Brachial Plexus + Vascular Supply

1. Brachial Plexus + Vascular Supply Dr. Fadel Naim Orthopedic Surgeon Faculty of Medicine IUG

2. Spinal Nerves • 31 pairs of spinal nerves are attached to the spinal cord. • 8 cervical • 12 thoracic • 5 lumbar • 5 sacral • 1 coccygeal • Each spinal nerve divides into a dorsal and ventral ramus.

3. Spinal Nerves Spinalnerve Dorsal branch Spinal nerve Ventral branch

4. Spinal Nerve Plexuses • Ventral rami of spinal nerves fuse and form networks with ventral rami of other spinal nerves. • Crossing of fibers • A peripheral nerve may contain axons from several spinal segments. • T2 – T12 do not form plexuses

5. Spinal Nerve Plexuses • Cervical plexus • Brachial plexus • Lumbar plexus • Sacral plexus

6. Brachial Plexus • The brachial plexus is an arrangement of nerve fibres running from the spine (vertebrae C5-T1) through the neck, the axilla, and into the arm.

7. The brachial plexus is responsible for cutaneous and muscular innervation of the entire upper limb • The brachial plexus is also responsible for innervation of deep structures as joints • It has influence over the diameter of blood vessels by sympathetic vasomotor nerves and sympathetic secretomtor supply to the sweat glands

8. Brachial Plexus • One can remember the order of brachial plexus elements by way of the mnemonic, “Ramiz Takes Daily Choclate and Bescuit“ • 5 Roots • 3 Trunks • 3 +3 Divisions • 3 Cords • 5 Branches

9. CORDS DIVISIONS TRUNKS ROOTS C5 UPPER LATERAL C6 POSTERIOR MIDDLE C7 C8 LOWER MEDIAL T1

10. Roots • The brachial plexus starts in the neck from the anterior rami of spinal nerves C5 - T1 (5th cervical to 1st thoracic spinal cord segments) • These rami are called roots. • Frequently it receives a contribution from one nerve higher or one nerve lower.

11. Trunks TRUNKS ROOTS C5 UPPER • The roots continue through the neck and, some of them merge, to form trunks. • C5 and C6 form the upper trunk • C7 continues as the middle trunk • C8 and T1 for the lower trunk C6 MIDDLE C7 C8 LOWER T1

12. Divisions • Each trunk of the brachial plexus divides into anterior and posterior divisions as the plexus passes posterior to the clavicle • Anterior divisions supply anterior (flexor) compartments of the upper limb • Posterior divisions supply posterior (extensor) compartments

13. Cords • These six divisions regroup to become the three cords. • The posterior cord is formed from the three posterior divisions of the trunks (C5-T1 ) • The lateral cord is the anterior divisions from the upper and middle trunks (C5-C7) • The medial cord is simply a continuation of the lower trunk (C8-T1) • In general, the lateral and medial cords supply the ventral aspect of the limb, whereas the posterior cord supplies the dorsal aspect

14. CORDS DIVISIONS TRUNKS ROOTS anterior C5 UPPER LATERAL C6 posterior POSTERIOR MIDDLE C7 C8 LOWER MEDIAL T1

15. Branches • Finally, the cords give rise to various branches that supply the upper limb structures. • Some arise from the cervical part of the plexus • Most of the branches to the upper limb muscles arise from the plexus in the axilla • The terminal branches of the cords arise inferior to the clavicle

16. Cords Give off Branches!! (in axilla) • Lateral Musculocutaneous Median • Medial Ulnar • Posterior Radial Axillary

17. The Musculocutaneous Nerve (C5-7) • Very variable, arises from the lateral cord. • It supplies the flexor muscles on the anterior aspect of the arm and the skin on the lateral side of the forearm

19. Injury to the Musculocutaneous Nerve • Injury to the musculocutaneous nerve in the axilla is uncommon because of its protected position • It is typically inflicted by a weapon • It results in paralysis of the coracobrachialis, biceps, and brachialis • Flexion of the elbow joint and supination of the forearm are greatly weakened • Loss of sensation may occur on the lateral surface of the forearm

20. The median nerve (C[5,] 6-8; T1) • The median nerve arises by lateral and medial heads from the lateral and medial cords, • The median nerve supplies most of the flexor muscles on the front of the forearm, most of the short muscles of the thumb • The median nerve supplies the skin on the lateral part of the front of the hand. • Articular branches to elbow, wrist, and carpal joints

22. Injuries to the Median Nerve • It is most commonly injured by stab wounds or broken glass just proximal to the flexor retinaculum at wrist

23. Injuries to the Median Nerve at the Elbow • Skin sensation is lost on • the lateral half or less of the palm of the hand and the palmar aspect of the lateral three and a half fingers. • the distal part of the dorsal surfaces of the lateral three and a half fingers.

24. The Hand of Benediction( Pope’s Blessing ) • No flexion is possible at the interphalangeal joints of the index and middle fingers, • When the patient tries to make a fist, the index and to a lesser extent the middle fingers tend to remain straight, whereas the ring and little fingers flex

25. The Ulnar Nerve (C7, 8; T1) • The ulnar nerve arises from the medial cord, • The ulnar nerve supplies: • Some of the flexor muscles of the anterior forearm • Many of the short muscles of the hand • The skin on the medial part of the palmar and dorsal aspect of the hand.

27. Injuries to the Ulnar Nerve • More than 27% of nerve lesions of the upper limb affect the ulnar nerve • Ulnar nerve injuries usually occur in four places: • Posterior to the medial epicondyle of the humerus • In the cubital tunnel • At the wrist. • In the hand.

28. Claw hand (main en griffe) • Ulnar nerve injury can result in extensive motor and sensory loss to the hand. • An injury to the nerve in the distal part of the forearm denervates most intrinsic hand muscles. • Difficulty making a fist because • The metacarpophalangeal joints become hyperextended,

29. Froment's sign • Froment's sign tests for palsy of the ulnar nerve, specifically, the action of adductor pollicis • If the patient is asked to grip a piece of paper between the thumb and the index finger • It is impossible to adduct the thumb because the adductor pollicis muscle is paralyzed.

31. The axillary nerve (C5, 6) • The axillary nerve is a branch of the posterior cord • The site of the axillary nerve may be represented by a horizontal line through the middle of the deltoid around the surgical neck . • It divides supplies the teres minor and deltoid and becomes the upper lateral brachial cutaneous nerve

32. Axillary Nerve

34. Axillary Nerve Injury • The axillary nerve is usually injured during fracture of the proximal end of the humerus • It may also be damaged during dislocation of the shoulder joint • Intramuscular injection of drugs in the deltoid muscle may injure the nerve • awareness of its location avoids injury to it during injections

35. Injury to the Axillary Nerve • Section of the axillary nerve results in: • The deltoid atrophies when the axillary nerve (C5 andC6) is severely damaged • Paralysis of the deltoid with incomplete abduction of the arm by the supraspinatus • Loss of sensation in a small patch of skin over the deltoid.

36. The Radial Nerve (C[5,] 6-8; [T1]) • The radial nerve may be regarded as the continuation of the posterior cord. • It spirals around the posterior aspect of the humerus under cover of the lateral head of the triceps and thereby reaches the lateral aspect of the limb (hence the name radial).

37. The radial nerve supplies the extensor muscles of the posterior arm and forearm and the skin on the posterior arm, forearm, and hand.

38. The Radial Nerve Injury • The radial nerve may be injured in the axilla by pressure of a crutch or by hanging the arm over the back of a chair • " saturday night palsy" • Loss of sensation in areas of skin supplied by this nerve also occurs.

39. Injury to the Radial Nerve • The characteristic clinical sign of radial nerve injury is wrist-drop • inability to extend the wrist and the digits at the metacarpophalangeal joints

43. Erb’s palsy Injuries to superior parts of the brachial plexus (C5 and C6) • Usually result from an excessive increase in the angle between the neck and the shoulder • These injuries can occur in a person who is thrown from a motorcycle or a horse and lands on the shoulder in a way that widely separates the neck and shoulder • This stretches or tears (avulses) superior parts of the brachial plexus. • Injury to the superior trunk of the plexus is apparent by the characteristic position of the limb ("waiter's tip position")

44. Neonatal Brachial Plexus Palsy • It is due to over traction on the neck as in: • Shoulder dystocia.      • After-coming head in breech delivery.

45. The usual clinical appearance: • Upper limb with: • An adducted shoulder • Medially rotated arm • Extended elbow. • (policeman’s or waiter’s tip hand) • The lateral aspect of the upper limb also experiences loss of sensation

46. Klumpke’s palsyInjuries to inferior parts of the brachial plexus(C7 and C8 and 1st thoracic roots) • Injuries to inferior parts of the plexus are much less common. • Lower brachial plexus injuries may occur when the upper limb is suddenly pulled superiorly • When a person grasps something to break a fall • A baby's upper limb is pulled excessively during delivery

47. Klumpke’s palsy • This results in the sign known as clawed hand due to loss of function of the ulnar nerve and the intrinsic muscles of the hand it supplies. • Loss of sensation along the medial side of the arm. • If the 8th cervical nerve is damaged, the anesthesia will involve the medial side of the forearm, hand, and medial two fingers.

49. BLOOD SUPPLY TO UPPER LIMB The arterial supply is mainly by; Subclavian artery Axillary artery Brachial artery Radial artery Ulnar artery Palmar arch Digital arteries

50. Subclavian artery It arise from bracheo- cephalic artery, pass behind clavicle bone over the first rib before entering the axilla where it continuous as axillary artery. Before entering axilla each subclavian gives off two branches: vertebral artery which supply to brain internal thoracic artery which supply to breast and thoracic cavity.