Nielsen M. Atlas of Human Anatomy
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of the axial skeleton. The large triangular scapula presents an extensive surface area for muscle attachment
and a large lateral fossa that articulates with the humerus of the free part of the upper limb. Except for the weak
joint formed between the clavicle and the sternum, the pectoral girdle is essentially unattached by ligaments or
joints to the axial skeleton. This was paramount in the evolutionary role of this limb as a steering device and
shock absorber during locomotion.
The pectoral, or shoulder, girdle consisting of the scapula and the
clavicle forms the base of the upper limb skeleton. The rod-like
clavicle forms a horizontal strut that links the scapula to the sternum
Pectoral Girdle
1 Scapula
2 Clavicle
Left pectoral girdle
Superior view
Left pectoral girdle
Lateral view
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lateral or acromial end is concave anteriorly. This is one of the more variable bones of the skeleton. It is
typically smooth and straight in females and rougher and more curved in males. The bone forms the ventral
strut of the pectoral girdle that props the shoulder joint away from the rib cage. It is subcutaneous and easily
palpable throughout its length. This combination of features makes it susceptible to fracture from falls onto
the limb. The clavicle articulates with the three bones — the scapula, sternum, and fi rst rib.
The clavicle has an S-shaped appearance that can range from an almost straight,
shallow S-curve shape to a deeper, more prominent S-curve shape. The curve at
the medial or sternal end of the bone is concave posteriorly, while the curve at the
Clavicle
1 Sternal end
2 Sternal facet
3 Impression for costoclavicular ligament
4 Shaft or body
5 Subclavian groove
6 Acromial end
7 Acromial facet
8 Tuberosity for coracoclavicular ligament
9 Conoid tubercle
10 Trapezoid line
Left clavicle
Superior view, lateral to right
Left clavicle
Inferior view, lateral to right
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Left clavicle
Anterior view, lateral to right
Left clavicle
Posterior view, lateral to left
Left clavicle
Lateral view, anterior to left
Left clavicle
Medial view, anterior to right
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ferior, and lateral) and is typically a very thin plate of bone. Its lateral angle is conspicuous as it forms the gle-
noid fossa, or shoulder socket that articulates with the head of the humerus. Its three prominent projections are
the anterior projecting coracoid process, the posterior projecting ridge called the spine, and the fl at laterally
projecting acromion, which forms the lateral expansion of the spine. The scapula articulates with two bones — the
clavicle and the humerus.
The scapula is a fl at, triangular bone with three prominent projections. The fl attened
triangular portion of the bone, the body, spans from the second to the seventh rib and
consists of three borders (superior, lateral, and medial) and three angles (superior, in-
Scapula
1 Subscapular fossa
2 Spine
3 Deltoid tubercle
4 Supraspinous fossa
5 Infraspinous fossa
6 Acromion
7 Clavicular facet
8 Acromial angle
9 Medial border
10 Lateral border
Left scapula
Anterior view, lateral to right
Left scapula
Lateral view, anterior to right
11 Superior border
12 Suprascapular notch
13 Inferior angle
14 Superior angle
15 Glenoid cavity
16 Supraglenoid tubercle
17 Infraglenoid tubercle
18 Neck
19 Coracoid process
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Left scapula
Superior view, lateral to left
Left scapula
Posterior view, Lateral to left
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anterior to posterior. The ends consist of a spongy core of bone covered with a thin lamina of compact bone.
The shaft is a cylinder of thick compact bone surrounding a large medullary cavity. The humerus articulates
with three bones — the scapula, ulna, and radius.
The humerus is the skeletal element of the brachium and it is the largest bone of
the upper limb. It has a long cylindrical shaft that expands at the proximal and
distal ends. The proximal end is rounded, while the distal end is fl attened from
Humerus
1 Head
2 Anatomical neck
3 Surgical neck
4 Greater tubercle
5 Lesser tubercle
6 Intertubercular sulcus or groove
7 Crest of greater tubercle
8 Crest of lesser tubercle
9 Shaft or body
10 Groove for radial nerve
11 Medial supracondylar ridge
12 Deltoid tuberosity
13 Capitulum
14 Trochlea
15 Olecranon fossa
16 Coronoid fossa
17 Radial fossa
18 Medial epicondyle
19 Groove for ulnar nerve
20 Lateral epicondyle
Left humerus
Anterior view, lateral to right
Left humerus
Posterior view, lateral to left
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Left humerus
Lateral view, anterior to left
Left humerus
Medial view, anterior to right
Left humerus
Superior view, lateral to left
Left humerus
Inferior view, lateral to right
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The ulna is the medial and longer bone of the antebrachium. It is thick and notched at its proxi-
mal end where it is a major contributor to the elbow joint. From the notched proximal end it
tapers to a thin shaft that ends distally as a small rounded head. The ulna articulates with two
bones— the humerus and the radius.
Ulna
1 Olecranon
2 Coronoid process
3 Ulnar tuberosity
4 Radial notch
5 Trochlear notch
6 Shaft or body
7 Interosseous border
8 Anterior border
9 Posterior border
10 Supinator crest
11 Head
12 Articular circumference
13 Ulnar styloid process
Left ulna
Posterior view, lateral to left
Left ulna
Anterior view, lateral to right
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Left ulna
Lateral view, anterior to left
Left ulna
Medial view, anterior to right
Left ulna
Superior view, lateral to left
Left ulna
Inferior view, lateral to right
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bone. The distal end is concave anteriorly and convex and grooved posteriorly. The ridge-like borders of the
shaft give it a triangular shape in cross section. The radius articulates with four bones — the humerus, ulna,
scaphoid, and lunate.
The radius is the lateral, slender, rod-like bone of the antebrachium. The rod-like shaft
expands at both ends. The proximal end forms a wheel-like head with a proximal con-
cavity, while the distal end expands from medial to lateral to form the widest part of the
Radius
1 Head
2 Articular facet
3 Articular circumference
4 Neck
5 Shaft or body
6 Radial tuberosity
7 Pronator tuberosity
8 Interosseous border
9 Anterior border
10 Posterior border
11 Radial styloid process
12 Suprastyloid crest
13 Dorsal tubercle
14 Groove for extensor muscle tendons
15 Ulnar notch
16 Carpal articular surface
Left radius
Anterior view, lateral to right
Left radius
Posterior view, lateral to left
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