23 Questions
What is the function of Brachioradialis?
Flexion of forearm
Which muscle is responsible for the extension and abduction of the hand?
Extensor Carpi Radialis Longus
Where does Extensor Digiti Minimi originate from?
Lateral epicondyle
Which muscle assists in extending the elbow joint, stabilizes the elbow joint, and abducts the ulna during pronation?
Anconeus
What is the function of Supinator?
Supination of the forearm
Which muscle is responsible for extension of the hand and digits 2, 3, 4, 5?
Extensor Digitorum
Where does Extensor Carpi Radialis Brevis insert?
Base of 2nd and 3rd Metacarpal
Which muscle originates from the lateral supraepicondylar ridge?
Brachioradialis
Which muscle assists triceps in extending the elbow joint, stabilizes the elbow joint, and abducts the ulna during pronation?
Anconeus
Which muscle originates from the distal 1/3 of the posterior Ulna and inserts into the extensor expansion of the 2nd digit?
Extensor indicis
Which muscle is responsible for thumb abduction and extension?
Extensor pollicis brevis
What is the historical significance of the snuff box?
It was used for tobacco inhalation
Which artery runs through the floor of the snuff box?
Radial artery
What is the function of the Extensor Pollicis Longus muscle?
2nd digit extension
In which layer of muscles does the Extensor Pollicis Longus belong?
Deep Layer
What is the origin of the Abductor Pollicis Longus muscle?
Posterior surface of proximal ulna and radius
What type of joint is the Elbow Joint?
Hinge type
Which ligament extends from the medial epicondyle of the humerus to the coronoid process of the ulna?
Ulnar collateral ligament
What reinforces the Elbow Joint by holding the radius and ulna together at their proximal articulation?
Annular ligament
Which ligament has a low attachment to the lateral epicondyle of the humerus?
Radial collateral ligament
What type of articulation does the Proximal Radioulnar Joint have?
Pivot type
Which ligament maintains constant tension during pronation and supination movements of the forearm?
Quadrate ligament
The Ulnar Collateral Ligament is composed of how many parts?
Three parts
Study Notes
Posterior Aspect of Forearm and Elbow Joint
Superficial Layer of Posterior Forearm
- Muscles: Brachioradialis, Extensor Carpi Radialis Brevis, Extensor Carpi Radialis Longus, Extensor Digitorum, Extensor Digiti Minimi, Extensor Carpi Ulnaris, and Anconeus
- Common innervation: Radial nerve
- Functions:
- Brachioradialis: flexion of forearm
- Extensor Carpi Radialis Brevis: extension and abduction of hand
- Extensor Carpi Radialis Longus: extension and abduction of hand
- Extensor Digitorum: extension of hand and 2-3-4-5 digits
- Extensor Digiti Minimi: extension of 5th digit
- Extensor Carpi Ulnaris: extension and adduction of hand
- Anconeus: assists triceps in extending elbow joint, stabilizes elbow joint, and abducts ulna during pronation and forearm extension
Deep Layer of Posterior Forearm
- Muscles: Supinator, Abductor Pollicis Longus, Extensor Pollicis Brevis, Extensor Pollicis Longus, and Extensor Indicis
- Common innervation: Radial nerve
- Functions:
- Supinator: forearm supination
- Abductor Pollicis Longus: thumb abduction and extension
- Extensor Pollicis Brevis: MCPJ, CMCJ extension (thumb)
- Extensor Pollicis Longus: IPJ, MCPJ, CMCJ extension (thumb)
- Extensor Indicis: extension of 2nd digit
Snuff Box
- Boundaries: Anteriorly - Abductor Pollicis Longus and Extensor Pollicis Brevis, Posteriorly - Extensor Pollicis Longus
- Contents: Radial artery, Scaphoid and Trapezium bones
Vessels of Posterior Forearm
- Arteries: Radial artery, Ulnar artery, Posterior interosseous artery, and Anterior interosseous artery
- Veins: Related to arteries
Nerves of Posterior Forearm
- Radial nerve: Superficial and deep branches
- Deep branch of radial nerve: Becomes posterior interosseous nerve after passing between two heads of Supinator
Radial Tunnel - Posterior Interosseous Nerve Compression Syndrome
- Musculo-aponeurotic tunnel: Lateral epicondyle of the humerus to the distal edge of the Supinator muscle
Elbow Joint
- Articulations: Humero-ulnar and Humero-radial
- Ligaments: Radial collateral ligament, Ulnar collateral ligament, and Annular ligament of Radius
- Joint type: Hinge type
- Articulations:
- Humero-ulnar: Trochlea of humerus and Trochlear notch of ulna
- Humero-radial: Capitulum of humerus and Head of radius
- Proximal radioulnar joint: Head of radius and Radial notch of ulna
FAT PADS SIGN
- Ulnar collateral ligament: Extends from the medial epicondyle of the humerus to the coronoid process of the ulna
- Triangular shape, composed of three parts: anterior, posterior, and inferior band
Blood Supply
- Collateral branches of brachial artery
- Recurrent branches of ulnar and radial arteries
Test your knowledge of the anatomy of forearm muscles including Supinator, Abductor pollicis longus, Extensor pollicis brevis, and Extensor pollicis longus. Identify their origins, insertions, innervations, and functions.
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