Elbow, wrist, hand anatomy and conditions Flashcards
What are lateral epicondylitis and medial epicondylitis more commonly known as?
Lateral- tennis elbow (resisted wrist extension- lateral epicondyle is the common extensor origin)
Medial- golfer’s elbow (less common- repeated strain on the common flexor origin)
What causes cubital tunnel syndrome?
Compression of the ulnar nerve behind the medial epicondyle
How does cubital tunnel syndrome present?
Parasthesia of the ulnar 1.5 fingers, and weakness of ulnar-innervated muscles
What often causes cubital tunnel syndrome?`
Tightness of the fascia overlying the tunnel, or tightness as the nerve passes through the septum at the two heads of flexor carpi ulnaris
Which muscles originate at the lateral epicondyle?
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor carpi ulnaris
RL RB CU
Which muscles originate at the medial epicondyle?
The flexors:
flexor carpi radialis
Flexor carpi ulnaris
Palmaris longus
Why do olecranon fractures usually require ORIF?
Unresisted traction of the triceps muscle means they are usually widely displaced
Which groups of patient are particularly prone to supracondylar fractures?
Children
What is a Colles fracture?
Extra-articular fracture of the distal radius, usually caused by FOOSH.
What is seen in 50% of Colle’s fractures?
Fracture of the ulnar styloid
What are the potential complications of this type of fracture?
Scaphoid fracture- non-union and AVN
What are the two groups of muscles of the hand and what broadly do they control?
Intrinsics- fine finger movements
Extrinsics- flexion and extension of fingers, flexion and extension of wrist
What are these muscles collectively, and what is their nerve supply?
Thenar muscles, median nerve
What is the main muscle which moves the little finger and what is its innervation?
Abductor digiti minimi
Ulnar nerve
What is the role of the interossei muscles?
Dorsal- abduct the fingers at MCPJs
Palmar-adduct the fingers at MCPJs
What nerve supplies the interossei muscles?
Ulnar
How many lumbrical muscles are there?
4
Where do flexor digitorum superficialis and profundus insert, respectively? What is their origin?
Superficialis- PIP
Profundus- DIP
Origin- the common flexor origin (medial epicondyle)
How is bowstringing of the flexor tendons prevented?
Trained to metacarpals/phalanges by a system of pulleys
What is the carpal tunnel formed by?
Carpal bones inferioly and the flexor retinaculum superiorly
Which nerve, and which 9 muscles, pass through the carpal tunnel?
Median nerve
FDS and FDP of the four fingers
Flexor pollicus longus
How do patients with carpal tunnel syndrome present?
Parasthesia in the thumb and 2.5 radial fingers, loss of sensation, weakness in the muscles supplied by the median nerve (e.g. thenar muscles, lateral lumbricals)
