PSIO 201 5th Edition Lecture 24Outline of Last Lecture Cardiac and Smooth MuscleOutline of Current Lecture I. Muscle Gross Anatomy III. Head MusclesIII. Respiratory MusclesIV. Arm MusclesCurrent LectureCharacteristic DescriptionDirection of muscle fibersRectus: Fibers run parallel to the midline Transverse: Fibers run perpendicular to the midline Oblique: Fibers run diagonal to the midlineSize Maximus: Largest Minimus: Smallest Longus: LongestLocationNamed for the bone(s) to which the muscle attaches, or region within which the muscle is found.Shape Deltoid: Triangular shape Rhomboid: Diamond shape Trapezius: Trapezoid shapeNumber of origins Biceps: Two origins Triceps: Three origins Quadriceps: Four originsAction Named for the action that the muscle performs.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.TABLE 2: Muscles of the face, head, and neckMuscle LocationActionOccipitofrontalis: Frontalis and OccipitalisComposite muscle that overlies the cranium; the two muscles are connected by an aponeurosis.Frontalis: Raises the eyebrows Occipitalis: Draws scalp posteriorlyOrbicularis oris Circular muscle that encircles the mouth.Puckers the mouth as in kissing.Orbicularis oculi Circular muscle that encircles each eye.Closes each eye as in blinking.Zygomaticus majorOriginates on the zygomatic bone and inserts on the skin at the corners of the mouth.Pulls the corners of the mouth superiorly as in smiling. PlatysmaOriginates on the fascia of the chest and deltoid and inserts on the mandible and skin below the mouth.Depresses the lower lip and mandible; tenses neck skin. Temporalis Originates on the temporal bone and inserts on the mandible. Elevates and retracts the mandible.MasseterOriginates on the maxillae and zygomatic bones and inserts on the mandible.Elevates and protracts the mandible. Sternocleidomastoid Originates on the sternum and clavicle and inserts on the mastoid process of the temporal bone.If one side contracts, the head rotates to the opposite side. If both contract, flexion of the head is the result.Muscle LocationActionRectus abdominisOriginates on the pubis and inserts superiorly on the lower ribs and xiphoid process.Flexes the vertebral column andcompresses the abdomen.External oblique Originates laterally on the lowerribs and inserts medially on the iliac crest and linea alba.Rotation of the trunk results if one side contracts. If both sides contract together, flexion of the vertebral column and compression of the abdomen isthe result.Internal obliqueLocated deep to the external oblique, the internal oblique originates laterally at the iliac crests and inserts medially at the linea alba and lower ribs.The internal oblique has the same action as the external oblique.Transverse abdominisLocated deep to the internal oblique, the transverse abdominis originates laterally on the iliac crest and the cartilages of the lower ribs. It inserts medially at the xiphoid process and linea alba.Contraction of the transverse abdominis compresses the abdomen.Erector spinae: Iliocostalis groupLongissimus group Spinalis group Composite group of muscles that individually originate on vertebral processes or ribs and insert on superior processes of the vertebral column.When one side contracts, the muscles laterally flex and rotate the vertebral column. When both contract, the muscles extend the vertebral column andmaintain erect posture.Biceps brachiiMuscle of the anterior arm withtwo points of origin on the scapula. It inserts on the radial tuberosity.Flexes and supinates the forearm; flexes arm.BrachialisDeep to the biceps brachii, the brachialis originates on the anterior distal humerus and inserts on the proximal ulna.Flexes the forearm.BrachioradialisOriginates on the distal humerus and inserts on the styloid process of the radius.Flexes the forearm.Triceps brachii Muscle of the posterior arm with three points of origin on the scapula and posterior humerus. It inserts on the Extends the forearm and extends the arm.olecranon process of the
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