Anatomy Notes February 17, 2009 Cavities of the Larynx I missed the first 2 slides!! -aditus: entry to the larynx from the pharyngeal Laryngeal muscles -Extrinsic muscles -suprahyoid muscles -infrahyoid muscles -Intrinsic muscles Extrinsic Muscles: -one attachment is in or on the larynx, while the other is outside of the larynx (meaning not in or on the larynx) -function: to position and support the larynx -includes 4 suprahyoud muscles and 4 infrahyoid muscles -all extrinsic muscles are paired except mylohyoid **need to be able to label muscles and know where it begins and ends/ and attaches*** 4 Suprahyoid muscles -extend superiorly from hyoid bone and form sling from mandible to hyoid bone to base of cranium Digastric: 2 bellies Ant. Belly attaches to mandible Post. Belly attaches to mastoid of the temp. bone Both bellies connect by intermediate tendon F: elevates hyoid; major laryngeal elevator as well Mylohyiod: Forms floor of the mouth Like a pinnate muscle Raphe: tendinous muscles that meet at midline F: elevates larynx; lowers mandible Geniohyoid: Genio= chin Loc. sup To mylohyoid From mandibular symphsis to hyoid F: moves hyoid forward; elevates larynx Stylohyoid: Long and slender Lies superficial to post. Bellyof digastric O: styloid process of temp. bone I: hyoid F: elevates hyoid 4 infrahyoid muscles: -Extend inf. From hyoid bone as well as from other laryngeal structures -main func. Is to depress and stabilize the larynx Sternohyoid: Loc. on ant. Surface of neck O: manubrium of sternum I: hyoid F: lowers hyoid, therefore lowers larynx Omohyoid: Omo= shoulder Loc on antereolateral surface of neck 2 bellies joined by intermediate tendon O: Superior border of scapula I: hyoid F: lowers hyoid Sternothyroid: Deep to sternohyoid and omohyoid Loc. in the anterior neck O: sternum and 1st costal cartilage I: oblique line of thyroid cartilage of larynx F: lowers larynx Thyrohyoid: Deep to sternohyoid and omohyoid Loc. in anterior neck O: oblique line of thyroid cartilage of larynx I: hyoid F: lowers hyoid or elevates larynx Intrinsic Muscles -both attachments are in or on the larynx -Function to: 1) open the larynx and vocal folds for respiration 2) close the VF for phonation 3) vary the length and stiffness of vocal folds for change in pitch 4) close the larynxagainst pressure -all intrinsic muscles are paired except for transverse arytenoids Cricothyroid (CT): 2 Parts: Pars oblique?outside portion Pars recta?inside portion O: thyroid I: cricoid F: adducts cricoid and tyroid to lengthen vocal folds Lateral Cricoartenoid (LCA): Loc. on lateral side of larynx; deep to thyroid cartilage Small, fan shaped O: lateral surface of cricoid I: muscular process of artenoids F: draws arytenoids forward ( adducts VF Posterior Cricoarytenoid (PCA) Loc. on posterior surface of larynx Fan shaped O: cricoid lamina I: muscular process of arytenoids F: only intrinsic muscle to aBduct the VF Transverse Arytenoid: Deep to the oblique arytenoids Unpaired O: Post. Surface of arytenoid I: Post. Surface of opposite arytenoid F: adducts VF Oblique Arytenoid: The oblique arytenoids cross over each other to form an ?X? Superficial to transverse artytenoid Transvers arytenoid + oblique arytenoids = interarytenoid muscle O: muscular process of one arytenoid I: apex of the opposite arytenoid F: tight adduction Thyroarytenoid: 2 Parts: Vocalis: medial to thyromuscularis; main mass of VF O: near thyroid notch I: vocal process of arytenoids F: increase tension and stiffness of vocal folds, may raise pithch Thyromuscularis: lateral aspect of thyroarytenoid; fibes parallel to vocal ligament O: near thyroid notch I: muscular process of the arytenoids F: pulls arytenoids toward thyroid angle (anteriorly) to shorten and relax VF
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