MUSCULAR
SYSTEM
Chapter 7
NAMING SKELETAL MUSCLES
 Location
 Size
 Direction of fibers
 Number of origins
 Location of origins and insertion
 Action flexor
 Extensor
 Levator and depressor
MUSCLES OF THE
HEAD AND NECK
 Muscles of the head and neck control human facial expressions
 Muscles of mastication control the mandible (lower jaw)
FACIAL EXPRESSIONS
 frontalis
 Expression: Surprise
 Location: Either side of forehead
 Function: Raises eyebrow and wrinkles forehead
 Depressor anguli oris
 Expression: doubt, disdain, contempt
 Location: along side of chin
 Function: depresses corner of mouth
FACIAL EXPRESSIONS
Orbicularis oris
 Expression: doubt, disdain, contempt
 Location: ring-shaped muscle found around mouth
 Function: compresses and closes the lips
Platysma
 Expression: horror
 Location: broad, thin muscular sheet covering the
side of neck and lower jaw
 Function: draws corners of mouth downward and
backward
FACIAL EXPRESSIONS
 Zygomaticus major
 Expression: laughing or smiling
 Location: extends diagonally upward from corner of
mouth
 Function: raises corner of mouth
 Nasalis
 Expression: Muscles of nose
 Location: over nasal bones
 Function: closes and opens nasal openings
FACIAL EXPRESSIONS
 Orbicularis oculi
 Expression: sadness
 Location: Surrounds eye orbit underlying the eyebrows
 Function: Closes the eyelid and tightens the skin on the forehead
MASTICATION
 Masseter
 Location: Covers the lateral surface of mandible
 Function: Closes the jaw
 Temporalis
 Location: Located on the temporal fossa of the skull
 Function: Raises the jaw, closes the mouth, and draws back the jaw
NECK
 Sternocleidomastoid
 Location: large muscles extending diagonally down sides of neck
 Function: flexes head; rotates head toward opposite side from muscle
MUSCLES OF THE
UPPER EXTREMITIES
 Muscles of the upper extremity help to move the:
 Shoulder (scapula)
 Arm (humerus)
 Forearm
 Wrist
 Hand
 Fingers
UPPER EXTREMITIES
 Trapezius
 Location: a lg triangular muscle located on the upper surface of the back.
 Function: Moves the shoulder; extends the head
 Deltoid
 Location: a thick triangular muscle that covers the shoulder joint
 Function: Abducts the upper arm
UPPER EXTREMITIES
 Pectoralis major
 Location: anterior part of chest
 Function: Flexes upper arm and helps to abduct the upper arm.
 Serratus
 Location: anterior chest
 Function: Moves scapula forward and helps to raise the arm.
UPPER EXTREMITIES
 Biceps brachii
 Location: upper arm to radius
 Function: flexes the lower arm
 Triceps brachii
 Location: posterior arm to ulna
 Function: extends the lower arm
UPPER EXTREMITIES
 Extensor and flexor carpi
 Location: extends from the anterior and posterior forearm to hand
 Function: moves the hand
 Extensor and flexor digitorum
 Location: extends from the anterior and posterior forearm to fingers
 Function: moves the fingers
MUSCLES OF THE TRUNK
 Trunk muscles control breathing and the movements of the abdomen
and the pelvis
 External intercostals
 Diaphragm
 Rectus abdominis
 External oblique
 Internal oblique
TRUNK
 External intercostals
 Location: found b/w the ribs
 Function: raises the ribs to help in breathing
 Diaphragm
 Location: dome-shaped muscle separating the thoracic and abdominal cavities
 Function: control breathing
TRUNK
 Rectus abdominis
 Location: extends from the ribs to the pelvis
 Function: compresses the abdomen.
 External oblique
 Location: anterior inferior edge of the last 8 ribs
 Function: depresses ribs, flexes the spinal column, compresses the abdominal cavity
TRUNK
 Internal oblique
 Location: beneath the external oblique, fibers running the opposite direction
 Function: depresses ribs, flexes the spinal column, compresses the abdominal cavity
MUSCLES OF THE
LOWER EXTREMITIES
 Assist in the movement of the thigh, leg, ankle, foot, and toes
 Gluteus maximus
- Tibialis anterior
 Gluteus medius
- Gastrocnemius
 Tensor fasciae
- Soleus
 Peroneus longus
- Sartorius
 Rectus femoris
LOWER EXTREMITIES
 Gluteus maximus
 Location: forms the buttocks
 Function: extends femur and rotates it outward.
 Gluteus medius
 Location: extends from deep femur to buttocks
 Function: abducts and rotates the thigh
LOWER EXTREMITIES
 Tensor fasciae
 Location: flat muscle found along the upper lateral surface of thigh
 Function: flexes, abducts, medially rotates thigh.
 Rectus femoris
 Location: anterior thigh
 Function: flexes thigh and extends lower leg
LOWER EXTREMITIES
 Sartorius
 Location: long, straplike muscle that runs diagonally across the anterior and medial
surface of the thigh
 Function: flexes and rotates the thigh and leg
 Tibialis anterior
 Location: front of tibia bone
 Function: dorsiflexes the foot; permits walking on the heels
LOWER EXTREMITIES
 Gastrocnemius
 Location: calf
 Function: points toes and flexes lower leg.
 Soleus
 Location: broad flat muscle found beneath calf
 Function: extends foot
LOWER EXTREMITIES
 Peroneus longus
 Location: superficial muscle found on the lateral side of the leg
 Function: extends and everts the foot and supports the arches.
HOW EXERCISE AND TRAINING CHANGE
MUSCLES
 Effect of training on muscle efficiency:
 Improved coordination
 Improvement of the respiratory and circulatory system
 Elimination or reduction of excess fat
 Improved joint movement
HOW EXERCISE AND TRAINING CHANGE
MUSCLES
 Effects of Training on Muscle Strength
 Increase in muscle size
 Improved antagonistic muscle coordination
 Improved functioning in the cortical brain region
INTRAMUSCULAR INJECTIONS
 Injections are made into the muscle, usually the deltoid muscle of the
upper arm, vastus lateralis (anterior thigh), dorsal gluteal or ventral
gluteal or buttocks
MUSCULOSKELETAL DISORDERS
Atrophy
Fibromyalgia
Strain
Hernia
Spasm
Myalgia
Abdominal
hernia
Inguinal hernia
Hiatal hernia
MUSCULOSKELETAL DISORDERS
Flatfeet
Mysathenia gravis
Tetanus
Recreational
Torticollis
Muscular
dystrophy
injuries
Tennis elbow
Shin splints
Rotator cuff
disease