Pectoral & Axillary Regions Flashcards
Mammary glands are modified ________ glands
Sweat
Where does the breast rest?
On pectoral fascia (above pectoralis major)
Interior to exterior:
Pectoralis major → Retromammary → Subcutaneous tissue →Mammary gland lobules (where milk is, converge on nipple) → Lactiferous ducts (15-20 open at nipple) → nipple
What innervates the breast?
Intercostal nerves (4th-6th)
The breast attaches to dermis of skin via suspensory ligaments called what?
Cooper’s ligaments (anchors fatty tissue to skin and gives form)
Breast blood supply
Axillary a. (on lateral side) and Subclavian a. (on medial side)
(Branches from anterior intercostal, lateral thoracic, and internal thoracic arteries)
Veins of the breast
Mainly to axillary vein via lateral thoracic veins and medial mammary veins ) less to medial
Lymphatic drainage of breasts
Nipple, Areola, Lactiferous Lobules → drained by subareolar lymph nodes
> 75% → axillary lymph nodes (pectoral, central, apical)
Remaining → parasternal, abdominal lymph nodes
Breast innervation
Mainly the anterior and lateral branches of 4th-6th intercostal nerves
Can get some from supraclavicular nn.
Fascia of pectoral region
Defines borders, surrounds muscle etc. Makes the deltopectoral triangle
What’s the deltopectoral triangle?
Where cephalic v. goes up from arm and dumps into subclavian and axillary veins
What makes up the superficial fascia of pectoral region?
Platysma
Supraclavicular nerves
Anterior/lateral branches of intercostal nerves
What’s in the Deltopectoral Triangle?
Deltoid, pectoralis major, middle 1/3 of clavicle make up borders
Cephalic vein, deltopectoral lymph nodes, deltoid branch of thoracoacromial a. (from axillary a.)
Clavipectoral Fascia of Pectoral region
Surrounds the subclavius and pectoralis minor muscles
Involves: cephalic vein, thoracoacromial a., lateral pectoral nerves pierce it
Becomes ‘suspensory ligament of axilla’
Pectoralis muscles are innervated by what?
Spinal nerves via branches from brachial plexus
Pectoralis major actions, innervation and blood supply
Actions:
- Adducts/medial rotates humerus
- Draws scapula anteriorly/inferiorly
- Clavicular part flexes humerus
- Sternal part extends humerus
Blood Supply:
-Pectoral branches of thoracoacromial arterial trunk
Innervation:
-Lateral/medial pectoral nerves
What pierces the pectoralis minor muscle?
Medial pectoral n.
How are medial/lateral pectoral nerves named?
Named for part of the brachial plexus that they come from
- Medial pectoral n: arises from medial cord of BP
- Lateral: from lateral cord of brachial plexus
Pectoralis minor actions, innervation and blood supply
Actions:
-Stabilizes scapula by pulling it anteriorly/inferiorly against posterior thoracic wall
Blood supply: pectoral branches of thoracoacromial arterial trunk
Innervation: Medial pectoral nerve
Subclavius actions, innervation and blood supply
Actions:
-Anchors/depresses clavicle
Blood supply: clavicular branches of thoracoacromial arterial trunk
Innervation: “nerve to subclavius”
Serratus anterior actions, innervation and blood supply
Actions:
-Protracts scapula, rotates scapula, hols scapula against thorax
Blood Supply: Lateral thoracic artery
Innervation: long thoracic nerve
Blood supply to pectoral region?
Supplied by axillary artery
- Pectoralis minor divides axillary a. into 3 main parts
- Anterior scalene divides the subclavian a. into 3 main parts
What are the 3 main parts of the axillary that are divided by the pectoralis minor?
- Superior thoracic artery
- Thoracoacromial trunk
- Subscapular artery
Vein drainage in Pectoral Region
Axillary vein
Boundaries of the Axilla
- Pyramid shaped space
- Apex
- Base (Ant/Post axillary folds)
- Anterior wall
- Posterior wall
- Medial wall
- Lateral wall
