Jul 09, 2019 extraocular muscles appear to be directly affected by the surrounding connective tissue, which form a fibroelastic pulley system that help the muscles maintain stable positions within the orbit and ensure that contraction of those muscles results in the desired action. Basic anatomy and physiology of the human eye 239 center, thickening to around 700. A tripartite ir with a lateral muscle belly inserting into the io 3. Priyanka bharti anatomy and physiology of extraocular muscles 2. The remaining space is taken up by the extraocular muscles, fascia, fat, blood vessels, nerves and the lacrimal gland.
An understanding of the anatomy and physiology of the visual system provides eye care. The anatomy of the muscle insertion scleromuscular junction of. These characteristics are related to the microscopic structure of skeletal muscle cells. Anatomy and physiology of extraocular muscles and applied aspects. Superiorly, the superior rectus arises from the annulus, which at this point is fused with the dura of the optic nerve. Functional anatomy of human extraocular muscles during fusional. Within the orbit, the eye is suspended by six extraocular muscles.
The primary blood supply for all of the extraocular muscles are the. Anatomical variations in their anatomy have been described in previous studies. The sclera is the fibrous layer of the eyeball completely surrounding the globe except the cornea. This video demonstrates the structure and function of the extraocular muscles. The annulus of zinn serves as the origin of six of the seven extraocular muscles fig. Anatomy of extraocular muscles and ocular motility 1. Extraocular muscle anatomy find, read and cite all the research you need on researchgate. Although the six extraocular muscles are generally similar between the three species.
The extraocular muscles eoms are a unique group of specialized muscles that are anatomically and physiologically distinct from other skeletal muscles. These include four rectus muscles, two oblique muscles, and the levator palpebrae. A 12 year, prospective study of extraocular muscle imaging in complex strabismus. Subramanian, in schmidek and sweet operative neurosurgical techniques sixth edition, 2012 muscle cone and annulus of zinn. Pdf fulltext international journal of ophthalmology. Six extraocular muscles extraocular muscle fibers are striated, skeletaltype fibers. Clark md a reika kono md, phd c weldon wright md a,d federico velez md a arthur l. The medial walls of the 2 orbits are parallel to each other. Orbital imaging revealed bilateral anomalous extraocular muscles inferolateral to the optic nerves. This concise, wellreferenced resource contains information on the clinical anatomy of the eye, its adnexa and visual pathways, histologic information. The orbit and extraocular muscles concise medical knowledge. Rubinstein1 1department of cell and developmental biology and pennsylvania muscle institute, university of pennsylvania school of medicine, philadelphia. Related posts of extraocular muscles anatomy video muscle anatomy cross section.
Functional anatomy of human extraocular muscles during fusional divergence. Research article control of movement functional anatomy of extraocular muscles during human vergence compensation of horizontal heterophoria joseph l. A 12year, prospective study of extraocular muscle imaging in. Sclera maintains iop and serves as the attachment site for the extraocular muscles, which maintain eye shape during ocular movement 14, 15 the retina and the lens surround the vitreous, in which.
In this article, we shall look at the anatomy of the extraocular muscles their attach. Magnetic resonance imaging demonstrates compartmental muscle mechanisms of human vertical fusional vergence. Eightmillimeter recession of the left lateral rectus muscle was performed at 23 months of age without complete postoperative improvement. Discussionorbital imaging, particularly using mri, has broadened understanding of the anatomy and physiology of the eoms and their associated connective tissues. Innervation jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj 12. Taking the place of the multiple texts traditionally needed to cover visual anatomy and physiology, clinical anatomy and physiology of the visual system, 3 rd edition dramatically lightens your load by providing one book that covers it all. Since these muscles are adapted to their roles in the control of eye movement, they exhibit fundamental differences from other skeletal muscles in terms of innervation, neuromuscular junctions, and mechanical properties 7. Extraocular muscles anatomy video human anatomy body. Reshma peter anatomy and physiology of extra ocular muscles and its applied aspects 2. Clark 2015 eoms during physiological eye movements. An analysis of extraocular muscle forces in the piked dogfish. Intrinsic muscles controls shape of lens and size of pupil.
There are seven extraocular muscles the levator palpebrae superioris, superior rectus, inferior rectus, medial rectus, lateral rectus, inferior oblique and superior oblique. Definition of the unique human extraocular muscle allotype by. Physiology of the extraocular muscles as described in chapter 4, the extraocular muscles perform two functions. At present, anatomy diagrams and anatomy models are usually used for. Anomalous extraocular muscles with strabismus american. Pdf the medial rectus is one of seven extraocular muscles.
Anatomy, physiology and the pediatric eye exam nathalie azar, md. They act to control the movements of the eyeball and the superior eyelid. However, all fibers apparently are active at all times and share some level of involvement in all ocular movements. Embryology mesodermal origin development begins at 34 weeks gestation. The physiological mechanisms of vergence have received less study than those of. The thin orbital floor is susceptible to blunt trauma, often causing a blowout fracture. The actions of the six muscles responsible for eye movement depend on the position of the eye at the time of muscle contraction.
Ocular anatomy and physiology relevant to anaesthesia. The six extraocular muscles four rectus and two oblique are located in the retrobulbar space and attach to the sclera and control the movement of the eyeball. Angle kappa angle made by visual axis with the anatomic axis, usually about 50 29. May,2,5,6 and susan warren 2 1department of biomedical engineering, duke university, durham, north carolina. Animations of extraocular cranial nerve and muscle function and damage university of. Six of these are responsible for eye movement, and are also known as oculorotatory muscles. A supernumerary rectus muscle between the ir and lr 2. Normal anatomy and anomalies of the rectus extraocular muscles in human. Note the synergistic movements of the superior rectus and oblique, as well as the inferior rectus and oblique muscles.
Fortynine extraocular muscles 37 lateral rectus muscles and 12 medial rectus muscles from 21 subjects females and 8 males without known ocular. Theyarealsopresentinthalamic nuclei other than the geniculate and in neocortical regions other than the occipital cortex. Additionally, the physiology and histology of extraocular muscles has been examined in several vertebrates including. Extraocular muscles second video in eye anatomy series. Definition of the unique human extraocular muscle allotype. Chapter 5 orbital geometry anatomy of extraocular muscles. Chapter 9 in leigh and zee chapter 5, section 1 in adler outline v.
To help memorize the innervation of the extraocular muscles, remember. Histology and physiology of the extraocular muscles. Comprehensive physiology coverage clarifies the integration between structure and function, eliminating your need for multiple books on the anatomy and physiology of the visual system. Anatomy and physiology of eye movements springerlink. The extraocular muscles are the six muscles that control movement of the eye and one muscle that controls eyelid elevation levator palpebrae. Extraocular musleseom they are six in number four recti. Mouse extraocular muscles and the musculotopic organization of their innervation martin o. Mechanic protection, lipid production, and tears distribution.
Request pdf ocular anatomy and physiology relevant to anaesthesia the orbit contains many delicate and vulnerable structures, but with a solid knowledge of the anatomy one can minimize the. There are 6 of these extraocular muscles that control eye movement cows only. Clark analyzed the bulk of the data, revised manuscript. Nerve supply in chapter 4, it was mentioned that the nerve supply to extraocular muscles is extraordinarily rich. The rectus muscles arise from a common tendinous ring otherwise known as the annulus of zinn, a thickening of periosteum located at the apex of the orbital cavity. The functional requirements for eoms are wide ranging and include i. Anatomy and physiology of the eye the orbital floor actually comprises bones. Mar 09, 2019 anatomy and physiology of extraocular muscles 1. The optostatic function requires that the muscles maintain a state of postural tonicity. Abnormality of one or more of these muscles or the nerves that. The yoked extraocular muscle movements in cardinal positions of gaze image at this site is used, with permission, in the following article, cowritten by nathan h. The term position of rest refers to the position of the eyes when all the extraocular muscles are relaxed or paralyzed.
At the very edge of the cornea, transparency is slowly lost over a 1mm 0. Introduction the extraocular muscles are located within the orbit, but are extrinsic and separate from the eyeball itself. Each muscle cell is composed of groups of myofibrils called sarcomeres. The extraocular muscles eom are responsible for controlling the movements of the eyeball and upper eyelid. The eoms faithfully, rapidly and accurately effectuate a variety of reflex and voluntary eye movements. The muscle then follows the contour of the eyeball running inferiorly to the ir 1. International journal of anatomy and research, original. Extraocular muscles eye movement eye muscles geeky medics. Within the orbit, the eye is suspended by six extraocular muscles four rectus muscles and two oblique muscles, suspensory ligaments, and surrounding orbital. Responsible for eye movement recti and oblique muscles. These muscles are also known as the extrinsic eye muscles, distinguishing them from intrinsic eye muscles which are responsible for controlling the movement of the iris. Clinical anatomy and physiology of the visual system.
The oculomotor nerve controls all the other extraocular muscles, as well as a muscle of the upper eyelid. The lateral walls of orbits slope backwards and medially making a right 90 angle with every other. The trochlear nerve controls the superior oblique muscle to rotate the eye along its axis in the orbit medially, which is called intorsion, and is a component of focusing the eyes on an object close to the face. Mice showed a standard eom organization pattern, although their eyes are set at the side of the head. The motor nerves are very thick, owing to the large number of. Occasionally, the nerve to the inferior oblique muscle or some of its branches may pierce the inferior rectus muscle 3,4, 12, 20. An emphasis on clinical application helps you better understand the processes that occur in disease and dysfunction. In humans, rems are loosely correlated with contractions of the middle ear muscles of the. In our study an incidence of this variation was estimated at in. Layerspecific differences of gene expression in extraocular.
Physiology of extraocular muscles visual axis passes from the fovea, through the nodal point of the eye to the point of fixation anatomic axis line passing from the posterior pole through centre of the cornea 28. Aug 04, 2020 eye movements for each extraocular muscle. An 8monthold boy with gorlin syndrome presented with a large rightface turn and constant exotropia of the left eye. The extraocular muscles eom are pivotal to the movement of the eye. The muscles cause rotation of the globe of the eye around a central point. Included will be external as well as internal structures, adnexa, and the bony orbit as well as muscles of the eye. The origin of the inferior oblique muscle is here and represents the only extraocular muscle origin not at the orbital apex. The extraocular muscles are located within the orbit, but are extrinsic and separate from the eyeball itself. This work is divided into chapters, the subjects of which are complete in themselves, the pupil may commence the study of the structure, use, and laws of the several parts of which the human system is composed, by selecting such chapters as fancy or utility may dictate, without reference to their present arrangement, as well commence with the.
Extensibility, the ability to extend or stretch, allows muscles to return to their resting length after having contracted. The four rectus muscles are the medial rectus, lateral rectus, superior rectus, and. Mouse extraocular muscles and the musculotopic organization. Superior rectus inferior rectus medial rectus lateral rectus two oblique muscles. Basic anatomy and physiology of the eye springerlink. This discrepancy between the vertical rectus muscle axis and the visual axis of the eye explains the secondary and tertiary functions of the vertical rectus muscles see muscle functions, following. The extraocular muscles eom are specialized skeletal muscles required by the visual system to locate and track objects. Jun 21, 20 extraocular muscles differ histologically from most other skeletal muscles in that they are made up of 2 different types of muscle cells. Nov 06, 2017 the extraocular muscles eoms are a group of unique skeletal muscles that are required to locate and accurately track objects by the visual system. Muscle activity both eyes face forwards and their long axes visual optic axes is located in sagittal plane, parallel with every other and with medial walls of the orbits. Anterior segment ischemia following surgery on two rectus muscles. Functional anatomy of extraocular muscles during human vergence compensation of horizontal heterophoria joseph l. The combined actions of these four rectus and two oblique muscles on each eyeball allow elevation, depression, adduction and abduction. The intraconal space is bounded by the four rectus muscles, from the annulus of zinn at the orbital apex, to their penetration through tenons capsule before attaching to the globe.
Each one of the two eyeballs is located in the orbit where it takes up about onefifth of the orbital volume figure 2. A medial muscle belly inserting medially into the ir 2. Dec 09, 2014 anatomy of extraocular muscles and ocular motility 1. Abnormality of one or more of these muscles or the nerves that supply them may result in a. Anatomy, head and neck, eye extraocular muscles statpearls. Pdf normal anatomy and anomalies of the rectus extraocular. Pdf a 12year, prospective study of extraocular muscle.
Extraocular muscles are special the motor units are small, with only from 5 to 18 muscle fibers contact by each motor nerve 4. The detailed embryologic and histologic features of extraocular muscle. Extraocular muscle an overview sciencedirect topics. The oculomotor nerve controls all the other extraocular muscles, as well as a muscle. While the pulley systems significance is not completely understood, it is. The organization of extraocular muscles eoms and their motor nuclei was investigated in the mouse due to the increased importance of this model for oculomotor research. Anatomy and physiology of extraocular muscles and applied. Anatomy and physiology of the eye will list and identify the basic structures of the eye, explaining the visual functions of each. Anatomy, physiology and the pediatric eye exam nathalie azar, md director, pediatric ophthalmlology and adult strabismus. This is an article covering the anatomy and movements of the eye muscles. The orbit contains the globe, orbital fat, extraocular muscles, nerves, blood vessels and part of the lacrimal apparatus. Six extraocular muscles extraocular muscle fibers are striated, skeletaltype fibers surgical anatomy of the orbit. The peripheral nervous system anatomy and physiology.
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