476 THE MUSCLES AND FASCIA. 



in front. It is perforated by the ulnar nerve and the inferior profunda and anasto- 

 motic arteries. At the elbow the deep fascia is attached to all the prominent 

 points round the joint viz. the condyles of the hurnerus and the olecranon process 

 of the ulna and is continuous with the deep fascia of the forearm. Just below the 

 middle of the arm, on its inner side, in front of the internal intermuscular septum, 

 is an oval opening in the deep fascia which transmits the basilic vein and some 

 lymphatic vessels. On the removal of this fascia the muscles, vessels, and nerves 

 of the anterior humeral region are exposed. 



The Coraco-brachialis, the smallest of the three muscles in this region, is sit- 

 uated at the upper and inner part of the arm. It arises by fleshy fibres from 

 the apex of the coracoid process, in common with the short head of the Biceps, 

 and from the intermuscular septum between the two muscles ; the fibres pass 

 downward, backward, and a little outward, to be inserted by means of a flat ten- 

 don into a rough ridge at the middle of the inner surface and internal border of 

 the shaft of the humerus between the origins of the Triceps and Brachialis anticus. 

 It is perforated by the musculo-cutaneous nerve. The inner border of the muscle 

 forms a guide to the position of the brachial artery in tying the vessel in the upper 

 part of its course. 



Relations. By its anterior surface, with the Pectoralis major above, and at 

 its insertion with the brachial vessels and median nerve which cross it; by its 

 posterior surface, with the tendons of the Subscapularis, Latissimus dorsi, and 

 Teres major, the inner head of the Triceps, the humerus, and the anterior circum- 

 flex vessels ; by its inner border, with the brachial artery, and the median and 

 musculo-cutaneous nerves ; by its outer border, with the short head of the Biceps 

 and Brachialis anticus. 



The Biceps (Biceps flexor cubiti) is a long fusiform muscle, occuping the whole 

 of the anterior surface of the arm, and divided above into two portions or heads, 

 from which circumstance it has received its name. The short head arises by a 

 thick flattened tendon from the apex of the coracoid process, in common Avith the 

 Coraco-brachialis. The long head arises from the supraglenoid tubercle on the 

 upper margin of the glenoid cavity, by a long rounded tendon, which is continuous 

 with the glenoid ligament. This tendon arches over the head of the humerus, 

 being enclosed in a special sheath of the synovial membrane of the shoulder-joint ; 

 it then passes through an opening in the capsular ligament at its attachment to the 

 humerus, and descends in the bicipital groove, in which it is retained by a fibrous 

 prolongation from the tendon of the Pectoralis major. The fibres from this tendon 

 form a rounded belly, and, about the middle of the arm, join Avith the portion of 

 the muscle derived from the short head. The belly of the muscle, narrow and 

 somewhat flattened, terminates above the elboAv in a flattened tendon, Avhich is 

 inserted into the back part of the tuberosity of the radius, a synovial bursa being 

 interposed between the tendon and the front of the tuberosity. The tendon of the 

 muscle is thin and broad ; as it approaches the radius it becomes narrow and tAvisted 

 upon itself, so that its external border becomes anterior, arid its posterior flat sur- 

 face is applied to the back of the tuberosity : opposite the bend of the elbow the 

 tendon gives off, from its inner side, a broad aponeurosis, the bicipital fascia (semi- 

 lunar fascia), which passes obliquely doAvnAvard and inAvard across the brachial 

 artery, and is continuous with the deep fascia of the forearm (Fig. 302). The 

 inner border of this muscle forms a guide to the position of the vessel in tying the 

 brachial artery in the middle of the arm. 1 



Relations. Its anterior surface is overlapped above by the Pectoralis major 

 and Deltoid ; in the rest of its extent it is covered by the superficial and deep 

 fasciae and the integument. Its posterior surface rests on the shoulder-joint and 



1 A third head to the Biceps is occasionally found (Theile says as often as once in eight or nine 

 subjects), arising at the upper and inner part of the Brachialis anticus, with the fibres of which it 

 is continuous, and inserted into the bicipital fascia and inner side of the tendon of the Biceps. In 

 most cases this additional slip passes behind the brachial artery in its course down the arm. Occa- 

 sionally the third head consists of two slips which pass down, one in front, the other behind the artery, 

 concealing the vessel in the lower half of the arm. 



