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Questions and Answers
What is the primary function of the muscles located in the anterior compartment of the arm?
What is the primary function of the muscles located in the anterior compartment of the arm?
Which artery begins as a continuation of the axillary artery?
Which artery begins as a continuation of the axillary artery?
What is the nerve supply of the biceps brachii muscle?
What is the nerve supply of the biceps brachii muscle?
Which superficial vein runs medially in the distal part of the arm?
Which superficial vein runs medially in the distal part of the arm?
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Which compartment of the arm contains muscles that primarily extend the elbow joint?
Which compartment of the arm contains muscles that primarily extend the elbow joint?
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What structure can be compressed against the medial side of the humerus?
What structure can be compressed against the medial side of the humerus?
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Which muscle extends from the coracoid process to the medial side of the humerus?
Which muscle extends from the coracoid process to the medial side of the humerus?
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Which of the following is a branch of the brachial artery that supplies the posterior compartment?
Which of the following is a branch of the brachial artery that supplies the posterior compartment?
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What type of nerve is the musculocutaneous nerve classified as?
What type of nerve is the musculocutaneous nerve classified as?
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Which of the following muscles originates from the anterior surface of the humerus?
Which of the following muscles originates from the anterior surface of the humerus?
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What is the primary role of the musculocutaneous nerve?
What is the primary role of the musculocutaneous nerve?
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Which artery is primarily responsible for the blood supply to the posterior compartment of the arm?
Which artery is primarily responsible for the blood supply to the posterior compartment of the arm?
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The radial nerve enters the arm by crossing which muscle?
The radial nerve enters the arm by crossing which muscle?
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Which of the following structures is NOT found in the cubital fossa?
Which of the following structures is NOT found in the cubital fossa?
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Which statement about the profunda brachii artery is correct?
Which statement about the profunda brachii artery is correct?
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What forms the floor of the cubital fossa?
What forms the floor of the cubital fossa?
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The inferior lateral cutaneous nerve of the arm is a branch of which nerve?
The inferior lateral cutaneous nerve of the arm is a branch of which nerve?
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Which muscle is innervated by the radial nerve?
Which muscle is innervated by the radial nerve?
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What is the lateral boundary of the cubital fossa?
What is the lateral boundary of the cubital fossa?
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Which compartment of the arm does the musculocutaneous nerve provide sensory innervation to?
Which compartment of the arm does the musculocutaneous nerve provide sensory innervation to?
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Study Notes
Arm Anatomy
- The arm extends from the shoulder to the elbow.
- It is divided into two compartments: anterior and posterior.
- The anterior compartment contains muscles that flex the elbow joint.
- The posterior compartment contains muscles that extend the elbow joint.
- The anterior and posterior compartments are separated by the medial and lateral intermuscular septa.
Anterior Compartment
- Muscles: Biceps brachii, Brachialis, Coracobrachialis
- Blood Vessels: Brachial Artery, Brachial Vein
- Nerve Supply: Musculocutaneous Nerve
Biceps Brachii
- Has two heads and two sites of insertion.
Coracobrachialis
- Originates from the coracoid process and inserts on the medial side of the humerus.
Brachialis
- Originates from the anterior surface of the humerus and inserts on the ulnar tuberosity.
Musculocutaneous Nerve
- Provides motor innervation to all muscles in the anterior compartment of the arm.
- Provides sensory innervation to skin on the lateral surface of the forearm.
Action of Anterior Compartment Muscles
- Elbow flexion.
- Shoulder flexion (Coracobrachialis and long head of biceps).
Brachial Artery
- Begins as a continuation of the axillary artery at the lower border of the teres major muscle.
- Terminates just distal to the elbow joint, where it divides into the radial and ulnar arteries.
- Palpable along its length.
- In proximal regions, it can be compressed against the medial side of the humerus.
Branches of the Brachial Artery
- Muscular branches
- Profunda brachii artery (largest, also supplies posterior compartment)
- Humeral nutrient artery
- Superior ulnar collateral artery
- Inferior ulnar collateral artery
- Terminal branches: Radial and Ulnar arteries
Veins
- Superficial Veins: Basilic vein and Cephalic vein.
- Deep Veins: Paired brachial veins.
- Basilic Vein: At the distal part of the arm, it runs medially then penetrates deep fascia to become medial to the brachial artery. Becomes the axillary vein at the lower border of the teres major muscle.
- Cephalic Vein: Passes superiorly on the anterolateral aspect of the arm and through the anterior wall of the axilla to reach the axillary vein.
Musculocutaneous Nerve
- Leaves the axilla and enters the arm by passing through the coracobrachialis muscle.
- Passes down the arm in the plane between the biceps brachii and brachialis muscles.
- Continues as the lateral cutaneous nerve of the forearm.
Posterior Compartment
- Muscles: Triceps (Three heads)
- Blood Vessels: Profunda brachii artery
- Nerve Supply: Radial nerve
Deep Artery of the Arm (Profunda Brachii Artery)
- The largest branch of the brachial artery.
- Accompanies the radial nerve along the radial groove as it passes posteriorly around the shaft of the humerus.
- Terminates by dividing into the middle and radial collateral arteries.
Radial Nerve
- Originates from the posterior cord of the brachial plexus and enters the arm by crossing the inferior margin of the teres major muscle.
- Enters the arm posterior to the brachial artery, medial to the humerus, and anterior to the long head of the triceps.
- Enters the forearm anterior to the lateral epicondyle of the humerus, just deep to the brachioradialis muscle.
Branches of the Radial Nerve
- Muscular branches: Triceps brachii, brachioradialis, and extensor carpi radialis longus muscles.
- Cutaneous branches include the inferior lateral cutaneous nerve of the arm and the posterior cutaneous nerve of the forearm.
Cubital Fossa
- Triangular depression anterior to the elbow joint.
Boundaries
- Superiorly: An imaginary line connecting the medial and lateral epicondyles.
- Medially: Pronator teres muscle.
- Laterally: Brachioradialis muscle.
Floor
- Brachialis and supinator muscles.
Roof
- Skin, subcutaneous tissue, fascia, reinforced by the bicipital aponeurosis.
Contents
- Terminal part of the brachial artery.
- Accompanying veins of the arteries.
- Biceps brachii tendon.
- Median nerve.
- Radial nerve.
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Description
Test your knowledge on the anatomy of the arm, specifically focusing on the anterior compartment. Explore the muscles, blood vessels, and nerve supply, including the important roles of the biceps brachii, brachialis, and coracobrachialis. This quiz is essential for students studying human anatomy.
