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Anatomy and Physiology, Seventh Edition

Rod R. SeeleyIdaho State UniversityTrent D. StephensIdaho State UniversityPhilip TatePhoenix College

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

*See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes.

Chapter 10Chapter 10

Lecture OutlineLecture Outline**

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Muscular SystemGross Anatomy

Chapter 10

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General Principles• Tendons: attach muscles to bones

– 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.

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Muscle attachment

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Muscle Types

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Examples of Muscle Shapes

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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

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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)

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Classes of Levers

• Class I– 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

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Muscle Anatomy: Anterior View

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Muscle Anatomy: Posterior View

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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

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Posterior Deep Neck Muscles

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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.

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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

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Muscles of the Hyoid

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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

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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

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Muscles of Larynx

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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

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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

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Deep Muscles of the Vertebrae

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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

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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

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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

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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

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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

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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

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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

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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

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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

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Intrinsic Muscles of the Hand

• Originate and insert in hand.

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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

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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

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Muscles that Move the Leg

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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

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Extrinsic Muscles of the Foot

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Extrinsic Muscles of the Foot

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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.