The scapula (plural: scapulae) is a roughly triangular shaped bone of the pectoral girdle with several articulations connecting to the humerus and clavicle.

Laterally is the glenoid fossa, anteriorly is the coracoid process and superiorly is the acromion that is continuous with the scapular spine and arcs anteriorly over the humeral head. The suprascapular notch lies immediately medial to the base of the coracoid process. The spinoglenoid notch lies posteriorly behind the neck.

Articulations

acromion: clavicle (forming the acromioclavicular joint)
glenoid cavity: humeral head (forming the glenohumeral joint)

Attachments

Musculotendinous

supraspinous fossa: supraspinatus muscle
infraspinous fossa: infraspinatus muscle, teres minor muscle
subscapular fossa: subscapularis muscle, serratus anterior
transverse scapular ligament and adjacent superior border of blade: inferior belly of omohyoid
acromion: acromial part of deltoid muscle, trapezius
scapular spine: spinous part of deltoid muscle, trapezius
coracoid process: coracobrachialis, pectoralis minor, short head of biceps muscle
lateral border (margo lateralis): teres minor muscle, teres major muscle
vertebral border (posterior): levator scapulae, rhomboid minor muscle, rhomboid major muscle
inferior angle: teres major muscle, a small slip of latissimus dorsi
supraglenoid tubercle: long head of biceps muscle
infraglenoid tubercle: long head of triceps muscle

Ligamentous

transverse scapular ligament: crosses suprascapular notch, with the suprascapular nerve below (within the resulting foramen) and the suprascapular vessels above
coracoacromial ligament
coracoclavicular ligament
coracohumeral ligament
glenohumeral ligaments: upper, middle, and lower bands
acromioclavicular ligament (weak)

Arterial supply

The scapula is surrounded by an arterial anastomosis, the scapular anastomosis which aims to ensure an adequate supply of blood to the upper limb, but has the added benefit of adequate supply to the bone itself. It consists of the: