384 THE MUSCULAR SYSTEM. 7 
The omo-hyoid is a double-bellied muscle, arising by its posterior belly from 
the superior border of the scapula and the suprascapular ligament. It. forms a 
narrow muscular band, directed obliquely forwards and upwards, to end in an 
intermediate tendon beneath the sterno-mastoid muscle. From this tendon the 
anterior belly proceeds upwards to its insertion into the body of the hyoid bone. 
The posterior belly of the muscle separates the posterior triangle into occipital 
and subclavian parts; the anterior belly crosses the common carotid artery at the 
level of the cricoid cartilage, and in the anterior triangle forms the boundary 
Hypoglossal nerve Vagus nerve 
Recurrent branch — | | Superior cervical ganglion of the sympathetic 
First cervical nerve \ \J 
StTYLOGLOSSUS 
Stylohyoid ligament 
STYLOHYOID 
SUPERIOR CONSTRICTOR 
Lingual nerve 
nerve 
oy A Hyocossus 
ib 
>} -GENIO-HYOGLOSSUS 
Pharyngeal branch of vagus—_\| \ \ 
DIGASTRIC \t : : SS ; ZEA = ‘o 
a eae NS a 
ees 
-GENIO-HYOID 
Descendens hy poglossi 
eid *MyLo-HyoIb (cut) 
MIDDLE CONSTRICTOR DIGASTRIC 
Descendens cervicis 
THYRO-HYOID 
> 
)) 
Internal laryngeal nerve fy) laa STERNO-HYOID 
/ OMO-HYOID 
Rif STERNO-THYROID 
OMO-HYOID 
Fic. 283.—THe Muscies oF THE Hyotp BoNE aND STyLomD PROCESS, AND THE EXTRINSIC MUSCLES 
OF THE TONGUE, WITH THEIR NERVES. 
between the muscular and carotid triangles. A process of the deep cervical fascia 
binds down the tendon and the posterior belly to the scapula and first rib. 
The sterno-hyoid muscle arises from the posterior surface of the presternum, 
from the back of the first costal cartilage, and from the clavicle. It passes 
vertically upwards in the neck, internal to the omo-hyoid and in front of the 
sterno-thyroid muscle, to be inserted into the body of the hyoid bone. Except 
near its origin the muscle les superficially in the anterior triangle, alongside the 
omo-hyoid and in front of the sterno-thyroid and thyro-hyoid muscles, the trachea, 
and the thyroid body. : 
The sterno-thyroid muscle arises beneath the sterno-hyoid from the back of 
the presternum and first costal cartilage. Broader than the preceding muscle, it 
