We can direct our gaze in various directions thanks to head movements and eyeball movements.
Movements of the eyeball are made possible by the external muscles of the eye (lat. musculi bulbi ). Razlikujemo šest mišića koji imaju hvatište na očnoj jabučici: gornji, donji, unutarnji i vanjski ravni mišić (lat. musculus rectus superior, inferior, medialis et lateralis ) and two oblique muscles, upper and lower (musculus obliqus superior et inferior ). Together, they move the eye in all directions to a certain degree, and a special mechanism enables corresponding (concominant, synonymous) movement of both eyes at the same time. The seventh motor muscle is m. levator palpebrae superior which serves as an upper eyelid lifter.
Eye muscle function
- M. levator palpebrae superior
- Function: lifts the upper eyelid
- M. rectus superior
- Basic function: lifts the eye upwards
- M. rectus inferior
- Basic role: lowering the eyeball – look
- M. rectus medialis
- Basic function: moves the eye horizontally and moves the eye towards the nose, i.e. performs adduction towards the medial plane of the body
- M. rectus lateralis
- Basic role: performs abduction, i.e. moves the eye temporally (outwards)
- M. obliquus superio r
- Basic role: inward rotation of the eyeball
- M. obliquus inferior
- Basic function: outward rotation of the eye
N. oculomotorius innervates all external eye muscles except:
- External level (m. rectus lateralis ) which is innervated by n. abducens.
- Upper oblique (m. obliquus superior ) which is innervated by n. trochlearis.
If the muscles of both eyeballs do not work equally, the images of objects will not fall on the same points on the retina. The patient will see the object in two places, he will have double images.
The most common disorders of the eyeballs:
- Strabismus
- Nystagmus
Autor:
bc. Livio Svržnjak, optometrist
