MUSCLES OF THE TRUNK. 199 



Attachments. It derives its fixed insertion from the inner surface of the 

 subscapularis, by an aponeurosis which is detached from that covering the 

 latter muscle. Its movable insertion is into the body of the hyoid bone, in 

 becoming confounded with the sterno-hyoideus, and in being intimately 

 united to the muscles of the opposite side. 



Relations. Outwardly, with the subscapularis, supraspinatus, small 

 pectoral, mastoido-humeralis which closely adheres to it, the jugular vein, 

 the sterno-maxillaris, and the cuticularis. Inwardly, with the scalenus, the 

 large anterior straight muscle of the head, the main trunk of the carotid 

 artery and the nerves accompanying it, the trachea, thyroid gland, and the 

 inferior face of the larynx. The jugular vein is entirely separated from 

 the carotid artery by this muscle in the upper half of the neck. 



Action. It is a depressor of the hyoid bone and its appendages. 



7. Great Anterior Straight Muscle of the Head. (Figs. 104 and 105, 10; 



106, 13.) 



Synonyms. Long flexor of the head Bourgelat. Trachelo-stiboccipitalis Girard. 

 (Eectus cap/'tis anticis major Ptrcivall. Trachelo-occ/'pitalis Leyh.} 



Form Structure Situation Direction. A long, flat muscle, fascicu- 

 lated in its posterior half, terminated in a tendinous cone at its anterior 

 extremity, and passing along the first cervical vertebrae in front. 



Attachments. Behind, to the transverse processes of the third, fourth, 

 and fifth cervical vertebras by as many fleshy digitations, the most inferior 

 of which are the longest fixed insertion. In front, into the imprints on the 

 body of the sphenoid bone and the basilar process, by its terminal tendon 

 moiaUe insertion. 



Relations. Outwardly, with the mastoido-humeralis, the subscapulo- 

 hyoideus, and the small anterior straight muscle. Inwardly, with the long 

 muscle of the neck and the muscle of the opposite side. In front, with the 

 common carotid, the nerves accompanying this artery, and the guttural 

 pouch, which lines it near its movable insertion. Behind, with the great 

 oblique muscle of the head and the occipito-atloid articulation. 



Action. It either directly flexes the head or carries it to one side, 

 according as it acts alone or with its fellow of the opposite side. 



8. Small Anterior Straight Muscle of the Head. 



Synonyms. Flexor capitis brevis Bourgelat. Atloido-suboccipitalis Girard, 

 (JRectus capitis anticus minor Percivall. Atloido-occipitalis inferior Leyh.) 



A small, entirely fleshy, prismatic fasciculus, lying to the external side 

 of the preceding muscle ; attached, posteriorly, to the inferior face of the 

 body of the atlas ; in front, to the body of the sphenoid bone and the basilar 

 process, beside the great anterior straight muscle. It is covered by the 

 guttural pouch, and covers the occipito-atloid articulation. It concurs in 

 flexing the head. 



9. Small Lateral Straight Muscle. 



Synonyms. Flexor capitis parvus Bourgelat. Atloido-styloideus Girard. (Obli- 

 quus capitis anticus Percivall The rectus capitis lateralis of Man.) 



Yet smaller than the preceding, and prismatic and entirely fleshy, like it 

 this muscle lies on the side of the occipito-atloid articulation ; it is attached 

 to the atlas, outside the small anterior straight muscle -fixed insertion ; and 

 to the inner face of the styloid process of the occipital bone movable insertion. 

 It is the congener of the two anterior straight muscles of the head. 



