ARTICULATIONS OF THE SACRUM. 427 



SECTION IV. 



LIGAMENTS OF THE PELVIS. 



The sacrum is joined at its base to the last lumbar vertebra, at Outline of 

 its apex to the coccyx, arid laterally to the two hip-bones. And the [at e ions! CU 

 hip-bones are connected together at the symphysis pubis in front. 



UNION OF PIECES OF THE SACRUM AND COCCYX. So long as Ligaments 

 the pieces of the sacrum and coccyx remain moveable they are 

 articulated as in the other vertebrae by an anterior and a posterior 

 common ligament, with an intervertebral disc for the bodies, and 

 by ligaments for the neural arch and processes. 



After the sacral vertebrae have coalesced, only rudiments of the and joined. 

 ligaments of the bodies are to be recognised ; and when the pieces 

 of the coccyx unite by bone, their ligaments disappear. 



LUMBO-SACRAL ARTICULATION. The base of the sacrum is Sacrum 

 articulated with the last lumbar vertebra by ligaments similar to iuSba? st 

 those uniting one vertebra to another (pp. 492 et seq.) ; and by one vertebra, 

 special ligament the lateral lumbo-sacral. 



Dissection. For the best manner of bringing these different Dissection, 

 ligaments into view, the dissector may consult the directions given 

 for the dissection of the ligaments of the vertebrae (pp. 492 et seq.). 



The common ligaments for the bodies of the two bones are anByiiga- 

 anterior and a posterior, with an intervening fibre-cartilaginous sub- Bother* 

 stance. Between the neural arches lie the ligamenta subflava, and vertebra, 

 between the spines the supra- and interspinous bands. The articular 

 processes are united by capsular ligaments with synovial membranes. 



The lateral lumbo-sacral ligament is a variable bundle of fibres, and by a 

 which reaches from the under surface of the tip of the transverse JS^Ji' 

 process of the last lumbar vertebra to the lateral mass at the base band - 

 of the sacrum. Widening as it descends, the ligament joins the 

 fibres in front of the sacro-iliac articulation. 



SACRO-COCCYGEAL ARTICULATION. The sacrum and coccyx are J^jJJ^ * d 

 united at the centre by a fibre-cartilage, and by an anterior and coccyx. 

 a posterior ligament. There are also lateral and interarticular 

 ligaments on each side. 



Dissection. Little dissection is needed for these ligaments. Dissection. 

 When the areolar tissue has been removed altogether from the 

 bones, the ligaments will be apparent. 



The anterior ligament (sacro-coccygeal) consists of a few fibres that An anterior 

 pass between the bones in front of the fibro-cartilage. 



The posterior ligament is wide at its attachment to the margin of a posterior 

 the lower opening of the sacral canal, but narrows as it descends llgament> 

 to be inserted in the coccyx. 



The fibro-cartilage resembles that between the bodies of the other with a fibro- 

 vertebrae, and is attached to the surfaces of the bones. 



Interarticular ligaments. The cornua of the sacrum and coccyx A band 

 do not usually form joints, but are united by a ligamentous band articular, 

 on each side. 



