Anatomy and Physiology, Seventh Edition Rod R. Seeley Idaho State University Trent D. Stephens Idaho State University Philip Tate Phoenix College Chapter 10 Lecture Outline* *See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Muscular System Gross Anatomy Chapter 10 Muscular System Gross Anatomy

General Principles Tendons: attach muscles to bones Muscle terminology Aponeurosis: a very broad tendon Muscle terminology Origin or head: muscle end attached to more stationary of two bones Insertion: muscle end attached to bone with greatest movement Belly: largest portion of the muscle between origin and insertion Agonist: muscle that, when it contracts, causes an action Antagonist: a muscle working in opposition to agonist Example: the biceps brachii can be used to lift weights and is the agonist, but when you move a bowling ball back to prepare to bowl, the biceps is the antagonist Synergists: muscles that work together to cause a movement Prime mover: plays major role in accomplishing movement Fixators: stabilize joint/s crossed by the prime mover; prevent movement of the origin of the prime mover.

Muscle attachment

Muscle Types

Examples of Muscle Shapes

Nomenclature Muscles are named according to: Location: pectoralis gluteus, brachial Size: maximus, minimus, longus, brevis Shape: deltoid, quadratus, teres Orientation: rectus Origin and insertion: sternocleidomastoid, brachioradialis Number of heads: biceps, triceps Function: abductor, adductor, masseter

Muscle Movements Muscles and their tendons and bones act together as lever systems to move either parts of the body or the whole body. Muscle contractions are a pull or force by relative positions of Lever: rigid shaft or bone Fulcrum: pivot point or joint Weight or resistance (force of gravity either in the form of the weight of the body parts or the weight of an object being lifted, pulled, or pushed)

Classes of Levers Class I Class II Class III Fulcrum between force and weight Seesaw Head movement at the atlantooccipital joint Class II Weight is between fulcrum and pull Wheelbarrow Standing on toes; metatarsophalangeal joint Class III Pull located between fulcrum and weight Person using a shovel Most common: biceps brachii with elbow as fulcrum Classes of Levers

Muscle Anatomy: Anterior View

Muscle Anatomy: Posterior View

Head and Neck Muscles Flexion: muscles deep within the neck along the anterior margins of the vertebral bodies Extension: posterior neck muscles attached to occipital bone Rotation and abduction: lateral and posterior groups Examples: sternocleidomastoid, trapezius, splenius muscles

Posterior Deep Neck Muscles

Muscles of Facial Expression Cutaneous; origin and insertion in the superficial fascia. Confined primarily to head and neck. Move the skin; some act as sphincters. Examples: orbicularis oris, orbicularis oculi, platysma.

Muscles of Mastication and Hyoid Mastication: chewing. Involves elevation/depression of the mandible and excursion to grind the teeth together Act with the muscles of hyoid in movement of the mandible Muscles of the cheek and tongue aid mastication by pushing the food under the teeth Examples: masseter, temporalis, pterygoids, digastrics

Muscles of the Hyoid

Tongue Movements Important in speech: changes shape Swallowing Moves food around in mouth Holds food in place during grinding Pushes food up to palate and back toward pharynx Intrinsic: entirely within the tongue and allow change in shape Extrinsic: insert in tongue and allow change in shape and movement

Swallowing and the Larynx Hyoid muscles: infra- and suprahyoid groups Suprahyoid muscles fix the hyoid, then thyrohyoid can elevate larynx When infrahyoid group fixes hyoid, suprahyoid muscles can help depress the mandible Swallowing: Elevation of pharynx and larynx Constriction of the pharynx from superior to inferior Salpingopharyngeus opens auditory tubes to equalize pressure between middle ear and atmosphere

Muscles of Larynx

Extrinsic Muscles of the Eye Rectus muscles: insert on sclera anterior to center of sphere. Move eyeball and thus pupil laterally, superiorly, inferiorly, and medially Oblique muscles: insert onto the posterolateral margin of the eyeball and both laterally deviate the eyeball. The superior oblique passes through a pulley-like trochlea

Muscles that Move the Vertebral Column Muscles that extend, laterally flex, and rotate the vertebral column. Used to produce erect posture Divided into deep and superficial groups Deep group: from vertebra to vertebra Superficial group extend from vertebrae to ribs

Deep Muscles of the Vertebrae

Thoracic Muscles Involved in breathing Four groups associated with rib cage Scalenes: elevate first two ribs during inspiration External intercostals: elevate the ribs Internal intercostals: depress ribs during expiration Transversus thoracis: depresses ribs during expiration Diaphragm: major movement of inspiration. Flattens during contraction and increases the volume of the thoracic cavity

Abdominal Wall Flex and rotate vertebral column, decrease volume of abdominal and thoracic cavities Aid in forced expiration, vomiting, defecation, urination, childbirth Crossing pattern of muscles adds strength to abdominal wall to support organs

Abdominal Wall Rectus Abdominis Linea alba in center Covered by rectus sheath Tendinous intersections divided muscle into sections Flexes vertebral column External abdominal oblique: flexes and rotates abdomen Internal abdominal oblique: flexes and rotates abdomen Transversus abdominis: compresses abdominal wall

Muscles of Pelvic Floor and Perineum Pelvic diaphragm: Funnel-shaped, supports the pelvic viscera. Pierced by anal canal, urethra and (vagina). Perineum: diamond-shaped area inferior to pelvic diaphragm. Anterior half of diamond is urogenital triangle; posterior half is anal triangle

Scapular Movements Muscles that attach the upper limb to the body and move or stabilize the scapula and clavicle. Originate on the axial skeleton. Trapezius, levator scapulae, rhomboideus, serratus anterior, pectoralis minor

Arm Movements Muscles that attach arm to thorax: pectoralis major, latissimus dorsi Deltoid and pectoralis major both act as flexors and extensors of the shoulder Deltoid abducts and medially and laterally rotates arm

Rotator Cuff Primary muscles holding humerus in the glenoid cavity Form a cuff or cap over the proximal humerus Involved in flexion, extension, abduction, adduction, rotation and circumduction Infraspinatus, subscapularis, supraspinatus, teres minor

Forearm Movement Movements at the elbow Extension: triceps brachii and anconeus Flexion: biceps brachii, brachioradialis, and brachialis Supination and pronation: Supination: supinator and biceps brachii Pronation: pronator quadratus and pronator teres

Wrist, Hand, and Finger Movements Muscles on anterior surface of forearm: flexion as well as abduction and adduction of the wrist. Muscles on posterior surface of forearm: extension and abduction. Retinacula- bands of deep fascia which hold tendons of muscles of forearm, blood vessels, and nerves close to wrist. Flexor retinaculum (transverse carpal ligament): on the flexor surface Extensor retinaculum (dorsal carpal ligament): on the extensor surface Wrist, Hand, and Finger Movements

Intrinsic Muscles of the Hand Originate and insert in hand.

Thigh Movement Originate on coxa; insert onto femur Anterior, posterolateral, deep Anterior: flex hip. Iliacus and psoas major often referred to as iliopsoas since they share a tendon of insertion Posterolateral: gluteals and tensor fasciae latae Extension of thigh Deep: thigh rotators

Leg Movements Quadriceps femoris: anterior surface of thigh Extension of the leg at the knee. Rectus femoris also flexes the hip. Insert by common tendon (patellar tendon) on and around the patella Patellar tendon extends from patella to tibial tuberosity Sartorius: flexes hip and knee, laterally rotates thigh Medial thigh muscles: adduction Posterior thigh muscles: hamstrings. Flexion and rotation of the knee

Muscles that Move the Leg

Ankle, Foot, and Toe Movements Extrinsic foot muscles Three leg compartments Anterior compartment: extensors involved in dorsiflexion and eversion/inversion of foot; extension of toes. Dorsiflex foot, extend toes. Lateral compartment: plantar flexion and eversion. Posterior compartment- Superficial muscles (plantar flexion) have common tendon of insertion called the calcaneal (Achilles) tendon. Gastrocnemius, plantaris Deep muscles: plantar flex and invert foot Ankle, Foot, and Toe Movements

Extrinsic Muscles of the Foot

Extrinsic Muscles of the Foot

Intrinsic Muscles of the Foot Analogous to intrinsics of hand, but serve in support and locomotion Flexion, extension, abduction and adduction of toes Deep fascia forms plantar aponeurosis.