Levator palpebrae superioris muscle
| Levator palpebrae superioris muscle |
|---|
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| Scheme of the eye muscles with the levator palpebrae superioris muscle (⑨) |
| origin |
| small sphenoid wing ( Ala minor ) |
| approach |
| upper eyelid |
| function |
| Lifting the upper eyelid |
| Innervation |
| Oculomotor nerve |
The muscle levator palpebrae superioris ( Latin - anat .; ' Muscle lifter of the upper eyelid' → eyelid lifter ; marked with the ⑨ in the illustration on the right) is a skeletal muscle of the eye muscles and as such belongs to the appendage organs of the eye . According to its function, it is located in the upper area of the eye socket (orbit). This function is to pull the upper eyelid ( superior palpebra ) up and back, causing the cleft of the eyelid ( rima palpebrarum ) to open . He also performs movements in the same direction with the rectus superior muscle (②), so that the upper eyelid rises when looking up and lowers when looking down.
anatomy
The levator palpebrae superioris muscle arises immediately in front of the tip of the orbit within the Zinn tendon ring ( annulus tendineus communis ; am) on the small wing of the sphenoid bone ( ala minor ), pulls forward above the muscle rectus superior (②) and attaches its tendon as a fan-like connective tissue plate ( aponeurosis ; here specifically: the levator aponeurosis ) in the septum orbitale ("orbital septum ") and the tarsus palpebrae ("lid cartilage ") (see also eyelid structure , 2nd paragraph).
The M. levator palpebrae superioris is innervated by the III. Cranial nerves , the oculomotor nerve (" eye movement nerve "), more precisely: from the smaller ("upper") of its two terminal branches, the superior ramus (see also ocular muscles # innervation ).
In its function as an eyelid lifter, the levator palpebrae superioris muscle is the direct antagonist of the outer eye muscle orbicularis oculi ("eye ring muscle").
pathology
A sub-function of the levator palpebrae superioris leads to a partial or complete drooping of the upper eyelid , called (Blepharo-) ptosis . As a rule, this also means a restriction in the movement ( synkinesis ) of the upper eyelid when looking vertically. A congenital ptosis is rarely the result of a paralysis of the oculomotor nerve , but rather that of a malformation of the levator palpebrae superioris itself Another congenital disorder is. Marcus Gunn phenomenon (Mandibulopalpebrale synkinesis), in which a paradoxical co - innervation of M. levator palpebrae superioris and musculus pterygoideus lateralis are present.
A so-called relative hyperfunction of the levator palpebrae superioris muscle can result from paretic restriction of the elevation of the gaze. In this case, an increased impulse to turn the gaze upwards is only incompletely implemented by the corresponding muscles, but it has a full effect on the synergistic movement of the muscle, which leads to an abnormal pulling up of the upper eyelid .
literature
- Herbert Kaufmann (Ed.): Strabismus . With contributions from Wilfried de Decker a. a. 3., fundamentally revised. and exp. Edition. Georg Thieme Verlag , Stuttgart 2004, ISBN 3-13-129723-9 (including the CD-ROMs “The virtual strabismus patient”, “Listing's level” and “ Computerized strabismus model 2.0 ”).
Web links
- Entry on the levator palbebrae superioris muscle in the Flexikon, a wiki of the DocCheck company