THE MUSCLES OF THE PHARYNX. 389 
the middle line. The highest fibres are attached to the pharyngeal spine of the 
occipital bone, and the lowest fibres are overlapped by the middle constrictor. A 
crescentic interval occurs above the muscle, below the base of the skull, in which 
the Eustachian tube and the levator 
and tensor palati muscles appear. 
The lower border of the muscle is ; 
separated from the middle constrictor Eustachian tube 
by the stylo-pharyngeus muscle and 
the glosso-pharyngeal nerve. It einer 
separates the interial carotid artery — Tevsor rarart 
Fibrous aponeurosis of the pharynx 
from the cavity of the pharynx and _ SUPERIOR 
. CONSTRICTOR 
tonsil. BUCcCcINATOR 
The middle constrictor muscle _ .....4-mandi- 
arises from the stylo-hyoid hgament _ bular ligament 
and both cornua of the hyoid bone. 
SryLo- 
From its origin the muscular fibres PHARYNGEUS 
radiate backwards, to be inserted into Mippte 
CONSTRICTOR 
the median raphe on the posterior 
aspect of the pharynx. The upper 
fibres overlap the lower part of the 
superior constrictor ; the lower fibres 
are concealed from view by the in- 
ferior constrictor muscle. In the 
interval between the middle and in- 
ferior constrictors are found the 
internal laryngeal artery and nerve. 
The inferior constrictor muscle 
arises from the oblique line of the 
thyroid cartilage, and from the side 
of the cricoid cartilage. Its fibres 
radiate backwards, to be inserted into 
-the median raphe on the back of the 
pharynx, the upper fibres overlapping 
the lower part of the middle con- 
strictor, the lower fibres blending 
with the muscular fibres of the cesophagus. Below the lower border of the muscle 
the inferior laryngeal artery and nerve enter into relation with the larynx. 
INFERIOR CONSTRICTOR 
Fia. 285.—PosTeRIOR VIEW OF THE PHARYNX AND 
CONSTRICTOR MUSCLES, 
The deeper longitudinal stratum of muscles in the pharyngeal wall is com- 
posed of the insertions of the stylo-pharyngeus and palato-pharyngeus. 
The stylo-pharyngeus muscle arises from the root of the styloid process on its 
inner side, and passing downwards between the carotid arteries, it enters the wall 
of the pharynx in the interval between the superior and middle constrictor muscles. 
Spreading out beneath the middle constrictor muscle, it is inserted into the superior 
and posterior borders of the thyroid cartilage and into the wall of the pharynx 
itself, becoming continuous posteriorly with the palato-pharyngeus. In the neck 
the glosso-pharyngeal nerve crosses it. 
The palato-pharyngeus occupies the soft palate and the pharyngeal wall. In 
the substance of the soft palate it consists of two layers, a postero-superior layer, 
thin, and continuous across the middle line with the corresponding layer on the 
opposite side, and an antero-inferior layer, which is thicker, and is attached to the 
posterior border of the hard palate. The levator palati and azygos uvule muscles 
are enclosed between the two layers, which unite at the posterior edge of the palate, 
receiving at the same time additional fibres arising from the Eustachian tube 
(salpingo-pharyngeus). The muscle descends to the pharynx in the posterior pillar 
of the fauces. Its fibres spread out in the form of a thin sheet in the wall of 
the pharynx, in continuity anteriorly with the stylo-pharyngeus, and are inserted 
into the posterior border of the thyroid cartilage, and behind that into the 
aponeurosis of the pharynx, reaching down as far as the lower border of the inferior 
