Brachial Plexus, lesions of the brachial plexuses. Examination of the shoulder muscles. Brachial plexus and its branches, brachial plexus injury.
Educational video describing the medical conditions related to the specific nerves of the brachial plexus.
Medial winging of the scapula is caused by injury to the long thoracic nerve.
Rhomboids winging of the scapular is caused by injury to the dorsal scapular nerve. When an injury occurs to the dorsal scapular nerve, it will cause rhomboids winging of the scapular and loss of shoulder abduction.
Cannot do OK sign: median nerve. The anterior interosseous nerve branches out from the median nerve within the forearm. Patient with paralysis of the anterior interosseous nerve will be unable to give the OK sign.
Pronator teres syndrome: median nerve. Pronator teres syndrome is entrapment neuropathy of the median nerve as it passes between the two heads of the pronator teres muscle.
Cubital tunnel syndrome: ulnar nerve. Pressure on the nerve at the elbow can cause numbness or pain in the elbow, hand, wrist or fingers.
Carpal tunnel syndrome: Median nerve. Carpal tunnel syndrome is caused by compression of the median nerve at the wrist.
Wrist drop: Radial nerve. A radial nerve injury classically occurs by fractures involving the distal third of the humeral shaft. The radial nerve supplies the extensor muscles which allow for extension of the wrist and fingers. If the muscles are not working properly, the patient will experience the condition known as “ wrist drop”.
Nerve injury with shoulder dislocation: Axillary nerve. The axillary nerve is commonly injured due to fractures or dislocations of the shoulder joint. When the nerve is injured:
•Weakness of shoulder abduction
•Atrophy of the deltoid
•Numbness in the deltoid region.
Claw hand deformity: Ulnar nerve. Pinching of the ulnar nerve often causes paresthesia in the fourth and fifth digits. Entrapment or injury of the ulnar nerve below the elbow may result in a claw hand deformity due to unopposed preserved function of the flexor digitorum profundus.
Horner’s syndrome: preganglionic root avulsion at the C8-T1 level. Horner’s syndrome is caused by an avulsion of the brachial plexus at the C8-T1 level. Horner’s syndrome is a combination of symptoms:
•Ptosis: dropping of the upper eyelid.
•Miosis: constriction of the pupil. The affected pupil is smaller.
•Anhidrosis: loss of facial sweating on the side with the lesion.
Nerve affected by the ganglion cyst around the shoulder: suprascapular nerve. The suprascapular nerve gives branches to the supraspinatus muscle as well as the infraspinatus muscle. Entrapment of the nerve can occur within the suprascapular notch or the spinoglenoid notch.
Lift off test: upper or lower subscapular nerve. Injury to the upper and/or lower subscapular nerve causes dysfunction of the subscapularis muscle. Inability to move to the handoff of the lower back constitutes an abnormal lift-off test which indicates a possible tear of the subscapularis tendon.
Guyon’s canal syndrome: ulnar nerve. The ulnar nerve enters the palm of the hand through the Guyon’ canal. Guyon’s canal syndrome is caused by entrapment of the ulnar nerve within the Guyon canal at the wrist.
Strong supinator of the elbow: musculocutaneous nerve. The biceps muscle is supplied by the musculocutaneous nerve and it is a strong supinator of the elbow. Injury to the musculocutaneous nerve may produce weakness of elbow flexion and weakness of forearm supination.
The nerve to the muscle used as a free flap: thoracodorsal nerve. The latissimus dorsi muscle is often used as a free flap for treatment of open fractures.
Erb’s palsy: injury at the Erb’s point is commonly sustained at birth. The nerve roots that are usually involved at C5 and partially C6. Impaired shoulder abduction, external rotation and elbow flexion with decreased sensation in the thumb and the index finger with normal scapular control.
Rotator cuff atrophy: suprascapular nerve. The suprascapular nerve can be affected by trauma, fractures, surgery or idiopathic. The suprascapular nerve supplies the supraspinatus and the infraspinatus muscles. If the nerve is injured, muscle atrophy may result.
Supinator syndrome: radial nerve. Supinator syndrome is also known as radial tunnel syndrome or posterior interosseous nerve syndrome. The radial nerve or the posterior interosseous nerve can become entrapped with the radial tunnel. The pain of supinator syndrome (Radial tunnel) is very similar to the symptoms of tennis elbow. The pain is usually distal to the lateral epicondyle and radiates down the forearm.
special thanks for NATHAN ELKINS FOR HIS CONTRIBUTION TO THIS VIDEO