Eyelid Anatomy and Muscles Quiz

Eyelids protect the eyeball from injury, control light entry, and lubricate the eyeball with tears during blinking.

The gray line divides the eyelid margin into anterior and posterior parts, and it corresponds to the most superficial portion of the orbicularis oculi muscle.

Eyelashes heighten the protection of the eye by filtering dust and foreign debris.

<p>The normal adult fissure width is between 8-11 mm.</p> Signup and view all the answers

<p>The orbicularis oculi muscle acts as a sphincter for forceful lid closure and controls voluntary and involuntary blinking.</p> Signup and view all the answers

<p>Meibomian gland orifices, located behind the gray line, secrete oils that prevent tear film evaporation.</p> Signup and view all the answers

<p>The two types of blinks are spontaneous and reflex blinks, with spontaneous being involuntary and reflex blinks occurring in response to stimuli.</p> Signup and view all the answers

<p>Clinically important changes in the lid fissure, such as widening, can occur in thyroid disease.</p> Signup and view all the answers

<p>High sympathetic tone contracts the muscle and widens the palpebral fissure.</p> Signup and view all the answers

<p>It distributes glandular secretions and tears over the conjunctiva and cornea during blinking.</p> Signup and view all the answers

<p>They lubricate the margin of the eyelid and prevent the escape of tear fluid.</p> Signup and view all the answers

<p>The orbital septum is a fibrous membrane that retains orbital fat and separates the eyelids from the orbital cavity.</p> Signup and view all the answers

<p>The septum extends from the orbital margin to the eyelids, fusing with structures in both upper and lower eyelids.</p> Signup and view all the answers

<p>This condition is called dermatochalasis, and its treatment is blepharoplasty.</p> Signup and view all the answers

<p>The septum weakens, allowing orbital fat to herniate forward.</p> Signup and view all the answers

<p>The septum is perforated by vessels and nerves that connect the orbital cavity to the face and scalp.</p> Signup and view all the answers

<p>Lacrimal puncti are tiny openings in both eyelids that help drain tears from the eye.</p> Signup and view all the answers

<p>The eyelashes, arranged in rows, act as barriers to prevent dust and sweat from entering the eye.</p> Signup and view all the answers

<p>The arterial supply of the eyelids is a network from both internal and external carotid arteries, including branches from the ophthalmic artery.</p> Signup and view all the answers

<p>Pretarsal venous drainage occurs into the angular vein medially and the superficial temporal vein laterally.</p> Signup and view all the answers

<p>Lymphatic drainage of the medial eyelid goes to the submandibular lymph nodes.</p> Signup and view all the answers

<p>The facial nerve innervates the orbicularis oculi muscle, responsible for closing the eyelids.</p> Signup and view all the answers

<p>Trichiasis is the misdirection of eyelashes from their normal sites of origin, which can irritate the eye.</p> Signup and view all the answers

<p>Lymphatic vessels from the lateral eyelid drain into preauricular and deep cervical lymph nodes.</p> Signup and view all the answers

<p>Distichiasis involves a second row of lashes emerging from the meibomian gland orifices, while metaplastic lashes originate directly from these orifices.</p> Signup and view all the answers

<p>Acquired ectropion can result from aging changes, mechanical reasons, or scarring, while congenital ectropion arises from developmental anomalies.</p> Signup and view all the answers

<p>Posterior blepharitis is associated with meibomian gland dysfunction, often linked to inflammatory conditions like ocular rosacea.</p> Signup and view all the answers

<p>Neurogenic blepharoptosis is due to nerve-related issues like third nerve palsy, while developmental blepharoptosis results from a dystrophy of the levator muscle.</p> Signup and view all the answers

<p>Madarosis refers to the loss of eyelashes, while poliosis is characterized by premature whitening of eyelashes and may also affect eyebrows.</p> Signup and view all the answers

<p>Involutional and aponeurotic ptosis.</p> Signup and view all the answers

<p>Epicanthal folds are bilateral vertical skin folds that overhang from the upper or lower lid towards the medial canthus, potentially causing pseudo-esotropia.</p> Signup and view all the answers

<p>Telecanthus involves increased distance between the medial canthi due to long medial tendons, while hypertelorism refers to wide separation of the orbits.</p> Signup and view all the answers

<p>Myasthenia gravis, myotonic dystrophy, and ocular myopathy are myogenic conditions associated with ptosis.</p> Signup and view all the answers

<p>Coloboma is a congenital partial or full-thickness eyelid defect, which can result in functional and aesthetic concerns for the affected individual.</p> Signup and view all the answers

<p>15 times per minute.</p> Signup and view all the answers

<p>Extremely dry conditions, strong air currents, and emotional stress.</p> Signup and view all the answers

<p>They provide shape and firmness to the eyelids.</p> Signup and view all the answers

<p>Approximately 30 in the upper and 25 in the lower tarsal plates.</p> Signup and view all the answers

<p>It regulates the width of the palpebral fissure.</p> Signup and view all the answers

<p>It is very infrequent during the first few months of life.</p> Signup and view all the answers

<p>The upper tarsus is 10 mm and the lower tarsus is 5 mm in height.</p> Signup and view all the answers

<p>It is smooth non-striated muscle.</p> Signup and view all the answers

<p>The orbital septum.</p> Signup and view all the answers

<p>Sebaceous glands, or Meibomian glands, lubricate the eyelid margin and prevent tear fluid from escaping.</p> Signup and view all the answers

<p>Dermatochalasis.</p> Signup and view all the answers

<p>High sympathetic tone contracts the muscle and widens the palpebral fissure.</p> Signup and view all the answers

<p>The orbital septum weakens, which can lead to herniation of orbital fat.</p> Signup and view all the answers

<p>The orbital septum fuses with the levator aponeurosis in the upper eyelid and capsulopalpebral fascia in the lower eyelid.</p> Signup and view all the answers

<p>It acts like a windshield wiper, distributing glandular secretions and tears over the conjunctiva and cornea.</p> Signup and view all the answers

<p>It serves as a significant barrier to infection, hemorrhage, and edema.</p> Signup and view all the answers

<p>Madarosis</p> Signup and view all the answers

<p>A second row of lashes arises from or behind the meibomian gland orifices.</p> Signup and view all the answers

<p>Acquired and congenital entropion.</p> Signup and view all the answers

<p>Meibomian gland dysfunction.</p> Signup and view all the answers

<p>Eversion of the lid margin, which can be congenital or acquired.</p> Signup and view all the answers

<p>The internal and external carotid arteries.</p> Signup and view all the answers

<p>They serve as tiny openings that help drain tears from the surface of the eye.</p> Signup and view all the answers

<p>The oculomotor nerve.</p> Signup and view all the answers

<p>Trichiasis is the misdirection of eyelashes, causing them to grow towards the eye and potentially lead to irritation or damage.</p> Signup and view all the answers

<p>Venous drainage is divided into pretarsal and postarsal systems.</p> Signup and view all the answers

<p>They drain to the submandibular lymph nodes.</p> Signup and view all the answers

<p>Eyelashes help prevent dust and sweat from entering the eyes.</p> Signup and view all the answers

<p>It is responsible for closing the eyelids.</p> Signup and view all the answers

<p>Treacher Collins Syndrome.</p> Signup and view all the answers

<p>It is most common during the first year of life and usually resolves spontaneously by ages 4-7.</p> Signup and view all the answers

<p>Keratoacanthoma is a benign but rapidly growing tumor, most common in immunosuppressed patients.</p> Signup and view all the answers

<p>Basal cell carcinoma is the most common malignancy, typically occurring in the head and neck, and it is locally invasive but non-metastasizing.</p> Signup and view all the answers

<p>The three main types are plaque-like, nodular, and ulcerating.</p> Signup and view all the answers