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Patient Presentation

A 15-year-old male comes to the emergency department complaining of severe pain over his right collarbone. He uses his left hand to hold his right arm close to and across the front of his body.

Relevant Clinical Findings History

While playing baseball, the patient reports colliding with the pitcher when running to first base. The impact knocked him off his feet and he fell on his right shoulder. His mother, and others nearby, reported hearing a loud snap. When he stood up, he was slouched and complained of extreme pain over his right clavicle.

Physical Examination

The following findings were noted on physical examination:

  • Prominence, ecchymosis, and tenderness over the right midclavicular region

  • Diffuse swelling over the right clavicle, shoulder, and arm

  • Right upper limb depressed (i.e., lower than left)

  • Mild numbness over right upper limb

  • Right radial pulse weaker than left

  • Lung sounds normal

Imaging Studies
  • Radiography of right shoulder revealed a midclavicular fracture (Fig. 9.1.1).

Clinical Problems to Consider
  • Anterior shoulder dislocation

  • Clavicle fracture

  • Shoulder separation


  1. Describe the anatomy of the shoulder.

  2. Describe the structures that stabilize and move the shoulder.

  3. Explain the anatomical basis for the signs and symptoms associated with this case.

Figure 9.1.1

Anteroposterior radiograph of the right shoulder showing a midclavicular fracture.


Shoulder and Arm

The shoulder includes the clavicle, scapula, and proximal humerus, with their associated ligaments, muscles, and tendons (Fig. 9.1.2). The shoulder girdle is formed by the clavicle and scapula and is anchored to the axial skeleton at the sternoclavicular (SC) joint.

Figure 9.1.2

Anterior view of the right shoulder showing the skeleton (A) and ligaments (B).


The clavicle is an f-shaped bone that acts as a strut to keep the shoulder joint and arm away from the body wall so that the upper limb can move freely. It contributes to two joints:

  1. Medially, the SC joint represents the sole articulation between the upper limb and axial skeleton. Injuries to the shoulder rarely involve the SC joint. It is stabilized by the several ligaments: anterior and posterior SC, costoclavicular, and interclavicular.

  2. Laterally, the acromioclavicular (AC) joint is surrounded by a relatively weak fibrous capsule, making it more vulnerable to injury. The joint is stabilized by ligaments: AC (along the superior aspect of the capsule) and coracoclavicular (CC) (trapezoid and conoid parts).

The subclavian vessels and brachial plexus pass between the clavicle and rib 1, a passage known as (the cervico-axillary canal), to enter the upper limb (Fig. 9.1.3).


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