MUSCLES OF TEE ANTERIOR LIMBS. 315 



2. Adductoe of the arm (Teres Internus, or Teres Major) (Fig. 181, 4). 



%riom!/Tn8.— Subscapulo-humeralis— Girard. (Great scapulo-humeralis—Leyh.) 



Form — Situation — Direction. — A long muscle, flattened on both sides, bulging 

 in its middle, contracted at its extremities, thick at its anterior, and thin at its 

 posterior border. It is situated behind the preceding, in the same oblique direc- 

 tion, and is parallel with the posterior portion of the long abductor, which it 

 appears to repeat in the internal scapular region. 



Structure. — It is almost entirely muscular, showing only some tendinous fibres 

 at its external surface and upper extremity. Its inferior extremity is terminated 

 by a flat tendon, which also belongs to the latissimus dorsi, and which has been 

 already described (see p. 260). 



Attachments. — It arises from the dorsal angle of the scapula, and the posterior 

 border of the subscapular muscle — origin ; it passes to the internal tuberosity of 

 the humerus, to be attached by its inferior tendon — termination. 



Relations. — Outwards, with the aponeurosis of the latissimus dorsi and that 

 of the long extensor of the forearm, which isolates it from the large extensor 

 muscle ; inwards, with the sen-atus magnus, from which it is separated by the 

 fibrous and cellular layers mentioned in the description of the subscapularis. Its 

 inferior extremity covers the short flexor and middle extensor of the forearm ; it 

 is covered by the long branch of the coraco-humeralis, and by the vessels and 

 nerves which send their ramifications to the arm, forearm, and foot. 



Action. — This muscle adducts the arm, and causes it to rotate inwards. If it 

 contracts at the same time as the long abductor, it du'ectly flexes the humerus. 



3. Coraco-humeralis, Coraco-brachialis, or Omo-brachialis 

 (Fig. 181, 10). 



Synonym. — Middle seapulo-humeralis — Leyh. 



Volume — Situation — Direction. — A small elongated muscle, which appears to 

 belong to the arm rather than the shoulder, as it is situated at the internal face 

 of the humerus, which it slightly crosses. If it is described as in the subscapular 

 region, it is because of its attachments and action, which are, in every respect, 

 analogous to those of the other muscles of the shoulder. 



Attachments — Form — Structure. — It commences on the beak of the coracoid 

 process by a small flat tendon, which is at first included between the supra-spinatus 

 and subscapularis, but afterwards leaves the interstice formed by these two muscles, 

 to be inflected and glide over the terminal tendon of the latter. This small 

 tendon is succeeded by two muscular branches — one deep, the other superficial. 

 The first is a wide, thin, and short band, almost entirely muscular, attached to 

 the body of the humenis above the internal tuberosity. The second forms a fleshy 

 body of a certain thickness, flattened on both sides, and strongly aponeurotic ; 

 the fasciculi composing it are longer as they are more posterior, and are inserted, 

 by their inferior extremities, into the imprints on the anterior face of the 

 humenis. 



Relations. — This muscle is covered by the flexor brachii, and by the pectoralis 

 magnus, which is partly attached to its tendon. It covers the internal insertion 

 of the subscapularis, the humerus, the common tendon of the latissimus dorsi, 

 the adductor of the arm, and a small portion of the short flexor and middle 

 extensor of the forearm. Its posterior border is margined by the vessels and 



