Human Anatomy - Axilla

Axillary lymph node drainage

(triangle) Subclavian lymphatic trunk apical group central group Pectoral (anterior) group Subscapular (posterior) group Humeral (lateral) group

Axillary Lymph Nodes

-Apical group (most proximal). -Central group. -Humeral (lateral) group. -Pectoral (anterior) group. -Subscapular (posterior) group. (Drain lymph from breast and drain upward toward venous circulation Lymph flow back into venous system -left drains through thoracic duct (majority) -right drains less, right half of head and neck and right upper limb Between internat jugular vein and subclavian vein)

Arteries around the scapula

-Dorsal scapular -Post. Circumflex humeral -Suprascapular -Subscapular (circumflex scapular) -Acromial branch of the thoracoacromial (draw)

Subscapular Artery

-Largest branch of axillary artery (most important, very big)

Base

formed by skin, subcutaneous tissue, and axillary fascia (when you place your hand in armpit, you are touching this - contains many arteries and nerves)

Enlargment of the axillary nodes results from ______

infections of the upper limb or cancer of the shoulder and thoracic region. The humeral group is the first one to be involved. Enlargement of the apical group may obstruct the cephalic vein

2 nerves vulnerable during this dissection

long thoracic nerve (innervates serratus anterior) and thoracodorsal nerve (innervates latissimus dorsi). These two nerves needs attention during cadaver dissection as well (easy to damage)

Damage to thoracodorsal nerve

no more monkey bars

The axilla contains ____

one apex, one base, and four walls

Anterior wall

pectorals major and pectorals minor

Posterior wall

scapula, subscapularis, trees major, and latissimus dorsi

Circumflex humeral arteries supply _____

shoulder muscles such as the deltoid, teres major and minor, and the long head of the triceps

Axillary vein becomes _____ which becomes ____ which becomes _____

subclavian vien brachiocephalic vein superior vena cava

Anatomoses around the scapula: Laterally

subscapular artery (circumflex branch), post. Circumflex scapular, acromial branch of thoracoacromial

Anatomoses around the scapula: Superiorly

suprascapular artery (not from axillary artery).

Apex

the entrance from the neck to axilla, the superior opening is the cervicoaxillary canal

Lateral wall

the intertubercular groove of the humerus

Medial wall

thoracic wall (1-4 ribs and intercostals muscles) and serratus anterior muscle

Branches of Axillary Artery: 2nd part

thoracoacromial lateral thoracic artery (runs to lateral aspect of thoracic wall and portion to breast)

Damage to long thoracic nerve

winged scapula

Large arteries in Neck/Shoulder Region: Subclavian

-Internal thoracic (by sternum) -Thyrocervical trunk (very short branch): (1)inf. Thyroid, (2)transverse cervicle, (3)suprascapular -Vertebral (through transverse process of cervical vertebra and into the cranium to provide blood into brainstem and cerebellum) -Costocervical trunk -Dorsal scapular (Subclavian before it passes beyond lateral edge first rib - after it is called the axillary artery, ends by inferior edge of trees muscle)

Axillary Vein

-Lies on the medial side of axillary artery. -Axillary vein has more abundant tributaries than the branches of the axillary artery. -Axillary vein has more anastomoses. -Axillary vein has more variations (veins and its tributaries)

Lateral Thoracic Artery

-May rise variously, supplies pectoral muscles, axillary lymph nodes, and the breast. -It is an important source of blood to the lateral part of the mammary gland in women

Large arteries in Neck/Shoulder Region: Axillary

-Superior thoracic -Thoracoacromial: (1)clavicular,(2)pectoral,(3)deltoid,(4)acromial -Lateral thoracic Subscapular: (1)circumflex scapular, (2)thoracodorsal -Ant. Circumflex humeral -Post. Circumflex humeral

Thoracoacromial Artery

-a short wide trunk, deep to the clavicular head of pectorals minor

The thoracoacromial artery divides into 4 branches

-acromial -deltoid -pectoral -clavicular

Neurovascular structures in the axilla

-axillary artery -axillary sheath -long thoracic nerve -axillary vein -subscapular nerve (axillary sheath - circulatory sheath wrapping all the arteries and nerves) - a lot of lymph nodes scattered in the area

Arterial Anastomoses around the scapula and ligation points

-no ligation (if you ligate artery here for too long you will completely cut off blood supply to upper limb - in-between the anterior/posterior circumflex arteries) -another branch traveling with radial nerve

There are ______ that supply ______ around the ______

5 blood scapula -which is very good

Superior Thoracic Artery

A small vessel, supplies muscles in the 1st and 2nd rib intercostals spaces and serratus anterior, anastomoses with intercostals arteries.

Axillary Vein Receiving Bypass

Axillary vein receives directly or indirectly from the thoracoepigastric vein, which collects blood from the superficial veins of the inguinal region. -Blood used to return to the heart through inferior vena cava now can go through superior vena cava. -This is the collateral route (a bypass) for venous return when inferior vena cava is obstructed.

Axillary Artery: 1st part

Between the lateral border of the 1st rib and the medial border of the pectoralis minor, enclosed in axillary sheath. Has one branch. -in front of pec minor

Axillary Artery: 3rd part

Between the lateral border of the pectoralis minor and the inferior border of teres major. Has three branches -beyond pec minor?

Axillary Artery: 2nd part

Posterior to the pectoralis minor. Has two branches. -behind pec minor

If compression of inferior vena cava _____

Situation: liver sirosis (liver hardens) If blood returned gets reduced, then blood cannot go back to heart easily, so will go through bypasses (anastomoses), and return through superior vena cava (will see superficial veins very clearly on anterior thoracic wall)

Axillary lymph node dissection

Sometimes is necessary for pathological analysis of tumor staging or surgical removal of metastatic malignant cells.

Circumflex Humeral Arteries

The anterior and posterior circumflex arteries anastomoses with each other

Compression of the Axillary Artery

This is needed when heavy bleeding of the arm happens. There are two compression locations: -One is at the third part of the artery - palpate the inferior part of the lateral wall of the axilla against the humerus. (above the clavicle, not easy to do) -Another is at the beginning of the artery - downward pressure in the angle between the clavicle and the attachment of the sternocleidomastoid muscle against the 1st rib. (easier way to do, pushing down on humerus)

Axilla (armpit)

a pyramidal shaped space between the arm and the thorax providing a passage for vessels and nerves to reach the upper limb neurovascular structures are ensheathed in a fascial sleeve called "axillary sheath" (axilla runs behind the teres minor)

Subscapular artery divides into ________

circumflex scapular and thoracodorsal arteries

Axillary artery ______

continues from subclavian artery -right common carotid -right subclavian artery -left subclavian artery -left common carotid -brachiocephalic trunk -aortic arch (vein travels with artery)

Anatomoses around the scapula: Medially

dorsal scapular artery (not from axillary artery)

slide 21

draw:Ligation at which one of the following points will completely cut off the blood supply to the upper limb? -C - area between anterior/posterior circumflex humeral arteries and the deep artery to the arm

Branches of Axillary Artery: 3rd part

subscapular, anterior and posterior circumflex humeral arteries (hug around surgical neck of humerus)

Subscapular artery supplies ______

subscapularis, teres major, serratus anterior, and latissimus dorsi

Branches of Axillary Artery: 1st part

superior thoracic artery (very small, provides blood to thoracic wall) - doesn't really need that because of intercostal arteries