Humerus

It is the bone found in the upper arm,

Its head articulates with the scapula at the glenoid cavity of the pectoral girdle where it forms a ball and socket joint.

Near the head are two roughened projections, the greater and lesser tuberosities.

These extend into a shaft which provides surface for muscle attachment.

Between the tuberosities is a groove.

It is along this groove than the tendon of the biceps muscles passes.

At the lower end is the trochlea which articulates with the forearm to form a hinge joint at the elbow.

umerus