Session 1.2b - Grey's Anatomy for Students - Regional Anatomy - Thorax - Pectoral Region Flashcards
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The cylindrical thorax consists of:
- a wall,
- two pleural cavities,
- the lungs, and
- the mediastinum
Give some functions of the thorax.
- houses the heart and lungs
- acts as a conduit for structures passing between the neck and abdomen
- plays a principal role in breathing
Give some functions of the thoracic wall.
- protects the heart and lungs
- provides support for the upper limbs
What helps provide support for the upper limbs, as well as the thoracic wall?
Muscles anchored to the anterior thoracic wall
What defines the pectoral region?
- Muscles anchored to the anterior thoracic wall and their associated
- – connective tissue
- – nerves
- – vessels
- Overlying skin
- Superficial fascia
The pectoral region is external to the ___
anterior thoracic wall
What does the pectoral region anchor?
The upper limb to the trunk
What does the pectoral region consist of?
- a superficial compartment
- a deep compartment
What is in the superficial compartment of the pectoral region?
Skin
Superficial fascia
Breasts
What is in the deep compartment of the pectoral region?
Muscles and associated structures
Nerves, vessels and lymphatics in the _______ compartment emerge from the ____ ____, the ______, and the _____
superficial; thoracic wall, axilla, neck
What does the breast consist of?
Mammary glands and associated skin and connective tissues
What are mammary glands?
Modified sweat glands
Where are the mammary glands?
In the superficial fascia anterior to the pectoral muscles and the anterior thoracic wall (Fig. 3.16).
Fig. 3.16
Label and caption the image
- Secretory lobules
- Areola
- LYMPHATIC AND VENOUS DRAINAGE PASSES FROM LATERAL AND SUPERIOR PART OF THE BREAST INTO AXILLA
- Axillary process
- PECTORAL AXILLARY NODES
- LATERAL AXILLARY NODES
- Lateral thoracic artery
- CENTRAL AXILLARY NODES
- APICAL AXILLARY NODES
- Pectoral branch of thoraco-acromial artery
- Internal thoracic artery
- Pectoralis major muscle
- Secretory lobules
- Suspensory ligaments
- Lactiferous sinuses
- Retromammary space
- PARASTERNAL NODES
- Mammary branches of internal thoracic artery
- LYMPHATIC AND VENOUS DRAINAGE PASSES FROM MEDIAL PART OF THE BREAST PARASTERNALLY
- SOME LYMPHATIC AND VENOUS DRAINAGE MAY PASS FROM INFERIOR PART OF THE BREAST INTO THE ABDOMEN
Breasts
What do the mammary glands consist of?
A series of ducts and associated secretory lobules.
What do the mammary gland ducts converge to form?
15 to 20 LACTIFEROUS DUCTS
Where do the lactiferous ducts open onto?
Independently onto the NIPPLE.
What is the nipple surrounded by?
A circular pigmented area of skin termed the AREOLA.
What surrounds the ducts and lobules of the mammary gland?
A well-developed, connective tissue stroma
What do the ducts and lobules condense to form?
In certain regions, these condense to form the suspensory ligaments of breast
What are suspensory ligaments of breast continuous with?
The dermis of the skin
What do the suspensory ligaments of breast do?
Support the breast
What happens to the suspensory ligaments of the breast in carcinoma?
Creates tension on these ligaments, causing pitting of the skin.
What is the predominant component of breast in nonlactating women?
Fat
What is the predominant component of breast in lactating women?
Glandular tissue is more abundant here
What does the breast lie on?
Deep fascia related to the pectoralis major muscle and other surrounding muscles
What is the layer of loose connective tissue that separates the breast from the deep fascia called?
The RETROMAMMARY SPACE
What does the retromammary space do?
Provides some degree of movement over underlying structures.
What part of the breast extends vertically from ribs II to VI?
The base, or attached surface
The base, or attached surface, of each breast extends where?
- vertically from ribs II to VI,
- transversely from the sternum to as far
- laterally as the midaxillary line
What is the arterial supply to the breast?
The breast is related to the thoracic wall and to structures associated with the upper limb; therefore, vascular supply and drainage can occur by multiple routes (Fig. 3.16):
- axillary artery
- internal thoracic artery
- 2nd to 4th intercostal arteries
What is the lateral arterial supply to the breast?
From vessels from the axillary artery
Which vessels from the axillary artery supply the breast?
Superior thoracic
Thoraco-acromial
Lateral thoracic
Subscapular
What is the medial arterial supply to the breast?
From branches from the internal thoracic artery
Other than the axillary and internal thoracic artery, what arteries supply the breast?
The second to fourth intercostal arteries via branches that perforate the thoracic wall and overlying muscle.
How do the 2nd-4th intercostal arteries supply the breast?
Via branches that perforate the thoracic wall and overlying muscle.
What is the venous drainage to the breast?
Veins draining the breast parallel the arteries
Where do veins draining the breast ultimately drain into?
The axillary, internal thoracic, and intercostal veins.
What is the innervation of the breast?
Innervation of the breast is via anterior and lateral cutaneous branches of the 2nd to 6th intercostal nerves.
What is the innervation of the nipple?
4th intercostal nerve.
What is the lymphatic drainage of the breast?
- lymphatic vessels
- parasternal nodes
- intercostal nodes
What is the main lymphatic drainage of the breast?
Approximately 75% is via lymphatic vessels
Where do the lymphatic vessels drain?
Laterally and superiorly into AXILLARY NODES (Fig. 3.16).
After the lymphatic vessels, where does most of the remaining drainage of the breast go?
Into parasternal nodes
Where are parasternal nodes?
Deep to the anterior thoracic wall
What are the parasternal nodes associated with?
The internal thoracic artery
A little bit of drainage of the breast may occur here ___?
Via lymphatic vessels that follow the lateral branches of posterior intercostal arteries and connect with intercostal nodes situated near the heads and necks of ribs.
Where do axillary nodes drain into?
Subclavian trunks
Where do parasternal nodes drain into?
Bronchomediastinal trunks
Where do intercostal nodes drain into?
Either the thoracic duct or the bronchomediastinal trunk
(In the Clinic - Axillary Tail of Breast)
What is it important for clinicians to remember about breast anatomy?
When evaluating the breast for pathology, remember that the upper lateral region of the breast can project around the lateral margin of the pectoralis major muscle and into the axilla.
(In the Clinic - Axillary Tail of Breast)
The upper lateral region of the breast enters where?
Into the axilla.
(In the Clinic - Axillary Tail of Breast)
What is the upper lateral region of the breast called?
The axillary process (axillary tail)
(In the Clinic - Axillary Tail of Breast)
Where can the axillary tail perforate?
Deep fascia
(In the Clinic - Axillary Tail of Breast)
Where can the axillary tail extend to?
As far superiorly as the apex of the axilla.
Describe the breast in men.
The breast in men is rudimentary
- consists only of small ducts
- often composed of cords of cells
- normally do not extend beyond the areola.
Can breast cancer occur in men?
Yes
(In the Clinic - Breast Cancer)
What is one of the most common malignancies in women?
Breast cancer
(In the Clinic - Breast Cancer)
Where does breast cancer develop?
In the cells of the
- acini
- lactiferous ducts
- lobules of the breast
(In the Clinic - Breast Cancer)
How does breast tumour grow and spread?
Tumour growth and spread depends on the exact cellular site of origin of the cancer.
(In the Clinic - Breast Cancer)
The exact cellular site of origin of the cancer affect what, as well as the tumour growth?
The response to surgery, chemotherapy and radiotherapy.
(In the Clinic - Breast Cancer)
How do breast tumours spread?
- Via the lymphatics and veins
- Direct invasion
(In the Clinic - Breast Cancer)
How is breast cancer diagnosed?
When a patient has a lump in the breast, a diagnosis of breast cancer is confirmed by a biopsy and histological evaluation.
(In the Clinic - Breast Cancer)
What does the clinician do when breast cancer is confirmed?
Stage the tumour
(In the Clinic - Breast Cancer)
What does staging the tumour mean?
STAGING THE TUMOUR means defining the:
- size of the primary tumour
- exact site of the primary tumour
- number and sites of lymph node spread, and
- organs to which the tumour may have spread.
(In the Clinic - Breast Cancer)
Why might we do a CT scan of the body on a patient with breast tumour?
Too look for metastases
(In the Clinic - Breast Cancer)
What does CT stand for?
Computed tomography
(In the Clinic - Breast Cancer)
Where can a breast tumour metastasise to?
Lungs (pulmonary metastases)
Liver (hepatic metastases)
Bone (bony metastases)
(In the Clinic - Breast Cancer)
Other than CT scans, what else can we do?
Further imaging
(In the Clinic - Breast Cancer)
What further imagining (other than CT scans) can we do?
Further imagining may include bone scanning using radioactive isotopes
(In the Clinic - Breast Cancer)
How does bone scanning using radioactive isotopes help diagnose breast cancer?
These are avidly taken up by the tumour metastases in bone.
(In the Clinic - Breast Cancer)
What is lymph drainage to the breast?
Lymph vessels pass to - axillary - supraclavicular - parasternal and may even pass to - abdominal lymph nodes, as well as to the opposite breast.
(In the Clinic - Breast Cancer)
Why is containment of nodal metastatic breast cancer potentially difficult?
Because breast cancer can spread through many lymph node groups due to the lymph drainage to the breast.
(In the Clinic - Breast Cancer)
What is the pathophysiology behind the ‘orange peel texture’ appearance in breast cancer?
Subcutaneous lymphatic obstruction and tumour growth pull on connective tissue ligaments in the breast, resulting in the appearance of an orange peel texture (PEAU D’ORANGE) on the surface of the breast.
(In the Clinic - Breast Cancer)
What can you be able to observe clinically when you look at the breast in breast cancer?
Appearance of an orange peel texture (PEAU D’ORANGE) on the surface of the breast
- due to subcutaneous lymphatic obstruction and tumour growth pull on connective tissue ligaments
Further subcutaneous spread induces a rare manifestation of breast cancer that
- produces a hard, woody texture to the skin (CANCER EN CUIRASSE).
(In the Clinic - Breast Cancer)
What does it mean if the breast looks hard and woody?
There has been further subcutaneous spread of the tumour, inducing a rare manifestation of breast cancer
(In the Clinic - Breast Cancer)
What do you sometimes visualise when you have further subcutaneous spread of the cancer?
A rare manifestation showing a hard, woody texture to the skin (CANCER EN CUIRASSE).
(In the Clinic - Breast Cancer)
What are the appearances and terms of how a breast appears when a patient has breast cancer?
PEAU D’ORANGE - orange peel texture
CANCER EN CUIRASSE - hard, woody texture
(In the Clinic - Breast Cancer)
What is a mastectomy?
Surgical removal of the breast
(In the Clinic - Breast Cancer)
What does a mastectomy involve?
Excision of the breast tissue to the pectoralis major muscle and fascia
(In the Clinic - Breast Cancer)
How is breast removed in the axilla?
Within the axilla the breast tissue must be removed from the medial axillary wall.
(In the Clinic - Breast Cancer)
What lies close to the medial axillary wall?
The long thoracic nerve
(In the Clinic - Breast Cancer)
What can damage to this nerve result in?
Paralysis of the serratus anterior muscle
(In the Clinic - Breast Cancer)
What clinical sign is produced on paralysis of the serratus anterior muscle?
A characteristic “winged” scapula
(In the Clinic - Breast Cancer)
What might be damaged on a mastectomy, and what are the associated sequelae?
The long thoracic nerve - this is closely applied to the medial axillary wall where the breast tissue within the axilla must be removed - causing paralysis of the serratus anterior muscle, producing a “winged” scapula
The nerve to lattisimus dorsi - affects extension, medial rotation and adduction of the humerus..
(In the Clinic - Breast Cancer)
What does damage to the nerve to the lattisimus dorsi muscle cause?
This may affect extension, medial rotation and adduction of the humerus.
What muscles do the pectoral region contain?
Pectoralis major
Pectoralis minor
Subclavius muscles
(Fig. 3.17 and Table 3.1)
Where do muscles of the pectoral region originate?
Pec major/minor and subclavius muscles originate from
the anterior thoracic walls
Where do muscles of the pectoral region insert?
Pec major/minor and subclavius muscles insert into
bones of the upper limb
Fig. 3.17
Label and caption the image
- PECTORALIS MAJOR
- SUBCLAVIUS
- Lateral pectoral nerve
- Thoraco-acromial artery
- PECTORALIS MINOR
- Medial pectoral nerve
- Lateral thoracic artery
- Clavipectoral fascia
Muscles and fascia of the pectoral region
What are the muscles of the pectoral region?
Pectoralis major
Subclavius
Pectoralis minor
What is the origin of pectoralis major?
Medial half of clavicle and anterior surface of sternum, first seven costal cartilages, aponeurosis of external oblique
What is the insertion of pectoralis major?
Lateral lip of intertubercular sulcus of humerus
What is the innervation of pectoralis major?
Medial and lateral pectoral nerves
What is the function of pectoralis major?
Adduction, medial rotation, and flexion of the humerus at the shoulder joint
What is the origin of subclavius?
Rib I at junction between rib and costal cartilage
What is the insertion of subclavius?
Groove on inferior surface of middle third of clavicle
What is the innervation of subclavius?
Nerve to subclavius
What is the function of subclavius?
Pulls clavicle medially to stabilize sternoclavicular joint; depresses tip of shoulder
What is the origin of pectoralis minor?
Anterior surfaces of the third, fourth, and fifth ribs, and deep fascia overlying the related intercostal spaces
What is the insertion of pectoralis minor?
Coracoid process of scapula
What is the innervation of pectoralis minor?
Medial pectoral nerves
What is the function of pectoralis minor?
Depresses tip of shoulder; protracts scapula
Which muscle is the largest of the pectoral region muscles?
PECTORALIS MAJOR
Which muscle is the most superficial of the pectoral region muscles?
PECTORALIS MAJOR
What structure does pectoralis major lie under?
It directly underlies the breast
How is pectoralis major separated from the breast?
By deep fascia and the loose connective tissue of the retromammary space
What muscle originates broadly from the anterior surface of the medial half of the clavicle, the sternum, and related costal cartilages?
Pectoralis major
What happens to the muscle of pectoralis major to its insertion?
They converge to form a flat tendon
Which muscle converges to form a flat tendon, then inserts into the lateral lip of the intertubercular sulcus of the humerus?
Pectoralis major
Which muscle adducts, flexes and medially rotates the arm?
Pectoralis major
Which muscles underlie pectoralis major?
SUBCLAVIUS and PECTORALIS MINOR MUSCLES
Describe subclavius size/orientation including origin and insertion.
The subclavius is small and passes laterally from the anterior and medial part of rib I to the inferior surface of the clavicle.
Where does pectoralis minor originate and insert?
The pectoralis minor passes from the anterior surfaces of ribs III to V to the coracoid process of the scapula.
Which pectoral region muscles pull the tip of the shoulder inferiorly?
Both the subclavius and pectoralis minor
What is the fascia called that encloses the subclavius and pectoralis minor?
CLAVIPECTORAL FASCIA
What type of fascia is the clavipectoral fascia?
A continuous layer of deep fascia
What does the clavipectoral fascia enclose?
Subclavius and pectoralis minor
Where does the clavipectoral fascia attach to?
Clavicle (above)
Floor of the axilla (below)
What forms the anterior wall of the axilla?
The muscles of the pectoral region
What is the axilla?
A region between the upper limb and the neck through which all major structures pass.
Nerves, vessels, and lymphatics that pass between the pectoral region and the axilla pass through what?
The clavipectoral fascia between the subclavius and pectoralis minor OR pass under the inferior margins of the pectoralis major and minor.
