Lecture 5.1: Axilla and Brachial Plexus

Question 1

Areas of Transition in Upper Limb

Answer 1

• Axilla
• Cubital Fossa
• Carpal Tunnel

Question 2

What is the Axilla Region?

Answer 2

The axilla is the region that connects the neck to the upper limb

Question 3

What are the components of the Axilla Region? (5)

Answer 3

• Bordered by pectoral girdle muscles and thoracic cage
• Neurovascular supply to upper limb runs through this region
• Filled with fat
• Tail of breast extends into region
• Contains important lymph node groups

Question 4

How are Axillary Folds formed?

Answer 4

The axillary folds are formed by muscle covered in skin

Question 5

Axillary Folds: Posterior Axillary Fold Muscles

Answer 5

• Latissimus dorsi

* Teres major

Question 6

Axillary Folds: Anterior Axillary Fold Miscles

Answer 6

• Pectoralis major

* Pectoralis minor

Question 7

Boundaries of the Axilla

Answer 7

Apex
Base
4 Walls (Posterior, Anterior, Lateral, Medial)

Question 8

What is on the Anterior Border?

Answer 8

• Pectoralis major

* Pectoralis minor

Question 9

What is on the Posterior Border?

Answer 9

• Subscapularis
• Latissimus dorsi
• Teres major

Question 10

What is on the Lateral Border?

Answer 10

Intertubecular suculus

Question 11

What is on the Medial Border?

Answer 11

• Serratus anterior

* Thoracic wall

Question 12

Functions of the Lymphatic System

Answer 12

• Drain excess extracellular fluid from body & return it to veins of circulatory
system
• Mount immune responses in the body.
• Transports fat and large protein molecules too big for venous transport
• Collects fluid (lymph) from the extracellular spaces in tissues
• This is transported by lymphatic vessels

Question 13

Lymph

Answer 13

• Typically Clear and Watery
• Foreign Particulates (ie: Bacteria)
• Malignant Cells

Question 14

What is Lymphoedema?

Answer 14

An accumulation of interstitial fluid

Question 15

What is a Plexus?

Answer 15

It is is a network of nerves or vessels in the body

Question 16

Where does the Brachial Plexus originate from?

Answer 16

• Plexus originates from cervical and thoracic spinal cord levels
• C5, C6, C7, C8, T1

Question 17

5 Main Brachial Plexus Nerves and Root Values

Answer 17

• Musculocutaneous Nerve (C5,6,7)
• Axillary Nerve (C5,6)
• Median Nerve (C5-T1)
• Radial Nerve (C5-T1)
• Ulnar Nerve (C8-T1)

Question 18

What is a Dermatome?

Answer 18

Area of skin supplied by the cutaneous (sensory) branches from a single spinal nerve

Question 19

What causes Erb’s Palsy (Erb-Duchenne Palsy)?

Answer 19

• Injury to the Upper Parts of the Brachial Plexus
• Paralysis of muscles of the shoulder/arm supplied by C5-C6
• “Waiter’s Tip” appearance

Question 20

What is the Appearance of Erb’s Palsy (Erb-Duchenne Palsy)?

Answer 20

1) Arm Medially rotated
2) Adducted Shoulder
3) Extended Elbow
4) Flexion at Wrist
5) Motor and Sensory Deficits

Question 21

What causes Klumpke’s Palsy (Paralysis)?

Answer 21

• Injury to the Lower Parts of the Brachial Plexus (C8 & T1)
• Often affects the short muscles of the hand
• Claw hand deformity results

Question 22

What causes Thoracic Outlet Syndrome?

Answer 22

Occurs when blood vessels or nerves in the space between your collarbone and your first rib (thoracic outlet) are compressed

Question 23

Neurovascular compression can occur due to…? (3)

Answer 23

• Cervical rib
• Hyperabduction of the shoulder (“Saturday night palsy”)
• Poor posture or heavy backpacks