FrançaisGet started

The brachial and lumbosacral plexuses

The nerve networks of the limbs: the roots, trunks and cords of the brachial plexus and its five terminal branches, the femoral, obturator and sciatic nerves, what each controls and what its injury causes (wrist drop, carpal tunnel, foot drop…).

  • 36 cards
  • 3 topics
  • Free
Study this deck

The outline, topic by topic

Each topic is weighted the way the exam weighs it.

  1. Concepts
  2. Scenarios
  3. Understand

A few cards from the deck

  • Brachial plexus: what is it?

    Show the answer

    The network formed by roots C5 to T1, organised into trunks, then divisions, then cords, which supplies the upper limb.

    Mixing the roots means each arm nerve gets several roots.

  • After a fracture of the humeral shaft, the patient can no longer lift the wrist. Which nerve is affected?

    • The radial nerve
    • The median nerve
    • The ulnar nerve
    • The axillary nerve
    Show the answer

    The radial nerve

    The radial nerve runs along the humerus in its groove and drives the extensors: wrist drop.

  • Musculocutaneous nerve: what is it?

    Show the answer

    A branch of the lateral cord supplying the arm's flexors (biceps, brachialis) and the skin of the lateral forearm.

    It flexes the elbow and helps supination.

  • Why is the radial nerve at risk in humeral fractures?

    • It lies against the bone, in the radial groove
    • It crosses the elbow joint
    • It runs through the carpal tunnel
    • It is very superficial at the wrist
    Show the answer

    It lies against the bone, in the radial groove

    A bone fragment can stretch or cut it.

  • Axillary nerve: what is it?

    Show the answer

    A branch of the posterior cord that winds around the humerus's surgical neck and supplies the deltoid.

    It allows shoulder abduction; its injury numbs a patch over the shoulder.

  • Night-time tingling of the thumb, index and middle fingers in a seamstress: which nerve is compressed?

    • The ulnar nerve at the elbow
    • The median nerve in the carpal tunnel
    • The radial nerve in the arm
    • The musculocutaneous nerve
    Show the answer

    The median nerve in the carpal tunnel

    That is carpal tunnel syndrome, the most common entrapment.

Study this deck