Anatomy Of Shoulder And Arm II Axilla and Its Contents Dr. Fadel Naim Orthopedic Surgeon Faculty of Medicine IUG-Gaza

SURFACE ANATOMY Anteriorly Posteriorly Clavicle Tip of coracoid process of scapula Greater tubercle of humerus Deltoid contour axilla and its folds Medial epicondyle shows head of humerus direction Lateral epicondyle show greater tuberosity direction Posteriorly Scapula acromian,crest of spine [T3] medial and lateral borders, inferior angle

Surface anatomy Anterior aspect Posterior aspect

Axilla (Arm pit)

AXILLA A pyramid-shaped space between the upper part of the arm and the side of the chest through which major neurovascular structures pass between neck & thorax and upper limbs.

Axilla 4 Sided pyramid Apex connected to the neck=Inlet Base Arm pit= Outlet Anterior wall Posterior wall Medial wall Lateral wall

Axillary Walls Bones Anterior Posterior Medial Lateral Clavicle Scapula Ribs Humerus

Muscles Anterior Posterior Medial Lateral Pectoralis major pectoralis minor subclavius Subscapularis teres minor teres major latissimus dorsi Serratus anterior Tendon of long head of biceps

Anterior wall: Is formed by Pectoralis major Pectoralis minor Subclavius Clavipectoral fascia Clavipectoral fasciac Pectoralis minor subclavius Pectoralis major

Muscles Anterior Posterior Medial Lateral Pectoralis major pectoralis minor subclavius Subscapularis teres minor teres major latissimus dorsi Serratus anterior Tendon of long head of biceps

Muscles Anterior Posterior Medial Lateral Pectoralis major pectoralis minor subclavius Subscapularis teres minor teres major latissimus dorsi Serratus anterior Tendon of long head of biceps

Muscles Anterior Posterior Medial Lateral Pectoralis major pectoralis minor subclavius Subscapularis teres minor teres major latissimus dorsi Serratus anterior Tendon of long head of biceps Coracobarchialis

Apex Of Axilla The entrance from neck to axilla The superior opening of the axilla to reach the arm Boundaries: 1st rib medially Clavicle anteriorly Upper border of the scapula posteriorly The arteries, veins, lymphatics, and nerves pass from the neck to the axilla through the cervico-axillary canal

Base Of Axilla Anterior axillary fold ( pectorails major ) Posterior axillary fold ( latissimus dorsi ) Chest wall ( medially ) Formed by: The concave skin Subcutaneous tissue Axillary (deep) fascia extending from the arm to the thoracic wall

Pectoralis Major Origin INSERTION Action Nerve Clavicular head: Medial half clavicle. Sternocostal head: Lateral manubrium Sternum Six upper costal cartilages External oblique aponeurosis INSERTION Lateral lip of bicipital groove of humerus Action Flexes and adducts arm. Sternal head: Adducts and medially rotates arm . Accessory for inspiration Nerve Medial pectoral nerve (from medial cord) Lateral pectoral nerve (from lateral cord)

Absent Pectoralis Major Deficiency or absence of the sternocostal part is not uncommon. No disability usually results The anterior axillary fold is absent on the affected side The nipple is more inferior than usual.

Poland syndrome The classic ipsilateral features of Poland syndrome include the following: Absence of sternal head of the pectoralis major muscle Hypoplasia and/or aplasia of breast or nipple Deficiency of subcutaneous fat and axillary hair Abnormalities of rib cage Upper extremity anomalies; short upper arm, forearm, or fingers

The Clavipectoral Fascia A fascial envelope extends from the axillary fascia, encloses the pectoralis minor and subclavius muscles, and then attaches to the clavicle The costocoracoid membrane: The part of the clavipectoral fascia superior to the pectoralis minor is pierced by the lateral pectoral nerve that primarily supplies the pectoralis major. The suspensory ligament of the axilla: The part of the clavipectoral fascia inferior to the pectoralis minor supports the axillary fascia and pulls it and the skin inferior to it upward during abduction of the arm, forming the axilla

Clavipectoral fascia Encloses subclavius Pectoralis Minor. It is pierced by : Cephalic vein. Lymph nodes from pectoral region to apical group of axillary lymph nodes Lateral pectoral nerve. Thoraco- acromial artery

Clavicle Subclavius Clavipectoral fascia Pectoralis major Subscapularis Pectoralis minor Teres major Latissimus dorsi

Subclavius Origin INSERTION Action Nerve Costochondral junction of 1st rib INSERTION Subclavian groove on inferior surface of middle third of clavicle Action Depresses clavicle and steadies it during shoulder movements Nerve Nerve to subclavius (upper trunk of brachial plexus)

Pectoralis Minor Origin 3, 4, 5 ribs INSERTION Action Nerve Important Medial and upper surface of coracoid process of scapula Action Elevates ribs if scapula fixed Pulls shoulder downward and forward Nerve Medial pectoral nerve (from medial cord of brachial plexus) Important The pectoralis minor muscle is covered by the clavipectoral fascia. The medial pectoral nerve pierces the pectoralis minor . Axillary artery is divided into three parts by pectoralis minor.

Subscapularis Origin INSERTION Action Nerve Medial two thirds of subscapular fossa INSERTION Lesser tuberosity of humerus Upper medial lip of bicipital groove Capsule of shoulder joint Action Medially rotates arm Stabilizes shoulder joint Nerve Upper and lower subscapular nerves (from posterior cord of brachial plexus)

Teres Major ORIGIN INSERTION ACTION NERVE Lower third of lateral side of inferior angle of scapula below teres minor INSERTION Medial lip of bicipital groove of humerus ACTION Medially rotates and adducts arm. Stabilizes shoulder joint NERVE Lower subscapular nerve (from posterior cord of brachial plexus)

Latissimus Dorsi ORIGIN INSERTION Spine T7 lumbar fascia spinous processes and supraspinous ligaments of all lower thoracic, lumbar and sacral vertebrae lumbar fascia posterior third iliac crest last four ribs (interdigitating with external oblique abdominis) inferior angle of scapula INSERTION Floor of bicipital groove of humerus after spiraling around teres major

Latissimus Dorsi ACTION NERVE Extends, adducts and medially rotates arm. Costal attachment helps with deep inspiration and forced expiration NERVE Thoracodorsal nerve (from posterior cord of brachial plexus)

Serratus Anterior ORIGIN INSERTION Upper 8 ribs and anterior intercostal membranes from midclavicular line. INSERTION Inner medial border scapula 1 and 2: upper angle 3 and 4: length of costal surface 5-8: inferior angle

Serratus Anterior Action Nerve A strong protractor of the scapula that is used when punching or reaching anteriorly ("boxer's muscle") Inferior part rotates the scapula, elevating its glenoid cavity so the arm can be raised above the shoulder Holds the scapula against the thoracic wall when doing push ups or when pushing against resistance Nerve Long thoracic nerve

Contents of axilla The three cords of the brachial plexus and their branches The axillary arteries and its branches The axillary vein and its tributaries The axillary lymph nodes Fibro-fatty tissue The axillary tail of Spence of mammary gland in females

Axillary a. Axillary v. Axillary lymph nodes Fat

AXILLARY ARTERY Beginning Termination Parts It begins as a continuation of the subclavian artery at outer border of 1st rib. Termination It ends at the lower border of teres major and continues as brachial artery. Parts The artery is divided into 3 parts by pectoralis minor muscle.

Parts of the Axillary Artery 1st part: From lateral border of 1st rib to upper border of pectoralis minor 2nd part: Behind pectoralis minor 3rd part: From lower border of pectoralis minor to lower border of teres major

Boundaries of the 1st Portion Anteriorly Clavicular portion of the pectoralis major The coracoclavicular fascia Crossed by cephalic vein Posteriorly: The long thoracic nerve Lateral: The 3 cords of the brachial plexus Medial: The axillary vein which overlaps the artery. It is enclosed, together with the axillary vein and the brachial plexus, in the axillary sheath

Boundaries of the 2nd Portion Anteriorly: The pectorales major and minor Posteriorly The posterior cord of the brachial plexus and the subscapularis muscle and shoulder joint Medially The axillary vein, separated from the artery by the medial cord of the brachial plexus Laterally The lateral cord of the brachial plexus

Boundaries of the 2nd Portion The brachial plexus thus surrounds the artery on three sides, and separates it from direct contact with the vein and adjacent muscles.

Boundaries of the 3rd Portion Anteriorly: The lower part of the pectoralis major above Fascia below The medial head of the median nerve Posteriorly The lower part of the subscapularis, The tendons of the latissimus dorsi and teres major The radial and axillary nerves On its lateral side: Coracobrachialis, biceps and humerus Lateral head and the trunk of the median, and the musculocutaneous On its medial side: The axillary vein The ulnar nerve Medial brachial cutaneous nerve

Relations

To remember the branches easily, The number of branches from each part The same as the number of the part 1st had 1 branch 2nd has 2 branches 3rd had 3 branches 1st =1 2nd =2 3rd =3

Some Times Life Seems A Pain The axillary artery branches into the following arteries: Superior thoracic artery Thoracicoacromial artery Lateral thoracic artery Subscapular artery Anterior humeral circumflex artery Posterior humeral circumflex artery

Branches Of Axillary Artery First part (1 branch) Second part (2 branches) Third part (3 branches) 1 superior thoracic a. (Highest thoracic a.) The superior thoracic artery (highest thoracic artery) is a small vessel that arises from the first part of the axillary artery, just inferior to the subclavius It runs inferomedially posterior to the axillary vein and supplies muscles in the 1st and 2nd intercostal spaces and the serratus anterior. It anastomoses with the intercostal arteries

Branches Of Axillary Artery First part (1 branch) Second part (2 branches) Third part (3 branches) 2 thoracoacromial a. 3 lateral thoracic a. The thoracoacromial artery: A short wide trunk, deep to the pectoralis minor. Divides into 4 branches deep to the clavicular head of the pectoralis major. Acromial Deltoid Pectoral Clavicular

Branches Of Axillary Artery First part (1 branch) Second part (2 branches) Third part (3 branches) 2 thoracoacromial a. 3 lateral thoracic a. The lateral thoracic artery Descends along the lateral border of the pectoralis minor Supplies: the pectoral muscles the axillary lymph nodes the breast An important source of blood to the lateral part of the mammary gland in women.

Branches Of Axillary Artery Third part (3 branches) 4 subscapular a. 5 anterior humeral circumflex a. 6 posterior humeral circumflex a. The subscapular artery: The largest branch of the axillary artery Descends along the lateral border of the subscapularis on the posterior axillary wall. Divides into the circumflex scapular artery thoracodorsal artery Supplies Subscapularis teres major serratus anterior latissimus dorsi muscles

Branches Of Axillary Artery Third part (3 branches) 4 subscapular a. 5 anterior humeral circumflex a. 6 posterior humeral circumflex a. Anterior and posterior humeral circumflex a : These arteries anastomose to form a circle around surgical circumflex humeral neck of humerus; larger posterior circumflex humeral artery passes through quadrangular space with axillary nerve

Arterial Anastomoses Around the Shoulder Many arterial anastomoses occur between the subclavian and axillary artery around the scapula. Several vessels join to form networks on the anterior and posterior surfaces of the scapula and around the humeral neck The Suprascapular artery The dorsal scapular artery The Superficial and deep branch of transverse cervical artery The Subscapular (via the circumflex scapular) artery The Anterior and posterior circumflex humeral artery

Scapular anastomosis A system connecting each subclavian artery and the corresponding axillary artery, forming an anastomosis around the scapula. It allows blood to flow past the joint regardless of the position of the arm. It includes: transverse cervical artery. transverse scapular artery. branches of subscapular artery. branches of thoracic aorta. vessels anastamose or join to connect the first part of the subclavian with the third part of the axillary, providing a collateral circulation. This collateral circulation allows for blood to continue circulating if the subclavian is obstructed.

The extreme mobility of the shoulder joint may result in kinking of the axilllary artery and occlusion of its lumen The importance of the collateral circulation becomes apparent when ligation of a lacerated subclavian or axillary artery is necessary. In either case, the direction of blood flow in the subscapular artery is reversed, enabling blood to reach the third part of the axillary artery.

Arterial Anastomoses Around the Shoulder Slow occlusion of the axillary artery (resulting from disease or trauma) often enables sufficient collateral circulation to develop, preventing ischemia Sudden occlusion usually does not allow sufficient time for a good collateral circulation to develop An inadequate supply of blood flow to the arm, forearm, and hand.

Ligation of the axillary artery distal to the subscapular artery and proximal to the deep artery of the arm cuts off the blood supply to the arm because the collateral circulation is inadequate

Compression of the Axillary Artery The axillary artery can be palpated in the inferior part of the lateral wall of the axilla Compression of the third part of this artery against the humerus may be necessary when profuse bleeding occurs If compression is required at a more proximal site, the axillary artery can be compressed at its origin by exerting downward pressure in the angle between the clavicle and the attachment of the sternocleidomastoid.

Axillary Vein Formation : Basilic vein + venae comitantes of the brachial artery Beginning : Lower border of teres major Course : It runs along the medial side of the axillary artery. Trmination : At outer border of the 1st rib. It becomes the subclavian vein. The cephalic v. joins the axillary v. just before it becomes the subclavian.

Injuries to the Axillary Vein Wounds in the axilla often involve the axillary vein because of its large size and exposed position. It may be injured in sports as well as when a person uses a crutch. When the arm is fully abducted, the axillary vein overlaps the axillary artery anteriorly. A wound in the proximal part of the axillary vein is particularly dangerous not only because of profuse bleeding but also because of the risk of air entering the vessel and producing air emboli

The veins of the right axilla, viewed from in front

Axillary Vein Thrombosis An uncommon condition that may be regarded as the upper limb equivalent of a deep venous thrombosis Commonly follows excessive use of the arm Less frequently, the vein is compressed by musculoskeletal abnormalities or enlarged lymph nodes. It may also follow mastectomy, radiotherapy, or venous cannulation, or may result from underlying visceral malignancy

Lymph Nodes of the Axilla The axillary lymph nodes are arranged in five principal groups: Apical Anterior (pectoral) Posterior (subscapular) Lateral ( humeral) Central

The 20-30 axillary nodes are divided into 5 groups - on the basis of location- The groups are arranged in a manner that reflects the pyramidal shape of the axilla. Humeral (lateral) nodes Pectoral (anterior) nodes Subscapular (posterior) nodes Central nodes Apical nodes

Efferent vessels from the apical group traverse the cervico-axillary canal.

The Apical Group Located along the medial side of the axillary vein and the first part of the axillary artery. Receives lymph from all other groups of axillary lymph nodes as well as from lymphatics accompanying the proximal cephalic vein

The Pectoral (Anterior) Group 3 – 5 lymph nodes Lie along the medial wall of the axilla, around the lateral thoracic vein and the inferior border of the pectoralis minor Receives lymph mainly from the anterior thoracic wall including the breast. Efferent lymphatic vessels from these nodes pass to the central and apical groups of axillary lymph nodes.

The Subscapular (Posterior) Group Consists of 6-7 lymph nodes that lie along the posterior axillary fold and subscapular blood vessels. Receives lymph from the posterior aspect of the thoracic wall and scapular region. Efferent lymphatic vessels pass from these nodes to the central and apical groups of axillary lymph nodes.

The Humeral (Lateral) Group Consists of four to six lymph nodes that lie along the lateral wall of the axilla, medial and posterior to the axillary vein. This group of lymph nodes receives nearly all the lymph from the greater part of upper limb Except that carried by lymphatic vessels accompanying the cephalic vein, which drains to the central and apical axillary nodes.

The Central Group Consists of three or four large lymph nodes situated deep to the pectoralis minor near the base of the axilla, in association with the second part of the axillary artery Receives lymph from the pectoral, subscapular, and humeral groups of axillary lymph nodes. Efferent vessels from the central group pass to the apical group of lymph nodes.

Enlargement of the Axillary Nodes The axillary lymph nodes enlarge and become tender when infections of the upper limb occur Infections in the pectoral region and breast, including the superior part of the abdomen, can also produce enlargement of axillary lymph nodes The humeral group of nodes is the first one to be involved in lymphangitis (inflammation of lymphatic vessels) resulting from a hand infection In carcinoma of the apical group, the lymph nodes often adhere to the axillary vein, which may necessitate excision of part of this vessel Enlargement of the apical group of lymph nodes may obstruct the cephalic vein superior to the pectoralis minor.

lymphangitis (inflammation of lymphatic vessels)

Palpation of the Axillary Lymph Nodes Axillary nodes are palpated at deep pressure using a circular motion with the pads of the three middle fingers of the examining hand in all five aspects of the axilla are examined. Patient standing or sitting with the hand of the examined side on the hip pushing hard medially

Start palpating the central nodes deep in the apex of the axilla between the pectoralis and subscapular muscles Proceeding down the mid-axillary chestwall, gently move the pads of the fingers medially and inside the border of the pectoral muscle and the pectoral node group Continue by palpating the subscapular nodes. Sweep back up and return to the axilla with the palm facing laterally, feeling inside the muscle of the posterior axillary fold (subscapular muscle). Check the lateral nodes with the palm of the hand facing the humeral head pressing on subclavian vein and the pulsating axillary artery. By placing the finger tips high up in the axilla to the outer border of 1st rib the apical group con be palpated

DRAINAGE On right side : On left side : The trunk drains into right lymph trunk. On left side : It drains into thoracic duct.