Periorbita
The periorbita is a funnel-shaped, tight connective tissue covering that lines the eye socket ( orbit ) and surrounds the eye and most of the external eye muscles .
The periorbita arises from the periosteum at the edge of the eye socket . Then it pulls down, tapering like a funnel, and attaches itself to the exit hole of the optic nerve ( canalis opticus ).
In the interior of the periorbita there are further layers of connective tissue, the eye fascia ( Fasciae orbitales ). They surround the individual eye muscles, covering the deepest layer, separated only by a small gap, the surface of the sclera as vagina bulbi ( Tenon's capsule ).
Both inside and outside the periorbita there is abundant fat tissue, the orbital fat pad ( corpus adiposum orbitae ). It serves the mechanical protection of the eye and also helps to fix the position of the eyeball. In the case of extreme emaciation (cachexia), this building fat is broken down and the eyeball sinks into the depths ( enophthalmos ).
A roll cartilage , the trochlea , is anchored dorsomedially to the periorbita . It serves as a deflection device for the tendon of the musculus obliquus superior (dorsalis) and is also eponymous for the cranial nerve supplying this muscle ( nervus trochlearis ).
Circular smooth muscles , the orbitalis muscle, are embedded in the periorbita . These muscles serve to tighten the periorbita and push the eyeball slightly forward (out of the eye socket). These smooth muscle fibers are innervated by sympathetic nerve fibers. If the head sympathetic system is damaged ( Horner's syndrome ), the eyeball sinks slightly ( enophthalmos ).
literature
- Albert J. Augustin: Ophthalmology. 3rd, completely revised and expanded edition. Springer, Berlin et al. 2007, ISBN 978-3-540-30454-8 .
- Herbert Kaufmann (Ed.): Strabismus. 3rd fundamentally revised and expanded edition. Georg Thieme, Stuttgart et al. 2004, ISBN 3-13-129723-9 .
