Clavicle
Updates to Article Attributes
The clavicle (or informally collar bone) is the only bone connecting the pectoral girdle to the axial skeleton and is the only long bone that lies horizontally in human skeleton.
Gross anatomy
Osteology
The clavicle is roughly "S-shaped" with a flattened, concave, lateral one-third and a thickened, convex, medial two-thirds. On the inferior surface of lateral third is the conoid tubercle for the attachment of the conoid ligament and lateral to this is the trapezoid line for attachment of the trapezoid ligament. On the inferior surface of the medial clavicle is the costal tuberosity and groove for subclavius for the attachment of sternocostal ligament and subclavius muscle respectively.
The female clavicle is shorter, thinner and less curved than the male clavicle.
Articulations
The clavicle articulates with acromion at the acromioclavicular joint laterally and the sternum at the sternoclavicular joint medially.
Attachments
- muscles: pectoralis major, sternocleidomastoid (clavicular head), deltoid, trapezius, subclavius
- ligamentous: acromioclavicular ligament, coracoclavicular ligament, sternoclavicular ligament, costoclavicular ligament
Blood supply
- nutrient branch from the suprascapular artery
Development
Ossification
It is the first bone to start ossification at around 5th-6th weeks of gestation but finishes around 21-25 years of age. The lateral end has intramembranous ossification. See main article: ossification centres of the pectoral girdle.
Variant anatomy
- forked clavicle
- supraclavicular foramen: the clavicle may be pierced by a branch of supraclavicular nerve
- coracoclavicular joint
- hypertrophic conoid tubercles
- At the attachment of the costoclavicular (rhomboid) ligament, there may be a tuberosity or depression (rhomboid fossa) of variable size that may mimic disease. A rhomboid fossa is more common in younger adults and males 4. See case 5.
Radiographic appearance
Plain films
On a chest x-ray image, the clavicles are superimposed over the apex of both the lungs and obscure the subtle lesions. An apical or lordotic view may then provide greater detail of the lung apices.
Chest x-rays are correctly aligned if the medial ends of clavicles are equidistant from spinous process of vertebrae at the T4/5 level.
Related pathology
- clavicular fracture: the weakest part of clavicle is the junction of lateral one third and medial two third and this is the most common site of fracture
- acromioclavicular joint injury
- sternoclavicular joint dislocation
- clavicle tumours
- sclerotic clavicle
- paediatric clavicle abnormalities
- osteolysis
- distal clavicular erosions
-</ul><h5>Blood supply</h5><ul><li>nutrient branch from suprascapular artery</li></ul><h4>Development</h4><h5>Ossification</h5><p>It is the first bone to start ossification at around 5th-6th weeks of gestation but finishes around 21-25 years of age. The lateral end has intramembranous ossification. See main article: <a href="/articles/ossification-centres-of-the-pectoral-girdle">ossification centres of the pectoral girdle</a>. </p><h4>Variant anatomy</h4><ul>- +</ul><h4>Blood supply</h4><ul><li>nutrient branch from the <a title="Suprascapular artery" href="/articles/suprascapular-artery">suprascapular artery</a>
- +</li></ul><h4>Development</h4><h5>Ossification</h5><p>It is the first bone to start ossification at around 5th-6th weeks of gestation but finishes around 21-25 years of age. The lateral end has intramembranous ossification. See main article: <a href="/articles/ossification-centres-of-the-pectoral-girdle">ossification centres of the pectoral girdle</a>. </p><h4>Variant anatomy</h4><ul>
Unable to process the form. Check for errors and try again.