Complaint: the parents discover, usually within their child’s first 2 years of life, that one or both collarbone(s) are entirely or partially absent.

 Assessment: absence of the clavicle can be felt on palpation. In addition, there tends to be a noticeably large forehead with widely placed eyes and a relatively small face. The chest is narrow and the shoulders hang. The anomaly may be unilateral or bilateral. A part of the clavicle may be absent, or the medial as well as the lateral part, but sometimes the entire clavicle. When the abnormality is bilateral, protraction of the shoulders is sometimes such that the shoulders can be approximated on the front side of the body (Fig. 5.1). Disability is minimal.

 Diagnosis: cleidocranial dysostosis

 Explanatory note: cleidocranial dysostosis. Heredity plays an important role here. In two thirds of cases the anomaly is familial (autosomal dominant hereditary). The anomaly is as common in boys as in girls. In addition to the absent clavicle other abnormalities may be present, such as a large forehead with a small face, a widened nose, hypertelorism, a small chest, and sometimes repeated voluntary shoulder and elbow dislocations. X-rays can show short and pointed distal phalanges of hands and feet. An extra epiphysis may be present in the proximal part of the metacarpal and metatarsal bones II to V. In a large number of cases hip abnormalities such as coxa vara may be present (Fig. 5.2). Children with this condition usually don’t become tall. Boys reach an average height of 156 cm as adults, and girls 144 cm.

 Supplementary assessment: X-ray of the clavicle to confirm the diagnosis and an anteroposterior X-ray of the pelvis to either show or rule out a coxa vara.

 Primary care treatment: do not forget to request an anteroposterior X-ray of the pelvis.

 When to refer: only when there is irritation of the brachial plexus. This may occur even if the clavicle is partially present. Also refer if there is a coxa vara.

 Secondary care treatment: cleidocranial dysostosis. Operative removal may be necessary if there is irritation of the brachial plexus due to a partially present clavicle.

 Complaint: one shoulder blade is higher than the other. There is a more or less noticeable swelling above the collarbone.

 Assessment: one shoulder blade is higher than the other and is rotated, and the upper edge of the shoulder blade projects above the collarbone. The shoulder blade is smaller than normal. Abduction of the involved shoulder tends to be limited (Fig. 5.3).

 Diagnosis: Sprengel deformity

 Explanatory note: Sprengel deformity. This anomaly is usually unilateral. In 70 % of cases there is another congenital abnormality present such as scoliosis, kyphosis, torticollis, Klippel-Feil syndrome¹ or Poland syndrome1. The deformity develops because in the second fetal month no distal migration of the shoulder blade occurs. Normally the scapula falls to equal levels between the second and seventh thoracic vertrebrae. The deformity varies in severity. The affected shoulder blade can be 1–12 cm higher than the normal contralateral side, with an average of 3–5 cm. Abduction is limited because of the rotation of the shoulder blade. However in about one-third of cases there is also a bony, connection between the shoulder blade and the fourth to seventh cervical vertebrae known as an omovertebral bone (Fig. 5.4). The severity of the limitation movement of varies considerably.

 Supplementary assessment: X-rays of the shoulders and additionally a CT-scan or MRI to visualize an omovertebral connection (often difficult to see on a standard X-ray).

 Primary care treatment: none.

 When to refer: when abduction is less than 120° or if there are cosmetic issues.

 Secondary care treatment: Sprengel deformity. No treatment should be carried out in mild cases with an abduction of 120° or more and if there are no cosmetic objections. Only if the abduction is less than 120° operative reposition of the shoulder blade will be considered. If the upper edge of the shoulder blade will project far above the collarbone but there is still a good abduction, resection of the supraspinous portion of the scapula may be considered. In severe cases, where the elevation is more than 5 cm, it is better to perform the operation in the first year of life. The operation can be performed between the ages of 3 and 8 years in less severe cases, with an elevation between 3 and 5 cm.

 Complaint: the patient can subluxate or dislocate one or both shoulders spontaneously or on command. There has been no appreciable trauma.

 Assessment: on command, the patient can dislocate the glenohumeral joint, in one or several directions (multidirectionally). In the latter case the examiner can shift the humeral head with respect to the glenoid cavity forwards and backwards (drawer test) (Fig. 5.6) and pull it downwards.

By pulling on the hanging arm one sees an indentation, the sulcus sign, which appears between the acromion and the humeral head. The sulcus sign is a consequence of a distal subluxation of the humeral head (Fig. 5.7).

 Differential diagnosis:

 Explanatory note: recurrent non traumatic glenohumeral joint subluxation/dislocation. There are two conditions in which painless repeated dislocation of the shoulder may occure: voluntary glenohumeral joint subluxation/dislocation and habitual glenohumeral joint subluxation/dislocation. One condition occurs after trauma and is painful: recurrent posttraumatic glenohumeral joint subluxation/dislocation (see p. 67).

 Supplementary assessment: X-rays and CT-scan of the shoulder.

 Primary care treatment: voluntary and habitual glenohumeral joint subluxation/dislocation are painless and need no manipulated reduction. These children can do it by themselves by contraction of certain shoulder muscles depending on the direction of the subluxation/dislocation. The patient is strongly discouraged from inciting dislocations. Physiotherapy will be prescribed with musclestrengthening exercises. The voluntary and habitual dislocations often disappear as the children get older.

 When to refer: when lifestyle rules and muscle strengthening exercises produce insufficient results. There is no need to refer a habitual glenohumeral joint subluxation/dislocation. Spontaneous cure occurs in most of the cases after about 2 years.

 Secondary care treatment: voluntary glenohumeral joint subluxation/dislocation. Operative treatment is seldom indicated and should be avoided as much as possible. Especially multidirectional dislocations often give disappointing results. Only in those cases where the dislocation occurs in a single direction should capsulorraphy be considered. In problem cases it may be necessary to place a bone block to limit motions and prevent dislocations. An anterior bone block for anterior and a posterior bone block for posterior subluxations/dislocations. Arthrodesis may be required as a last resort in those cases that remain symptomatic despite other treatments.

 Complaint: a recurrent subluxation/dislocation may occur after trivial traumas after a significant initial trauma that has resulted in a dislocation.

 Assessment: the mobility of the shoulder joint is normal. A stability test for the shoulder is the drawer test in which the patient sits on a chair and lets his arms hang, relaxed. The examiner fixes the scapula with one hand while fixing the humeral head with the other. The humeral head can now be moved forwards, backwards and downwards with respect to the glenoid cavity (Fig. 5.6). The examiner will feel that something has shifted or “jumped up” in the case of a lesion of the glenoid labrum. About the same feeling can be experienced when you rub the knuckles of your fists over each other. This test serves to assess anterior as well as posterior and inferior instability. Posterior instability can be assessed with what is known as the posterior stress test. In this test the shoulder is brought into 90° anteflexion and internal rotation, and the elbow is flexed. The examiner holds back the shoulder blade with one hand and presses the elbow posteriorly with the other hand. The test is positive when there is pain and/or posterior displacement of the humeral head (Fig. 5.8). Anterior instability can be determined using the apprehension test. The patient sits in a chair, lies down or stands. The arm is abducted to 90° and maximally externally rotated. The test is positive if this is painful or if the humeral head (sub)luxates anteriorly (Fig. 5.9).

 Differential diagnosis:

 Explanatory note: recurrent posttraumatic glenohumeral joint subluxation/dislocation. In 99 % of cases these are anterior subluxations/dislocations and in less than 1 % posterior. In rare cases there is multidirectional instability.