Muscles of the Forearm & Hand Flashcards
(33 cards)
What are the compartments of the forearm, their parts, and the number of muscles in each?
Anterior compartment (Flexors) - 8
- Superficial (4)
- Intermediate (1)
- Deep (3)
Posterior compartment (Extensors) - 11
- Superficial (6)
- Deep (5)
Muscles of the anterior compartment of the forearm
Superficial:
1. Pronator Teres
2. Flexor carpi radialis
3. Palmaris
4. Flexor carpi ulnaris
Intermediate:
1. Flexor digitorum superficialis
Deep:
1. Flexor digitorum profundus
2. Pronator quadratus
3. Flexor pollicis longus
Muscles of the posterior compartment of the forearm
Superficial:
1. Brachioradialis
2. Extensor carpi radialis longus
3. Extensor carpi radialis brevis
4. Extensor digitorum
5. Extensor digiti minimi
6. Extensor carpi ulnaris
Deep:
1. Supinator
2. Abductor pollicis longus
3. Extensor pollicis brevis
4. Extensor pollicis longus
5. Extensor indicis
What is the CFO (common flexor origin)
-The medial epicondyle of the humerus
-This is the origin or the superficial muscles of the anterior compartment:
* Pronator teres
*Flexor carpi radialis
* Palmaris longus
* Flexor carpi ulnaris
Pronator teres: Compartment and OIAI
Compartment: Anterior compartment, superficial
Origin: Medial epicondyle of the humerus (CFO)
Insertion: Lateral Radius
Action: Pronation
Innervation: Median nerve
Flexor carpi radialis: Compartment and OIAI
Compartment: Anterior compartment, superficial
Origin: Medial epicondyle of the humerus (CFO)
Insertion: 2nd & 3rd metacarpals
Action: Wrist flection and wrist abduction
Innervation: Median nerve
Palmaris longus: Compartment & OIAI
Compartment: Anterior compartment, superficial
Origin: Medial epicondyle of the humerus (CFO)
Insertion: Palmar aponeurosis (fan)
Action: Wrist flexion
Innervation: Median nerve
What is the palmar aponeurosis
- A thickening of palmar fascia
- continuous withe the palmaris longus tendon
Flexor carpi ulnaris: Compartment & OIAI
Compartment: Anterior compartment. superficial
Origin: Medial epicondyle of the humerus (CFO) & the olecranon of the ulna
Insertion:
- Pisiform
- Hook of hamate
- 5th metacarpal
Action:
- Wrist flection and wrist adduction
Innervation: Ulnar nerve
The trick for the superficial anterior compartment
- CFO:
- They all have the same origin!
- PASS/FAIL/PASS/FAIL
- Thumb on CFO
Index - P: Pronator Teres
Middle - F: Flexor carpi radialis
Ring - P: Palmaris longus
Pinky - Flexor carpi ulnaris
Flexor digitorum superficialis: Compartment & OIAI
Compartment: Anterior compartment, intermediate
Origin:
- Medial epicondyle of the humerus (CFO)
- Anterior surface of the radius and ulna
Insertion:
- 4 Tendons split and insert on middle phalanges 2-5
Action:
- Flexion of the wrist
- Flexion of the metacarpophalangeal joints 2-5
- Flexion of the proximal interphalangeal joints 2-5
Innervation: Median nerve
Flexor digitorum profundus: Compartment & OIAI
Compartment: Anterior compartment, Deep
Origin:
- Ulna
- Interosseus membrane
Insertion: Distal phalanges 2-5
Action:
Same as FDS
- Flexion of the wrist
- Flexion of the metacarpophalangeal joints 2-5
- Flexion of the proximal interphalangeal joints 2-5
AND
- Flexion of DIP 2-5
Innervation:
- Medial half: Median nerve
- Lateral half: Ulnar nerve
Flexor digitorum memory trick
Flexor digitorum Superficialis - Splits in two to allow, Flexor digitorum Profundus to Pass through
Flexor pollicis longus: Compartment & OIAI
Compartment: Anterior compartment, Deep
Origin:
- Anterior radius
- interosseus membrane
Insertion: Distal phalanx of the thumb
Actions: Flexion of the thumb
Innervation: Median nerve
Pronator quadratus: Compartment & OIAI
Compartment: Anterior compartment, Deep
Origin: Distal anterior surface of the ulna
Insertion: Distal anterior surface of the radius
Action: Pronation
Innervation: Median nerve
What is the Flexor Retinaculum?
- Fibrous connective tissue band
- Located on the palmar surface of the hand (near wrist)
- Forms the roof of the carpal tunnel
- Holds the tendons of the flexor muscles in place
- Allows median nerve to pass into the hand
Brachioradialis: Compartment & OIAI
Compartment: Posterior compartment, superficial
Origin: Lateral supracondylar ridge of the humerus
Insertion: Styloid process of radius
Actions: Flexes forearm at the elbow
Innervation: Radial nerve
Extensor carpi radialis longus & brevis: Compartment & OIAI
Compartment: Posterior compartment, Superficial
Origin: Lateral epicondyle of the humerus (CEO)
Insertion: 2nd & 3rd metacarpals
Actions: Extension of the wrist and Abduction of the wrist
Innervation: Radial nerve
Extensor carpi ulnaris: Compartment & OIAI
Compartment: Posterior compartment, superficial
Origin: Lateral epicondyle of humerus (CEO)
Insertion: 5th metacarpal
Actions:
- Extension of wrist
- Adduction of wrist
Innervation: Radial nerve
Extensor digitorum: Compartment & OIAI
Compartment: Posterior compartment, superficial
Origin: Lateral epicondyle of the humerus (CEO)
Insertion: Phalanges 2-5, posterior surface
Actions:
- Extension of wrist
- Extension of fingers (MCPs, PIPs, DIPs)
Innervation: Radial nerve
Extensor digiti minimi: Compartment & OIAI
Compartment: Posterior Compartment, superficial
Origin: Lateral epicondyle of humerus (CEO)
Insertion: posterior surface of the 5th digit
Actions:
- Extension of wrist
- Extension of pinky finger
Innervation: Radial nerve
Supinator: Compartment & OIAI
Compartment: Posterior compartment, Deep
Origin:
- Lateral epicondyle of humerus (CEO)
- Proximal ulna
Insertion: Lateral proximal radius
Actions: Supination
Innervation: Radial nerve
Abductor pollicis longus: Compartment & OIAI
Compartment: Posterior compartment, Deep
Origin: Proximal ulna & posterior surface of radius
Insertion: 1st metacarpal
Actions: Abduction of thumb & wrist
Innervation: Radial nerve
Extensor pollicis longus: Compartment & OIAI
Compartment: Posterior compartment, deep
Origin:
- Posterior ulna
- Interosseus membrane
Insertion:
- Distal phalanx of thumb
Actions:
- Extension of thumb
Innervation: Radial nerve
