LIMBS Flashcards
What are the boundaries of the carpal tunnel?
- Ulnar side = pisiform and hook of hamate
- Radial side = scaphoid and trapezoid
- Roof = flexor retinaculum
- Floor = Carpal bones
What are the contents of the carpal tunnel?
- Median nerve
- 10 tendons = 4 for FDP, 4 for FDS, flexor carpi radialis, flexor pollicis longus
What muscles does the median nerve supply in the hand?
Motor – the “LOAF” muscles of the thenar eminence:
- Lateral two lumbricals
- Opponens pollicis
- Abductor pollicis
- Flexor pollicis brevis
What does the median nerve do before and after entering the carpal tunnel?
- Palmar cutaneous branch (sensory to thenar skin) arises 5 cm proximal to the wrist joint, ulnar to FCR and passes over the flexor retinaculum
- Main nerve passes deep to the flexor retinaculum, to the radial side of the tendons of FDS
- The recurrent motor branch to thenar muscles arises at the distal end of the carpal tunnel
- The median nerve finally ends by dividing into medial and lateral branches to supply the radial 3.5 digits
Which structures are at risk in carpal tunnel surgery?
- the median nerve
- the palmar cutaneous branch of median nerve (sensation to the thenar eminence)
- the recurrent branch of median nerve (motor supply to thenar muscles)
- the superficial palmar arch (blood supply to hand)
- the ulnar nerve as it passes through flexor retinaculum (if the incision it placed too far towards the ulnar side).
what are the variations of the recurrent motor branch of the median nerve?
- Extraligamentous branch (50%)
- arises from the volar radial aspect of the median nerve distal to the transverse carpal ligament and recurrent to the thenar muscles.
- The nerve hooks radially and upwards to enter the thenar muscle mass between the FPB and APB muscles
- Subligamentous branch (30%)
- arises from the anterior surface of the nerve within the carpal tunnel
- emerging distal to the flexor retinaculum and recurrent to the thenar muscles
- Transligamentous branch (20%)
- arises from the anterior surface of the nerve within the carpal tunnel
- pierces the flexor retinaculum
what is Kaplan’s cardinal line in carpal tunnel surgery?
- Kaplan described an anatomical guideline for locating the recurrent motor branch of the median nerve.
- Kaplan’s line is a line drawn from the distal border of the abducted thumb to the hook of hamate.
- The recurrent motor branch of the median nerve entering the thenar muscle mass is estimated by the intersection of Kaplan’s line and a vertical line from the radial border of the middle finger.
what are the boundaries of the poplital fossa?
diamond shape.
Looking at the back of the knee boundaries are
- superior - biceps femoris (lateral), semimembranosus and semitendinosus (medially)
- inferiorly - heads of gastrocnemius
What are the contents of the popliteal fossa?
- popliteal artery (deepest structure - hence difficult to palpate pulse)
- popliteal vein
- tibial nerve
- common peroneal nerve
What are the branches of the popliteal artery?
Five genicular arteries:
• superior and inferior medial
- superior and inferior lateral
- middle.
what are the boundaries of the cubital fossa?
Boundaries
- Brachioradialis
- Pronator teres
- Line joining humeral condyles
Roof
- Deep fascia of forearm
- Bicipital aponeurosis
Floor
- Brachialis
What are the contents of the cubital fossa?
Medial → lateral (NATN - nerve, artery, tendon, nerve)
Median nerve
- Passes between 2 heads pronator teres
Brachial artery
- Divides into radiall & ulnar arteries
Biceps tendon
Radial nerve
- Superficial cutaneous
- Posterior interosseus
