Anatomy (Brachial Plexus and Axilla)

Question 1

Plexus Formation

Answer 1

• Spinal nerves fuse, bifurcate, then rejoin in a complex fashion to form a plexus

Question 2

Brachial Plexus Characteristics (3)

Answer 2

• Motor & Sensory innervation of upper limb and muscles
• Formed by ventral primary rami of cervial spine nerves (C5-T1)
• Pattern from cervical roots to arm as follows:

Roots, Trunks, Divisions, Cords, Branches (terminal nerves)

“Rex & Taylor Drink Cold Beer”

Question 3

How’re the cords named?

Answer 3

• By anatomical relationship to axillary artery

Question 4

Long Thoracic Nerve Injury (2)

Answer 4

• Superficial to serratus anterior muscle
• Causes “winged scapula”

Question 5

Brachial Plexus Organization (4)

Answer 5

• Most branches contsin two or more spinal cord levels
• Lower spinal cord levels innervate lower parts of limb (C5/Shoulder & T1/Hand)

Anterior - innervates anterior compartment muscles (flexors)

Posterior - innervated posterior compartment muscles (extensors)

Question 6

Axilla Characteristics (2)

Answer 6

• Anterior, Posterior, Medial, Lateral, & Inferior borders
• Contians artery & vein, lower brachial plexus, lymph nodes & vessels, and fat

Question 7

Collateral Circulatrion & Anasomosis

Answer 7

• Occur mainly around joints
• Allow blood or nerve signals to take different routes to find destination
• Anastomosis is the “communication” between vessels