Axilla and brachial plexus

• between the arm and thoracic wall
• has a base, four walls, and an apex
• contains brachial plexus and axillary artery

skin and fascia of the concave armpit

pectroalis major and minor

formed by the lateral border of the pectoralis major

upper portion of the serratus anterior muscle on thoracic wall

• subscapularis muscle above
• teres major and latissimus dorsi below

teres major and latissimus dorsi

intertubercular groove of humerus

• 1st rib medially
• clavicle anteriorly
• superior border of the scapula posteriorly
• nerves and blood vessels pass through the apex

Extension of the cervical fascia that surrounds the nerves and blood vessels to form a neurovascular bundle

• lower infraclavicular part of the brachial plexus and branches
• axillary artery and branches
• axillary vein and tributaries
• axillary lymph nodes (20-30 in 5 groups)
• longhead of biceps
• short head of biceps
• coracobrachialis
• fat and loose areolar tissue

• from subclavian
• from lateral border of 1st rib to the lower border of the teres major
• divided into 3 parts

• superior thoracic artery
• supplies upper part of the thoracic wall including pectoral muscles

• thoracoacromial artery
• lateral thoracic artery

• 4 branches
• supply primarily the pectoral muscles and the anterior part of the deltoid
• CADP

• supplies the pectoral muscles and serratus anterior
• female - lateral mammary branches to the breast

• subscapular artery
• anterior humeral circumflex
• posterior humeral circumflex

• larget branch of the axillary
• circumflex scapular and thoracodorsal artery
• supplies the subscapularis, latissimus dorsi, and adjacent muscles

runs anteriorly around the surgical neck of humerus and anasomoses with the posterior humeral circumflex

runs posteriorly around the humerus and supplies the shoulder joint and adjacent muscles

• unions of ventral rami and C5-8, and greater part of the ventral ramus of T1.
• (small contribution may be made by the C4 and T2)

Roots, Trunks, Divisions, Cords, Branches

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• five segmentral ventral rami
• (C5-T1)

• Upper trunk - C5 and 6
• Middle Trunk - C7
• Lower Trunk - C8 and T1
• Each split to form an anterior and posterior division

• C5-7
• Anterior division of upper and middle trunks unite

• C8 T1
• Anterior division of the lower trunk continues alone

• C5-T1
• posterior divisions of all 3 trunks unite

• Musculocutaneous
• median nerve
• ulnar nerve
• axillary nerve
• radial nerve

• above the clavicle in the posterior trianlge of the neck
• roots emerge between salenus anterior and scalenus medius muscles

behind the clavicle in the apex of the axilla

• below the clavicle in the axilla where they are found behind the pectoralis minor muscle
• surround the 2nd part of the axillary artery on 3 sides

lower part of the axilla cords split to form terminal branches

• from roots:
• muscular branches for scaleni muscles and longus colli (C5-8)
• branch that joins the phrenic nerve (C5)
• Dorsal scapular nerve (C5)
• Long Thoracic nerve (C5-7)
• From trunks:
• Nerve to subclavius (C5,6)
• Suprascapular nerve (C5, 6)

derived from the 3 cords of plexus, but may be traced through the plexus to the spinal nerves

• lateral pectoral nerv (C5-7)
• Musculocutaneous nerve (c5-7)
• lateral root of median nerve (C5-7)

• Medial pectoral nerv (C8 T1)
• Medial Cutaneous Nerve of Arm (C8 T1)
• Medial cutaneous nerve of forearm (C8 T1)
• Ulnar nerve (C7,8 T1)
• Medial root of median nerve (C8 T1)

• Upper subscapular (C5,6)
• Thoracodorsal nerve (C6-8)
• Lower subscapular nerve (C5-6)
• Axillary nerve (C5-6)
• Radial Nerve (C5-8 T1)