Muscles in the forearm Flashcards
What are the superficial flexors in the anterior compartment?
- Pronator Teres (PT)
- Flexor Carpi Radialis (FCR)
- Palmaris Longus (PL)
- Flexor Carpi Ulnaris (FCU)
- Flexor Digitorum Superficialis (FDS)
What are the deep flexors of the anterior compartment?
- Flexor Digitorum Profundus (FDP)
- Flexor Pollicis Longus (FPL)
- Pronator Quadratus (PQ)
What are the superficial extensors in the posterior compartment?
- Extensor Carpi Radialis Longus (ECRL)
- Extensor Carpi Radialis Brevis (ECRB)
- Extensor Carpi Ulnaris (ECU)
- Extensor Digitorum (ED)
- Extensor Digiti Minimi (EDM)
What are the deep extensors of the posterior compartment?
- Extensor Indicis (EL)
- Abdcutor Pollicis Longus
- Extensor Pollicis Longus (EPL)
- Extensor Pollicis Brevis (EPB)
What are the borders of the Snuff box?
- Extensor Pollicis Longus - outer
- Extensor Pollicis Brevis - middle
- Abductor Pollicis Longus - outer
- Two extensors converge
Pronator Teres (PT) - lies laterally in the superficial group of anterior compartment
What is the origin?
- Medial epicondyle of humerus via common flexor tendon
- The adjacent supra epicondylar ridge
- Ulnar head-medial side of coronoid process
Where is the insertion?
- Lateral surface, mid-shaft of radius
What is the nerve supply?
- Median Nerve (C6, C7)
What is the action?
- Pronation of forearm at proximal radio-ulnar joint
Flexor Carpi Radialis (FCR) - lies laterally in the superficial group of anterior compartment
What is the origin?
- Medial epicondyle of humerus via common flexor tendon
Where is the insertion?
- Palmer surface of bases of metacarpals 2 and 3
What is the nerve supply?
- Median Nerve (C6, C7)
What is the action?
- Flexion and Abduction at wrist
Palmaris Longus (PL) - centrally positioned small vestigial muscle
What is the origin?
- Medial epicondyle of humerus via common flexor tendon
Where is the insertion?
- Flexor retinaculum and apex of palmer aponeurosis
What is the nerve supply?
- Median Nerve (C7, C8)
What is the action?
- Weak wrist flexor
- Tightens palmar fascia
Flexor Carpi Ulnaris (FCU) - Most medial of superficial group of anterior compartment
What is the origin?
- Medial epicondyle of humerus via common flexor tendon
- Medial border of olecranon and posterior border of ulna
Where is the insertion?
- Pisiform and hook of hamate and base of metacarpal 5
What is the nerve supply?
- Ulnar Nerve (C7, C8)
What is the action?
- Flexion and adduction at wrist joint
- Synergic action in abduction of digit 5
Flexor Digitorum Superficialis (FDS) - large ‘intermediate’ muscle
What is the origin?
- Medial epicondyle of humerus via common flexor tendon
- Coronoid process of ulna
- Proximal 2/3 anterior border of radius
Where is the insertion (four distal attachments, tendons)?
- Either side palmar surface of middle phalanx of each finger
What is the nerve supply?
- Median Nerve (C8, T1)
What is the action?
- Flexion at wrist, Metacarpalphalangeal and PIP (middle of the finger joint) joint
- Tendon arrangement increases power of grip
Flexor Digitorum Profundus (FDP) - deep on medial side of anterior compartment and hugs the ulna
What is the origin?
- Medial side of coronoid process of ulna
- Anterior and medial surfaces of ulna
- Anterior half of the interosseous membrane
Where is the insertion?
- Base of palmar surface of distal phalanx of each finger
What is the nerve supply?
- Ulnar Nerve (C8, T1)
- Anterior interosseous nerve (C7,8,T1)
What is the action?
- Flexion of distal interphalangeal joint of fingers
- Flexion of PIP, MCP joints
- Flexion of wrist joints
Flexor Pollicis Longus (FPL) - lies lateral to FDP in deep layer of anterior compartment
What is the origin?
- Anterior surface of radius and adjacent interosseous membrane
Where is the insertion?
- Base of palmar surface of distal phalanx of thumb
What is the nerve supply?
- Anterior interosseous nerve (C7, C8)
What is the action?
- Flexion at CMC, MCP, and IP joint of thumb
Pronator Quadratus (PQ)- deepest muscle in forearm that cannot be observed or palpated
What is the origin?
- Oblique ridge on anterior surface of distal fourth of ulna
Where is the insertion?
- Lateral border and anterior surface of distal fourth of radius
What is the nerve supply?
- Median nerve (C7, C8) - anterior interosseous branch
What is the action?
- Pronation of forearm at distal RU joint
- Dynamic stabiliser of the distal RU joint
Extensor Carpi Radialis Longus (ECRL) - on lateral side partly beneath brachioradialis
What is the origin?
- Lateral supracondylar ridge of humerus
Where is the insertion?
- Dorsal surface base of metacarpal 2
What is the nerve supply?
- Radial nerve (C6, C7)
What is the action?
- Extension of wrist
- Radial deviation of wrist
Extensor Carpi Radialis Brevis (ECRB) - adjacent and partly covered by the ECRL
What is the origin?
- Lateral epicondyle of humerus via common extensor tendon
Where is the insertion?
- Dorsal surface base of metacarpal 2 and 3
What is the nerve supply?
- Posterior interosseous nerve (C7, C8)
What is the action?
- Extension of wrist
- Radial deviation of wrist
Extensor Carpi Ulnaris (ECU)
What is the origin?
- Lateral epicondyle of humerus via common extensor tendon
- By shared aponeurosis from posterior border of ulna
Where is the insertion?
- Tubercle medial side of base of metacarpal 5
What is the nerve supply?
- Posterior interosseous nerve (C7, C8)
What is the action?
- Extension at wrist joint
- Ulna deviation at wrist joint
Extensor Digitorum (ED)
What is the origin?
- Lateral epicondyle of humerus via common extensor tendon
Where is the insertion?
- 4 tendons
- Bases of middle and distal phalanges of each finger
What is the nerve supply?
- Posterior interosseous nerve (C7, C8)
What is the action?
- Extension of the MCP joint of each finger
- Assists extension of IP joints
Extensor Indicis (EL) - medial aspect of posterior compartment
What is the origin?
- Posterior surface of distal ulna and interosseous membrane
Where is the insertion?
- Dorsal digital expansion of index finger
What is the nerve supply?
- Posterior interosseous nerve (C7, C8)
What is the action?
- Extension of IP and MCP joints of index finger
Abdcutor Pollicis Longus (APL)
What is the origin?
- Posterior surface of upper ulna and middle radius and intervening interosseous membrane
- Tendon with Extensor Pollicis Brevis
Where is the insertion?
- Radial side of base of metac 1
What is the nerve supply?
- Posterior interosseous nerve (C7, C8)
What is the action?
- Assists extension and abduction at 1st carpometacarpal joint
- Assists abduction at wrist
Extensor Pollicis Longus (EPL)
What is the origin?
- Posterior surface of middle 1/3rd of ulna and interosseous membrane
Where is the insertion?
- Dorsal surface of base of distal phalanx of thumb
What is the nerve supply?
- Posterior interosseous nerve (C7, C8)
What is the action?
- Extension at IP joint
- Assists extension at MCP, CMC and wrist joints
Extensor Pollicis Brevis (EPB)
- What is the origin?
- Posterior surface of middle of ulna and interosseous membrane
- Where is the insertion?
- Dorsal surface of base of proximal phalanx of thumb
- What is the nerve supply?
- Posterior interosseous nerve (C7, C8)
- What is the action?
- Extension of MCP and CMC of thumb
