KIN 100 MUSCLES OF THE ANTERIOR FOREARM

what are all the muscles of the superficial layer of the anterior forearm?

1. pronator teres

2. palmaris longus

3. flexor carpi radialis

4. flexor carpi ulnaris

what are all the muscles of the middle layer of the anterior forearm?

5. flexor digitorum superficialis

what are all the muscles of the deep layer of the anterior forearm?

6. flexor digitorum profundus

7. flexor pollicis longus

8. pronator quadratus

pronator teres (layer, prox and distal attachments, innervation, actions)

layer: superficial

prox: common flexor origin and coronoid process of the ulna

distal: mid-shaft of radius on lateral surface

innervation: median nerve

actions: forearm pronation, assists with elbow flexion

what’s the other name for wrist abduction?

radial deviation

what’s the other name for wrist adduction?

ulnar deviation

flexor carpi radialis

layer: superficial

prox: common flexor origin

distal: base of 2nd metacarpal

innervation: median nerve

actions: wrist flexion, wrist abduction (radial deviation)

palmaris longus

layer: superficial

prox: common flexor origin

distal: palmar aponeurosis

innervation: median nerve

actions: wrist flexion, tenses palmar aponeurosis

note: vestigal muscle, absent on one or both sides in 15% of the population

what’s a vestigial muscle?

• an organ or part of the body that has become absent and/or functionless in the course of evolution

• we just dont use it anymore!!

• ex. palmar longus: 15% of population doesn’t have it on one or both sides.

  • some say we used to use it to climb trees, but not anymore!!

which muscles of the anterior forearm flex the elbow? + what muscles of the arm help with it?

• pronator teres

• biceps brachii

• brachialis

what muscles of the anterior forearm flex the wrist?

• flexor carpi radialis

• palmaris longus

• flexor carpi ulnaris

• flexor digitorum superficialis

• flexor digitorum profundus

flexor carpi ulnaris

• layer: superficial

• prox: common flexor origin, olecranon procress, posterior shaft of ulna

• distal: pisiform, hook of hamate, base of 5th metacarpal

• innervation: ulnar nerve

• actions: wrist flexion, wrist adduction

flexor digitorum superficialis

• layer: middle

• prox: common flexor origin, shaft of radius

• distal: middle phalanges of digits 2-5

• innervation: median nerve

• actions: wrist flexion, flexion of all the joints in the wrist and hand EXCEPT for the distal interphalangeal joints

flexor digitorum profundus

• layer: deep

• prox: interosseous membrane and ulna (does not cross the elbow)

• distal: distal phalanges of digits 2-5

• innervation:

  • medial half: ulnar nerve

  • lateral half: median nerve

• actions: wrist flexion, flexion of all joints in the wrist and hand INCLUDING the distal interphalangeal joints

flexor pollicis longus

• layer: deep

• prox: interosseous membrane and radius (does not cross elbow)

• distal: distal phalanx of thumb

• innervation: median nerve

• actions: flexes all the joints of the thumb

pronator quadratus

• layer: deep

• prox: distal surface of ulna

• distal: distal surface of radius

• innervation: median nerve

• actions: forearm pronation

which muscles of the anterior forearm pronate the forearm?

• pronator teres

• pronator quadratus

which muscles of the anterior forearm are innervated by the median nerve?

• pronator teres

• flexor carpi radialis

• palmaris longus

• flexor digitorum superficialis

• lateral half of flexor digitorum profundus

• flexor pollicis longus

• pronator quadratus

which muscles of the anterior forearm are innervated by the ulnar nerve?

• flexor carpi ulnaris

• medial half of the flexor digitorum profundus

which muscles of the anterior forearm abduct the wrist?

• flexor carpi radialis

which muscles of the anterior forearm adduct the wrist?

• flexor carpi ulnaris

which muscles flex the joints in the wrist and hand? and to what degrees?

• flexor digitorum superficialis (flexes all the joints in the wrist and hand EXCEPT the distal interphalangeal joints)

• flexor digitorum profundus (flexes all the joints in the wrist and hand INCLUDING the distal interphalangeal joints)

• flexor pollicis longus (flexes all the joints of the thumbs)

label this diagram of the deep muscles of the anterior forearm

1. flexor digitorum profundus

2. flexor pollicus longus

3. pronator quadratus

what is the flexor retinaculum and what is its purpose?

• a band of connective tissue that attaches to the bony landmarks of the carpals:

  • tubercle of scaphoid, tubercle of trapezoid, hook of hamate, pisiform

• the bands of connective tissue create a space deep to itself which is the carpal tunnel (i think)

label this diagram of the carpal tunnel

1. pisiform

2. triquetrum

3. hamate

4. capitate

5. trapezoid

6. trapezium

7. flexor carpi radialis

8. flexor pollicis longus

9. flexor digitorum profundus

10. flexor digitorum superficialis

11. median nerve

12. palmaris longus

13. ulnar nerve and artery