Extraocular muscles anatomy pdf human

Comparative anatomy of the extraocular muscles in four. Pdf the medial rectus is one of seven extraocular muscles. The six extraocular muscles controlling eye movements include four rectus muscles superior rectus, inferior rectus, medial rectus, lateral rectus, and two oblique muscles superior oblique and inferior oblique. We have found that special fiber subpopulations of human masseter and extraocular muscles, as well as the bag fibers of human, rat and cat muscle spindles, were reactive to this antibody. The extraocular muscles are among the fastest muscles in the human body, yet they are extremely fatigueresistant.

Extraocular muscles differ histologically from most other skeletal muscles in that they are made up of 2 different types of muscle cells. There are seven extraocular muscles the levator palpebrae superioris, superior rectus, inferior rectus, medial rectus, lateral rectus, inferior oblique and superior oblique. The extraocular muscles are located within the orbit, but are extrinsic and separate from the eyeball itself. The superior rectus moves the eye upwards and medially in the vertical plane. The fine structure of human extraocular muscle spindles. A particular fiber type contains myhc slow tonic, and it is multiply innervated. The other six, the four rectus muscles and the two oblique muscles. Extraocular muscles, movements extrinsic eye muscles 3d. Pdf normal anatomy and anomalies of the rectus extraocular. The lateral rectus is innervated by the abducens nerve cn vi. These include four rectus muscles, two oblique muscles, and the levator.

Eye movements are the result of the action of the extraocular muscles eoms. Janbaz ah, lindstrom m, liu jx, pedrosa domellof f. In humans, smooth pursuit first occurs at 4 to 6 weeks of age. The four rectus muscles are the medial rectus, lateral rectus, superior. Upward gaze is because of the function of the two superior recti. The third cranial nerve, the oculomotor nerve, innervates all the extraocular muscles except the lateral rectus and the superior oblique muscles. Animat ions of extraoc ular cranial nerve and m uscle function and damage university of liverpool. The detailed embryologic and histologic features of extraocular muscle tendons from early. Understanding and misunderstanding extraocular muscle pulleys. Anatomy, head and neck, eye extraocular muscles statpearls. Anatomy of the eye with extraocular muscles youtube.

These are slow accurate eye movements requiring visual feedback from central foveal fixation. Pdf assessment of extraocular muscles position and. Learn vocabulary, terms, and more with flashcards, games, and other study tools. The extraocular eye muscles are innervated by three cranial nerves. Assessment of extraocular muscles position and anatomy by 3dimensional ultrasonography. Abstract extraocular muscles are classically grouped as four rectus and two oblique muscles.

There is the seventh extraocular muscle that provides the elevation of the upper eyelid, and that is the levator palpebrae superioris. Extraocular muscles, movements extrinsic eye muscles 3d human anatomy organs the extraocular muscles are the six muscles that control movement of. Current concepts of mechanical and neural factors in ocular motility. Sixtyfour human eyes from embryos and fetuses, ranging in size from. Ninja nerds, join us in this video where we show the anatomy of the eye, along with the extraocular eye muscles, through the use of a model 14. Normal anatomy and anomalies of the rectus extraocular muscles in human. The low innervation ratio allows extraocular muscles to increase or decrease force in.

The primary function of the choroid is to nourish and provide oxygen to the outer layers of the retina, specifically the rods, cones, and retinal pigment epithelium. There are six eoms the medial, lateral, superior and inferior recti. The human extraocular muscle spindles have lost, either by aging or phylogenetically, the privilege of contractile chambers isolated by a fluid periaxial space from extrafusal fibre activity and sensory terminals are subject to the direct mechanical influences of anomalous intrafusal fibres. These muscles are the four rectus musclesthe inferior, medial, lateral, and superior rectiand the superior and inferior oblique muscles. They act to control the movements of the eyeball and the superior eyelid. Intermediate filaments in the human extraocular muscles. Both the superior recti pull up the eyeball and allow the individual to look in an upward direction. Extraocular muscles basic and clinical anatomy lecturio.