276 LABORATORY MANUAL OF HUMAN ANATOMY 



(a) Supraorbital nerve (N. supraorbitalis) . 



(b) Frontal ramus (ramus frontalis). 



(c) Supratrochlear nerve (N. supratrochlearis) . 



The peripheral distribution of these nerves has already been 

 studied in the dissection of the face. 



Trochlear Nerve (N. trochlearis) (O. T. Patheticus, or Fourth Cran- 

 ial Nerve). 



Carefully remove the fat along the medial wall of the orbit 

 until the M. obliquus is found. On its hinder part find the troch- 

 lear nerve. Notice the abundance of fat in the orbit (corpus 

 adiposum orbitae). 



Lacrimal Nerve (N. lacrimalis). 



Look for it on the lateral wall of the orbit along with the A. 

 lacrimalis above the superior margin of the M. rectus lateralis. 

 Besides the branches to the lacrimal gland, secure the anasto- 

 motic ramus to the zygomatic nerve (ramus anastomoticus cum 

 N. zygomatico}. The student will recall having studied the ter- 

 minals of the N. lacrimalis (rami palpebrales) in the dissection 

 of the upper eyelid. 



Elevator Muscle of Upper Eyelid (M. levator palpebrae superioris). 

 Study this muscle carefully. On lifting it, the minute branch 

 of the N. oculomotorius innervating it may be seen approaching 

 it from the upper surface of the M. rectus superior. 



Lacrimal Glands. 



(a) Superior lacrimal gland (glandula lacrimalis superior}. 



(b) Inferior lacrimal gland (glandula lacrimalis inferior). 



(c) Accessory lacrimal glands [inconstant] (glandulae lacrimales ac- 



cessoriae). 



(d) Excretory ductules (ductuli excretorii [Gl. lacrimalis]). 



Fascia of Eyeball (Fascia bulbi [Tenoni]) (O. T. Capsule of Tenon). 

 Divide the N. frontalis in the middle of the orbit and reflect 

 the stumps. Cut through the M. levator superioris in the middle 

 and reflect. With the point of a sharp narrow-bladed knife 

 make an oblique valvular opening into the eyeball at the junction 

 of cornea and sclera. Introduce the tip of a blow-pipe and inflate 

 the eyeball with air. On withdrawal, the valve-like character 

 of the opening prevents the escape of the air. Pick up with 



