AR TICULA TIONS. LIGA ME NTS. 43 1 



The inferior scapular ligament extends from the glenoid margin to the 

 spine. Under it pass the infraspinatous divisions of the suprascapular vessels 

 and nerves. (Fig. 249.) 



THE STERNO-CLAVICULAR ARTICULATION. 



1. Class. Diarthrosis, since capsule and motion are present. 



2. Subdivision. Arthrodia simple gliding articular surfaces. 



3. Technical Name. Sterno-clavicular articulation. 



4. Osteological Units. Sternum and clavicle. 



5. Sub divisional Parts. Manubrium and sternal end of clavicle. 



6. Articular Surfaces. Sternal of clavicle, clavicular of sternum. 



7. Basis. A capsule lined by synovial membrane. 



8. Local Subdivisions. Should be none. 



9. Strengthening Bands. None. Periosteal purely. 



10. Incorporated Tendons. None. 



1 1. Bony Limitations. Manubrium and first rib. 



1 2. Nerve-supply. Brachial plexus by nerve to subclavius. 



13. Ligamentous Muscles. Subclavius and sterno-mastoid. 



Rhomboid 

 ligament 

 Anterior 

 sterno- 

 clavieular 

 ligament 



FIG. 300. ANTERIOR VIEW OF STERNO-CLAVICULAR JOINT. 



(The capsule is cut into on the left side to show the interarticular fibro- cartilage dividing the joint 



into two cavities.) 



1 . Name all tlie ligaments of this articulation. 



The capsular, the basis of the joint. The interclavicular binds the clavicles to 

 the sternum. The costo-clavicular, or rhomboid. The interarticular fibro- 

 cartilage. 



2. How many synovial cavities has the articulation ? 



Two, separated from each other by the interarticular fibro-cartilage. This 

 cartilage is attached to the capsule like others of its class, as the temporo-man- 

 dibular and the inconstant acromio-clavicular interarticular fibro-cartilage. 



3. In practical dissection, when yon wish to remove the clavicle, what is the most 

 difficult structure to divide ? 



The costo-clavicular ligament binding the clavicle very firmly to the first rib. 



4. What muscle do you find under the clavicle, and what is its surgical impor- 

 tance ? 



The subclavius muscle, arising in front of the costo-clavicular ligament from 

 the first rib. It is inserted into the middle third of the clavicle on the under sur- 

 face of the bone. In fracture of the clavicle in the middle or outer third, the 



