Brachial plexus (2)


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  • Sometimes contribution frm c7
  • All posterior cord branch innervates the muscles of the posterior axillary wall except the radial nerve
  • Axillary nerve is accompanied by the posterior circumflex humeral artery
  • Therefore fracture or obstruction of the humerus at the levels of this areas could be dangerous to the related nerves.
  • Brachial plexus (2)

    1. 1. BRACHIAL PLEXUS 2/10/2014 1
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    4. 4. • INTRODUCTION; The brachial plexus is a network of nerves that is responsible for the cutaneous and muscular innervations of the entire upper limb with two exceptions; The trapezius muscle which is innervated by the SPINAL ACCESSORY NERVE and An area close to the axilla which is innervated by the INTERCOASTOBRACHIALIS NERVE. 2/10/2014 4
    5. 5. • The brachial plexus begins in the neck extending through the axillary inlet into the axilla where almost all the branches of the plexus arises after it has crossed the first rib. 2/10/2014 5
    6. 6. 2/10/2014 6
    7. 7. ARRANGEMENT/FORMATION OF THE PLEXUS • The brachial plexus is formed by the union of the ventral rami of the lower four cervical nerves (C5-C8) and the greater part of the ventral ramus of the first thoracic nerve (T1) forming the roots of the plexus. 2/10/2014 7
    8. 8. • These roots passes through the gap between the anterior and middle scalene muscles with the subclavian artery. • The roots unite to form the 3 trunks at the inferior border of the neck viz; 2/10/2014 8
    9. 9. • Superior trunk- formed by the union of C5 & C6 at the lateral border of the scalenus medius muscle. • Middle trunk- formed as a continuation of C7 • Inferior trunk- formed from the union of C8 & T1 posterior to the scalenius anterior muscle. • the three trunks incline laterally, and either just behind or above the clavicle each divides into an anterior and a posterior division. 2/10/2014 9
    10. 10. • The anterior division will supply the anterior compartments of the upper limb while the posterior division supplies the extensor compartment of the upper limb. • The six (6) divisions of the brachial plexus unite to form the three cords; 2/10/2014 10
    11. 11. • The lateral cord; formed by the union of the anterior divisions of the superior and middle trunk. • Medial cord; formed as a continuation of the anterior division of the inferior trunk. 2/10/2014 11
    12. 12. • Posterior cord; formed by the union of the posterior divisions of the three trunks. • The cords of the plexus bear the relationship to the second part of the axillary artery that is indicated by their names; • The lateral cord is lateral to the axillary artery, the medial cord is medial to it while the posterior is posterior to it. 2/10/2014 12
    13. 13. 2/10/2014 13
    14. 14. Branches of the plexus • Branches are described as supraclavicular and infraclavicular. • The supraclavicular branches arises from the roots and trunks and are approachable through the neck. • Supraclavicular branches; 1. Long Thoracic Nerve (C5-C7)- passes through the cervicoaxillary canal and posterior to other BP components to supply the serratus anterior muscle. 2/10/2014 14
    15. 15. 2/10/2014 15
    16. 16. 2. Dorsal Scapular nerve (C5)- pierces the middle scalene muscle and runs deep to supply the levator scapulae, enters the deep surface of the Rhomboids muscle supplying it. 3. Suprascapular Nerve (C5-6)- passes laterally through the posterior triangle of the neck and through the suprascapular foramen to enter the posterior scapular region; supplies the supraspinatus, infraspinatus muscles and glenohumeral joint. 2/10/2014 16
    17. 17. • 4. Nerve to Subclavius (C5-6)- originates from the superior trunk of the brachial plexus; • passes anteroinferiorly over the subclavian artery and vein; • innervates the subclavius muscle. 2/10/2014 17
    18. 18. • Infraclavicular branches of the plexus; • Lateral cord 5. Lateral Pectoral Nerve (C5-7)- is the most proximal of the branches from the lateral cord, passes anteriorly, together with the thoraco-acromial artery, to penetrate the clavipectoral fascia that spans the gap between the subclavius and pectoralis minor muscles. It innervtes the pectorialis major muscle. 2/10/2014 18
    19. 19. 6. Musculocutaneous Nerve (C5-7)- is a large terminal branch of the lateral cord, passes laterally to penetrate the coracobrachialis muscle and pass between the biceps brachii and brachialis muscles in the arm, and innervates all three flexor muscles in the anterior compartment of the arm. innervates the coracobrachialis muscle, biceps brachii and brachialis muscles.  It therefore supplies the anterior compartment muscles of the arm continuing as the lateral cutaneous nerve of the forearm. 2/10/2014 19
    20. 20. 2/10/2014 20
    21. 21. 7. Lateral Root of Median nerve (C5-7)- is the largest terminal branch of the lateral cord and passes medially to join a similar branch from the medial cord to form the median nerve. • Medial cord • 8. Medial Root of Median Nerve (C8-T1)- it joins the lateral roots from the lateral cord to form the median nerve (C5-T1). • The median nerve is formed anterior to the third part of the axillary artery by the union of lateral and medial roots originating from the lateral and medial cords of the brachial plexus. 2/10/2014 21
    22. 22. • It passes into the arm anterior to the brachial artery, through the arm into the forearm where branches innervate most of the muscles in the anterior compartment of the forearm (except for the flexor carpi ulnaris muscle and the medial half of the flexor digitorum profundus muscle, which are innervated by the ulnar nerve). 2/10/2014 22
    23. 23. • The median nerve continues into the hand to innervate: • the three thenar muscles associated with the thumb; • the two lateral lumbrical muscles associated with movement of the index and middle fingers; • the skin over the palmar surface of the lateral three and one-half digits and over the lateral side of the palm and middle of the wrist. 2/10/2014 23
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    25. 25. 9. Medial Pectoral Nerve (C8-T1)- receives a communicating branch from the lateral pectoral nerve and then passes anteriorly between the axillary artery and axillary vein. innervates the pectorialis minor muscle and part of the pectorialis major muscle too. 10. Medial Cutaneous Nerve of the arm (C8-T1)- supplies the skin of the medial side of the arm and superior part of the forearm and also the floor of the axilla. 11. Medial cutaneous Nerve of the Forearm (C8-T1)innervates the skin on the medial side of the forearm.  Known as the “fools nerve”. 2/10/2014 25
    26. 26. 12. Ulnar Nerve (C8-T1)- is a large terminal branch of the medial cord. Transverse the arm into the forearm without branching.  innervates one and a half muscles in the anterior compartment of the forearm (flexor carpi ulnaris, flexor digitorum profundus).  innervates also all the intrinsic muscles of the hand except (3 thernar muscles and 2 lumbricals).  It innervates skin over the palmar surface of the little finger, medial half of the ring finger, and associated palm and wrist, and the skin over the dorsal surface of the medial part of the hand. 2/10/2014 26
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    28. 28. • Posterior cord 13. Upper Subscapular (C5-6)- is short, passes into the subscapularis muscle innervating it. 14. Thoracodorsal Nerve (C6-8)- the longest of the 3 side branches of the posterior cord, it passes vertically along the posterior axillary wall and innervates latissimus dorsi. 15. Lower Subscapular Nerve (C5-6)- inervates the teres major muscle as well as the inferior part of the subscapularis muscle. 2/10/2014 28
    29. 29. 2/10/2014 29
    30. 30. 16. Axillary Nerve (C5-6)- a terminal branch of the posterior cord, passes inferiorly and laterally along the posterior wall of the axilla to exit the axilla through the quadrangular space . It passes posteriorly around the surgical neck of the humerus. innervates the teres minor and the deltoid muscle 2/10/2014 30
    31. 31. 2/10/2014 31
    32. 32. 17. Radial Nerve (C5-8, T1)- is the largest terminal branch of the posterior cord.  The largest branch of the brachial plexus.  It passes out of the axilla and into the posterior compartment of the arm by passing through the triangular interval between the inferior border of the teres major muscle, the long head of the triceps brachii muscle, and the shaft of the humerus.  It is accompanied through the triangular interval by the profunda brachii artery, which originates from the brachial artery in the anterior compartment of the arm.  Supplies all the extensor muscles of the posterior compartment of the upper limb.  Skin on the posterior aspect of the arm and forearm. 2/10/2014 32
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    35. 35. • Variations in the formations of the brachial plexus are common. • In addition to the five (5) ventral rami (C5-8) and T1 that form the roots of the brachial plexus, small contributions may be made by the ventral ramus of C4 or T2. 2/10/2014 35
    36. 36. • When the contribution from C4 is more than that of T1, the root of the plexus starts from C4 and ends at C8. • This type of brachial plexus is termed prefixed. • When the contribution from T2 is more and the superior root is C6, it is termed postfixed. 2/10/2014 36
    37. 37. • • • • Variation may also occur in the; Formation of trunks, division and cords. Origin and or contribution of branches. Relation to axillary artery and scalene muscle. • In some individuals, trunk divisions or cord formations may be absent in one or other parts of the plexus; however the make up of the terminal branches remain unchanged. 2/10/2014 37
    39. 39. 1. Surgical neck of humerus; The Axillary Nerve, which supplies the teres minor and deltoid muscle, a major abductor of the humerus at the shoulder joint. 2. Radial groove; Radial Nerve, which supplies all the extensor muscles of the upper limb. 3. Medial epicondyle; Ulnar Nerve which supplies medial one and half part of the hand and the anterior compartment of the forearm. 2/10/2014 39
    41. 41. • The brachial plexus is an extremely complex structure. • When damaged, it requires meticulous clinical history taking and examination. • Brachial plexus injuries are important because they affect movements and cutaneus sensations in the upper limb. • Diseases, stretching and wounds in the posterior triangle of the neck or in the axilla may produce brachial plexus injuries. 2/10/2014 41
    42. 42. • Signs and symptoms of the injuries depends on the side of the plexus that is involved. • 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. 2/10/2014 42
    43. 43. • Injury to the superior trunk of the plexus is apparent by the characteristic position of the limb ("waiter's tip position"), in which the limb hangs by the side in medial rotation. • Upper brachial plexus injuries can also occur in a newborn when excessive stretching of the neck occurs during delivery. • Various terms are used to describe superior brachial plexus injuries; • Erb palsy (paralysis), Erb- Duchenne palsy (paralysis), Duchenne-Erb palsy (paralysis), and upper radicular syndrome. 2/10/2014 43
    44. 44. 2/10/2014 44
    45. 45. • The inferior parts of the brachial plexus may also be injured during a breech birth when the infant’s limb are pulled over the head. • These events injure the inferior trunk of the brachial plexus (C8-T1) and may pull the dorsal and ventral roots of the spinal nerves from the spinal cord. • The short muscles of the hand are affected, and a claw hand results. 2/10/2014 45
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    48. 48. GOODMORNING 2/10/2014 48