The document provides detailed information about the anatomy of the brachial plexus and the nerves of the upper limb. It describes the formation and branches of the brachial plexus, including the roots, trunks, divisions, cords and branches. It also discusses the muscles, arteries, veins and ligaments associated with the shoulder and upper limb.

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2. Upper extremity

3. Surface anatomy Clavicle Manubrium Jugular notch (suprasternal notch) Deltoids Scapula, Acromion, spine, coracoid process, fossa, borders Humerus, tubercle, body Ulna, head, olecranon process, ulnar nerve Radius, radial nerve, styloid process Carpals, pisiform, scaphoid and trapezium, anatomical snuff box

4. Brachial Plexus

5. Brachial plexus formation…. The brachial plexus starts from the five ventral rami of the spinal nerves , after they have given off their segmental supply to the muscles of the neck . These are the five roots . These roots merge to form three trunks : "superior" or "upper" C5-C6, "middle" C7, and "inferior" or "lower" C8-T1. Each trunk then splits to form an anterior and a posterior division .

6. Brachial plexus formation…. The six divisions will regroup to become the cords . The cords are named by their position in respect to the axillary artery . The posterior cord is formed from the three posterior divisions of the trunks. The lateral cord is the anterior divisions from the upper and middle trunks. The medial cord is simply a continuation of the lower trunk.

7. Brachial plexus formation… Branches of the brachial plexus 3 branches from the roots Dorsal scapular nerve arises from C5 root, supplies the rhomboid muscles and levator scapulae . Nerve to subclavius arises from C5 and C6 roots, supplies the subclavius muscle Long thoracic nerve arises from C5 , C6 and C7 roots, supplies serratus anterior

8. Brachial plexus formation… 1 branch from the trunks Suprascapular nerve arises from the superior trunk, supplies supraspinatus and infraspinatus muscles 3 branches from the lateral cord Lateral pectoral nerve supplies pectoralis major and pectoralis minor ( by communicating with the medial pectoral nerve ) from C5, C6, C7. Musculocutaneous nerve from C5 and C6 it supplies coracobrachialis , brachialis and biceps brachii . It then becomes the lateral cutaneous nerve of the forearm . Lateral root of the median nerve supplies C5, C6 and C7 fibres to the median nerve.

9. Brachial plexus formation… 5 branches from the posterior cord Upper subscapular nerve supplies subscapularis (upper part) from C5 and C6 Thoracodorsal nerve supplies latissimus dorsi with nerve fibres from C6, C7 and C8 Lower subscapular nerve supplies the lower part of subscapularis and teres major from C5 and C6. Axillary nerve from C5 and C6, it supplies deltoid and a small area of overlying skin by its anterior branch. Its posterior branch supplies teres minor and deltoid muscles then becomes the upper lateral cutaneous nerve of the arm Radial nerve nerve fibres from all 5 roots (C5- T1 ) largest nerve of the plexus supplies triceps brachii, the skin of the posterior arm as the posterior cutaneous nerve of the arm , anconeus , and the extensor muscles of the forearm .

10. Brachial plexus formation… 5 branches from the medial cord medial pectoral nerve from C8 and T1, it supplies pectoralis major and pectoralis minor medial root of the median nerve supplies C8 and T1 fibres to the median nerve. medial cutaneous nerve of the arm supplies the front and medial skin of the arm from C8 and T1 medial cutaneous nerve of the forearm supplies medial skin of the forearm from C8 and T1 ulnar nerve C7, C8 and T1 fibres supplies flexor carpi ulnaris , the medial 2 bellies of flexor digitorum profundus , most of the small muscles of the hand and the skin of the medial side of the hand and medial one and a half fingers

11. Anesthesia of the Brachial Plexus The fact that the nerves of the brachial plexus are grouped together acts as a benefit as well. Local anesthetics such as lidocaine or bupivacaine can be injected in close proximity to these nerves , rendering an entire arm insensate and immobile. The process of injecting local anesthetic for this purpose is called regional nerve blockade or more simply, a nerve block, and it is a common procedure in anesthesia . After an onset time of approximately 10 to 15 minutes, the targeted arm will be fully anesthetized and ready for surgery . The patient can remain awake during the ensuing surgical procedure, or he can be sedated with medications or fully anesthetized with general anesthesia

12. Peripheral nerve blockade The use of peripheral nerve blockade (in this case, a "brachial plexus nerve block") offers several advantages when compared to general anesthesia or local anesthesia: The patient can remain awake and breathing on their own, thus protecting themselves from aspiration of stomach contents into the lungs. By avoiding general anesthesia, patients with adverse reactions to general anesthetics ( viz. malignant hyperthermia, severe post-operative nausea and vomiting, known hypersensitivity to agents) can be successfully treated. Similarly, patients who experience nuisance side effects from general anesthesia such as nausea, vomiting, or excessive sleepiness can minimize these symptoms. There is no need to perform an endotracheal intubation , the procedure of inserting a breathing tube into the trachea. Occasionally, such intubation is unexpectedly difficult to perform, causing injury to the patient. The affected limb's sympathetic nerves are anesthetized, leading to vasodilation . This improves blood flow to the affected limb and makes microvascular surgical procedures technically simpler. The limb can remain numb for several hours after surgery, providing excellent pain relief. Deep and superficial structures of the limb are similarly anesthetized, allowing extensive surgical exploration and correction to occur. This is in contrast to locally injected local anesthetics, which tend only to numb superficial structures in the immediate vicinity of the injection.

13. Brachial plexus blockade Brachial plexus blockade is the preferred anesthetic technique when: Surgery is expected to be limited either to a region between the midpoint of the humerus and the fingers (in which case the brachial plexus block should be either a supra-clavicular , infra-clavicular , subcoracoid, or axillary block), OR surgery is expected to be limited to a region between the midpoint of the humerus and the shoulder (in which case the brachial plexus block should be an interscalene block). Because of the distribution of the local anesthetics on the various portions of the brachial plexus, surgeries crossing the midpoint of the humerus often reveal patchy, unanesthetized portions of the arm. Such procedures probably should not be performed under regional nerve block alone. AND There are no contra-indications to a block such as infection at the intended injection site, significant anti-coagulation , allergy or hypersensitivity to local anesthetic medications, or disproportionate risk in the event of a local anesthetic toxic reaction ( seizure ) such as gastric aspiration in a patient who has not adequately fasted, AND There will not be a need to perform a neurologic examination immediately following the surgical procedure, AND Patient prefers this technique over other available and reasonable approaches.

14. Injuries Two injuries types are recognised in brachial plexus injuries: Traumautic and Obstetric. Traumatic injuries often are the result of high velocity RTA's (Road Traffic Injuries). The most common form of injury are the motorcycle drivers falling, with either the head/neck pushed to the side (upper plexus lesions) or with their arm abducted (stretched upwards) which produces a lower plexus injury. The brachial plexus is susceptible to injuries that produce abduction of the thoracic limb from the body wall or a direct blow to the lateral surface of the scapula .

15. The cardinal signs of brachial plexus avulsion are: a weakness in the arm diminished reflexes corresponding sensory deficits The nerve roots are stretched or torn from their origin by this trauma, since the meningeal coverings of the nerve roots are thinner than those in the peripheral nerve. The epineurium of the peripheral nerve is contiguous with the dural mater , providing extra support to the peripheral nerves. In cases where the nerve roots have been torn, recovery is unlikely without new experimental surgical techniques. The diagnosis may be confirmed by an EMG examination in 5-7 days. The evidence of denervation will be evident. If there is no nerve conduction 72 hours after the injury, then avulsion is most likely.

16. Brachial Plexus and Nerves of Upper limb Supraclavicular nerve Origin Muscle distribution Dorsal scapular Ventral rami of C4, C5 Rhomboids & Lev. scapulae Long thoracic Ventral rami of C4- C7 Serratus anterior Nerve to subclavius Superior trunk, C4- C6 Subclavius, sternoclavicular joint Suprascapular Superior trunk, C4-C6 Supraspinatus, infraspinatus, glenohumeral (shldr) joint

17. Infraclavicular nerves Origin Muscle distribution Lateral pectoral Lateral cord, C5-C7 Pectoralis major, pectoralis minor Musculocutaneous Lateral cord, C5-C7 Coracobrachialis, biceps brachii, brachialis, Median Lateral cord, C6-C7 Flexor carpi ulnaris, flexor digitorum profundus Medial pectoral Medial cord, C8-T1 Pectoralis major/minor Medial brachial cutaneous Medial cord C8-T1 Skin on medial side of arm. Medial antebrachial cutaneous Medial cord, C8-T1 Skin over medial side of forearm

18. Infraclavicular nerve Origin Muscle distribution Ulnar Terminal of medial cord, C7, C8- T1 Half of flexor forearm muscles, small muscles of hand, skin on medial of hand to ring finger Upper subscapular Posterior cord, C5-C6 Superior subscapularis Thoracodorsal Posterior cord, C6-C8 Latissimus dorsi Lower subscapular Posterior cord, C5-C6 Inferior subscapularis and teres major Axillary Terminal posterior cord, C5- C6 Teres minor, deltoids, shoulder joints, skin over inferior deltoids. Radial Terminal posterior cord, C5- C6 Triceps brachii, anconeus, brachioradialis, extensor muscles of forearm, skin over post. Aspect of arm and forearm.

19. Muscle Origin Insertion Nerve Action Biceps brachii Coracoid process, supraglenoid tubercle Radial tuberosity, biciptal aponeurosis Musculocutaneous C5 – C6 Supinates forearm, flexes forearm Brachialis Anterior surface of distal humerus Coronoid process, ulna tuberosity Musculocutaneous C5 – C6 Flex and adducts arms Cracobrachialis Coronoid process of scapula Mid3rd medial surface humerus Musculocutaneous C5 – C7 Flex and adducts arm Triceps brachii LH:Infraglenoid tubercle Lat hd: post humerus sup. To radial groove Medial Hd: post. Humerus inf. To radial groove Olecranon of ulna and fascia of forearm Radial nerve C6 – C8 Extend forearm, long head steadies head of humerus Anconeus Lateral epicondyle Humerus Lat. Surface olecranon sup of ulna Radial nerve C7 – T1 Assist triceps to extend forearm, stabilize elbow, adducts ulna in pronation

20. Break

21. Axillary artery Boundaries = lateral border first rib to superior border of Teres minor muscle Division: 1st division = from lateral border first rib to medial border of pectoralis minor Branch = supreme thoracic artery 2nd division = from medial border of pectoralis muscle to lateral border of same muscle Branch = Thoraco acromial artery Lateral thoracic artery 3rd division = from lateral border of pectoralis minor to superior border of the Teres minor muscle Branch = Subscapular artery Anterior circumflex humeral artery Posterior circumflex humeral artery

22. Brachial artery Boundaries = distal edge of Teres major muscle to Cubital fossa. Branches = 1. Deep brachial or Profunda brachii artery = to posterior compartment of the arm Recurrent branch anastomose with the posterior circumflex humeral artery Lateral branch anastomose with the Radial recurrent artery. Posterior branch anastomose with Recurrent interosseous artery. Collateral branches Superior ulnar artery anastomose with posterior recurrent ulnar artery. Inferior ulnar artery anastomose with anterior recurrent ulnar artery.

23. Venous return Deep veins = 2 to 3 joins to form the venae comitantes brachiales freely anastomose about the brachial artery. superficial veins Cephalic veins to the anterior of the lateral epicondyle to the deltopectoral triangle, pierces the clavipectoral fascia to join the axillary vein distal to first rib.. Basilic vein = medial epicondyle along the deep medial antebrachial joins the brachial vein near the teres major muscle to form the axillary veins. Median cubital veins = the connecting veins between the cephalic and the basilica veins at the cubital Fossa, it lies at the bicipital aponeurosis..

24. Lymphatic drainage Deep lymphatics accompany brachial veins into the axillary lymph nodes. Superficial lymphatics along the superficial veins into the: supratrochlear lymph nodes near the medial epicondyle superficial drainage bypass most axillary nodes into the subclavian vein.

25. Ligaments of the Glenohumeral Joint. There are several important ligaments in the shoulder. Ligaments are soft tissue structures that connect bones to bones. A joint capsule is a watertight sac that surrounds a joint. In the shoulder, the joint capsule is formed by a group of ligaments that connect the humerus to the glenoid. These ligaments are the main source of stability for the shoulder. They help hold the shoulder in place and keep it from dislocating. These are the glenohumeral ligaments (GHL) Another ligament links the coracoid to the acromion - coracoacromial ligament (CAL). This ligament can thicken and cause Impingement Syndrome Ligaments attach the clavicle to the acromion in the AC joint. Two ligaments connect the clavicle to the scapula by attaching to the coracoid process, a bony ridge on the scapula - coracoclavicular ligaments (CCL) Ligaments of the Shoulder Complex: CCL - coracoclavicular ligaments CAL - coracoacromial ligaments SGHL - Superior GlenoHumeral Ligament MGHL - Muperior GlenoHumeral Ligament IGHL - Inferior GlenoHumeral Ligament

26. Ligaments of the Rotator Cuff The tendons of the rotator cuff are the next layer in the shoulder joint. Tendons are much like ligaments, except that tendons attach muscles to bone. Muscles move the bones by pulling on the tendons. One important tendon that travels through the shoulder joint is the biceps tendon . The biceps tendon actually begins at the top of the shoulder socket (the glenoid) and then passes across the front of the shoulder to connect to the biceps muscle. (The biceps is the muscle that weightlifters are always showing off). The rotator cuff tendons are a group of four tendons that connect the deepest layer of muscles to the humerus. They are the tendons of the rotator cuff muscles (left) Tendons of the shoulder: From front to back: Subscapularis Biceps Tendon Supraspinatus Infraspinatus Teres Minor

27. Muscles of the shoulder There are 30 muscles providing movement and support for the shoulder complex. 15 muscles move and stabilize the scapula; 9 muscles provide for glenohumeral joint motion; and 6 support the scapula on the thorax There are three important groups of muscles around the shoulder: 1. Surface muscles (Extrinsic): The large deltoid muscle forms the outer layer of muscle. This is the largest, strongest muscle of the shoulder. The deltoid muscle takes over lifting the arm once the arm is away from the side. Pectoralis Major provides movement and support in the front of the shoulder

28. Deep ( Intrinsic) muscles . Deep muscles (Intrinsic): The rotator cuff tendons attach to the deep rotator cuff muscles. These 4 muscles are involved in raising the arm from the side and rotating the shoulder in the many directions. The rotator cuff mechanism also helps keep the shoulder joint stable by holding the humeral head in the glenoid socket. These muscles are: subscapularis, supraspinatus, infraspinatus and teres minor. 3. Back Muscles (Posterior): These muscles are at the back of the shoulder that stabilise and move the scapula on the trunk of the body. This group includes the trapezius, rhomboids, levator scapulae, and the serratus anterior muscles; and are concerned with stabilisation and rotation of the scapula.

29. Bursas of the Shoulder Sandwiched between the rotator cuff muscles and the outer layer of large bulky muscles is a structure known as a bursa. Bursae are everywhere in the body. They are found wherever two body parts move against one another and there is no joint to reduce the friction. A bursa is simply a sac between two moving surfaces that contains a small amount of lubricating fluid. Think of a bursa like this: If you press your hands together and slide them against one another, you produce some friction. In fact, when your hands are cold you may rub them together briskly to create heat from the friction. Now imagine that you hold in your hands a small plastic sack that contains a few drops of salad oil. This sack would let your hands glide freely against each other without a great deal of friction.

30. Muscles of the Back

31. Superficial muscles Muscle Origin Insertion Action Nerve Trapezius Occiput, nuchal line Clavicle, acromion, spine of scapula Rotator, adductor, lowers the scapula. Spinal accessory nerve Latissimus dorsi Thoraco-Lumbar fascia,spines of lumbar & sacral, iliac crest, lower 4 ribs Intertubercular groove or bicipital groove. Extends, adducts, median rotator of shoulder Thoraco dorsal ( long subscapular)

32. Superficial, rhomboid layer… Muscle Origin Insertion Action Nerve Levator scapula Post, tubercle and transverse process C1-4 Medial border scapula, higher Elevator and rotator of scapula Dorsal scapular nerve Rhomboid minor Nuchal lig. Spine C7-T1 Medial border scapula, lower Adduct scapula medially, depressor of scapula Dorsal scapular nerve Rhomboid major Spine T2 – T5, supraspinous lig. Medial border lower Adduct scapula medially, depressor Dorsal scapular nerve

33. Deep muscles of the back, transverse- costal group Splenius capitis – from nuchal lig, spine of C7, T1-3 to occiput , mastoid Splenius cervicis – spines of T3-6 to transverse process C1-3 Erector spinae – med crest of scarum to lower 6 ribs Iliocostalis lumborum – from spines T11 – L5, iliac crest to sacrum Iliocostalis thoracis - from lower 6 rib angle to rib 1-6/trnsvrs proc. C7 Iliocostalis cervicis - angle rib 3-6 to trnsvrs poc. C4-6 Longissimus thoracis- mid crest sacrum Longissimus cervicis- transvrs proc T1 - 5 Longissimus capitis- transvrs proc. T1- 5, artic. Proc C5 - 7 Spinalis thoracis - spines T11 – L2 Spinalis cervicis - C7 to spine C2

34. Deep layer, Transverse-spinal group Semispinalis thoracis – transvrs proc. T6 -10 to spines C6-T4 Semispinalis cervicis – transvrs proc. T1-T6, to spines C2-C5 Semispinalis capitis – Transvrs proc. C7-T7, to nuchal plane of occiput Spinalis capitis - transvrs proc. C7-T7, to nuchal plane occiput Multifidus Sacral – post sacrum to spines o C2 – L5 Lumbar – mamillary proc. Thoracic – from transvrs process Cervical – from articular proc C4 – C7 Rotatores Longi – transvrs proc of 1 vertebra to spine 2 vertebra above Breves – transvrs proc of 1 vertebra to next vertebra above Interspinalis – connects apices of spines of adjoining vertebra Intertransverse- interconnects anterior tubercle of transvrs process

35. Suboccipital muscle Rectus capitis posterior major From spinous process of axis, to inf nuchal line. Extend and rotate the head to same side Tubercle post arch of atlas, to inf nuchal line. Extends head. Rectus capitis posterior minor Tubercle on post arch atlas to inferior nuchal line. Extends head. Obliquus capitis inferior apex, and spine of atlasTrnsvrse proc. Atlas, turns head same side Obliquus capitis superior Transvrs proc. Atlas to occipital bone between nuchal lines. Extends head and bends it to same side.

36. Actions, general…. Nerve supply by all posterior primary divisions of spinal nerves. Splenius – draws head back, bends head laterally, rotates ace to same side. Iliocostalis- bends vertebral column to side, lumborum depress ribs Longissimus thoracis and cervicis bends column to side, depress ribs Longissimus capitis extends head, bends head to side, rotates face to same side Semispinalis thoracis & cervicis - rotates column to same side. Semispinalis capitis – extends head rotates head to opposite side. Multifidus rotates column to opposite side. Rotatores rotates column to opposite side. Intertransverse bends column to same side.

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