Brachial Plexus and Applied Anatomy.pptx

The brachial plexus is a network of nerves that extends from the neck to the armpit, originating from spinal nerves \(C5\) through \(T1\). It transmits motor and sensory signals to the shoulder, arm, and hand, allowing for movement and sensation in the upper limb. Injuries to this network can cause weakness, numbness, or paralysis, often resulting from trauma, inflammation, or stretching, and may require surgery depending on severity.   Function and structure Function: The brachial plexus is crucial for upper limb function, controlling muscles for raising your arm, moving your hand, and feeling sensations like heat and cold.  Structure: The plexus is a complex network with five main parts: roots, trunks, divisions, cords, and terminal branches.  Roots: The five roots emerge from the spinal cord at \(C5\), \(C6\), \(C7\), \(C8\), and \(T1\).  Trunks: The roots merge into three trunks: upper (\(C5\)-\(C6\)), middle (\(C7\)), and lower (\(C8\)-\(T1\)).  Divisions: Each trunk splits into an anterior and posterior division.  Cords: The divisions then combine to form the lateral, posterior, and medial cords.  Branches: The cords give rise to the major nerves of the arm, such as the musculocutaneous, axillary, radial, median, and ulnar nerves.  Injury Causes: Injuries are typically caused by trauma that stretches, compresses, or tears the nerves, such as from sports injuries, accidents, or difficult childbirth (Erb's palsy).  Symptoms: A brachial plexus injury can lead to a range of symptoms, including a limp or paralyzed arm, lack of muscle control, numbness or a complete lack of feeling, and sometimes sharp or burning pain.  Treatment: Mild injuries may heal on their own, but more severe cases may require surgery to restore function. Pain management is also a key part of treatment. 

1. Brachial P lexus & Applied Anatomy DR MATHEW JOSEPH MBBS, MD(AIIMS), BCC(Palliative Medicine) Assistant Professor Department of Anatomy Amala Institute of Medical Sciences, Thrissur Visiting Faculty - Buon Ma Thout Medical University, Vietnam SSGP Nodal Officer - Kerala University of Health Sciences

2. As per: Competency based Undergraduate curriculum AN10.3: Describe, identify, and demonstrate formation, branches, relations, area of supply of branches, course and relations, and terminal branches of brachial plexus. AN10.5: Explain variations in formation of brachial plexus. AN10.6: Explain the anatomical basis of clinical features of Erb’s palsy and Klumpke’s paralysis.

3. Brachial plexus • Nerve plexus that supplies the upper extremity. • Arises by combination of lower four ervical spinal nerves and first thoracic spinal nerve .

4. Spinal nerve s : 31 pairs of spinal nerves, one on each side of spinal cord Spinal nerves are grouped as Cervical : 8 pairs Thoracic : 12 pairs Lumbar : 5 pairs Sacral : 5 pairs Coccygeal :1 pair

5. Each spinal nerve has two roots – Dorsal sensory root – Ventral motor root Sensory root has dorsal root ganglion (sensory ganglion) Motor root arises from ventral horn cells of the spinal cord and supplies muscle and organs. Lateral horn cells are present in thoracic, upper lumbar, and sacral region of spinal cord.

6. Each spinal nerve divides into ventral and dorsal ramus Dorsal ramus supplies muscles and skin of back. Ventral ramus supplies anterolateral part of trunk and limb.

7. B rachial P lexus Nerve plexus that is derived from ventral primary rami of lower four cervical spinal nerves (C5–C8) and first thoracic spinal nerve (T1).

8. Components of Brachial Plexus 1. Roots : Ventral primary rami of C5–C8 and T1 nerves. 2. Trunks : Three trunks derived from roots (upper, middle, and lower). 3. Divisions : Each trunk divides into anterior and posterior divisions. 4. Cords : Divisions join to form three cords (medial, late ral, posterior). 5. Branches : Various nerves arise from each cord.

9. Components of Brachial Plexus Roots Ventral primary rami of lower four cervical spinal nerves (C5–C8) and first thoracic spinal nerve (T1) forms the roots of brachial plexus

10. Roots Prefixed brachial plexus : If ventral ramus of 4th cervical spinal nerve (C4) contributes in the brachial plexus, it is called prefixed brachial plexus Post-fixed brachial plexus : If ventral ramus of 2 nd thoracic spinal nerve (T2) contributes in the brachial plexus, it is called post-fixed brachial plexus

11. Components of Brachial Plexus Trunks Roots of the brachial plexus joins to form three trunks Upper trunk formed by joining of C5 and C6 roots Middle trunk as a continuation of C7 root Lower trunk formed by joining C8 and T1 roots.

12. Trunks Relations • Trunks of brachial plexus lies in neck. • Trunks descend downward and laterally. • Lower trunk passes posterior to the subclavian artery, whereas upper and middle trunks pass behind the artery. Human Anatomy/Yogesh Sontakke

13. Divisions Each trunk divides into anterior and posterior divisions. Trunks divide in the lowest part of the neck to form divisions. Divisions enter the axilla through cervicoaxillary canal where they form cords. Components of Brachial Plexus

14. Components of Brachial Plexus Cords Divisions join to form three cords Lateral cord formed by union of ventral divisions of upper and middle trunks Medial cords as a continuation of ventral divisions of lower trunk Posterior cords formed by union of dorsal divisions of all trunks

15. Cords Relations Relations with 2nd part of axillary artery: Medial cord lies medial P osterior cord lies posterior L ateral cord lies lateral

16. Some Interesting Facts How to identify cords of brachial plexus: Practical guide Trace the following nerves upward Lateral root of median nerve or musculocutaneous nerve to identify lateral cord (lies lateral to the axillary artery). Medial root of median nerve or ulnar nerve to identify medial cord (lies between axillary artery and vein). Radial nerve to identify the posterior cord or reflect the axillary artery as posterior cord lies deep to the artery. Roots, trunks, and divisions of brachial plexus lie in the neck, whereas cords and their branches lie in the axilla. Neet

17. Branches of Brachial Plexus

18. Branches of Brachial Plexus Branches of roots 1. Nerve to S erratus anterior or L ong thoracic nerve (C5, C7) Neet 2. Nerve to R homboideus minor and major ( D orsal scapular nerve) (C5) 3. Branches to L ongus coli and S caleni muscles (C5–C8) 4. Phrenic nerve (C3–5)

19. Branches of Brachial Plexus Branches of lateral cord 1. Lateral pectoral nerve 2. Musculocutaneous nerve 3. Lateral root of median nerve

20. Branches of Brachial Plexus Branches of medial cord 1. Medial pectoral nerve 2. Medial cutaneous nerve of arm 3. Medial cutaneous nerve of forearm 4. Ulnar nerve 5. Medial root of median nerve

21. Branches of Brachial Plexus Branches of posterior cord Neet 1. Upper subscapular nerve 2. Nerve to latissimus dorsi 3. Lower subscapular nerve 4. Axillary neve 5. Radial nerve

22. Case scenerio 1 A 24 year old male presented to orthopedics department with h/o a tree branch falling on right shoulder 3 months ago. H/o inability to raise his right arm and numbness on lateral aspect of right forearm .

23. Erbs Palsy

24. Case Scenerio 2 A 50 year old male presented with history of fall from a construction building and tried to grab on a steel bar with his right hand. H e gives h/o inability to completely open his right hand. h/o loss of sensation on the inner aspect of forearm and hand. h/o drooping of right eyelid and blurring of vision on the same side.

25. Klumpke’s Palsy

26. Discussion: Common fractures of Humerus The most common fractures at humerus are: At the surgical neck of humerus At the shaft Supracondylar region Medial epicondyle Lateral epicondyle Intercondylar region

27. Winging of scapula

28. Thank You