A: Forearm + hand Flashcards
What muscles are responsible for pronation?
Pronator teres + pronator quadratus
Supination muscle
Biceps brachii + Supinator
What are the superficial muscles in forearm?
Pronator teres, Flexor carpi radialis, Palmaris longus, Flexor carpi ulnaris.
Intermediate muscles in forearm?
Flexor digitorum superficialis
Deep muscles in forearm?
Flexor digitorum profundus- flexes fingers
Flexor pollicus longus - flexes thumb
Pronator quadratus
Innervation of muscles in forearm
Median nerve innervates all muscles in anterior forearm, except flexor carpi ulnaris & flexor digitorum profundus (medial half). These are both innervated by the ulnar nerve.
Dupuytren’s contracture syndrome
When palmar aponeurosis tightens
Carpal tunnel structure
Roof = flexor retinaculum
Floor + side = carpal bones
What is in the carpal tunnel
Carpal tunnel contains:
- 4 tendons from flexor digitorum superficialis
- 4 tendons from flexor digitorum profundus
- Tendon of flexor pollicus longus
- Median nerve
Flexor digitorum superficialis movement
Flexor digitorum superficialis can flex wrist, knuckle, and proximal interphalangeal joint on finger but not the distal interphalangeal joint.
Flexor digitorum profundus movement
Can flex wrist, knuckle and both finger joints.
Short muscles of thumb
- Abductor pollicis brevis
- Flexor pollicis brevis
- Opponens pollicis
How are short muscles of thumb innervated?
Median nerve
Muscles for little finger
- Abductor digiti minimi
- Flexor digiti minimi brevis
- Opponens digiti minimi
How are muscles for little finger innervated
ulnar nerve
Injury to median nerve in carpal tunnel:
- Numbness to lateral 3.5 digits.
- Palm skin not affected
- Thenar muscles paralysed, so loss of opposition.
- Flexion + abduction of thumb weakened.
Injury to median nerve due to wrist laceration
- Numbness to lateral 3.5 digits + posterior distal parts of digits + skin of palm
- Thenar muscles paralysed, so loss of opposition.
- Flexion + abduction of thumb weakened.
- Paralysis of lateral two lumbricals –> impaired fine control movements of index + middle fingers.
Injury to median nerve in elbow
- Pronation is weak or lost.
- Wrist flexion is weak & associated with ulnar deviation (flexor carpi ulnaris is unopposed). – Wrist abduction is weak.
- Flexion of index & middle fingers is absent, & flexion is weakened in ring & little fingers grip is weak.
- Thumb: Opposition & flexion of distal phalanx are lost; thumb abduction is weak.
What muscles in anterior compartment + skin does ulnar nerve supply?
flexor carpi ulnaris + medial half of flexor digitorum profundus.
Supplies skin on medial 1.5 digits, medial part of back of hand + medial side of palm
Superficial branch of ulnar nerve innervation?
Supplies skin on anterior surface of medial 1.5 digits.
Deep branch of ulnar nerve?
innervates all small muscles of hand except 3 thenar muscles, lateral 2 lumbricals.