508 ANATOMY IX A NUTSHELL. 



4. A.NTERIOB ETHMOIDAL FORAMEN is for the anterior ethmoidal vessels 

 and nasal branch of the ophthalmic nerve. 



POSTERIOB ETHMOIDAL FORAMEN is for the posterior ethmoidal vessels. 



The superior surface of the horizontal portion is convex and has depressions 

 and eminences for the frontal convolutions, also grooves for branches of the 

 anterior and middle meningeal arteries. 



* Ossification. This hone has two centers of ossification, one for each half. 



Ajrticulation. It articulates with the following hones: (1) the two 

 parietal, (2) the sphenoid. (3) the ethmoid. (4) two nasal. (5) two superior 

 maxillary, (6) two Lachrymal, (7) two malar, thus making twelve bones. 



Attachment of Muscles. — It has three pairs of muscles attached to it. 

 l Corrugator supercilii, (2) Orbicularis palpebrarum, (3) Temporal. 



Blood Supply.- The middle and small meningeal arteries on the cerebral 

 surface and the frontal and supraorbital on the outer surface. The ethmoidal 

 arteries and other branches of the ophthalmic artery pass to the horizontal 

 plate 



Corrugator supercilii. — Description. — This muscle, which is situated be- 

 neath the Occipito- frontalis and Orbicularis palpebrarum at the inner end of 

 the superciliary ridge, is small and pyramidal. 



Origin. — From inner end of the superciliary ridge of temporal bone. 



[nsertion. — Into the deep surface of the skin opposite the middle of the 

 supraorbital arch. 



A.CTION. To draw the eye brow downward and inward, which produces 

 the vertical wrinkles in the forehead. 



Nerve Supply. — Temporal branch of the facial nerve, or by fibers of the 

 third nerve which join this nerve. 



Blood Supply. — Supra-orbital and frontal from ophthalmic artery. 



Orbicularis palpebrarum. -Description. — This muscle, which surrounds 

 the circumference of the orbil and eye lids, consists of an orbicular portion and 

 a palpebral portion. 



Origin of Orbicular Portion. — (1) From internal angular process of the 

 frontal bone, (2) nasal process of superior maxillary bone. (3) borders and 

 anterior surface of the tendo oculi. 



[NSERTION. Into the skin of the eye lids, forehead, temple, and cheek. 

 ii- upper fibers blending with the Occipito-frontalis and the Corrugator super- 

 cilii. 



Origin <>v Palpebral Portion. - From the bifurcation of the tendo oculi. 

 This portion is thinner and paler than the other portion. 



INSERTION. Into ; i raphe on the outer side of the eye lids, the external 

 tarsal ligament, and malar bone. 



Ai TION. To close the eye lids. 



\u:\ i. Supply. Temporal branch of facial nerve or by fibers of the third 

 nerve which join this nerve. 



Blood Supply. Supra-orbital, frontal from ophthalmic, and branches 

 from the temporal. 



Temporal. Description. -This is a large and radiating muscle situated 

 in the temporal fossa. 



