FASCLA AND MUSCLES OF THE HEAD AND NECK. 373 
a. Extension and Flexion. 
Latissimus dorsi Psoas magnus and parvus 
Erector spince Reetus abdominis 
Multifidus spine (acting on both sides) Pyramidalis abdominis | 
Obliquus externus abdominis 
Obliquus internus 35 
Transversalis abdominis (acting on both 
sides) 
Pyriformis 
Glutei 
Obturator (externus and internus) 
Sartorius 
Tensor fasciv femoris 
Iliacus 
Rectus femoris 
Adductors (in erect position) 
6. Lateral Movement. 
Flexors and extensors of side only | Quadratus lumborum 
THE FASCIA AND MUSCLES OF THE HEAD AND NECK. 
FASCLA. 
The superficial fascia of the head and neck possesses certain features of special 
interest. Over the scalp it is closely adherent to the skin and subjacent epicranial 
aponeurosis, and contains the superficial vessels and nerves. Beneath the skin of 
the eyelids it is loose and thin and contains no fat. Over the face and at the 
side of the neck it is separated from the deep fascia by the facial muscles and 
the platysma myoides. In the hollow between the buccinator and the masseter 
it 1s continuous with a pad of fat (swetorial pad) occupying the interval between 
these muscles. 
The deep fascia of the head and neck presents many remarkable characters. 
Over the scalp it 18 represented by the epicranial aponeurosis, the tendon of the 
occipito-frontalis muscle. This is a tough membrane, tightly stretched over the 
calvarium, from which it is separated by loose areolar tissue. It is attached 
posteriorly, partly through the agency of the occipitalis muscle, to the superior 
curved line of the occipital bone; anteriorly it joins the frontalis muscle and the 
orbicularis palpebrarum, and has no bony attachment ; laterally it is attached to 
the temporal ridge and the mastoid process. Below the temporal ridge it is con- 
tinuous with the temporal fascia, a stout layer of fascia attached to the temporal 
ridge and zygomatic arch, which covers and gives origin to the temporal 
muscle. This fascia separates into two layers above the zygoma, to enclose a 
quantity of fat along with branches of the temporal and orbital arteries. On the 
face the fascia is practically non-existent anteriorly in relation to the facial muscles. 
Posteriorly it forms the thin masseteric fascia, and is much thicker in relation to 
the parotid gland, for which it forms a capsule. 
In the neck the deep fascia invests the muscles, and forms aponeurotic cover- 
ings for the pharynx, trachea, cesophagus, glands, and large vessels. It encloses 
the sterno-mastoid muscle, and can be traced backwards over the posterior triangle 
to the trapezius and deeper muscles, which it surrounds; it can be traced forwards 
over the anterior triangle to the middle line of the neck, over which it forms a 
continuous membrane. Above the sternwm the fascia, after enclosing the sterno- 
mastoid, is attached in the form of two layers to the front and back of the 
episternal notch. The layer enclosing the infrahyoid muscles passes across the 
middle line of the neck in front of the trachea, and is attached above to the hyoid 
bone, below to the sternum, clavicle, and first rib. A third layer of fascia passes 
inwards in front of the trachea, enclosing the thyroid body. Beneath the sterno- 
