Innervation and Localization of the Motor Points of Triceps Surae Muscle
Olave, E.; Retamal, P.; Galaz, C.; & Cruzat, C.
The knowledge of innervation of muscles is generally described, but we can complement the point where the nerves penetrate the muscle belly, from the biometric standpoint. In order to know the innervation and motor points in the components of the triceps surae muscle, 18 formolized lower limbs of adult Chilean individuals were studied. Planes dissection was performed by identifying the point nerve of the lateral and medial head of gastrocnemius muscle and soleus muscle. All specimens were schematized and photographed. We identified the source of the branches, about a line drawn between the most prominent parts of the femoral epicondyles (BECL), as well as the points of entry into the muscle belly, classifying these branches as principal (BR) and secondary ( SBR). In all samples the innervations came from the tibial nerve. The medial head of the gastrocnemius muscle received one branch (BR1) in 15 cases and two (BR1 and BR2) in 3 cases. The BR1 origin is located on average 23.6 ± 11.5 mm distal to the BECL, in 15 cases the BR1 split up into four SBR. The points where these latter entered in muscular belly regarding BECL were on average: 40.4 + 11.1 mm (SBR1) distal to this line and 46.9 ± 9.1 mm (SBR2). The lateral head received one branch in 17 cases and two in 1 case; the origin of BR1 was found on average to 35.6 ± 11,8 mm distal to the BECL; in 12 cases the BR1 was divided up in four SBR. Regarding to BECL the SBR entered in muscle belly distal to this line, 49.4 ± 9.3 mm (SBR1) and 52.4 ± 10.6 mm (SBR2). The soleus muscle received his branch from a common trunk with the lateral head of the gastrocnemius in 7 cases and one direct branch BR1 in 6 cases and two branches (BR1 and BR2) in 5 cases, of which 3 of them received one anterior branch and posterior branch; the origin of BR1 was located 40.4 ± 14.4 mm distal to the BECL; the common trunk origin was located at 20.2 mm distal from this line. The BR1 was divided up into seven SBR. These results are a contribution to the anatomy of the motor points, which can be used as a reference for application of electrical stimulation therapy and for electromyographic studies in our population.
Key words: Anatomy; Innervation; Triceps surae muscle; Motor points.