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Questions and Answers
Which muscle is primarily responsible for supinating the forearm and flexing it when in a supine position?
What is the function of the median cutaneous nerve of the arm?
Which group of lymph nodes drains primarily the anterior compartment of the upper limb?
From which nerve does the long thoracic nerve branch off?
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Which vessel does the cephalic vein enter before becoming the subclavian vein?
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What is the primary action of the pectoralis major muscle?
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Which nerve innervates the serratus anterior muscle?
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Which muscle serves to anchor and depress the clavicle?
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What is the origin of the pectoralis minor muscle?
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What contents are enclosed in the axillary sheath?
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Which part of the axillary artery gives rise to the superior thoracic artery?
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The axilla is bounded medially by which muscle?
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What are the branches of the second part of the axillary artery?
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Study Notes
Muscles of the pectoral region
-
Pectoralis Major:
- Origin: Clavicle - Rib 6
- Insertion: Intertubercular sulcus of humerus
- Nervation: Lateral and medial pectoral nerve
- Action: Flexes, adducts, and medially rotates the arm
-
Pectoralis Minor:
- Origin: 3rd - 5th ribs
- Insertion: Coracoid process of scapula
- Nervation: Lateral or medial pectoral nerve
- Action: Stabilizes the scapula
-
Subclavius:
- Origin: 1st rib
- Insertion: Inferior surface of the clavicle
- Nervation: Nerve to subclavius
- Action: Anchors and depresses clavicle
-
Serratus Anterior:
- Origin: 1st - 8th ribs
- Insertion: Medial border of scapula
- Nervation: Long thoracic nerve
- Action: Protracts and rotates scapula
Walls of the Axilla
- Anterior: Pectoralis Major, Pectoralis Minor, Clavipectoral Fascia
- Lateral: Humerus
- Posterior: Subscapularis, Latissimus Dorsi, Teres Major
- Medial: Serratus Anterior overlying the thoracic wall
Contents of the Axilla
- Axillary Sheath: Enclosing the axillary artery and vein
- Brachial Plexus: Three cords and their branches
- Biceps Brachii Muscles: Short head and tendon of the long head
- Coracobrachialis Muscle
- Axillary Lymph Nodes
The Axillary Artery
- First part: Between the lateral border of the 1st rib and the medial border of the pectoralis minor. Branches: Superior thoracic artery.
- Second part: Posterior to the pectoralis minor. Branches: Thoracoacromial and lateral thoracic arteries.
- Third part: From the lateral border of pectoralis minor to the inferior border of teres major. Branches: Subscapular, anterior circumflex humeral, and posterior circumflex humeral arteries.
The Axillary Vein
- Three parts corresponding to the three parts of the axillary artery.
- Cephalic vein enters the axillary vein superior to the pectoralis minor, close to its transition into the subclavian vein.
The Axillary Lymph Nodes
- Five principal groups:
- Pectoral (anterior)
- Subscapular (posterior)
- Humeral (lateral)
- Central
- Apical
- Efferent vessels from the apical group ultimately unite to form the subclavian lymphatic trunk which joins other lymphatic trunks to make the right lymphatic duct.
Brachial Plexus
-
Supraclavicular Branches:
- Dorsal scapular
- Long thoracic
- Suprascapular
- Subclavian
-
Infraclavicular Branches:
- Lateral pectoral
- Medial pectoral
- Medial cutaneous nerve of arm
- Medial cutaneous nerve of forearm
- Thoracodorsal
- Upper subscapular
- Lower subscapular
Contents of the Anterior Compartment of Upper Limb
- Upper arm: Divided into anterior and posterior compartments, separated by the humerus and medial and lateral intermuscular septae.
-
Anterior Compartment Contains:
- Muscles of the anterior compartment
- Brachial artery
- Basilic vein
- Musculocutaneous, median, and ulnar nerves
Muscles of the Anterior Compartment of Upper Limb
-
Biceps Brachii:
- Origin: Short head: tip of coracoid process; Long head: supraglenoid tubercle of scapula
- Insertion: Radial tuberosity
- Nervation: Musculocutaneous nerve
- Action: Supinates the forearm, and when supine, flexes the forearm.
-
Coracobrachialis:
- Origin: Tip of coracoid process
- Insertion: Medial surface of humerus
- Nervation: Musculocutaneous nerve
- Action: Helps flex and adduct arm
-
Brachialis:
- Origin: Anterior surface of humerus
- Insertion: Coronoid process of ulnar tuberosity
- Nervation: Musculocutaneous and radial nerve
- Action: Flexes forearm
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Description
Test your knowledge on the muscles of the pectoral region, including Pectoralis Major, Pectoralis Minor, Subclavius, and Serratus Anterior. Explore their origins, insertions, nerve supply, and actions. This quiz is ideal for students studying human anatomy or those interested in muscle functions.
