peau d’orange

Question 22

The breast vascular supply and drainage can occur by multiple routes :

Answer 22

Laterally, vessels from the superior thoracic, thoraco-acromial, lateral thoracic, and axillary artery—subscapular arterial branches

Medially, branches from the internal thoracic artery; the second to fourth intercostal arteries via branches that perforate the thoracic wall and overlying muscle.

Question 23

Veins draining the breast parallel the arteries and ultimately drain into the axillary, internal thoracic, and intercostal veins

Answer 23

Breast Venous drainage

Question 24

Approximately 75% is via lymphatic vessels that drain laterally and superiorly into axillary nodes
Lymphatic vessels from the medial part of the breast accompany the perforating arteries and drain into the parasternal nodes on the deep surface of the thoracic wall
Lymphatic vessels associated with lateral parts of the breast emerge from or drain into the axillary region of the upper limb

Answer 24

Breast- Lymphatics

Question 25

These vessels lay just below the surface of the skin, and may be a structure similar to a blood vessel (vein or artery) or may merely be the space between body cells.. The breasts contain a greater concentration of lymphatic vessels than any other part of the body.

Answer 25

Lymphatic Vessels of the Breast

Question 26

Axillary nodes drain into the

Answer 26

subclavian trunks

Question 27

Intrapectoral nodes drain into the

Answer 27

subclavian trunks

Question 28

Subclavian Nodes drain into the

Answer 28

subclavian trunks

Question 29

Parasternal nodes drain into the

Answer 29

bronchomediastinal trunks

Question 30

Intercostal nodes drain either into

Answer 30

the thoracic duct or into the bronchomediastinal trunks.

Question 31

may be from the size of the head of a pin to the size of a lima bean. If swollen, they can easily triple in size. During a Breast Self Examination the nodes should be monitored for swelling, which could indicate an infection or a malignancy in the breast and warrant further investigation.

Answer 31

Lymph nodes

Question 32

The Axillary nodes (in the armpit) in particular are the ones that may be partially removed surgically when cancer is found in the breast. The reason for this is that a major portion of the lymphatic circulation from the breast goes toward the upper outer quadrant of each breast and then moves back to the axillary nodes. Therefore, the thinking is that if any cells are “out and about”, they will most likely go to the axillary nodes and be caught up for elimination from the body. A dozen or two of these nodes (there may be as many as 60 or more nodes in the armpit) are excised and evaluated to determine if a mass in the breast might be malignant, and the malignancy has become metastatic (started to spread to other parts of the body).

Answer 32

Lymph nodes biopsy for Cancer

Question 33

is being used to reduce the number of lymph nodes that have to be removed during a lymph node biopsy. It is not that simple to remove a specific number of lymph nodes, due to the difficulty of finding them hidden among the fatty tissues. In a SNB, a dye is injected directly into the location of the suspicious mass in the breast, and the lymphatic vessels that are charged with the duty of cleansing that particular location will pick up that dye after a short while and take it back to their node. When the biopsy is done, the node with the dye is more likely to be identifiable, making the removal of a larger number of nodes unnecessary

Answer 33

Sentinel Node Biopsy (SNB)

Question 35

Once the associated lymph node is found, it is excised (removed surgically) and dissected under a microscope to see if it has any of those wandering malignant cells. If ANY cells have left the malignant mass, it is extremely likely that the associated lymph node will have picked some of them up. if one or more malignant cells are found, more have likely been released and chemo-therapy most likely will be prescribed. if no malignant cells are found in the “sentinel node”, it is accepted that there have most likely not been any malignant cells released from the breast mass, and chemo-therapy will probably NOT be prescribed.

Answer 35

Sentinel Node Biopsy (SNB) Biopsy results

Question 36

When breast implants are used, they may either be located between the Pectoral muscles and the ribs (submuscular), or in front of the Pectoral muscles, but behind the breast tissues (subglandular). The lower attachment of the breast to the chest wall is usually near the sixth rib when a breast reaches full maturity at the end of puberty. This attachment point (in relation to the sixth rib) actually changes over a woman’s lifetime, moving in the downward direction as she ages. Note that this is only the attachment point, and the breast ptosis or sagging is a totally separate issue.

Answer 36

Breast implants

Question 37

is via anterior and lateral cutaneous branches of the second to sixth intercostal nerves which carry general sensation from the skin of the breast.

Answer 37

Innervation of the breast

Question 38

The nipple is innervated by

Answer 38

the fourth intercostal nerve.

Question 39

Origin: Medial half of clavicle and anterior surface of sternum, first seven costal cartilages, aponeurosis of external oblique

Insertion: Lateral lip of intertubercular sulcus of humerus

Innervation: Medial and lateral pectoral nerves

Function: Adduction, medial rotation, and flexion of the humerus at the shoulder joint

Answer 39

Pectoralis major

Question 40

Origin: Rib I at junction between rib and costal cartilage

Insertion: Groove on inferior surface of middle third of clavicle

Innervation: Nerve to subclavius

Function: Pulls clavicle medially to stabilize sternoclavicular joint

Answer 40

Subclavius

Question 41

Origin: Anterior surfaces of the third, fourth and fifth ribs, and deep fascia overlying the related intercostal spaces

Insertion: Coracoid process of scapula

Innervation : Medial pectoral nerves

Function: Depresses tip of shoulder; protracts scapula

Answer 41

Pectoralis minor

Question 42

A continuous layer of deep fascia,, encloses subclavius and pectoralis minor and attaches to the clavicle above and to the floor of the axilla below.

Answer 42

Clavipectoral fascia