APPENDIX. 449 



Extensor carpi ulnaris arises by a small but strong tendon from 

 the external part of external condyle of the humerus, is massive 

 and fusiform, and passes under a tendinous arch from the back part 

 of the lower end of the ulna in a shallow groove. The tendon then 

 passes down on the inner edge of the foot to be attached to the 

 head of the metacarpal bone of the fifth toe ; it is crossed over near 

 its insertion by the tendon of the ext. rain, digiti. 



Extensor minimi digiti is a cylindrical muscle closely bound 

 down by an aponeurotic sheath to the ridge between the outer 

 and anterior surface of the ulna. Above, it arises from the fore 

 part of the external condyle, but almost all the way down it is 

 attached to the ulna by means of its aponeurotic sheath. It continues 

 fleshy down to the wrist-joint, and is tied down by the annular 

 ligament in the shallow groove in front of the lower end of the bone. 

 It changes its direction beyond the annular ligament, inwards and 

 backwards, crossing the tendon of the last muscle, and is inserted 

 into the upper and inner part of the metacarpal bone of the 

 fifth toe. 



Extensor digitorum communis. — In connection with the origin of 

 this muscle is a very thick intermuscular septum, which is attached 

 all along the edge which separates the inner from the anterior sur- 

 faces of the ulna, and separates the last muscle from the common 

 extensor. This septum is attached superiorly to the external condyle 

 of the humerus by means of an excessively strong portion of the 

 common investing aponeurosis of the forearm. This portion of 

 the aponeurosis forms a baud consisting principally of elastic fibre 

 of a yellow colour, and fully an inch thick at the lower part of its 

 extent ; it splits into two portions, which are attached to the mar- 

 gins of the groove to which the tendon of the last muscle passes. 

 The muscle itself arises from the deep surface of nearly the upper 

 half of this band ; it is aponeurotic where the muscle arises from it, 

 but entirely elastic in its texture below ; its fibres superiorly arise 

 from the external condyle of the humerus, rapidly converge to form a 

 in i ivc conical compressed double penniform muscle, which termi- 

 nates a little above the carpus in numerous laterally-connected 

 tendons, which are arranged in the form of a flattened ribbon in a 

 shallow groove on the lower and fore part of the ulna, tied down by 

 the transverse ligament, and with an extensive synovial apparatus 



