Muscle gross anatomy I Claudia Stanescu Ph D Office Hours in Gittings 108 Tue 10 11am Wed 11 12 Thurs 1011 and 2 3 Fri 10 12 or by appointment Objectives 1 Describe the general locations and specific actions of the skeletal muscles listed in this section 2 Given the origin and insertion of a skeletal muscle predict the muscle s action 3 Given a specific body movement i e flexion of the arm predict the agonist antagonist and synergist in performance of that movement Muscles of the face Frontalis raises eyebrows Galea aponeurotica epicranial aponeurosis tendon connects 2 muscles to each other Occipitalis brings scalp posteriorly Occipitofrontalis Epicranius Frontalis Occipitalis Actions Frontalis raises eyebrows and wrinkles forehead Occipitalis draws scalp posteriorly Muscles of the face Orbicularis oculi decrease size of round opening blinking Orbicularis oris round decrease size of opening pucker Zygomaticus major raises corners of mouth up smiling Platysma often not shown on pulls lip inferiorly models depresses mandible Actions Orbicularis oculi closes the eye as in blinking Orbicularis oris puckers the mouth for speech kissing muscle Platysma moves the lower lip inferiorly and posteriorly depresses mandible Zygomaticus major pulls the corners of the mouth superiorly smiling muscle Muscles that move the mandible important in mastication chewing and speech moving mandible up and down Temporalis when they shorten it pulls the mandible up elevates and retracts origin posterior insertion anterior anterior posterior pulls mandible back Masseter elevates and proctracts origin anterior insertion posterior posterior anterior pulls mandible forward Actions Temporalis elevates and retracts the mandible Masseter elevates and protracts the mandible Muscles that move the head Sternocleidomastoid under platysma upside down Actions of sternocleidomastoid When both contract flexion of the head When one side contracts rotation of head to opposite side lateral flexion of the head Respiratory muscles Internal intercostals External intercostals Diaphragm dome like half sphere seperates thoracic cage from abdominal pelvic flattens when contracted when flat air comes in to lungs Respiratory muscles Diaphragm central tendon when contracts flattens only muscle that is active when at rest expands thoracic cavity which allows inspiration inhilation when it goes back to dome it decreases tc volume and you exhale different with labored breathing Actions of diaphragm Primary muscle of inspiration When contracted moves downward and expands the thoracic cavity When the diaphragm relaxes it becomes dome shaped and the thoracic cavity size decreases expiration is a passive process Respiratory muscles involved in labor breathing External intercostals superficial fibers go in movement like putting hands in pockets medially Internal intercostals deep fibers opposite and go laterally Actions pull ribs up External intercostals expand the thoracic cavity during forced inspiration Internal intercostals decrease the size of thoracic cavity during forced expiration pull ribs down Muscles that move the vertebral column Rectus abdominis Transversus abdominis Internal obliques Linea alba External obliques Actions Rectus abdominis flexes vertebral column and compresses abdomen Obliques external internal compresses abdomen rotation of trunk if one side contracts Transversus abdominis compresses abdomen Abdominals transverse section Muscles that move the vertebral column Iliocostalis Spinalis Longissimus Actions Errector spinae group Longissimus spinalis iliocostalis When contracting together extend the vertebral column When one side contracts lateral flexion of the vertebral column Muscles that move the pectoral girdle clavicle and scapula Pectoralis minor Actions Protracts and depresses the scapula Origin upper ribs Insertion scapula If the scapula is stabilized the origin and insertion switch and the action of this muscle is to assist in inspiration Reverse Action Anterior deep view Muscles that move the pectoral girdle Trapezius Actions Upper portion elevates the scapula and clavicle and extends the head Middle portion adducts the scapula Lower portion depresses scapula Muscles that move the pectoral girdle Levator scapulae Rhomboid minor Rhomboid major Actions Levator scapulae elevates the scapula Rhomboid major and minor adduct elevate and inferiorly rotate the scapula Muscles that move the arm Pectoralis major Deltoid Anterior trunk Actions Deltoid anterior fibers flex and medially rotate arm middle fibers abduct the arm and posterior fibers extend and laterally rotate the arm Pectoralis major flexes adducts and medially rotates the arm Muscles that move the arm Supraspinatus Infraspinatus Latissimus dorsi Actions Supraspinatus abduction of the arm Infraspinatus adducts the arm Latissimus dorsi adducts extends and medially rotates the arm Muscles that move the forearm Biceps brachii Actions Flex the forearm Flex the arm Supinates the hands Muscles that move the forearm Brachioradialis Brachialis Actions Brachialis flexes the forearm Brachioradialis flexes the forearm Muscles that move the forearm Triceps brachii Actions Extends the forearm Extends the arm Muscles that move the hand Action Hand flexors Flexor carpi radialis Palmaris longus Flexor carpi ulnaris Anterior Muscles that move the hand Extensor carpi ulnaris Extensor digitorum Action Hand Finger extensors Posterior