Wrist and Hand - Forearm muscles

Question 1

What are the deep digit flexors? Origins and insertions?

Answer 1

Flexor Pollicis Longus - Origin @ the anterior radius and inserts @ the distal phalanx of the thumb

Flexor Digitorum Profundus - Origin @ the ulna and inserts @ the distal phalanges of the fingers

Question 2

What is the flexor muscle @ the intermediate layer? What is its function? Origin and insertion?

Answer 2

Flexor Digitorum superficialis - Origin @ the medial epicondyle of the humerus and inserts @ the middle phalanges of the fingers

• Flexes digits but not the distal phalanx

Question 3

What are the flexor muscles of the superficial layer? Functions? Origins and insertions?

Answer 3

Flexor Carpi Radialis - Origin @ the medial epicondyle and inserts @ the base of metacarpal 2

• Function is to flex and radially deviate wrist

Flexor Carpi Ulnaris - Origin @ the medial epicondyle and inserts @ metacarpal 5 and the pisiform/hamate

• Function is to flex and radially deviate wrist

Palmaris Longus - Origin @ the medial epicondyle and inserts @ the palmer fascia

• Function is to anchor the skin and fascia of the hand and is a weak wrist flexor

Question 4

What is radial and ulnar deviation?

Answer 4

Radial deviation - wrist moves towards radius

Ulnar deviation - wrist moves towards ulna

Question 5

What are the superficial forearm extensors? Function? Origins and insertions?

Answer 5

Extensor Carpi Radialis Longus - Origin @ the lateral epicondyle and inserts @ the base of metacarpal 2

• Extends and radially deviates wrist

Extensor Carpi Radialis Brevis - Origin @ the lateral epicondyle and inserts @ the base of metacarpal 3

• Extends and radially deviates wrist

Extensor Digitorum - Origin @ the lateral epicondyle and inserts @ the dorsal digital expansion or “Extensor Hood” which is a fibrous extension of extensor digitorum tendons on the back of the fingers

• Extends the digits

Extensor Digiti Minimi - Origin @ the lateral epicondyle and inserts @ the dorsal digital expansion of the little finger

• Extends little finger

Extensor Carpi Ulnaris - Origin @ the lateral epicondyle and inserts @ the base of the 5th metacarpal

• Extends and ulnar deviates wrist

Question 6

What are the deep forearm extensors? Function? Origins and insertions?

Answer 6

Extensor Indicis - Origin @ the posterior surface of the distal 1/3rd of the ulna and inserts @ the extensor expansion of the index finger

• Extends index finger

Extensor Pollicis Longus - Origin @ the posterior surface of the middle 1/3rd of the ulna and inserts @ the dorsal aspect of the base of the distal phalanx of thumb

• Extends all the joints in the thumb

Extensor Pollicis Brevis - Origin @ the posterior surface of the distal half of the radius and inserts @ the dorsal aspect of the base of the proximal phalanx of thumb

• Extends all joints in the thumb except for interphalangeal joint

Abductor Pollicis Longus - Origin @ the posterior aspect of the proximal half of the ulna and 1/3rd of radius. Inserts @ the lateral aspect of the base of the 1st metacarpal bone

• Abducts and extends the thumb