The pectoral girdle, consisting of the clavicle and the scapula, attaches each upper limb to the axial skeleton. The clavicle is an anterior bone whose sternal end articulates with the manubrium of the sternum at the sternoclavicular joint. The sternal end is also anchored to the first rib by the costoclavicular ligament. The acromial end of the clavicle articulates with the acromion of the scapula at the acromioclavicular joint. This end is also anchored to the coracoid process of the scapula by the coracoclavicular ligament, which provides indirect support for the acromioclavicular joint. The clavicle supports the scapula, transmits the weight and forces from the upper limb to the body trunk, and protects the underlying nerves and blood vessels.
The scapula lies on the posterior aspect of the pectoral girdle. It mediates the attachment of the upper limb to the clavicle, and contributes to the formation of the glenohumeral (shoulder) joint. This triangular bone has three sides called the medial, lateral, and superior borders. The suprascapular notch is located on the superior border. The scapula also has three corners, two of which are the superior and inferior angles. The third corner is occupied by the glenoid cavity. Posteriorly, the spine separates the supraspinous and infraspinous fossae, and then extends laterally as the acromion. The subscapular fossa is located on the anterior surface of the scapula. The coracoid process projects anteriorly, passing inferior to the lateral end of the clavicle.
acromial end of the clavicle
lateral end of the clavicle that articulates with the acromion of the scapula
acromial process
acromion of the scapula
acromioclavicular joint
articulation between the acromion of the scapula and the acromial end of the clavicle
acromion
flattened bony process that extends laterally from the scapular spine to form the bony tip of the shoulder
clavicle
collarbone; elongated bone that articulates with the manubrium of the sternum medially and the acromion of the scapula laterally
coracoclavicular ligament
strong band of connective tissue that anchors the coracoid process of the scapula to the lateral clavicle; provides important indirect support for the acromioclavicular joint
coracoid process
short, hook-like process that projects anteriorly and laterally from the superior margin of the scapula
costoclavicular ligament
band of connective tissue that unites the medial clavicle with the first rib
fossa
(plural = fossae) shallow depression on the surface of a bone
glenohumeral joint
shoulder joint; formed by the articulation between the glenoid cavity of the scapula and the head of the humerus
glenoid cavity
(also, glenoid fossa) shallow depression located on the lateral scapula, between the superior and lateral borders
inferior angle of the scapula
inferior corner of the scapula located where the medial and lateral borders meet
infraglenoid tubercle
small bump or roughened area located on the lateral border of the scapula, near the inferior margin of the glenoid cavity
infraspinous fossa
broad depression located on the posterior scapula, inferior to the spine
lateral border of the scapula
diagonally oriented lateral margin of the scapula
medial border of the scapula
elongated, medial margin of the scapula
pectoral girdle
shoulder girdle; the set of bones, consisting of the scapula and clavicle, which attaches each upper limb to the axial skeleton
scapula
shoulder blade bone located on the posterior side of the shoulder
spine of the scapula
prominent ridge passing mediolaterally across the upper portion of the posterior scapular surface
sternal end of the clavicle
medial end of the clavicle that articulates with the manubrium of the sternum
sternoclavicular joint
articulation between the manubrium of the sternum and the sternal end of the clavicle; forms the only bony attachment between the pectoral girdle of the upper limb and the axial skeleton
subscapular fossa
broad depression located on the anterior (deep) surface of the scapula
superior angle of the scapula
corner of the scapula between the superior and medial borders of the scapula
superior border of the scapula
superior margin of the scapula
supraglenoid tubercle
small bump located at the superior margin of the glenoid cavity
suprascapular notch
small notch located along the superior border of the scapula, medial to the coracoid process
supraspinous fossa
narrow depression located on the posterior scapula, superior to the spine
1. Which part of the clavicle articulates with the manubrium?
A) shaft
B) sternal end
C) acromial end
D) coracoid process
B
2. A shoulder separation results from injury to the ________.
A) glenohumeral joint
B) costoclavicular joint
C) acromioclavicular joint
D) sternoclavicular joint
C
3. Which feature lies between the spine and superior border of the scapula?
A) suprascapular notch
B) glenoid cavity
C) superior angle
D) supraspinous fossa
D
4. What structure is an extension of the spine of the scapula?
A) acromion
B) coracoid process
C) supraglenoid tubercle
D) glenoid cavity
A
5. Name the short, hook-like bony process of the scapula that projects anteriorly.
A) acromial process
B) clavicle
C) coracoid process
D) glenoid fossa
C
1. Describe the shape and palpable line formed by the clavicle and scapula.
The clavicle extends laterally across the anterior shoulder and can be palpated along its entire length. At its lateral end, the clavicle articulates with the acromion of the scapula, which forms the bony tip of the shoulder. The acromion is continuous with the spine of the scapula, which can be palpated medially and posteriorly along its length. Together, the clavicle, acromion, and spine of the scapula form a V-shaped line that serves as an important area for muscle attachment.
2. Discuss two possible injuries of the pectoral girdle that may occur following a strong blow to the shoulder or a hard fall onto an outstretched hand.
A blow to the shoulder or falling onto an outstretched hand passes strong forces through the scapula to the clavicle and sternum. A hard fall may thus cause a fracture of the clavicle (broken collarbone) or may injure the ligaments of the acromioclavicular joint. In a severe case, the coracoclavicular ligament may also rupture, resulting in complete dislocation of the acromioclavicular joint (a “shoulder separation”).