Presentation on theme: "Brachial Plexus Dr. Sama-ul-Haque Dr. Nivin Sharaf."— Presentation transcript:
1 Brachial PlexusDr. Sama-ul-Haque Dr. Nivin Sharaf
2 BRACHILAL PLEXUSThe brachial plexus is a somatic nerve plexus formed by intercommunications among the ventral rami of the lower four cervical nerves ( C 5 - C 8) and the first thoracic nerve (T 1). The plexus is responsible for the motor innervation to all of the muscles of the upper limb with the exception of the trapezius and levator scapula.), and the sensory innervation of the upper limb except an area just above the point of the shoulder (supplied by supraclavicular nerves) and the dorsal scapular area which is supplied by cutaneous branches of dorsal rami.
4 FORMATION OF THE BRACHIAL PLEXUS RootsThe ventral rami of spinal nerves C5 to T1 are referred to as the roots of the plexus.TrunksShortly after emerging from the intervertebral foramina , these 5 roots unite to form three trunks.The ventral rami of C5 & C6 unite to form the Upper Trunk.The ventral ramus of C 7 continues as the Middle Trunk.The ventral rami of C 8 & T 1 unite to form the Lower Trunk.DivisionsEach trunk splits into an anterior division and a posterior division.The anterior divisions usually supply flexor musclesThe posterior divisions usually supply extensor muscles
7 FORMATION OF THE BRACHIAL PLEXUS CONT. CordsThe anterior divisions of the upper and middle trunks unite to form the lateral cord.The anterior division of the lower trunk forms the medial cord.All 3 posterior divisions from each of the 3 cords all unite to form the posterior cord.The cords are named according to their position relative to the axillary arteryTerminal branches:Musculo CutaneousUlnar n.Median n.Axillary n.Radial n.Terminal Branches are mixed nerves containing both sensory and motor axons.Musculocutaneous nerve is derived from the lateral cord.This nerve innervates the muscles in the flexor compartment of the armCarries sensation from the lateral ( radial) side of the forearm. (Figs. 2,3)Ulnar nerve is derived from the medial cordMotor innervation is mainly to intrinsic muscles of the handSensory innervation is from the medial ( ulnar) 1 & 1/2 digits ( the 5th. and 1/2 of the 4th. digits). (Figs. 2,3)Median nerve is derived from both the lateral and medial cordsMotor innervation is to most of the flexors muscles in the forearm and intrinsic muscles of the thumb (thenar muscles).Sensory innervation is from the lateral ( radial) 3 & 1/2 digits ( the thumb and first 2 and 1/2 fingers). (Figs. 2,3)Axillary nerve is derived from the posterior cord.Motor innervation is deltoid and teres minor muscles that act on the shoulder joint.Sensory innervation is from the skin just below the point of the shoulder. (Figs. 2,3)Radial nerve is also derived from the posterior cord.Called “Great Extensor Nerve” because it innervates the extensor muscles of the elbow, wrist and fingers.Sensory innervation is from the skin on the dorsum of the hand on the radial side. (Figs. 2,3)
9 Relations of Brachial plexus BRANCHES (Fig. 4) Nerves that are branches from portions of the brachial plexus usually contain only 1 type of axon; either sensory or motor)From the RootsDorsal Scapular nerveDerived from C5 rootMotor nerve to the Rhomboideus major and minor musclesLong Thoracic nerveDerived from C 5,6,7Innervates the serratus anterior muscleFrom the Upper TrunkNerve to subclavius muscleSuprascapular nerveInnervates supra and infraspinatus musclesFrom the Lateral CordLateral Pectoral nerveInnervates the clavicular head of the pectoralis major muscleFrom the Medial CordMedial Pectoral nerveInnervates the sternocostal head of the pectoralis major muscleInnervates the pectoralis minor muscleNote : the medial and lateral pectoral nerve often join together to act as a single nerve innervating both the pectoralis major & minor musclesCutaneous BranchesMedial brachial cutaneousCarries sensation from the lower medial portion of the armMedial antebrachial cutaneousCarries sensation from the medial (ulnar portion of the forearm)
13 Brachial Plexus Injuries The brachial plexus lies in the posterior triangle of the neck between the scalenus anterior and scalenus medius muscles. At the root of the neck, it lies behind the clavicle.The most common injury is severe traction with the arm in abduction e.g. after a motor cycle accident. Partial paralysis may also result from shoulder dislocation. Direct injury to the brachial plexus can result from a stab or gunshot wound.:
14 Brachial Plexus Injuries In Adults:Sports most commonly associated:Football, baseball, basketball,volleyball, wrestling, andgymnastics.Nerve injuries can result from: Blunt force trauma, poor posture or chronic repetitive stress.
15 Brachial Plexus Injuries Patients generally present with pain and/or muscle weakness.Some patients may experience muscle atrophy.
17 Erb- Duchenne palsyInjury to Superior part of Plexus. Occurrence: Due to excessive increase in the angle between neck and the shoulder. Roots Involved: C5 and C6 Muscles Involved: Shoulder Arm
39 Baby’s upper limb is pulled excessively during delivery
40 Claw HandAetiology:brachial plexus lesion (C8-T1),Ulnar, and/ or Median nerve injuryThis occurs when all fingers are clawed. It is the result of hyperextension at the metacarpophalangeal joints and flexion of the interphalangeal joints.