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Clavicle, sternum and ribs dislocation

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Clavicle Bone Dislocation (SC and AC Joints)

Dislocations involving the clavicle (collarbone) occur at its joints at either end and are relatively common injuries, particularly in sports and trauma [1].

Sternoclavicular (SC) Joint Dislocation: This occurs where the clavicle meets the sternum (breastbone) [1, 2].

  • Anterior SC Dislocation: This is the most frequent type, usually resulting from indirect force applied to the front or side of the shoulder [1, 2]. The mechanism often involves leverage over the first rib, causing the sternal end of the clavicle to displace forward (anteriorly) and sometimes slightly upward [1]. It presents as a visible or palpable bump over the SC joint [1].
  • Superior SC Dislocation: Less common, resulting from a downward force on the distal clavicle [1].
  • Posterior SC Dislocation: This type is rare but potentially dangerous [1, 2]. It usually occurs from a direct blow to the front of the sternal end of the clavicle or a strong force compressing the shoulders together [1]. The clavicle displaces backward (posteriorly) behind the sternum, potentially compressing vital structures in the neck and upper chest, such as the trachea (windpipe), esophagus, and major blood vessels [1, 2]. This constitutes a medical emergency requiring prompt reduction [1, 2].

Diagnosis of SC joint dislocations is often made by physical examination (visible deformity, pain, tenderness) and confirmed with X-rays (serendipity view) or CT scans, especially for posterior dislocations to assess mediastinal structures [1, 2].

Acromioclavicular (AC) Joint Dislocation/Separation: This occurs where the clavicle meets the acromion (part of the shoulder blade) [1, 3]. These injuries are more accurately termed "separations" and are graded based on the severity of ligament damage (AC ligament and coracoclavicular ligaments - conoid and trapezoid) [1, 3].

  • Mechanism: Most commonly caused by a direct blow to the point of the shoulder (e.g., falling directly onto the shoulder) or a fall onto an outstretched hand [1, 3].
  • Classification (Rockwood Types) [3]:
    • Type I: Sprain of the AC ligament, no significant displacement.
    • Type II: Rupture of the AC ligament, sprain of the CC ligaments, slight clavicle elevation.
    • Type III: Rupture of both AC and CC ligaments, significant clavicle elevation (usually less than 100% displaced).
    • Types IV, V, VI: More severe displacements (posterior, markedly superior, or inferior) involving extensive soft tissue disruption.

AC joint separations typically present with pain localized to the top of the shoulder, often with a visible step-off or prominence of the distal clavicle (more pronounced in higher grades) [1, 3]. Diagnosis is confirmed with X-rays, sometimes including weighted views to assess the degree of separation, although this is becoming less common [1, 3].

Anatomy of the acromioclavicular (AC) joint, top view, showing the articulation between the clavicle and the acromion [4].

Treatment:

  • SC Joint: Anterior dislocations can often be reduced by direct pressure but may be unstable and redislocate easily [1, 2]. If asymptomatic, they may be treated conservatively with a sling [1]. Posterior dislocations require urgent closed reduction under sedation or anesthesia; if closed reduction fails or is unstable, open surgical reduction and fixation may be necessary [1, 2].
  • AC Joint: Treatment depends on the grade [1, 3]. Types I and II are typically managed non-operatively with a sling, ice, pain control, and progressive rehabilitation [3]. Type III injuries are treated based on patient factors (activity level, symptoms), with options ranging from non-operative management to surgical repair/reconstruction of the CC ligaments [3]. Types IV, V, and VI generally require surgical intervention [3].

Maintaining reduction of both SC and AC joint dislocations non-operatively can be challenging [1]. While slings and braces help with comfort, redislocation is common if significant ligamentous injury has occurred [1]. Surgery aims to restore and maintain joint alignment, often involving ligament repair or reconstruction [2, 3].

Sternum and Rib Dislocation/Separation

True dislocations of the sternum itself are rare, as it's largely composed of fused segments (manubrium, body, xiphoid process) [1]. Injuries typically involve fractures or dislocations at the joints connecting other bones to the sternum (like the SC joint mentioned above) or separations at the cartilaginous junctions [1].

  • Manubriosternal Joint Dislocation: Separation at the joint between the manubrium and the body of the sternum, usually due to significant trauma [1].
  • Xiphisternal Joint Separation: Separation of the xiphoid process from the sternal body, often from direct trauma [1].

Rib injuries often involve fractures, but separations or "dislocations" can occur where the ribs connect anteriorly or posteriorly [1]:

  • Costovertebral Joint Dislocation: Displacement of the head of the rib from its articulation with the thoracic vertebrae. This is very rare and usually associated with severe, high-energy trauma [1].
  • Costochondral Separation: Separation of the rib from its costal cartilage anteriorly [1].
  • Sternocostal Separation: Separation of the costal cartilage from the sternum [1].

These anterior separations (costochondral and sternocostal) are more common than posterior dislocations and often result from direct blows to the chest wall or forceful coughing/sneezing [1]. Symptoms include sharp, localized pain, tenderness over the affected junction, and pain exacerbated by deep breathing, coughing, or twisting movements [1]. A "popping" sensation might be felt at the time of injury [1].

Diagnosis is primarily clinical, as cartilage separations are often not visible on standard X-rays [1]. Ultrasound or CT/MRI may sometimes be used [1].

Treatment for sternal joint separations and costochondral/sternocostal separations is usually conservative, focusing on pain management (analgesics, ice), rest, activity modification, and avoiding activities that aggravate the pain [1]. Deep breathing exercises are encouraged to prevent respiratory complications [1]. Healing can take several weeks to months [1]. Surgical intervention is rarely required [1].

Video demonstrating osteopathic manipulative techniques potentially used for rib cage dysfunction or pain, which may sometimes be related to minor rib subluxations or costovertebral joint restrictions rather than true traumatic dislocations. True traumatic rib dislocations usually require different management.

 

Differential Diagnosis of Acute Clavicle/Shoulder/Chest Wall Pain After Trauma

Condition Key Features / Distinguishing Points Typical Investigations / Findings
Clavicle Fracture Direct trauma or fall. Pain, swelling, deformity, crepitus along the clavicle shaft. Patient often supports arm. X-ray (AP +/- angled views) confirms fracture line in clavicle.
AC Joint Separation (Types I-VI) Fall onto point of shoulder. Pain, tenderness localized to AC joint. Visible step-off/deformity in higher grades (III-VI). X-ray (AP +/- weighted views) shows widening of AC joint and/or superior displacement of distal clavicle relative to acromion.
SC Joint Dislocation (Anterior/Posterior) Indirect or direct trauma. Pain, deformity over SC joint. Anterior: visible bump. Posterior: may have dyspnea, dysphagia, vascular compromise (emergency). X-ray (serendipity view helpful). CT scan essential for posterior dislocations to assess displacement and mediastinal structures.
Shoulder (Glenohumeral) Dislocation Often fall on outstretched arm or direct blow. Severe pain, arm held fixed (e.g., abducted/externally rotated in anterior). Loss of normal shoulder contour (squared-off appearance). X-ray (AP, axillary/scapular Y views) confirms humeral head displaced from glenoid fossa.
Proximal Humerus Fracture Fall on shoulder/outstretched arm, common in elderly. Severe pain, swelling, ecchymosis, inability to move arm. Shoulder joint itself is usually congruent. X-ray confirms fracture of humeral head/neck/tuberosities.
Rib Fracture(s) Direct blow or crush injury. Localized chest wall pain, tenderness, crepitus, pain with breathing/coughing. Potential for pneumothorax/hemothorax. Chest X-ray (may miss non-displaced fractures). Rib series or CT scan more sensitive. Assess for lung injury.
Costochondral / Sternocostal Separation Direct blow, cough/sneeze. Sharp, localized pain/tenderness at rib-cartilage or cartilage-sternum junction. Pain with breathing/twisting. No bony deformity usually. Clinical diagnosis primarily. X-rays usually normal (cartilage not visible). Ultrasound may show separation.
Sternum Fracture Direct anterior chest trauma (e.g., steering wheel injury). Localized sternal pain, tenderness, possible deformity/crepitus. Lateral chest X-ray or CT scan confirms sternal fracture. Assess for associated injuries (cardiac contusion).
Shoulder Impingement / Rotator Cuff Tear May be acute-on-chronic or related to specific movement/minor trauma. Pain with overhead activity, weakness with specific movements (abduction/rotation). Usually no gross deformity. Clinical exam (impingement signs, strength testing). X-ray usually normal unless chronic changes. Ultrasound/MRI confirms rotator cuff tear.

 

References

  1. Skinner HB, McMahon PJ. Current Diagnosis & Treatment in Orthopedics. 5th ed. McGraw Hill; 2014. Chapter 5: Shoulder & Humerus Trauma.
  2. Wirth MA, Rockwood CA Jr. Dislocations of the Sternoclavicular Joint. In: Rockwood CA, Matsen FA III, Wirth MA, Lippitt SB, eds. The Shoulder. 4th ed. Saunders Elsevier; 2009:573-607.
  3. Mazzocca AD, Arciero RA, Bicos J. Evaluation and treatment of acromioclavicular joint injuries. Am J Sports Med. 2007 Feb;35(2):316-29.
  4. Drake RL, Vogl W, Mitchell AWM. Gray's Anatomy for Students. 4th ed. Elsevier; 2019. Chapter 7: Upper Limb.