Winging of scapula is due to damage to the nerve supply of which muscle that becomes prominent on action?
Correct Answer: Serratus anterior
Description: ANSWER: (A) Serratus anterior REF: Gray's anatomy 39th edition page 558 See APPENDIX-7 below for "BRACHIAL PLEXUS LESIONS" Since question asks particularly "ON ACTION" - A is coorect. Iatrogenic injury of the spinal accessory nerve (usually via accidental damage during minor neck surgery) is the most common cause of accessory nerve palsy. Although rare, this kind of damage can cause extensive morbidity, including numbness, paralysis, pain, and winging of the scapula. A lesion of the pyramidal system above the pons produces weakness of the ipsilateral sternocleidomastoid and contralateral trapezius. In jugular foramen syndrome, caused by pathologies including nasopharyngeal carcinoma or a glomus tumour, lesions of the glossopharyngeal, vagus and accessory nerves coexist. The accessory nerve can be injured more dis tally in the neck by trauma or by surgical exploration in the posterior triangle. If the accessory nerve is sacrificed as part of a radical neck dissection, and the innervation of trapezius is lost APPENDIX - 7 Brachial Plexus Lesions-chart 1 Nerve (Segment) Motor Deficit(s) Sensory Deficits Long Thoracic (C 5, 6, 7) Winged Scapula- Serratus Anterior None Suprascapular (C 5, 6 ) Hard to start shoulder abduction - Supraspinatus None Axillary (C 5, 6 ) Difficult abducting arm to horizontal - Deltoid Lateral side of arm below point of shoulder Loss of shoulder roundness - Deltoid Musculocutaneous C 5, 6, (7) Very weak flexion of elbow joint- Biceps & Brachialis Lateral forearm Weak supination of radioulnar joint -Biceps Radial (C 5 - Tl) Drop Wrist - Extensor carpi radialis iongus & brevis, Ext. carpi ulnaris Posterior lateral &arm; dorsum of hand Difficulty making a fist - synergy between wrist 1 extensors and finger flexors Median (EUR 5 - Tl) at Elbow Pronation of radioulnar joints-Pronator teres & quadratus Radial portion of palm; palmar surface 8i tips of radial 3% Weak wrist flexion - FI. carpi radialis digits Weakened opposition of thumb - thenar muscles "Ape Hand"- thumb hyper extended and adducted - thenar muscles "Papal Hand" Loss of flexion of I.P. joints of thumb & fingers 1 & 2 - Fl. pollices Iongus ; FL digit, superficialis, FL digit profundus Median (C 5 - Tl) at Wrist Weakened opposition of thumb - thenar muscles Palmar surface & tips of radial "Ape Hand"- thumb hyper extended and adducted - thenar muscles 3% digits Ulnar (C 8, Tl) at Elbow "Clawing" of fingers 3 & 4- M.P. joints hyper extended: P.I.P. Flexed - Interossei& Lumbricals Ulnar and dorsal aspect of palm and of ulnar VA digits Loss of abduction & adduction of M.P joints of fingers -Interossei Thumb - abducted and extended - adductor pollices Loss of flexion of D.I.P. joints of fingers 4 8t 5 - Fl. digit profund. Ulnar (C 8, Tl) at Wrist "Clawing" of fingers 3 & 4- M.P. joints hyper extended; P.I.P. Flexed - Interossei & Lumbricals Ulnar and dorsal aspect of palm and of ulnar 1 xk digits Loss of abduction & adduction of M.P joints of fingers - Interossei Thumb - abducted and extended - adductor pollices Upper and Lower Root Lesions-chart 2 Lesion Motor Deficits Sensory Deficits Nerves Erb s Palsy (C5,6) Loss of abduction, flexion and rotation at shoulder; Weak shoulder extension - deltoid, rotator cuff Posterior and lateral aspect of arm - axillary n. Axillary, Suprascapular, Upper and Lower subscapular Very weak elbow flexion and supination of radioulnar joint - biceps brachii & brachiaiis Radial side of Forearm- musculocutaneous n. Thumb and 1st finger - superficial hr. of radial; digital brs. - Median n. Musculocutaneous: Radial N. brs. to supinator & brachioradialis muscles Susceptible to shoulder dislocation - loss of rotator cuff muscles Suprascapular, Upper and Lower subscapular "Waiters Tip" position Klumke's Palsy (C8, Tl) Loss of opposition of thumb -Tnenar muscles Ulnar side of forearm, hand & ulnar 1 Vi & digits - ulnar and medial antebrachial cutaneous Thenar branch of Median nerve Loss of adduction of thumb - Adductor pollices Ulnar nerve Loss of following finger movements: abduction and adduction of M.P. joints; flexion at M.P. & extension of LP. joints. Lumbricals & interossei Deep branch of Ulnar & Median Very weak flexion of P.I.P. & D.I.P. joints FI Digit. Super. & Profund. Ulnar and Median
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