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The upper limb is attached to the axial skeleton by way of the scapula
scapula is the coracoclavicular ligament (see Fig. 34.1).
and clavicle. It should be noted that this involves only two small
jointsathe acromioclavicular and sternoclavicular joints. The main
The deltopectoral triangle, clavipectoral fascia and the
attachment between the upper limb and the axial skeleton is muscular. • This is a weak joint. The main bond between the clavicle and the
anatomical spaces (Fig. 32.2)
The muscles of the outer chest wall (Figs 32.2 and 32.3) • The deltopectoral triangle is the region that is bounded by deltoid,
See Muscle index, p. 162. pectoralis major and superiorly by the small bare length of clavicle that
• Muscles of the outer anterior chest wall include pectoralis major and does not provide an origin for either of these muscles.
pectoralis minor. • The clavipectoral fascia is a sheet of strong connective tissue. The
• Muscles of the back and shoulder include: latissimus dorsi, trapez- uppermost part of this fascia forms the floor of the deltopectoral tri-
ius, deltoid, levator scapulae, serratus anterior, teres major and minor, angle. It is attached superiorly to the clavicle around the subclavius
rhomboids major and minor, subscapularis, supraspinatus and muscle. Below it splits to enclose pectoralis minor. The fascia con-
infraspinatus. tinues downwards as the suspensory ligament of the axilla and becomes
continuous with the fascial floor of the armpit. The clavipectoral fascia
The sternoclavicular joint (Fig. 32.1) is pierced by four structures in total. Two structures drain inwards: (1)
• Type: atypical synovial joint. the cephalic vein and (2) lymphatics from the infraclavicular nodes.
• The articulation is between the sternal end of the clavicle and the Similarly, two structures pierce the fascia to pass outwards: (3) the tho-
manubrium. The articular surfaces are covered with fibrocartilage as racoacromial artery and (4) the lateral pectoral nerve (which supplies
opposed to the usual hyaline. pectoralis major and minor).
• A fibrocartilaginous articular disc separates the joint into two • Two important anatomical spaces are found in the shoulder region
cavities. (Fig. 32.4):
• The fulcrum of movement at this joint is the costoclavicular liga- • The quadrangular space is an intermuscular space through which
ment, i.e. when the lateral end of the clavicle moves upwards the medial the axillary nerve and posterior circumflex humeral vessels pass
end moves downwards. through backwards to encircle the surgical neck of the humerus. It
is bounded above by subscapularis and teres minor and below by
The acromioclavicular joint teres major. The long head of triceps and the surgical neck of the
• Type: atypical synovial joint. humerus are medial and lateral boundaries, respectively.
• The articulation is between the lateral end of the clavicle and the • The triangular space is bounded by teres major, teres minor and
medial border of the acromion. As for the sternoclavicular joint, the the long head of triceps. The circumflex scapular artery passes
articular surfaces are covered with fibrocartilage and an articular disc from front to back through this space to gain access to the
hangs into the joint from above. infraspinous fossa.

The pectoral and scapular regions 75