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Trapezius

                       


- Discussion:
    - trapezius and serratius anterior  stabilize scapular base from which the arm operates;
    - trapezius, which arises from spinous processes of  cervical and thoracic vertebrae  & inserts on spine of scapula
           and acromion, is innervated by spinal accessory nerve and branches from third and fourth cervical roots;
    - its upper fibers shrug shoulder & aid in suspension of shoulder girdle;
    - middle portion aids in adduction and rotation of the inferior angle of the scapula;
    - lower segments, together w/ serratus anterior, clamp scapula to chest wall so that it cannot rotate or slip sideways;

- Innervation:
    - inevated by branches of the ansa cervicalis and the spinal accessory nerve from 3rd & 4th cervical roots;
          - note: that in the posterior cervical triangle, the spinal accessory nerve is located superficially in the subcutaneous tissue;

- Actions:
    - its upper portion shrug shoulder & aid in suspension of shoulder girdle;
    - middle portion aids in adduction & rotation of inf. angle of scapula;
    - lower segments, together w/ serratius anterior clamp scapula to chest wal so that it cannot rotate or slip sideways;

- Upper Division:
    - origin: external occipital protuberance, medial 1/3 of superior nuchal line, ligamentum nuchae & spinous process of 7th cervical vert;
    - insertion: lateral 1/3 of clavicle and acromion process;
    - action:
         - rotation of scapula so glenoid cavity faces superior;
         - when acting with the other sections of trapezius it adducts scapula;
    - reversed origin insertion action:
         - laterally flexes head and neck to side of contraction;
         - rotates head and neck away from side of contraction;
         - acting bilaterally, extension of the head and neck;
    - nerve supply: spinal accessory and ventral ramus of C2, C3, C4;
    - synergists:
         - levator scapulae, clavicular head of  sternocleidomastoid, middle and lower trapezius;

- Middle Division of Trapezius:
    - origin: spinous process of 1st - 5 th thoracic vertebrae;
    - insertion: superior border of spine of scapula, draws back acromion process;
    - nerve supply: spinal accessory nerve and ventral ramus, C2, C3, C4;
    - synergists: spinal accessory nerve and ventral ramus, C2, C3, C4;

- Lower Division Trapezius:
    - origin: spinous process of 6th to 12th thoracic vertebrae;
    - insertion: medial 1/3 of spine of the scapula;
    - action:
         - rotation of scapula to face the glenoid cavity superior gives inferior stabilization of scapula;
         - aids to maintain spine in extension;
         - draws back acromion process;
    - nerve supply: spinal accessory nerve and ventral ramus, C2, C3, C4;
    - synergists: trapezius upper and lower divisions;

- Paralysis of Trapezius:
    - most often arises from mishandled cervical node biopsy, trauma, or from radical neck dissection (due to injury to spinal accessory nerve);
    - clinical findings:
          - drooping of the shoulder, lateral winding of the scapulae, and weak forward elevation of the shoulder and weakened shoulder abduction;
          - patients may be more prone to brachial plexus palsy, frozen shoulder, subacromial impingement, and thoracic outlet syndrome;

- Modified Eden Lange Procedure:
    - described by Eden in 1924 and Lange in 1959;
    - attempts to restore the 3 anatomical and functional aspects of the trapezius;
    - pt is placed in lateral position;
    - trapezius is dissected off its origin of the scapular spine;
    - levator scapulae and rhomboids are identified;
         - each of these muscles are detatched from medial aspect of scapulae (along with a small piece of bone);
    - levator scapulae is transfered laterally to scapular spine;
         - replaces superior portion of trapezius;
    - rhomboid minor is transferred to supraspinatus fossa;
         - replaces middle portion of trapezius;
    - rhomboid major is transferred to infraspinatus fossa;
         - replaces inferior portion of trapezius



Transfer of the Levator Scapulae, Rhomboid Major, and Rhomboid Minor for Paralysis of the Trapezius.

Treatment of trapezius paralysis

Accessory nerve injury

Surgical Management of Trapezius Palsy.

Identification of the Spinal Accessory Nerve Within the Surgical Field During Primary Exploration of the Brachial Plexus in Infants With Obstetric Palsy.

Clinical signs of accessory nerve palsy

Injuries to the spinal accessory nerve