S MR. E. J. SIDEBOTHAM ON THE [JaU. 20, 



mass arising from whole length of sternum and ensifonn appendix. 

 Fibres converge to a tendon — the posterior ones underlying the 

 anterior ones — which is ultimately united with tendons of chondro- 

 humeral and pectoralis quartus and is inserted into outer lip of 

 bicipital groove of humerus. Its anterior fibres are continuous for a 

 short distance with clavicular portion of deltoid. 



/3. Underlies preceding portion. It arises in close connection with 

 it from middle of sternum opposite third, fourth, and fifth ribs. Its 

 fibres converge to a flat narrow tendon, which is inserted into outer 

 lip of bicipital groove on a level with upper portion of preceding 

 tendon. 



Rectus sternalis. — Arises by three tendinous slips from junction 

 of fourth, fifth, and sixth ribs with sternum. It is inserted into 

 anterior surface of first rib at about its middle. 



Pectoralis quartus. — Arises from fascia lying between scapula and 

 pectoraHs major. It is inserted into outer lip of bicipital groove of 

 humerus with chondro-humeral. 



Chondro-humeral. — A thin band arising in middle line from apo- 

 neurosis covering externa! oblique. Inserted with pectoralis quartus. 



Supraspinatus. — Arises from supraspinous fossa, inserted into 

 anterior part of neck of humerus, and shoulder capsule. 



Infraspinatus. — Arises from infraspiuous fossa. Inserted just 

 below preceding. 



Teres minor. — Arises from ventral half of posterior border of 

 scapule between infraspinatus and scapular head of triceps. Inserted 

 just below infraspinatus. 



Teres major. — A thick fleshy muscle, arising from posterior 

 superior angle of scapula. Inserted by a flattened tendon into inner 

 lip of bicipital groove. 



Beltoid. — Clavicular and scapular positions quite distinct, ex- 

 cepting just at their insertions. 



Clavicular portion arises from anterior border of outer half of 

 clavicle and from a small portion of acromion. Inserted into 

 anterior surface of humerus at its upper third, being connected both 

 at its origin and insertion with pectoralis major. 



Scapular j)ortion arises from posterior surface of spine of scapula 

 and upper portion of infraspiuous fossa. Inserted just above clavi- 

 cular portion. 



Coraco-brachialis (brevis). — Arises from coracoid, and is inserted 

 into inner part of neck of humerus. 



Subscapularis. — Arises from subscapular fossa. Inserted into 

 inner part of humerus, near to neck. 



Levator scapulee. — Arises by a rounded tendon from anterior arch 

 of atlas just internal to acromio-trachelien, and by a few fibres 

 behind this. Its fibres, diverging, are inserted into ventral third of 

 spine of scapula and acromion. 



Biceps. — Arises by a flat undivided tendon from coracoid and 

 upper margin of glenoid. It consists of two bellies, which are 

 distinct, but closely applied, the coraco-radial one being superficial. 

 If the tendon is forcibly torn, the coraco-radial head is seen to arise 



