Anatomy of the forearm Flashcards
Elbow joint
Synovial hinge joint- flexion/ extension
Also proximal radioulnar joint
- pivot joint for supination/ pronation
Ligaments
Stabilise/ strengthen joint
Radial collateral ligament
Annular ligament
Ulnar collateral ligament
Cubital fossa
Triangle region over anterior elbow
Between lateral epicondyle, medial epicondyle, bracioradialis, pronator teres
Median cubital vein
Important for venepuncture
Sits in cubital fossa
Forearm compartments
Flexor compartment
Extensor compartment
Long tendons enter hand
Flexor compartment
Anterior forearm
Superficial muscles
- 3 flexors of wrist
- 1 pronator
Intermediate muscles
- 1 flexor of digit 2-5
Deep muscles
- 1 flexor of digits 2-5
- 1 flexor of thumb
- 1 pronator
Superficial flexor layer
Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor carpi ulnaris
Intermediate flexor layer
Flexor digitorum superficialis
Deep flexor layer
Flexor digitorum profundus
Flexor pollicis longus
Pronator quadratus
Extensor compartment
Posteiror forearm
Superficial muscles
- 3 extensors of wrist
- 1 extensor of digits 2-5
- 1 accessory extensor to digit 5
- bracioradialis and anconeus
Deep muscles
- 2 extensors of thumb
- 1 abductor of thumb
- 1 accessory extensor of digit 2
- 1 supinator
Superficial extensor layer
Extensor carpi radialis longus/ brevis
Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris
Brachioradialis: flexor when half pronated
Anconeus: stabilise elbow
Deep extensor layer
Supinator
Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus
Extensor indicis
Anatomical snuff box
Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus
Wrist abduction
Flexor carpi radialis
Extensor carpi radialis (longus and brevis)
Wrist adduction
Flexor carpi ulnaris
Extensor carpi ulnaris
Muscles involved in supination
Biceps brachii
Supinator
Muscles involved in pronation
Pronator teres
Pronator quadratus
Carpal tunnel
Tunnel for flexor tendons to digits and median nerve
Contents
- median nerve
- flexor policis longus
- flexor digitorum superficialis
- flexor digitorum profundus
Flexor retinaculum
Transverse carpal ligament
Prevents bowing of tendons
Extensor retinaculum
Prevents bowing of tendons
Separates tendons into compartments
Long tendon insertions
Flexor digitorum profundus
- into distal phalanx
Extensor digitorum
- into middle and distal phalanx
Flexor digitorum superficialis
- into middle phalanx
Arterial supply
Cubital fossa: brachial artery divides into
- radial artery: under brachioradialis
- ulnar artery: under flexor carpi ulnaris, gives off common interosseous
Anastomosis around elbow joint
Nerve supply
Musculocutaneous nerve
Radial nerve
Median nerve
Ulnar nerve
Median nerve
Lies mid forearm between FDS and FDP
Branch- atnerior interosseous nerve
Passes through carpal tunnel
Motor supply to anterior compartment except FCU/ medial part of FDP
Sensory supply to lateral palm and d1,2,3, 1/2d4
Ulnar nerve
Motor supply to FCU and medial part FDP
Sensory supply to medial hand including 1/2d4 and d5
Radial nerve
Enters forearm on lateral side under brachioradialis
Divides into two branches
- superficial branch: under brachioradialis, winds round to dorsum of hand
- deep branch- posterior interosseous nerve: passes through supinator muscle, enters extensor compartment
Deep branch supplies posterior compartment
Superficial branch supplies lat dorsum hand
Clinical: superficial layer of flexor compartment
Golfers elbow
Epicondylitis at CFO
Tendon inflammation due to overuse/ excessive gripping
Clinical: superficial layer of extensor compartment
Tennis elbow
Epicondylitis at CEO
Tendon inflammation due to overuse/ forceful extension
Clinical: carpal tunnel
Carpal tunnel syndrome
Median nerve compression
Due to increased pressure in carpal tunnel
Associated with trauma, obesity, pregnancy
Clinical: ulnar nerve
Cubital tunnel syndrome
Clinical: radial nerve
Wrist drop
