results of brachial plexus surgery have not fullfilled their expectations. [3]. Experimental work in this field is limited [4]. The rat model offers advantages, including ...
Surgical Radiologic Anatomy
Surg Radiol Anat (1992) 14 : 85-86
Journal of Clinical Anatomy
© Springer-Verlag 1992
Reports of the Socidt Anatomique de Paris
Anatomical basis of rat brachial plexus reconstruction
JA Bertelli 1,3, JC Mira 1, A Gilbert2, GA Michot 2 and J Legagneux 2 LLaboratoire de Neurobiologie, Groupe Rrgrnrration des Nerfs Prriphrriques et des Muscles Squelletiques, 45, rue des Saints-P~res, F-75006 Paris, France 2Laboratoire de Microchirurgie, Ecole de Chirurgie des Hopitaux de Paris, 17, rue de Fer ~t Moutin, F-75005 Paris, France 3Laboratoire d'Anatomie, Biomrdicale de Saints-P~res, 45, rue des Saints-P~res, F-75006 Paris, France
Microsurgical techniques have largely i m p r o v e d the t r e a t m e n t of lesions in the peripherarnn, and brachial plexus [1, 2]. Unfortunately results of brachial plexus surgery have not fullfilled their expectations [3]. Experimental work in this field is limited [4]. The rat model offers advantages, including relatively rapid regeneration, that requires a fairly short o b s e r v a t i o n period. The rat brachial plexus anatomy was studied in 42 adult animals. The dissections involved the whole brachial plexus, terminal branches, roots and rootlets. The caliber of all structures were measured. The innervation and vascularization of biceps brachii muscle were studied. The localization of biceps motoneurons were demonstrated by retrograde tracing with horseradish peroxidase [5]. Eletrophysiologycal studies were also carrried out. The median n. was dissected in the forepaw in order to individualize a c u t a n e o u s territory only innervated Offprint requests : JA Bertelli, 34, rue de Guynemer, F-75006, Paris, France
by this nerve. The femoral, peroneal and sural nn. were dissected as possible source of n. grafts for brachiat plexus reconstruction and their caliber and length measured. Intracardiac injection of green latex allowed the study of the vascularizaton of the brachial plexus, peroneal, sural and femoral nn. The five roots of the brachial plexus are provided by the anterior primary divisions of 5th, 6th, 7th and 8th cervical spinal nn. (C5, C6, C7, C8) and the first thoracic n. (T1).The roots are formed by 2 to 5 anterior and 2 to 5 posterior rootlets. C5 + C6 form the superior trunk, C7 the middle trunk, and C8 + T1 the inferior trunk (Fig. 1). The anterior division of the superior and middle trunks form the lateral cord, the anterior divisions of the middle and inferior trunks the medial cord, and the posterior divisions of all trunks form the posterior cord (Fig. 2). The musculocutaneous n. is the terminal branch of the lateral cord, axillary and radial nn. of the posterior cord, and the ulnar an median
nn. of the medial cord (Fig. 2). The vascutarization of the roots is provided by the vertebral a. The acromial trunk and cervical trunk (thyro-cervical trunk in man) supply the remaining of brachial plexus (Figs. 1, 3). The biceps brachii muscle and musculocutaneous n. represent an interesting model for the study of motor regeneration. Motoneurons of the biceps are localized in C5, C6 and also C7 medullary segments. The median n., second intercomissural space and skin from index finger represent a model for the study of sensory regeneration. The peroneal and sural nn. are the source o f conventional n. grafts, femoral and sural nn. for vascularized grafts. The brachial plexus of the rat is similar in its components, and branching to that of the human. It has a discrete structure and clear anatomic landmarks; anatomic localization is relatively simple. This work was funded in part by IMMUNOFRANCE
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JA Bertelli et al : Anatomical basis of rat brachial plexus reconstruction
Figs. 1-3 1 Superior, middle and inferior trunks of the brachial plexus. Vascularization is ensured by the cervical trunk (TC). (ST) superior trunk, (MT) middle trunk, (IT) inferior trunk (VA) vertebral a_ 2 (L) Lateral, (M) Medial and (P) Posterior cords and terminal branches of brachial plexus: (MN) musculocutaneous, (A) axilary, (R) radial, (U) ulnar, and (MN) median n. 3 The vertebral a. (VA) supplies the roots of the brachial plexus 1 Les troncs suprrieur (ST), moyen (MT), et infrrieur (IT). La vascalarisation est assur6 par le tronc cervical (TC). (VA) a. vert~hrale. 2 Les fascicules latrral (L), mrdial (M) et postrrieur (P) et tes branches terminales du plexus brachial: Les nn. musculocutan6 (MC), axillaire (A), radial (R), ulnaire (U) et mrdian (MN). 3 L'a. vertrbrate (VA) foumit la vascularisation pour les racines du plexus brachial
References 1. MiUesi H, Gamgleber J, Berger A (1977) Erfahrtmgen mit der Mikrochirurgie periph~er Nerven. Chit Plast Reconstrut 3:47-55 2. Narakas A (1978) Surgical treatment of traction injuries of the Brachial Plexus. Clin Orthop 33:71-90 3. Leffert R D (1980) Reconstruction of the shoulder and elbow following brachial plexus injuries. In: Omer G, Spinner M (eds) Management of peripheral n. problems. WB Saunders, Philadelphia 4. Gu Y, Ma M (1991) Nerve transfer for treatment of root avulsion of the brachial plexus: Experimental studies in a rat model. J Reconst Microsurg 7:15-21 5. Mesulam, MM (1982) Tracing Neural Connections with horseradish peroxidase. Wiley, New York
Received August 19,1992/AcceptedNovember 8, 1992
