Thorax: The Pectoral Region Flashcards

1
Q

Name two parts (and constituents) of the pectoral region.

A

•Superficial compartment constitutes the breast, superficial fascia and skin.
•Deep compartment constitutes the muscles and associated structures.

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2
Q

What do we mean when we say the muscles of the pectoral region are axio-appendicular?

A

-They extend from the thoracic cage to the bones of the upper limb.

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3
Q

Name and briefly describe the three subcutaneous nerves of the pectoral region.

A

•Supraclavicular nerves
-They extend from the cervical plexus in the neck.
-They supply skin over upper thoracic wall.
•Lateral cutaneous nerves
-Branch from the intercostal nerves.
-Supply skin over lateral thoracic and abdominal walls.
•Anterior cutaneous nerves
-Branch from the intercostal nerves.
-Supply skin over the anterior thoracic and abdominal walls.

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4
Q

Dermatomes for:
A. Nipple
B. Xiphoid process
C. Umbiculus

A

A. T4
B. T6
C. T10

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5
Q

What are the three branches of the intercostal nerves?

A

-Lateral cutaneous
-Anterior cutaneous
-Small collateral

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6
Q

What are the three blood vessels of the pectorial region and their branches?

A

•Descending thoracic aorta
-Posterior intercostal and subcostal branches.
•Subclavian artery
-Internal thoracic branches
-Supreme intercostal branches
•Axillary artery
-Superior thoracic branches
-Lateral thoracic branches
-Thoraco-acromial branches

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7
Q

Name the four pectoral muscles

A

-Pectoralis major muscle
-Pectoralis minor muscle
-Subclavius muscle
-Serratus anterior

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8
Q

What is the origin, insertion, innervation and action of the pectoralis minor muscle?

A

ORIGIN
-Anterior surface of rib 3-5.
-Deep fascia over intercostal spaces 3-5.
INSERTION
-Coracoid process of scapula.
INNERVATION
-Medial pectoral nerve
ACTION
-Depression of the tip of the shoulder.
-Protraction of scapula.

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9
Q

What is the origin, insertion, innervation and action of the serratus anterior?

A

ORIGIN
-Lateral surface of upper 8-9 ribs.
-Deep fascia overlying related intercostal spaces.
INSERTION
-Medial border of scapula.
INNERVATION
-Long thoracic nerve
ACTION
-Protraction and rotation of scapula.
-Keeps the medial border and inferior angle of the scapula against the thoracic wall.

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10
Q

What is the origin, insertion, innervation and action of the pectoralis major muscle?

A

ORIGIN
-Clavicular head, abdominal head and sternal head.
INSERTION
-Lateral lip of the intertubercular sulcus (humerus).
INNERVATION
-Medial and lateral pectoral nerves
ACTION
-Adduction
-Medial rotation and flexion of humerus.

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11
Q

What is the origin, insertion, innervation and action of the subclavius muscle?

A

ORIGIN
-Rib 1 @ junction btwn the rib and costal cartilage.
INSERTION
-Groove on inferior surface of middle 1/3 of clavicle.
INNERVATION
-Nerve to subclavius.
ACTION
-Depression of the tip of the shoulder.
-Pulls the clavicle medially to stabilise the sternoclavicular joint.

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12
Q

What are the two extrathoracic muscles?

A

External oblique muscle
Ructus abdominis muscle

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13
Q

What is the origin, insertion, innervation and action of the rectus abdominis muscle?

A

ORIGIN
-Pubic crest and tubercle
-Pubic symphysis
INSERTION
-Costal cartilages of ribs 5-12
-Xiphoid process
INNERVATION
-Anterior rami of lower 6 thoracic spinal nerves.
ACTION
-Compresses abdominal contents
-Tenses abdominal wall
-Flexes vertebral column

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14
Q

What is the origin, insertion, innervation and action of the external oblique muscle?

A

ORIGIN
-Muscle slips of outer surface of lower 8 ribs.
INSERTION
-Aponeurosis ending at linea alba.
-Lateral lip of pubic crest.
INNERVATION
-Anterior rami of lower 6 thoracic spinal nerves.
ACTION
-Compresses abdominal contents.

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15
Q

Fascia found in the pectoral region?

A

Clavicopectoral fascia

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16
Q

What does the clavicopectoral fascia enclose?

A

-Partially encloses the subclavius muscle, completely encloses the pectoralis minor muscle.

17
Q

Structures that passes through the clavicopectoral fascia (4)

A

-Cephalic vein
-Lymphatics
-Thoraco-acromial artery
-Lateral pectoral nerve

18
Q

Between which two ribs do breast lie? (Generally)

A

2nd and 6th ribs

19
Q

Where does the nipple generally lie?

A

Lies over the 4th intercostal space

20
Q

What do we call the superolateral extension around the pectoralis major muscle?

A

Axillary tail/ process

21
Q

Lobules converge to form which structure?

A

Lactiferous ducts

22
Q

Circular pigmented area that surrounds the nipple.

A

Areola

23
Q

More abundant component in non-lactating female?

A

Fat

24
Q

Most abundant component in lactating females?

A

Glandular tissue

25
Q

Layer of loose connective tissue which separates the breast from the deep fascia?

A

Retromammary space

26
Q

Explain the arterial supply of the breast (5)

A
  1. Axillary artery
    -Superior thoracic artery
    -Lateral thoracic artery
    -Subscapular artery
    -Thoraci-acromial artery
  2. 2nd to 4th posterior intercostal arteries
  3. Internal thoracic arteries
27
Q

Venous drainage of the breast? (3)

A

-Axillary vein
-Internal thoracic vein
-Posterior intercostal veins

28
Q

Nerve supply of the breast

A

-2nd to 6th intercostal nerves with the nipple being specifically innervated by the 4th intercostal nerve.

29
Q

Lymphatic drainage of the breast

A

-Most drain into the axillary lymph nodes.
-Most of the remaining into the parasternal nodes.
-Some into the intercostal nodes.

30
Q

Five groups of the axillary lymph nodes

A

-Apical
-Central
-Anterior (pectoral)
-Posterior (subscapular)
-Lateral (humeral)

31
Q

Where do apical nodes drain into?

A

-The subclavian trunks

32
Q

Where does the parasternal nodes drain into?

A

-Bronchomediastinal trunks

33
Q

Where does the intercostal nodes drain into? (2)

A

-Bronchomediastinal trunks and thoracic duct.