Appendicular Skeleton Bones

Study Notes

The appendicular skeleton consists of four parts: shoulder (pectoral) girdle, upper extremities, pelvic girdle, and lower extremities.

The shoulder girdle consists of the clavicle and scapula, which articulate with each other at the Acromioclavicular joint.
The clavicle is a long, slender bone that lies horizontally across the root of the neck just beneath the skin.
The clavicle articulates with the sternum and 1st costal cartilage medially and with the acromion process of the scapula laterally.
The scapula is a flat triangular bone that lies on the posterior chest wall.
The scapula has a spine that projects backward, forming the acromion, which articulates with the clavicle.
The superolateral angle of the scapula forms the pear-shaped glenoid cavity, which articulates with the head of the humerus at the shoulder joint.

The bones of the upper extremities are divided into four groups: bones of the arm, bones of the forearm, bones of the wrist, and bones of the hand.
The humerus articulates with the scapula at the shoulder joint and with the radius and ulna at the elbow joint.
The upper end of the humerus has a head and articulates with the glenoid cavity of the scapula.
The lower end of the humerus possesses the rounded capitulum for articulation with the head of the radius and the pulley-shaped trochlea for articulation with the trochlear notch of the ulna.

The forearm contains two bones: the radius and the ulna.
The radius is the lateral bone of the forearm.
The radius articulates with the humerus at the elbow joint and with the ulna at the proximal radioulnar joint.
The distal end of the radius articulates with the scaphoid and lunate bones of the wrist at the wrist joint and with the ulna at the distal radioulnar joint.
The ulna is the medial bone of the forearm.
The ulna articulates with the humerus at the elbow joint and with the head of the radius at the proximal radioulnar joint.
The proximal end of the ulna is large and is known as the olecranon process, which forms the prominence of the elbow.

The wrist connects the hand to the forearm and is composed of eight carpal bones aligned in a proximal and distal row.
The proximal row consists of the scaphoid, lunate, triquetral, and pisiform bones.