Axilla & Chest

Clinical Correlation of the Breast

For descriptive purposes, clinicians divide the breast into four quadrants (G 195B). The superolateral (upper outer) quadrant contains a large amount of glandular tissue and is a common site for breast cancers to develop. From this quadrant, an "axillary tail" of breast tissue often extends into the axilla.In advanced stages of breast cancer, the tumor may invade the underlying pectoralis major muscle and its fascia. When this happens, the tumor and breast become fused to the chest wall, a condition that can be detected by palpation during a physical examination. As the breast tumor enlarges, it places traction on the suspensory ligaments, resulting in dimpling of the skin overlying the tumor.

3 parts of axillary artery

Part1: Lateral Border of 1st Rib & Medial Pectoralis Major Part 2: Posterior to Pectoralis Minor Part 3: Lateral Border of Pectoralis Minor to Inferior border of Teres Major

Axillary Nerve

Passes anterior to lat. and teres major but posterior to humerus. Only motor AND sensory nerve to posterior upper limb

Posterior cord of Brachial plexus is composed of:

Posterior divisions of Upper, Middle, and Lower trunks

Branches of Posterior Cord

Radial, Axillary, Upper, Middle (Thoracodorsal N.), and Low subscapular nerve

Describe injury of the thoracodorsal nerve

The thoracodorsal nerve is vulnerable to compression injuries and surgical trauma during mastectomy. Injury of the thoracodorsal nerve affects the latissimus dorsi muscle resulting in a weakened ability to extend, adduct, and medially rotate the arm.

The roots of the brachial plexus actually combine quickly to form:

The upper (superior), middle and lower (inferior) trunks

Brachial plexus is made up of what roots?

Ventral rami of C5-T1

The middle trunk splits into:

Anterior (which will join the the upper anterior to form the lateral cord) and the posterior division (which will join the others to form posterior cord)

The upper trunk splits into:

Anterior (which will join to become lateral cord) and posterior (whcih will join to form posterior cord)

The lower trunk splits into:

Anterior division (forming medial cord ENTIRELY) and posterior division (going under and forming that upper "M")

The medial cord is composed of:

Anterior division of lower trunk ONLY

Name the borders of the Axilla

Apex of the Axilla: bounded by the clavicle anteriorly, the superior border of the scapula posteriorly, and the first rib medially Base of the axilla - skin and fascia of the armpit Anterior wall - anterior axillary fold (pectoralis major muscle), pectoralis minor muscle, and clavipectoral fascia Posterior wall - posterior axillary fold (teres major and latissimus dorsi muscles) and the subscapularis muscle that covers the anterior surface of the scapula Medial wall - upper portion of the thoracic wall and the serratus anterior muscle, which overlies this wall Lateral wall - intertubercular sulcus of the humerus

What passes through Quadrangular space?

Axillary Nerve and Posterior circumflex humeral artery

circumflex scapular artery

Branch of subscapular artery (which is ab ranch of thrird part of axillary artery) to muscles on the posterior surface of the scapula (teres minor, teres major, supra spinatus, inferaspinatus, suprascapularis along with other anastomoses of axxilary and subclavical artery such as dorsal scapular, and suprascapular)

posterior circumflex humeral artery

Branch of third part of Axillary Artery. The posterior circumflex passes posterior to surgical neck of humerus and through the quadrangular space with the axillary nerve (which stems from the posterior branch of the brachial plexus between M's)

perforating veins

Connect the superficial and deep venous system

function of the sternocostal head of pectoralis major

adducts and pedialy rotates

acromion

an extension of the scapula that forms the high point of the shoulder

apex of the axilla

apex of the axilla is bounded by the clavicle anteriorly, and more superior structures enter the axilla by passing posterior to it

sternal angle

at level of second costal cartilage

subscapular muscle

attached to subscpular fossa of the scapula, laterally attached to lesser tubercle of humerus. it medially rotates the humerus and therefuore part of the rotator cuff muscle group.

Laterally, the deltopectoral triangle narrows to form the

deltopectoral groove

subclavius muscle

depresses the clavicle

superficial fascia contains

fat, superficial veins, and cutaneous nerves frequently used for drawing blood and injecting medications..

Function of the calvicular head of pectoralis major

flexes the humerus

axillary vein

formed at lateral border of teres minor by joining of two brachial veins, to form one giant vein leading into the lateral border of the first rib where it becomes the subclavian artery

jugular notch

found between sternal ends of the clavicles

The pec minor muscle attahcments:

inferiorly: ribs 3 to 5 near their costal cartilages Superiorly:coracoids process draws the glenoid cavity of the scapula anteriorly and inferiorly

long thoracic nerve

innervates antererior serratus muscles, formed by ventral rami of C5-C6

middle subscapular nerve (thoracodorsal nerve)

innervates lats

Upper subscapular nerve

innervates subscapularis muscle

Lowe subscapular nerve

innervates subscapularis muscle and teres major muscle

cubital fossa.

inside of elbow

The roots of the brachial plexus emerge from

interscalene triangle

3 cords of brachial plexus

lateral, posterior, medial

Pectoral Fascia is a continuation of:

pectoral fascia is continuous with the axillary fascia that forms the base of the axilla

lateral pectoral nerve innervates

pectoralis major

subclavian artery

prior to becoming the axillary artery, located on the lateral side of the first rib

medial wall fo the axilla is formed by the

serratus anterior muscle, innervated by long thoracic nerve

serratus anterior muscle

supplied blood by the lateral thoracic artery, and innervated by the long thoracic nerve (C5-C7 branch). extensive anterior attachments on the upper eight or nine ribs (G 506; G 519). The posterior attachment of the serratus anterior muscle is on the anterior surface of the scapula along the entire length of its medial border, but the bulk of the muscle converge on the inferior angle of the scapula (you cannot see the posterior attachment at this time). the serratus anterior muscle protracts the scapula (slides it forward), and the portion attaching to the inferior angle is important in "glenoid-up" rotation of the scapula

Lateral thoracic artery

supplies blood to anterior serratus

What nerve branches from the Upper root of the brachial plexus?

suprascapular nerve, before the upper trunk

hypothenar eminence

the fleshy mass at the base of the little finger

thenar eminence

the fleshy mass at the base of the thumb

bassilic and cephalic vein combine at the cubital fossa to form

the median cubital vein

Pec major and minor receive blood from

thoracoacromial artery

Second part of axillary artery has how many branches

2: thoracoacromial and lateral thoracic artery

Third part of Axillary Artery

3* Branches: Posterior Circumflex humeral artery, anterior Circumflex humeral artery, Subscapular artery* Subscapular Artery divides into thoracodorsal artery and circumflex scapular artery

anterior and posterior circumflex humeral arteries

(The posterior may be larger) they supply the deltoid muscle The posterior circumflex passes posterior to surgical neck of humerus and through the quadrangular space with the axillary nerve (which stems from the posterior branc of the brachial plexus between M's)

medial cutaneous nerve of the forearm and the medial cutaneous nerve of the arm

2 inferior branches of the medial cord, with the Forearm most lateral and the arm most medial. The med. cut. of the arm is often absent and the med. cut. of the forearm handles the territoy.

Lateral Thorarcic Artery

In 35% of females, the lateral thoarcic artyry may arise from the subscapular or thoracoacomial artery. The lateral thoracic artery supplies blood to the major pectoral muscle, serratus anterior muscle, and axillary lymphnodes, and lateral thoracic wall. In females it also supplies to lateral portion of the breast.

Median nerve is formed by

Lateral Root of Median nerve and Medial Root of Median Nerve

musculocutaneous nerve stems from

Lateral cord

3 msucles that form the posterior wall of axilla

Latismuss doris, teres major, and subscapularis

Ulnar Nerve

Most "lateral" terminal branch off of medial nerve

Medial Pectoral Nerve

Most anterior/proximal of the 3 medial nerve branches Innervates both Pec Major and Minor

Lateral Pectoral Nerve

Most distal/inferior of the Lateral cord branches, innervates only pec major

terminal branches of the brachial plexus

Musculocutaneous, Median, Ulnar (With Radial under neath from posterior cord)

deltopectoral triangle

Narrow, triangular groove bordered by clavicle, deltoid, and pectoralis major muscles. Also known as Clavipectoral triangle

cutaneous nerves

Nerves that go into skin, giving off terminal branches that ascent into dermi

First part of axillary artery has how many branches

None that you need to know about (superior thoracic)

thoracroacromial artery

Supplies the Deltoid, Pec Major, Pec Minor, Subclavius

Pectoral fascia is connected to the overlying skin of the breast by

Suspensory ligaments of the breast (cooper's ligaments) that pass beteen lobes of the mammary glands

The lateral cord is composed of: (moving distally)

The Upper and Middle trunk anterior divisions

Describe injury of the axillary nerve

The axillary nerve courses around the surgical neck of the humerus and may be injured during a fracture or during an inferior dislocation of the shoulder joint. Injury of the axillary nerve affects the deltoid muscle and teres minor muscle, resulting in a weakened ability to abduct and laterally rotate the arm.

The breast is anterior to the

The breast is anterior to the pectoral fascia

Damage to long thoracic nerve causes

The long thoracic nerve is vulnerable to stab wounds and to surgical injury during mastectomy. Injury of the long thoracic nerve affects the serratus anterior muscle. When a patient with paralysis of the serratus anterior muscle is asked to push with both hands against a wall, the medial border of the scapula protrudes on the affected side, a condition known as "winged scapula." However, paralysis of the trapezius muscle due to damage to the accessory nerve can also result in winging of the scapula.

Location of medial and lateral pectoral nerves

The medial pectoral nerve typically is found emerging from the anterior surface of pectoralis minor to enter the deep surface of the pectoralis major (N 419; T 28.34). The lateral pectoral nerve is related to the medial border of pectoralis minor.

subscapular artery

The subscapular artery courses inferiorly for a short distance before dividing into the circumflex scapular artery (to muscles on the posterior surface of the scapula) and the thoracodorsal artery (to the latissimus dorsi muscle)

Winging of the scapula

When the serratus anterior is paralyzed, the inferior angle of the scapula moves posteriorly away from the chest wall to make a noticeable ridge beneath the skin of the back, a condition known as winging of the scapula. Paralysis of the trapezius yields a similar change in appearance of the back. At first look, the examiner may be unable to decide whether winging of the scapula is due to a serratus anterior or a trapezius paralysis. The determination is then made by requiring the patient to perform a motion for which one of the muscles is significantly more important than the other. If that important muscle is damaged, the winging will become worse; if that important muscle is intact, the winging will become less noticeable. For example, when the patient abducts the arm, a motion for which trapezius action on the scapula is particularly important, trapezius-winging will become more prominent but a serratus-winging will lessen (or remain unchanged). When the patient flexes the arm, a motion for which serratus action on the scapula is particularly important, a serratus-winging will worsen but any winging caused by a paralyzed trapezius will diminish. The serratus anterior is not only a rotator of the scapula, but it also protracts (pulls anteriorly) this bone. Consequently, winging due to a paralyzed serratus anterior will be accentuated by applying a dorsally directed force to the scapula that the paralyzed serratus is unable to resist. In diagnosis, this is accomplished by asking the patient to hold his or her hands stretched out in front of the body and then lean against a wall supported by the outstretched hands. This maneuver stresses the protracting ability of the serratus and causes a serratus-winging to become even worse. Had the appearance of winging at rest been due to a weak trapezius, the winging would virtually disappear when the patient performed such a test.

cephalic vein

a large vein of the arm that empties into the axillary vein

Clavipectoral fascia

between pectoralis major and minor, attached to clavicle superiorly, and is attached to the axillary fascia inferiorly

carpal bones

bones of the wrist

thoracodorsal artery

branch of subscapular artery (branch of axillary artery 3rd branch) that supplies the latismuss dorsi

lactiferous ducts and sinuses

carry and store milk

only structure found in the deltopectoral triangle

cephalic vein

2 heads of pectoralis major

clavicular head and sternocostal head

axillary sheath

connective tissue structure that surrounds the axillary vessels and brachial plexus

Pectoral Region function

covers anterior thoracic wall and partial lateral thoracic wall