- Discussion:
- serratus anterior arises from upper eight ribs, inserts on vertebral border of scapula, is innervated by
long thoracic nerve, and functions to draw scapula
forward in sports such as a jab in boxing;
- paralysis produces characteristic prominence ("medial winging") of vertebral border of the scapula; (consider
Parsonage Turner)
- this is in contrast to paralysis of the
trapezius which is associated w/ lateral winging;
- origin:
- superior lateral surfaces of upper 8 or 9 ribes at the side of chest;
- arises from the upper 8 ribs, inserts on vertbral border of scapula;
- insertion:
- costal surface of vertebral border along inferior angle of scapula;
- paralysis produces winging of the vertbral border of the scapula;
- action:
- functions to draw scapula forward;
- abducts scapula and rotates it to point glenoid cavity superior;
- stabilizes vertebral border of scapla to thoracic cage, along with
rhomboids and middle
trapezius;
- nerve supply: long thoracic,
C5,
C6,
C7;
- vascular supply:
- it is supplied by circumflex scapular artery, which emerges at lateral border of scapula and divides into cutaneous scapular & periscapular arteries;
- it has the advantage of a constant vascular pedicle and a well- hidden donor site, although the scar does spread;
- Management of Serratus Paralysis: (winging of scapula)
- paralysis causes medial winging;
- paralysis may be traumatic (sports, MVA ect..), atraumatic (post-infectious neuritits, allergic rxns), or iatrogenic (mastectomy, thoracotomy);
- patients will note weakened forward flexion;
- in most cases, serratus paralysis will resolve over 6 months;
- diff dx:
- paralysis of the
trapezius may also cause winging of the scapula;
-
lung carcinoma
-
Long thoracic neuropathy caused by an apical pulmonary tumor
- on physical exam, manually fix the inferior scapula to the chest wall in about of 35 deg of rotation, and note effect on forward flexion;
- slightly more or less rotation may improve forward flexion;
- split pectoralis major transfer:
- reconstruction for serratus anterior palsy is a two-incision, split pectoralis major transfer without fascial graft
- references:
-
Pectoralis major transfer for serratus anterior paralysis
-
Results of Transfer of the Pectoralis Major Tendon to Treat Paralysis of the Serratus Anterior Muscle
-
Split pectoralis major transfer for serratus anterior palsy.
-
spaculopexy: (from
Vukov, et al. (1996))
- if physical exam demonstrates that manual fixation of the scapula will improve forward flexion, then a loose spaculopexy (opposition of the scapula to the chest wall) may improve function;
- incision is made along the inferomedial border of the scapula;
- the infero-medial border of the scapula is defined;
- the scapula is oppose to the chest wall in the appropriate degree of rotation;
- the nearest distal rib is cleared of soft tissue;
- w/ appropriate retractors in place, a small drill hole is made in both the tip of the scapula and the adjacent rib;
- a Vicry ribbon (or similar material) is then passed circumferentially around the rib and thru then thru the holes in the rib and scapula;
- ref:
Isolated Serratus Anterior Paralysis: A Simple Surgical Procedure to Reestablish Scapulo-humeral Dynamics.
- Serratus Anterior Flaps:
- inferior three slips of serratus anterior may be used for free tissue transfer for coverage of dorsal & palmar defects in the hand;
- there are three separate slips that are easily divisible for contouring;
- this flap has low donor site morbidity;
- free scapular fascial flap resurfaced with skin graft provides less bulk than cutaneous scapular flap
Winging Scapula. Shoulderdoc.co.uk
Serratus anterior paralysis in the young athlete.
The serratus anterior free-muscle transplant for reconstruction of the injured hand: an analysis of the donor and recipient sites.
