136 



muscle appears in two parallel bauds ; (18) a fission of the anterior belly 

 of the digastric occurred in one subject, in which the posterior belly of 

 that muscle was normal. Corresponding instances are numerous, and are 

 described by many authors ("Platner de Musculo Digastric© Maxillae 

 Inferioris," Lipsiae, 1737); (19) the supinator brevis I have likewise 

 seen split, the division corresponding to the point of perforation of the 

 posterior interosseous muscle ; (20) several remarkable cases of high 

 division of the superficial, or perforated flexor of the fingers, have oc- 

 curred to me, similar to JNo. 14 of my former paper. In that instance, 

 the digastric portion of the flexor sublimis supplied the index and mid- 

 dle fingers ; while in one of the recent cases, the digastric division of 

 the muscle supplied the index and little fingers; while the middle 

 finger tendon originated mainly from the radial origin ("Journal of 

 Anatomy," vol. i. p. 319). 



The cause of fission is easily understood, as resulting from the sub- 

 sequent atrophy of connecting fibres, or from the separation of the 

 component parts of complex muscles. The muscles in which this species 

 of deformity has occurred to me from time to time are : — 



Pectoralis major. 

 Pectoralis minor. 

 Serratus magnus. 

 Stcrno-cleido mastoid. 

 Biceps cubiti. 

 Adductor magnus. 

 Supinator brevis. 

 Flexor sublimis digitorum. 

 Flexor brevis digitorum. 

 Infra-spinatus. 

 Deltoid. 



Coracobrachialis. 

 Supinator longus. 

 Psoas parvus. 

 Bracbialis anticus. 



Pyriformis. 

 External pterygoid. 

 Extensor communis digi- 

 torum. 



Extensor brevis digitorum 



pedis. 

 Platysma. 

 Gluteus maximus. 

 Gluteus medius. 

 Quadratus femoris. 

 Trapezius. 

 Crico-tbyroid. 

 Pronator radii teres. 

 Pronator quadratus. 

 Flexor brevis pollicis. 



Latissimus dorsi. 



Orbicularis palpebrarum. 



Levator anguli scapulas. 



Rbomboideus. 



Splenitis. 



Com plexus. 



Subscapulavis. 



Extensor digitorum pedis 



longus. 

 Scalenus anticus. 

 Digastric. 



Extensor carpi radialis lon- 

 gior. 



Extensor carpi radialis bre- 

 vior. 



Varieties by suppression I have seen frequently in the case of some 

 muscles. Psoas parvus has occurred four times — that is, once in fifteen 

 subjects. Palmaris longus, although more constant in general than 

 plantaris, in the proportion of three to two ; yet, during the past session, 

 has been much more frequently absent than the latter, palmaris being 

 present in seven out of every ten, and plantaris in nine out of ten. Of 

 the other muscles, I have found a case of deficiency in the teres major 

 (" Journal of Anatomy and Physiology," vol. i., p. 317) — a muscle whose 

 deficiency bu s not, I think, ever before been noticed. Suppression has 

 thus occurred in my experience to — 



Platysma myoides. 



Zygomaticus major. 



Zygomaticus minor. 



Levator labii superioris. 



Orbital part of orbicularis palpebrarum. 



Pvramidalis nasi. 



Occipito-frontalis. 



Levator palpebral superioris. 



Tensor tarsi. 



Trapezius — occipital portion. 

 Trapezius — cervical portion (1). 

 Sternal head of sterno-mastoid (1). 



