Podcast
Questions and Answers
What is the primary shape of the axilla?
What is the primary shape of the axilla?
Which structure does NOT form a boundary of the axillary inlet?
Which structure does NOT form a boundary of the axillary inlet?
What component does the axilla NOT contain?
What component does the axilla NOT contain?
Which is the correct order of the brachial plexus stages?
Which is the correct order of the brachial plexus stages?
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How many anterior rami contribute to the formation of the brachial plexus?
How many anterior rami contribute to the formation of the brachial plexus?
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Which trunk of the brachial plexus is formed by the union of C5 and C6 roots?
Which trunk of the brachial plexus is formed by the union of C5 and C6 roots?
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Which type of division does each trunk of the brachial plexus split into?
Which type of division does each trunk of the brachial plexus split into?
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Which root is NOT part of the brachial plexus?
Which root is NOT part of the brachial plexus?
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What is the contribution range of the lateral cord of the brachial plexus?
What is the contribution range of the lateral cord of the brachial plexus?
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Which cord is positioned medial to the second part of the axillary artery?
Which cord is positioned medial to the second part of the axillary artery?
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Which of the following nerves is a branch of the posterior cord?
Which of the following nerves is a branch of the posterior cord?
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Where does the axillary artery begin?
Where does the axillary artery begin?
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Which branch of the axillary artery passes anterior to the surgical neck of the humerus?
Which branch of the axillary artery passes anterior to the surgical neck of the humerus?
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What nerves originate from the upper trunk of the brachial plexus?
What nerves originate from the upper trunk of the brachial plexus?
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Which nerve has contributions from C8 and T1?
Which nerve has contributions from C8 and T1?
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Which of the following correctly identifies the components of the posterior cord?
Which of the following correctly identifies the components of the posterior cord?
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What is the primary muscle innervated by the axillary nerve?
What is the primary muscle innervated by the axillary nerve?
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Which structure exits the axilla through the quadrangular space?
Which structure exits the axilla through the quadrangular space?
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The superior lateral cutaneous nerve of the arm is responsible for sensation from which area?
The superior lateral cutaneous nerve of the arm is responsible for sensation from which area?
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What are the contents of the posterior quadrangular space?
What are the contents of the posterior quadrangular space?
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Which of the following muscles is not innervated by the axillary nerve?
Which of the following muscles is not innervated by the axillary nerve?
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Which nerve is responsible for causing 'winging of scapula' when paralyzed?
Which nerve is responsible for causing 'winging of scapula' when paralyzed?
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Which space contains the circumflex scapular vessels?
Which space contains the circumflex scapular vessels?
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Which nerve and artery are found in the lower triangular interval?
Which nerve and artery are found in the lower triangular interval?
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Study Notes
Axilla and Brachial Plexus
- The axilla is the gateway to the upper limb, transitioning between the neck and arm.
- It's pyramidal in shape, with four walls, an inlet (apex), and a base.
- The axillary inlet (apex) connects superiorly to the neck.
- Its boundaries include the clavicle, scapula, and first rib.
- The floor (base) is formed by the skin of the armpit.
- The axilla contains the brachial plexus, axillary artery, axillary vein, axillary lymph nodes, and the tail of the breast in females.
Brachial Plexus
- Formed by the anterior rami of C5, C6, C7, C8, and most of T1.
- The brachial plexus has five stages:
- Roots: The ventral rami of the spinal nerves.
- Trunks: Three trunks (superior, middle, and inferior) are formed by the union of the roots.
- Divisions: Each trunk divides into anterior and posterior divisions.
- Cords: The divisions combine to form three cords (lateral, medial, and posterior) within the axilla.
- Terminal branches: These nerves ultimately branch off from the cords and supply the muscles and sensory areas of the upper limb.
Axillary Artery
- The main blood supply to the upper limb.
- Begins at the lateral border of the first rib, a continuation of the subclavian artery.
- It terminates at the lower border of the teres major muscle, becoming the brachial artery.
- It has branches: anterior and posterior circumflex humeral arteries.
Axillary Nerve
- Originates from the posterior cord of the brachial plexus.
- Exits the axilla through the quadrangular space, entering the posterior scapular region.
- Related to the posterior circumflex humeral vessels and the posterior surface of the surgical neck of the humerus.
- Innervates the deltoid and teres minor muscles.
Pectoral Region
- Includes three major muscles: Pectoralis major, Pectoralis minor, and Subclavius.
- Pectoralis major has clavicular, sternocostal, and abdominal heads.
- Pectoralis minor originates on the ribs and inserts on the coracoid process.
- Subclavius is a smaller muscle below the clavicle that stabilizes it.
Serratus Anterior
- A muscle with its origin on the upper ribs.
- It inserts on the medial anterior border of the scapula.
- Its paralysis causes winging of the scapula.
Scapular Region Muscles
- Supraspinatus, Infraspinatus, Teres minor, Teres major, and Subscapularis.
Spaces of the Scapular Region
- Posterior quadrangular space, bordered by teres minor, teres major, humerus, and the long head of the triceps brachii.
- Upper triangular space, superiorly teres minor, inferiorly teres major, laterally long head of triceps brachii.
- Lower triangular space, bordered by long head of triceps brachii, shaft of humerus, teres major.
- These spaces contain nerves and vessels related to the shoulder.
Back Muscles
- Trapezius: This large superficial back muscle affects scapular movement.
- Levator scapulae; The specific function of the levator scapulae muscle has to do with the upward and downward motion of the scapula.
- Rhomboid major and minor: These muscles are located deep to the Trapezius and help in the retraction of the scapulae.
- Latissimus dorsi: This large, broad, flat muscle extends and adducts the arm across the chest.
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Description
Explore the intricate anatomy of the axilla and the brachial plexus in this quiz. Learn about the structures that connect the neck to the upper limb, including their boundaries and functions. This quiz covers essential concepts related to the anatomy vital for understanding the upper extremity.
