anatomy muscle test

All muscles cross at least one joint

Typically, the bulk of the muscle lies proximal to the joint crossed

All muscles have at least two attachments: the origin and insertion

Muscles can only pull; they never push

During contraction, the muscle insertion moves toward the origin

• Produce movement
• Maintain posture
• Stabilize joints
• Generate heat

a muscle contracting to pull on an attached bone (bones are never pushed)

attachment to an immoveable (less movable) bone

attachment to a movable bone

origin

muscle with the major responsibility for a certain movement

muscle that opposes or reverses a prime mover

muscle that aids a prime mover in a movement and helps prevent rotation

stabilizes the origin of a prime mover

• rigid bar – bones
• fulcrum – point on which bar moves; joint
• object - moved against resistance; weight
• force – supplies energy for movement; muscles

muscle contracts and changes length

shortening contraction

lengthening contraction

muscle contracts but does not change length

• usually attached to bones
• under conscious control
• striated

• wall of heart
• not under conscious control
• striated

• walls of most viscera, blood vessels, skin
• not under conscious control
• not striated

Found mainly in the walls of hollow organs (visceral muscle)

• (a) Produce movement
• (b) Maintain posture
• (c) Stabilize joints
• (d) Generate heat

• (1) Irritability – ability to receive and respond to a stimulus
• (2) Contractility – ability to shorten when an adequate stimulus is received
• (3) Extensibility – abilty to stretch/extend
• (4) Elasticity – ability to return to original shape

• Frontalis
• Obicularis oculi
• Obicularis oris
• Buccinator
• Zygomaticus
• Platysma

raises eyebrows, wrinkles forehead

closes, blinks eye

closes, protrudes lips

compresses cheeks

raises corners of mouth

draws down corners of mouth

• Masseter
• Temporalis
• Platysma
• Medial pterygoid
• Lateral pterygoid

elevates mandible

elevates mandible

lowers mandible (frown)

elevates mandible

depress mandible

• Sternocleidomastoid
• Splenius capitis & Semispinalis capitis
• Erector Spinae

neck flexion, rotation

neck extension & rotation

neck/vertebral extension

• Trapezius
• Rhomboids (major/minor)
• Levator scapulae

• Serratus anterior
• Pectoralis Minor

scapula adduction, rotation

retracts & elevates scapula

Elevates

Pulls scapula anterior and downward

Raises ribs & pulls scapula anterior

• Pectoralis major
• Deltoid
• Latissimus dorsi
• Coracobrachialis
• Teres major
• Teres minor
• Subscapularis
• Supraspinatus
• Infraspinatus

humerus flexion, adduction, medial rotation

humerus abduction (extension & flexion)

humerus extension, adduction

arm flexion & adduction

extends, adducts & rotates arm

lateral rotation of arm

Medial rotation

Arm Abduction

Lateral rotation

• Biceps brachii
• Brachialis
• Brachioradialis
• Triceps brachii
• Pronator terez & quadratus
• flexor retinaculum

flexion at elbow, supination

flexion at elbow

flexion at elbow

extension at elbow

pronation

• Flexor carpi radialis
• Palmaris longus
• Flexor digitorum
• Flexor carpi ulnaris
• . Extensor carpi ulnaris
• Extensor digitorium
• Extensor carpi radialis

wrist flexion, abduction

wrist flexion

wrist and finger flexion

wrist flexion, adduction

wrist extension, adduction

wrist and finger extension

wrist extension, abduction

• Rectus abdominus
• Transverse abdominus
• External obliques
• Internal obliques
• Erector spinae

vertebral flexion

vertebral rotation

vertebral rotation

vertebral rotation

vertebral extension