Mastering the diagnosis points of clavicle fracture will help you get twice the result with half the effort!

The clavicle is arranged in an S shape between the stem of the sternum and the acromion. It is the only bony support connecting the upper limbs and the trunk. The clavicle is located under the skin and is superficial. It is prone to fractures when subjected to external forces, accounting for 5% to 10% of systemic fractures. It mostly occurs in children and young adults.

What are the types of clavicle fractures? According to the analysis of anatomical characteristics, where is the most common location for clavicle fractures?

According to the injury mechanism and fracture characteristics, according to the Allman and Neer classification, clavicle fractures can be divided into: type Ⅰ fracture (fracture of the middle 1/3 of the clavicle), type Ⅱ fracture (fracture of the 1/3 outside the clavicle) and type Ⅲ fracture (in the clavicle) 1/3 fracture).

Among them, fractures of the inner third of the clavicle are the most rare, accounting for 5% to 6% of the total number of fractures, and can be further divided into three types. Type I: The fracture line is located inside the attachment point of the riboclavicular ligament, the ligament remains intact, and the fracture has no obvious displacement. Type Ⅱ: Injury to the riboclavicular ligament, with obvious displacement of the fracture. Type Ⅲ: fracture of the articular surface of the inner clavicle.

According to the relative relationship between the coracoclavicular ligament and the fracture site, fractures of the outer third of the clavicle can be divided into 5 types. Type I: The fracture is located between the coracoclavicular ligament and the acromioclavicular ligament. The fractured end is stable without significant displacement. Type Ⅱ: The fracture is located on the outer 1/3 of the clavicle, the coracoclavicular ligament is separated from the medial bone end, and the proximal end of the fracture is displaced upwards and backwards due to the traction of the sternocleidomastoid muscle and trapezius muscle. It is difficult to reset and fix. Fracture nonunion occurred. Type Ⅲ: The fracture is located on the articular surface of the outer end of the clavicle, and the coracoclavicular ligament is intact. It is easy to be confused with degree I acromioclavicular joint dislocation. Type IV: It is more common in children under 16 years of age. Periosteal sleeves can be worn at the proximal end of the fracture, and the coracoclavicular ligament is still connected to the periosteal sleeve or part of the bone. Type V: seen in the elderly, it is a wedge-shaped fracture or a comminuted fracture, and the coracoclavicular ligament loses connection with the two main fractures, the far and near.

The clavicle is an "S"-shaped tubular bone with a dense honeycomb structure and no obvious medullary cavity. The outer side is curved backwards and is concave, and the inner side is semi-convex forward. The outer 1/3 section is flat and the inner 1/3 is approximately triangular. The middle 1/3 is the transitional junction of the inner and outer ends, with the smallest diameter, only the subclavian muscle and the thin pectoralis major aponeurosis are attached, and it is at the intersection of two opposite arc-shaped protrusions, which is the mechanical weakness of the clavicle point. When the axial load acts on the curved clavicle, a shear stress will be formed. Fractures are easily caused in the middle 1/3, and about 80% of clavicle fractures occur here.

What are the typical displacement characteristics of clavicle fractures?

After the middle section of the clavicle fracture, due to the traction of the sternocleidomastoid muscle, the proximal fractured end can shift upwards and backwards, and the distal fractured end can be pulled by the pectoralis major, pectoralis minor and subscapularis muscles due to the weight of the limbs It shifts forward and downward, and the traction of these muscles and the subclavian muscles causes an overlapping shift to the inside. Fractures of the outer end of the clavicle often cause the distal end of the fracture to shift downwards and the proximal end upwards due to the gravity of the shoulder; if the displacement is greater, the coracoclavicular ligament injury should be suspected.

What are the diagnostic points of clavicle fractures?

(1) There is a history of trauma.

(2) Tilt the affected shoulder inward, forward, and downward, with the healthy hand supporting the affected elbow, the head tilted to the affected side, and the lower jaw to the healthy side.

(3) Swelling, pain and tenderness at the clavicle fracture, the displaced fracture end can be felt, and shoulder dysfunction.

(4) The symptoms of green branch fractures in children are mild, but there is tenderness at the clavicle, and they cry because of the pain when lifting the upper limbs or holding them from under the armpit.

(5) X-rays of the shoulder or chest show fractures.