What is the medial portion of the annulus of Zinn?
The medial portion of the ring also encompasses the optic foramen through which the optic nerve and ophthalmic artery pass. A memory aid for the specific nerves in the structure is the mnemonic for the contents of the annulus of Zinn.
What is the tendinous ring of Zinn?
The tendinous ring, also known as the annulus of Zinn, is the common origin of the four rectus muscles ( extraocular muscles ). The tendinous ring straddles the lower, medial part of the superior orbital fissure. It attaches to a tubercle on the greater wing of the sphenoid bone (at the margin of the superior orbital fissure).
What passes through the tendinous ring of the eye?
The tendinous ring straddles the superior orbital fissure and through it (from superior to inferior) pass: The medial portion of the ring also encompasses the optic foramen through which the optic nerve and ophthalmic artery pass.
Where does the tendinous annulus attach to the bone?
The tendinous annulus attaches to the greater and lesser wings of the sphenoid bone as well as to the periosteum, the dense connective tissue lining the orbit. The annulus crosses over the inferior portion of the superior orbital fissure and runs superior and medial to the optic foramen ( Figure 2 ).
Which structure does not pass through the annulus of Zinn?
Correct Answer: Ophthalmic artery The lacrimal, frontal and trochlear nerves, as well as the ophthalmic vein, pass through the superior orbital fissure outside of the annulus of Zinn.
What muscles originate from the annulus of Zinn?
Extraocular Muscles The four rectus muscles (each about 3–4 cm long) originate from the annulus of Zinn at the orbital apex, which is contiguous with the dura surrounding the optic nerve and the periorbita.
What travels through the common tendinous ring?
Through it (from superior to inferior) pass: superior division of the oculomotor nerve (CN III) nasociliary nerve (a branch of the ophthalmic nerve) inferior division of the oculomotor nerve (CN III)
Which structures passes by common tendinous ring?
The following structures pass through the tendinous ring (superior to inferior): Superior division of the oculomotor nerve (CNIII) Nasociliary nerve (branch of ophthalmic nerve) Inferior division of the oculomotor nerve (CNIII)
What artery passes through optic canal?
the ophthalmic arteryThe optic canal is a very important structure due to the structures that pass through this canal, mainly the optic nerve and the ophthalmic artery.
What is the common origin of the four rectus muscles called?
The annulus of Zinn is the common origin point for the rectus muscles and spans the superior orbital fissure and orbital apex. It consists of superior and inferior tendons. The superior tendon is involved with the entire superior rectus muscle as well as portions of the medial rectus and lateral rectus muscles.
What muscles attach to common tendinous ring?
The ring blends with the dural sheath of the optic nerve, medially. The common tendinous ring provides attachment for all four rectus muscles.
Which extraocular eye muscle does not originate at the common tendinous ring?
The superior obliqueThe superior oblique is one of the two noteworthy oblique extraocular muscles. These muscles are unique in that they do not originate from the common tendinous ring, have an angular attachment to the eyeball, and they attach to the posterior aspect of the eyeball.
Where does the inferior oblique originate?
[2] Unlike all other extraocular muscles, the inferior oblique does not originate from the annulus of Zinn or common tendinous ring. Instead, the inferior oblique originates from the orbital floor just lateral to the nasolacrimal groove.
What are intraocular muscles?
The intraocular muscles include the ciliary muscle, the sphincter pupillae, and the dilator pupillae. [1] The ciliary muscle is a smooth muscle ring that controls accommodation by altering the shape of the lens, as well as controlling the flow of aqueous humor into Schlemm's canal.
What is the muscle cone of the eye?
The myofascial cone is a structure within the orbit involved in the movement and support of the globe, or more simply the eye. It also serves as the physical division between the intraconal and extraconal compartments, but the cone itself is included in the contents of the intraconal space 1.
What is the annulus of Zinn?
The annulus of Zinn, also known as the annular tendon or common tendinous ring, is a ring of fibrous tissue surrounding the optic nerve at its entrance at the apex of the orbit. It is the common origin of the four rectus muscles of the group of extraocular muscles .
Who is the Zinn zonule named after?
It is named for Johann Gottfried Zinn. It should not be confused with the zonule of Zinn, though it is named after the same person.
What is the annulus of Zinn?
Tendinous ring. The tendinous ring, also known as the annulus of Zinn, is the common origin of the four rectus muscles ( extrao cular muscles ). The tendinous ring straddles the lower, medial part of the superior orbital fissure. It attaches to a tubercle on the greater wing of the sphenoid bone (at the margin of the superior orbital fissure).
What is the medial portion of the ring?
The medial portion of the ring also encompasses the optic foramen through which the optic nerve and ophthalmic artery pass. A memory aid for the specific nerves in the structure is the mnemonic for the contents of the annulus of Zinn.
Which portion of the ring encompasses the optic foramen through which the optic nerve and ophthalmic?
Through it (from superior to inferior) pass: The medial portion of the ring also encompasses the optic foramen through which the optic nerve and ophthalmic artery pass. A memory aid for the specific nerves in the structure is the mnemonic for the contents of the annulus of Zinn.
Which part of the ring encompasses the optic nerve?
The medial portion of the ring also encompasses the optic foramen through which the optic nerve and ophthalmic artery pass.
