Clavicle is an S-shaped long bone that connects the sternum, or breastbone, to the scapula, or shoulder blade. It lies just beneath the skin at the front of the shoulder, above the first rib, and forms part of the pectoral girdle: the bony framework linking the upper limb to the trunk.
Where is the clavicle located?
The left clavicle and right clavicle extend across the upper front of the chest on their respective sides. Each runs from the upper part of the sternum towards the acromion, the projecting part of the scapula that forms the top of the shoulder.
The clavicle is subcutaneous, meaning it lies immediately beneath the skin, along much of its length. Its outline forms the visible boundary between the lower neck and the upper chest. The shoulder joint itself lies farther out to the side and below the acromial end.
Behind and beneath the clavicle are the subclavian vessels and the brachial plexus, the network of nerves supplying the upper limb. The subclavius muscle lies against its underside, with the first rib below. These relations place the clavicle above the passage through which major vessels and nerves enter the upper limb.
What are the parts and surfaces of the clavicle?
The clavicle has a shaft, the central length of the bone, between a sternal end and an acromial end. The sternal end is towards the midline of the body and is relatively bulky. The acromial end is farther from the midline and flattened from above downwards.
Viewed from above, the shaft has a double curve. Its medial portion, nearest the midline, curves forwards, while its lateral portion, towards the shoulder, curves backwards. This gives the bone its characteristic S-shaped outline.
The superior surface, facing upwards, is generally smooth. The inferior surface, facing downwards, is rougher because it bears sites for muscle and ligament attachment. A ligament is a strong band of connective tissue that joins bones and helps stabilise a joint.
What are the main bony landmarks of the clavicle?
The inferior surface carries useful landmarks for understanding how the clavicle is secured to neighbouring structures. A tubercle is a small bony prominence, while a line is an elongated ridge.
| Landmark | Location | Attachment or relationship |
|---|---|---|
| Impression for the costoclavicular ligament | Inferior surface near the sternal end | Attaches the ligament linking the clavicle to the first rib and its cartilage |
| Subclavian groove | Inferior surface of the shaft | Provides attachment for the subclavius muscle |
| Conoid tubercle | Inferior surface near the acromial end, towards the back | Attaches the conoid part of the coracoclavicular ligament |
| Trapezoid line | Inferior surface extending forwards and laterally from the conoid tubercle | Attaches the trapezoid part of the coracoclavicular ligament |
The coracoclavicular ligament connects the clavicle to the coracoid process, a hook-like projection of the scapula. Its conoid and trapezoid parts help maintain the relationship between the clavicle and scapula.
Which joints does the clavicle form?
The sternoclavicular joint lies between the sternal end of the clavicle and the manubrium, the upper part of the sternum. The first costal cartilage, which connects the first rib to the sternum, also contributes to this joint. An articular disc, a pad of fibrocartilage, separates the joint into compartments and helps accommodate the contacting surfaces.
The acromioclavicular joint lies between the acromial end of the clavicle and the acromion. It permits small sliding and rotational movements as the scapula changes position on the chest wall.
Both are synovial joints, meaning their contacting bone surfaces meet within a fluid-containing joint cavity enclosed by a capsule. The sternoclavicular joint allows the clavicle to rise, lower, move forwards and backwards, and rotate along its length. Together, these joints allow the shoulder girdle to move rather than remain fixed against the trunk.
Which muscles attach to the clavicle?
The muscular system includes muscles attached to the clavicle that move the head, neck or arm, or help move and stabilise the shoulder girdle. The main muscle attachments are:
- Sternocleidomastoid: attaches to the upper surface of the medial part and helps move the head and neck.
- Pectoralis major: attaches to the anterior surface of the medial part and helps move the arm forwards and towards the body.
- Deltoid: attaches to the anterior border of the lateral part and contributes to movement of the arm at the shoulder.
- Trapezius: attaches to the posterior border of the lateral part and helps position the shoulder girdle.
- Subclavius: attaches to the inferior surface and helps stabilise and lower the clavicle.
What does the clavicle do?
In the skeletal system, the clavicle provides the only bony connection between the upper limb and the trunk. It acts as a strut, holding the scapula and shoulder away from the chest so that the arm has room to move.
It also transfers forces from the upper limb through the shoulder girdle towards the sternum. Its position above the major vessels and nerves entering the arm provides a bony boundary over these structures, rather than enclosing them completely.
How can you identify the clavicle in the 3D model?
In the 3D model next to this article, rotate to an anterior view, looking towards the front of the body, and select a clavicle. You can then isolate your selection, zoom in or out, and rotate the view in different directions. Use these controls in combination to change the viewing angle without assuming that every anatomical surface detail is represented.
You can also hide or fade selected structures, switch layers, or pull parts apart. To explore another viewing arrangement, cut a section along the sagittal, coronal or transverse plane, then rotate and zoom the view. These controls provide different ways to explore the model.