159 



The plan upon which the muscles of a typical limb are arranged can 

 be thus distinctly understood, and may be resolved into a definite and 

 symmetrical system. For the basal joint we have a system of muscles 

 around the orbicular articulation (see diagram): — 



Besides these articular muscles, we have four external abductor 

 muscles from the basal bone inserted into the primal limb bone — one 

 internally, the other more externally ; one of these is the glutseus maxi- 

 mus or deltoid; the second, teres major, or tensorvaginae femoris; thirdly, 

 the sartorius, or dorsi epitrochlear; fourthly, part of the pectoralis major, 

 also represented by glutaeus maximus. Internally we have a group of 

 adductor muscles, their antitheses or opponents, the pectineus, adduc- 

 tors, quadratus femoris, and gracilis.* In front we find four flexor 

 muscles, behind four extensors, so we might represent the section through 

 the middle of the typical limb thus — 



Of the forearm muscles there are several series — one from either 

 condyle to the forearm bones, the long pronator, and supinator. There 

 are also transverse, inferior and superior, anterior and posterior, special 

 forearm muscles, the first of which is developed as the pronator quadratus, 

 above and below, as peroneo-calcanian, and the second as the coronoid 

 slip of pronator teres above, or the tibial head of the soleus ; the third as 

 extensor ossis metacarpi pollicis or hallucis ; the last is the supinator 

 brevis, or popliteus — all these are typical lateralizers ; then we have 

 the flexor and extensor muscle series — one for each of the metacarpal 

 bones, and a flexor and extensor muscle for the first, second, and third 

 phalanx of each finger ; finally, the list is completed by a dorsal and 

 palmar pair of interosseous muscles for each finger ; a palmar pair of 

 fascial tensors not represented on the dorsal aspect. 



* It may facilitate the understanding of some of these muscle-groups if we classify 

 them functionally, thus : — 



Muscles joining Upper Limb to Trunk. Do. Lower. 



1. Trapezio-deltoid and Sterno mastoid, . . 



2. Dorsi-epitrochlearis, 



3. Levator scapulae, Serratus magnus, I 



and posterior belly of omo-hyoid, J ' ' 



4. Rhomboidei, 



5. Latissimus dorsi, 



6. Pectoralis major, 



7. Chondo-epitrochleari', 



Flexors. 



Coraco-radial, = Longhead of biceps. 

 Gleno-ulnar, = Origin of semimem. and 



ins. of semiten. 

 Brachio-radia), = Short head of biceps. 

 Brachialis ant., = Ins. of semimembranosus. 



= Gluteus maximus. 

 = Sartorius. 



= Psoas magnus and parvus. 



= Quadratus lumborum. 

 = Agitator caudae. 

 = Adductor longus. 

 = Gracilis. 



Abductors. 



Teres major, = Tensor vaginae femoris. 



It will be seen that of these the first and fifth pass from the spines of the vertebrae to 

 the limb ; the sixth from the haemal spines ; the third and fourth from the pleurapo- 

 physes ; the second from the neurapopliysis ; and the seventh from the haemapophysis, 



