QuestionSBA
QuestionChoice
The sternocleidomastoid has two origins. The medial head originates from the sternum and the lateral head originates from the medial clavicle. So when there is a mid-clavicular fracture (most commonly the middle 1/3rd of the clavicle), the sternocleidomastoid elevates the medial aspect of the clavicle, whilst the lateral aspect of the clavicle drops as the trapezius is unable to hold the lateral segment up against the weight of the upper limb.
10007755
a
Sternocleidomastoid
QuestionChoice
This muscle originates from the 3rd-5th ribs and inserts onto the coracoid process of the scapula. Therefore it does not exert any mechanical forces on the clavicle and is not responsible for this altered position.
10007758
d
Pectoralis minor
QuestionChoice
This muscle originates from the transverse processes of C3-C6 vertebrae and inserts onto the upper face of the upper rib. Therefore, this muscle does not exert any mechanical forces onto the clavicle and does not contribute to the altered position of the clavicle in this form of fracture.
10007759
e
Scalenus anterior
QuestionChoice
The clavicular head of pectoralis major originates from the clavicle and the sternocostal head originates from the sternum and the upper 6 costal cartilages. The fibres then collectively insert onto the intertubercular sulcus of the humerus. This muscle is responsible for medial rotation and adduction of the shoulder at the glenohumeral joint so following a fracture of the midclavicle, the shoulder is medially rotated and partially adducted.
10007757
c
Pectoralis major
QuestionChoice
The trapezius does not originate or insert onto the medial aspect of the clavicle. This muscle is unable to hold the lateral aspect of the clavicle against the weight of the upper limb, leading to a dropped shoulder appearance when clavicle is broken.
10007756
b
Trapezius
Concept
Chapter
2693
4623
Clavicle fractures
Topic
145
Orthopaedics
14098
Picture
1520
Clavicle_Fracture_Left.jpg
images/mc6t34s11682329910043.jpg
images/mc6t34s11682329910043_256.jpg
images/mc6t34s11682329910043_512.jpg
4PcJDYC5jXfAZYild1eYd/eIfo/o
Topic
145
Orthopaedics
A 20-year-old man presents to A&E with severe right-sided upper chest pain following a road-traffic accident. On examination, they appear to have a "dropped shoulder" appearance. A fracture around his area of pain is suspected.

An X-ray is taken and a diagnosis of a mid-clavicular fracture is made. [lightgallery]

Which of the following muscles contributes to the elevation of the medial segment of the clavicle?
a