THE SKELETON OF THE ANTERIOR LIMB. 159 
skull and the chain of elements commonly occurring in mammals 
and other vertebrates in this region. In most mammals the term 
“lesser”, as applied to it, is inappropriate. The muscle tendon 
contains near the jugular process a small ossification representing 
a detached styloid process. This connection, together with the 
hyoid bone itself, indicates the relation of the embryonic hyoid arch, 
from which the skeletal structures in question are derived. The 
greater cornu belongs to the succeeding visceral arch, and is con- 
nected with the superior cornu of the thyreoid cartilage of the 
larynx by the lateral hyothyreoid ligament. It is commonly 
represented in mammals by a small thyreohyal process. 
THE SKELETON OF THE ANTERIOR LIMB. 
The skeleton of the anterior limb is divisible into two portions, 
namely, a proximal portion, comprising the scapula and the 
clavicle, and a distal portion, comprising the supports of the 
free extremity. The scapulae and clavicles of the two sides 
together form the pectoral girdle. The pectoral girdle is lightly 
constructed, and, apart from its muscular connections, which 
constitute its main support, is directly attached to the axial skeleton 
only through the sternoclavicular ligament. 
The skeleton of the free extremity is divisible into proximal, 
middle, and distal segments. The proximal segment contains 
a single bone, the humerus; the middle segment two elements, the 
radius and ulna; while the distal segment comprises, in addition 
to the accessory sesamoid bones, twenty-eight elements of the 
regular series, of which nine form the carpus, five the metacarpus, 
and fourteen the phalanges of the digits. 
THE SCAPULA. 
The scapula (Fig. 66) is a somewhat triangular plate of bone 
lying in the natural position on the lateral surface of the anterior 
part of the thorax, with its apex directed downward and forward. 
In the rabbit, as in quadrupedal mammals generally, the main 
surfaces are respectively medial and lateral, and differ in this respect 
from the human condition, in which, from the transverse widening 
