MUSCLES OF THE TRUNK. 195 



of the atlas ; they are carried from thence forward, upward, and inward, to 

 to be attached termination 1, To the styloid process of the occipital bones ; 

 2, To the external surface of that bone, on the imprints which border the 

 mastoid crest posteriorly ; 3, To the mastoid crest itself. This muscle is 

 covered by the mastoid tendon of the small complexus, by the superior 

 aponeurosis of the splenius, and that of the mastoido-humeralis. It covers 

 the occipito-atloid articulation, the occipital insertion of the posterior 

 straight muscles of the head, and the origin of the occipito-styloid and 

 digastric muscles. It inclines the head on the atlas, and slightly extends it. 



10. Posterior Great Straight Muscle of the Head. (Fig. 104, 5.) 



Synonyms. Small complexus and great posterior straight muscle Bourgelat. Long 

 and short axoido-occipitalis Girard. (Complexus minor and rectus capitis posticus 

 major. Percivall. Leyh gives this muscle the same designations as Girard. It is the 

 rectus capitis posticus major and medius of Man.) 



Form Structure Situation. Elongated, prismatic, easily divisible into 

 two fasciculi one superficial, the complexus minor of Bourgelat (and Per- 

 civall) ; the other deep, the great posterior straight muscle of Bourgelat (and 

 the rectus capitis posticus major of Percivall) entirely fleshy, and formed of 

 parallel fibres, this muscle is lodged, with the small posterior straight 

 muscle, in a triangular space circumscribed by the cord of the cervical liga- 

 ment and the internal border of the oblique muscles. 



Attachments. It is attached, by its superior extremity, to the whole 

 extent of the uneven lip which terminates the spinous process of the axis 

 fixed insertion. Its anterior extremity is insinuated beneath the small, 

 oblique muscle, and is fixed to the occipital bone, behind the superior 

 insertion of the great complexus, whose tendon receives some of the fibres 

 of the superficial fasciculus movable insertion. 



Relations. Above, with the great complexus ; below, with the small 

 straight muscle ; inwards, with the cord of the cervical ligament and the 

 analogous muscle of the opposite side ; outwards, with the oblique muscles. 



Action. This muscle, a congener of the great complexus, aids in ; 

 extending the head. 



11. Small Posterior Straight Muscle. (Fig. 104, 6.) 



Synonyms. Atloido-occipitalis Girard. (Eectus capitis posticus minor Percivall. 

 The Atloido-occipitalis superior of Leyh. The rectus capitis posticus minor of Man.) 



A very small, wide, and triangular muscle, flat above and below, and lying 

 immediately upon the fibrous capsule of the occipito-atloid articulation. It 

 is attached, posteriorly, to the superior face of the atlas origin ; in front, to 

 the external surface of the occipital bone, below the preceding muscle, whose 

 action it shares. 



B. Inferior Cervical or Trachelian 'Region. 



The muscles composing this region are situated in front of the cervical 

 vertebras, and are, for the most part, grouped around the trachea, which they 

 envelop as in a kind of sheath. They are eleven in number : the cuticular 

 muscle of the neck, the mastoido-humeralis, sterno-maxillaris, sterno-hyoideus, 

 sterno-thyroideus, omo- or subscapulo-hyoideus, the great and small anterior 

 straight muscles of the head, the small straight lateral muscle, the scalenus, and 

 the long muscle of the neck. 



