[Music] scapula it is a large flat triangular bone which is in the posterior lateral part of the chest wall it lies opposite the second to seventh ribs it takes part in the formation of the shoulder girdle it presents with two surfaces Coastal and dorsal three borders lateral medial and upper three Angles Superior inferior and lateral and three processes spinus AC chromian and coracoid the coastal surface faces forwards and medially this surface presents a fosa called the subscapular fosa it presents with a ridge near the lateral border and is separated from it by a Groove the coastal surface has several other ridges as well dorsal surface it is divided into two halves by a projection known as the spine the upper smaller part is known as the supraspinous fosa the spinoglenoid notch lies between the lateral border of the spine and the dorsal aspect of the scapular neck the lateral border it extends from the lower part of the glenoid cavity till the inferior angle the infraglenoid TU circle is a rough raised area just below the glenoid cavity medial border it extends from the superior to the inferior angle the upper border it extends from the superior angle to the suprascapular notch the suprascapular notch transmits the suprascapular nerve inferior angle it is the point where the lateral and medial borders meet it lies at the level of the seventh rib Superior angle it is the point where the medial and Superior borders meet lateral angle it forms the glenoid cavity which articulates with the head of the humorus to form the shoulder joint the neck is the adjoining constricted part the supraglenoid tubercle is a rough area above the glenoid cavity the lateral angle has the following attachments glenoidal laum it is attached to the margins of the glenoid cavity to deepen the glenoid cavity capsular ligament of the shoulder joint is attached to the margins of the glenoid cavity outside the labrum and also encloses the origin of the long head of the biceps brachi spine of the scapula it is a spinous horizontal projection on the doors dorsal aspect of the scapula and divides the dorsal surface into supraspinous and infraspinous fos it is triangular in shape and has three borders the lateral border is free thick and rounded the anterior border is fused with a dorsal surface the posterior border has an upper and a lower lip the spine of the scapula has two surfaces the upper surface helps in forming the supraspinous fosa the lower surface helps in forming the infraspinous fosa a chromian process it arises from the lateral end of the spine and projects forwards it hangs over the glenoid cavity it has two borders and two surfaces the lateral border is continuous with the lower lip of the crest of the spine the medial border is continuous with the upper lip of the crest of the spine and presents an oval facet for articulation with the clavicle upper surface is subcutaneous and rough the lower surface is smooth coracoid process it projects from above the head of the glenoid cavity it is divided into ascending and horizontal Parts the horizontal part presents with lateral border medial border and an upper surface which has the conoid tubercle at the bend and the trapezoid Ridge which extends laterally from the conoid tubercle and finally the lower surface determination of the side the glenoid cavity should face laterally and upwards the surface with the spine should face backwards the sharp inferior angle should face downwards the coracoid process should face forwards and laterally oif the scapula undergoes enchondral oif it is aifi from cartilage by eight centers one Primary Center and seven secondary centers two centers appear in the coracoid process two centers appear in the acromium process one Center appears in the medial border one Center in the inferior angle and one Center appears in the lower part of the rim of the glenoid cavity Primary Center it appears in the eighth week of intra utrine life and fuses at 15 years coracoid process appears in the first year of life and fuses at 15 years all the other secondary centers appear around puberty and fuse by the 20th year an important point to note here is that if the two centers appearing for a chromian fail to unite it may be interpreted as a fracture on radi ological examination in such cases a radiograph of the opposite acroman will mostly reveal similar failure of Union on the opposite side clinical application congenital High scapula it is also known as prangles deformity of the scapula normally the scapula first develops in the neck in intra utrine life and then descends down into the back of the chest sometimes this descent doesn't occur hence the scapula remains in the neck region the scapula is usually hypoplastic it might be connected to the cervical portion of the vertebral column by a band of fibrous tissue cartilage or bone any attempt at surgical correction may result in damage to the brachial plexus