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Dr. SREEKANTH THOTA DEPARTMENT OF ANATOMY UPPER LIMB Slide 2 Upper Limb The upper limb is divided into the shoulder (junction of the trunk with the arm), arm, elbow, forearm, wrist, and hand. Slide 3 How to study upper limb? 1. Bones of the Upper Limb 2. Brachial Plexus 3. Muscles of the Upper Limb a. Shoulder b. Arm c. Forearm d. Hand 4. Blood vessels of upper limb 5. Lymphatics of upper limb 6. Joints of upper limb Slide 4 Bones of the Upper Limb Best way to learn bones of upper limb is during the anatomy lab, looking at Netter and follow your instructor. Slide 5 Brachial Plexus The brachial plexus is a somatic plexus formed by the anterior rami of C5 to C8, and most of the anterior ramus of T1. It originates in the neck, passes laterally and inferiorly over rib I, and enters the axilla. Slide 6 Slide 7 Brachial Plexus All major nerves that innervate the upper limb originate from the brachial plexus, mostly from the cords. The parts of the brachial plexus, from medial to lateral, are roots, trunks, divisions, and cords. Slide 8 Slide 9 Brachial Plexus Injuries Injuries to the brachial plexus affect movements and cutaneous sensations in the upper limb. Signs and symptoms depend on the part of the plexus involved. Injuries to the brachial plexus result in paralysis and anesthesia. Slide 10 Branches of the Brachial Plexus Roots: The roots of the brachial plexus are the anterior rami of C5 to C8, and most of T1. 1. Dorsal scapular nerve (C5) 2. Long thoracic nerve (C5, 6, and 7) Slide 11 Trunks In the inferior part of the neck, the roots of the brachial plexus unite to form three trunks 1. Superior trunk, from the union of the C5 and C6 roots. 2. Middle trunk, which is a continuation of the C7 root. 3. Inferior trunk, from the union of the C8 and T1 roots. The inferior trunk lies on rib I posterior to the subclavian artery; the middle and superior trunks are more superior in position. Slide 12 Branches of the trunks The only branches from the trunks of the brachial plexus are two nerves that originate from the superior trunk (upper trunk): 1.Suprascapular nerve (C5 and 6) 2.Nerve to the subclavius muscle (C5 and 6) Slide 13 Divisions Each of the three trunks of the brachial plexus divides into an anterior and a posterior division. No peripheral nerves originate directly from the divisions of the brachial plexus. Slide 14 Cords The three cords of the brachial plexus originate from the divisions and are related to the second part of the axillary artery. The anterior divisions of the upper and middle trunks unite to form the lateral cord, the anterior division of the lower trunk continues as the medial cord, and the posterior divisions of all three trunks join to form the posterior cord. Slide 15 Cords Slide 16 Brachial plexus Slide 17 Relationships to the axillary artery. Slide 18 Branches of the lateral cord 1.Lateral pectoral nerve(C5, 6, 7) 2.Musculocutaneous nerve(C5, 6, 7) 3.Lateral root of median nerve(C5, 6, 7) Slide 19 Branches of the brachial plexus Slide 20 Branches of the medial cord 1.Medial pectoral nerve(C8; T1) 2.Medial cutaneous nerve of arm (C8; T1) 3.Medial cutaneous nerve of forearm(C8; T1) 4.Ulnar nerve(C8; T1) 5.Medial root of median nerve(C5, 6, 7, 8; T1) Slide 21 Branches of the posterior cord 1.Upper subscapular nerve(C5, 6) 2.lower subscapular nerve(C5, 6) 3.Thoracodorsal nerve(C6, 7, 8) 4.Axillary nerve(C5, 6) 5.Radial nerve(C5, 6, 7, 8; T1) Slide 22 Slide 23 Relations Roots and trunks lie in the neck- Supraclavicular part Cords and branches lie in the axilla- Infraclavicular part Slide 24 Branches of the Brachial Plexus and Their Distribution Slide 25 1. Dorsal scapular nerve (C5) Rhomboid minor, rhomboid major, levator scapulae muscles Slide 26 2. Long thoracic nerve (C5, 6, 7) Serratus anterior muscle Slide 27 3. Suprascapular nerve (C5, 6) Supraspinatus and infraspinatus muscles Slide 28 4. Nerve to subclavius (C5, 6) Subclavius Slide 29 5. Lateral pectoral nerve (C5, 6, 7) Pectoralis major muscle Slide 30 6.Musculocutaneous nerve (C5, 6, 7) Coracobrachialis, biceps brachii, brachialis muscles Slide 31 7. Median nerve(C5, 6, 7, 8; T1) All muscles in the anterior compartment of the forearm (except flexor carpi ulnaris and medial half of flexor digitorum profundus), three thenar muscles of the thumb and two lateral lumbrical muscles Slide 32 8. Medial pectoral nerve (C8; T1) Pectoralis major and minor muscles Slide 33 9. Medial cutaneous nerve of arm(C8; T1) Skin of medial side of arm Slide 34 10. Medial cutaneous nerve of forearm (C8; T1) Skin of medial side of forearm Slide 35 11.Ulnar nerve (C8; T1) All intrinsic muscles of the hand (except three thenar muscles and two lateral lumbricals); also flexor carpi ulnaris and the medial half of flexor digitorum profundus in the forearm Slide 36 12. Upper subscapular nerve (C5, 6) Subscapularis muscle Slide 37 13. Lower subscapular nerve (C5, 6) Subscapularis and teres major muscles Slide 38 14. Thoracodorsal nerve (C6, 7, 8) Latissimus dorsi muscle Slide 39 15. Radial nerve (C5, 6, 7, 8; T1) All muscles in the posterior compartments of arm and forearm Slide 40 16. Axillary nerve (C5, 6) Deltoid, teres minor Slide 41 Brachial plexus lesions Slide 42 Slide 43 Slide 44 44 Injury to C5-6 at Erbs point Muscles paralysed Deltoid, biceps, brachialis, barachioradialis Posture waiters tip deformity Mechanism of injury : fall on shoulder or excessive pulling of head of new born during delivery Erb-Duchennes Palsy Slide 45 45 Slide 46 46 Klumpkes palsy Injury to C8-T1 Muscles paralyzed small muscles of hand Deformity Claw hand Mechanism : Sudden superior pull Slide 47 Symptoms : Clawed hand due to loss of innervation of Intrinsic muscle of the hand Slide 48 Radial nerve Slide 49 wrist-drop The characteristic clinical sign of radial nerve injury is wrist-drop. Slide 50 Fracture of the Humeral Shaft A midhumeral fracture may injure the radial nerve in the radial groove in the humeral shaft. Fracture is not likely to paralyze the triceps because of the high origin of the nerves to two of its three heads. Slide 51 SATURDAY NIGHT PALSY WRIST DROP Radial Nerve Injury in Axilla: Mechanism: 1.Crutches pressing in axilla 2.Saturday night palsy! Main Effect: Slide 52 Axillary nerve Slide 53 Note the left deltoid muscle atrophy. Slide 54 Musculocutaneous nerve Slide 55 Median nerve Slide 56 56 Slide 57 57 Carpal Tunnel syndrome Common in computer professionals. Due to constant dorsiflexion of wrist while typing the keyboard Slide 58 Slide 59 Ulnar nerve Slide 60 60 Slide 61 Slide 62 Cutaneous Nerves of upper limb