(c) The lateral angle, formed by the junction of the superior and axillary
borders, is the thickest part of the bone and is sometimes called the head of the
scapula. The head presents a smooth, slightly depressed, articular surface, the glenoid
fossa or cavity, which accommodates the head of the humerus. The glenoid lip is a
fibrocartilaginous rim attached around the margin of the glenoid cavity. The head is
separated from the main portion (body) of the bone by a thickened, slightly constricted
part, called the neck.
c. The Clavicle. The clavicle or collarbone (figure 2-7) is a long, slender
S-shaped bone with a middle portion, the shaft or body, and two extremities. The
sternal extremity is rounded. The acromial extremity is flat. The shaft, or body, has two
surfaces, a superior and an inferior, separated by anterior and posterior borders. The
medial two-thirds of the anterior border presents a convexity and the lateral one-third
presents a concavity. The superior surface is comparatively smooth and can be easily
palpated. Near its sternal end, a broad, roughened area called the costal tuberosity
marks the inferior surface. Laterally, near the posterior border is a well-marked
roughened eminence, the coronoid tubercle.
ARTICULATIONS OF THE HAND
a. Sternoclavicular. The sternoclavicular joint works with a sliding movement.
It represents the articulation of the clavicle with the clavicular notch of the sternum and
with the cartilage of the first rib. An articular disk of fibrocartilage is interposed between
the clavicle and the sternum.
b. Acromioclavicular. The acromioclavicular joint also glides. It is the
articulation between the acromial end of the clavicle and the medial edge of the
acromion process of the scapula.
c. Movements of the Shoulder Girdle. The movements of the clavicle at the
sternoclavicular joint are those of elevation, depression, protraction (forward), retraction
(backward), and circumduction. The scapula at the acromioclavicular joint moves in a
ARTICULATIONS OF THE UPPER FREE EXTREMITY
a. Shoulder. The shoulder is a ball-and-socket joint between the head of the
humerus and the glenoid cavity of the scapula. A fibrocartilaginous lip (glenoid labrum)
deepens the fossa. The movements allowed by the shoulder include flexion (swinging
forward), extension, abduction, adduction, and circumduction.
b. Elbow. The elbow is a hinge joint. The trochlear notch of the ulna articulates
with the trochlea of the humerus and the fovea capitis of the radius articulates with the
capitulum of the humerus. The movements permitted by the elbow are those of flexion