432 PRACTICAL ANATOMY. 



subclavius depresses the inner segment of the bone, while the weight of the arm 

 elevates the outer fragment. These anatomical facts led up to the empiric prac- 

 tice of elevating the elbow and adjusting the inner to the outer clavicular frag- 

 ments in the treatment of fracture' of this bone. 



ELBOW-JOINT. 



1. Class. Diarthrosis, because of free motion and a capsule. 



2. Subdivision. Ginglymus, because of motion in two directions. 



3. Technical Name. Humero-radio-ulnar articulation. 



4. Osteological Units. Humerus, radius, ulna. 



5. Subdivisional Parts. Two humeral condyles, a radial head, an olecranon 

 process, a coronoid process, a greater sigmoid cavity, two condylar ridges, an 

 olecranon fossa, a coronoid fossa, a radial fossa. 



6. Radial and Ulnar Articular Surfaces of Ihnncnts. Humeral surfaces of 

 radius and ulna. The ulnar surface of the humerus is called the trochlea. The 

 radial head of the humerus is called the capitellum. 



7. Basis. A capsule lined by synovial membrane. 



8. Local Suh&visums. Anterior, posterior, internal, and external. 



9. Strengthening Bands. None. 



10. Incorporated Tendons. None. 



1 1. Bone Limitations. Olecranon and coronoid processes, humerus. 



12. Nerve-supply. Ulnar, median, musculo-cutaneous, musculo-spiral. 



13. Blood-supply. FYom the anastomosis about the joint. 



14. Ligamentous Muscles. Biceps, brachialis anticus, supinator longus or 

 brachio-radialis ; triceps and anconeus ; pronator radii teres, flexor carpi radialis, 

 palmaris longus, flexor sublimis dig.itorum, flexor carpi ulnaris ; supinator brevis, 

 extensor carpi radialis longior, extensor carpi radialis brevior, extensor communis 

 digitorum, extensor minimi digit!, extensor carpi ulnaris. 



Through what would a fracture immediately above the condyles pass ? 

 Through the external and internal condylar ridges, through the olecranon, 

 radial, and coronoid fossae of the humerus. 



SUPERIOR RADIOULNAR ARTICULATION. 



1. Class. Diarthrosis, because of free motion. 



2. Subdivision. Lateral ginglymus, motion in two directions only. 



3. Technical Name. Superior radio-ulnar articulation. 



4. Osteological Units. Radius and ulna. 



5. Subdivisional Parts. Head of radius and lesser sigmoid of ulna. 



6. Articular Surfaces. Radial of ulna, ulnar surface of radius. 



7. Basis. An orbicular capsule lined by synovial membrane. 



8. Local Subdivisions of Capsule. None. 



9. Strengthening Bands of the Orbicular Capsule. None. 

 10. Incorporated Tendons of Obsolete Muscles. None. 



I i. Bony Limitations. The ulna and humerus. 



12. Nerve- and Blood-supply. Same as elbow-joint. 



13. Ligamentous Muscles. Supinator brevis and supinator longus. 

 Name the muscles inserted in the vicinity of this articulation. 



The biceps into the bicipital tuberosity of the radius. The brachialis anticus 

 into the coronoid process of the ulna. The triceps into the olecranon process 

 of the ulna. 



Give the origin and insertion of the orbicular ligament. 



It describes three-fourths of a circle, and is attached to the anterior and pos- 

 terior lips of the lesser sigmoid cavity of the ulna. 



