MUSCLES

Types of Muscle

Skeletal Most common Attached to bone (via tendons) Voluntary Striated

Cardiac Muscle In the heart only Involuntary Striated

Smooth Muscle Surrounds organs Slow, long contractions Involuntary Non-striated; forms dense sheets

The Neuromuscular System

Complex linking of the muscular and neurological systems

Constant use and practice improves the quality, efficiency and ability of these systems to work together E.g. agility training

The Motor Unit Nerves transmit impulses in waves- the resulting

contraction is called a muscle twitch 1 nerve + the muscle fibers it innervates = motor unit 1 nerve stimulates many muscle fibers, thereby producing

muscle movements. 1 nerve + a few muscle fibers =fine movements (eg

blinking) 1 nerve + lots of fibers = gross/big movements (eg

contraction of the quadriceps) All-or-None Principle

When a motor unit is stimulated to contract, either ALL of the muscle fibers will contract, or none will

Types of Muscle Contraction

Concentric Muscle fibers shorten E.g. bicep flexion

Eccentric Muscle fibers lengthen Eg bicep extension

Isometric Contraction without change in length of muscle; no

motion; decreased risk of injury E.g. pushing against a wall; doing a abdominal plank.

http://www.youtube.com/watch?v=A1haS8hR1lE

Muscle Origin vs Insertion

Origin where the muscle attaches to more stationary

of the bones of skeleton. Usually more superior

Insertion Where the muscle attaches to the bone that

moves most Usually more inferior

Antagonistic Pairs

Skeletal muscles are arranged as opposing pairs

Agonist Prime mover of the body part Eg. During knee extension, quadriceps are the

agonist Antagonist

Counter-acts the agonist Eg. During knee extension, hamstrings are the

antagonist

Label the following muscles of the lower limb:

Flexor hallicus longus Anterior tibialis Soleus Gastrocnemius Patella Quadriceps Hamstrings Gluteus medius, minimus, maximus Abductor muscles Adductor muscles Peroneals

Can you label these muscles??

Muscles of the Leg and their Functions

Leg- refers to lower limb below the knee Thigh = hip to knee

Muscle/Muscle Group

Origin Insertion Action

Toe/foot extensors

Anterior tibia/fibula

Distal phalanges (toes)

Extend the toes

Tibialis Anterior

Ant. Tibia Top of foot Dorsiflexion of ankle; foot inversion

Gastrocnemius

Lateral and medial heads both originate on femur

Achilles tendon, which inserts on the heel (calcaneus)

Plantar flexes ankle; flexes knee

Soleus Upper fibula Tendon combines with gastroc to form achilles heel.

Plantar flexes ankle

Flexor hallicus longus

Posterior fibula End of big toe (ie the distal aspect)

Flexes big toe

Peroneals Fibula 1st and 5th metatarsals

Plantar flexion; eversion

Muscles of the Thigh and HipMuscle/ Muscle Group

Origin Insertion Action Location

Quadriceps femoris

Iliac spine (pelvis) & proximal femur

Come together as patellar tendon, insert on tibia

Knee extension and hip flexion

Hamstrings Pelvis Head of fibula and tibia

Hip extension; knee flexion; internal knee rotation

Gluteus maximus

Pelvis and lower spine (iliac crest, sacrum, coccyx)

Proximal femur (greater trochanter) and iliotibial tract ( IT band)

Hip extension, external rotation

Gluteus medius & minimus

Lateral pelvis Greater trochanter/ femur

Abduction; internal hip rotation

Hip adductors Distal pelvis Along the femur

Hip/ thigh adduction

Groups: Figure out where each muscle is located- ie anterior, posterior, medial,

lateral

Questions:

While out trail running, Marie steps on a root and experiences an eversion of her ankle. a) What is this injury? (what happens to the sole of the foot) b) Which muscles will be injured? c) Which muscles would have contracted to aid ankle eversion?

Many athletes, especially women, have muscular imbalances between their quadriceps and hamstring muscle groups(quads are often stronger). a) Why are these athletes at a higher risk for injury? b) What joint is most likely to be injured? c) What type of injury might result at this joint?

The gluteus maximus is one of the strongest muscles in the body. a) What would happen to hip/thigh rotation if other muscles do not

compensate for this strength? b) Which muscles are the antagonists to hip extension by the glutius

maximus?

The TrunkMuscle/Group Origin Insertion Action Location

Rectus Abdominus Pubic crest Xyphoid process and inferior ribs

Flex trunk; expiration; “bearing down”

External ObliquesANDTransverse abdominis

Lower 8 ribs Pelvis Flex and rotate vertebrae; compress abdomen during expiration

Quadratus Lumborum

Pelvis and lumbar vert.

Lower rib and upper lumbar vert.

Extends and bends vert. column; helps with breathing

Erector Spinae

Diaphragm Sternum, ribs, lumbar vert.

Central tendon Respiration; anatomical border, separating thoracic and abdominal cavities

Intercostals Inferior of each rib

Superior of each rib

respiration Layers of muscle b/w each rib

Jeff sustained a serious injury to the left side of his trunk. What muscle group(s) are affected? What movements will be compromised?

What could happen if the diaphragm was punctured or torn in half?

A pregnant woman is in a car accident and sustains an injury to her rectus abdominus (baby is fine). What might be the consequences?

Shoulder and BackMuscle/group

Origin Insertion Action Location

Latissimus dorsi

Sacrum, lumbar, thoracic vert

Humerus Adduction, extension, interior rotation of arm

Pectoralis major

Clavicle, sternum, external obliques

Humerus Adduction, flexion, internal rotation of arm

Rotator Cuff (4 muscles)

Scapula Humerus Shoulder stabilization and rotation

Trapezius Base of occipital bone (head); cervical and thoracic vert.

Scapula and shoulder bone bones (acromion, clavicle)

Moves the scapula; extends the neck

Deltoids (anterior, lateral, posterior)

Clavicle, acromion, scapula

Humerus Flexion, extension, abduction and rotation of arm

Arm

Muscle/Group

Origin Insertion Action Location

Biceps brachiii

2 places on the scapula

Radius Elbow flexion; forearm supination

Triceps brachii

3 heads on posterior humerus

Ulna (olecranon- point of elbow)

Elbow extension

Hand Flexors

Elbow area Hand/fingers

Flex wrist, hand, fingers

Hand Extensors

Elbow area Hand/fingers

Extend wrist, hand, fingers

Joints

Types: Fibrous joints – no movement- eg sutures of the

skull Cartilaginous joints- some movement- eg between

the vertebrae Synovial joints- lots of movement

6 common types: Ball and socket (eg the hip, shoulder) Gliding (eg foot) Hinge (elbow, knee) Pivot (neck) Saddle (thumb) Ellipsoid (wrist)

Synovial Joints

Separated by a lubricating fluid and cartilage

Joined by ligaments that also help form the joint capsule (surrounds and protects joint)

Joint Injuries http://www.youtube.com/watch?v=9QTCBrefXso

Tendinitis Inflammation of a tendon via irritation due to

overuse/abnormal use Tx- rest, cold, heat therapy, anti-inflammatories

Tears, Sprains, Pulls Tear/pull= injury to muscle Sprain = injury to ligaments and tendons 3 levels of severity: 1st degree injury is mild; 2nd is moderate;

3rd is severe Dislocations

When bone displaced from original position Symptoms:

Joint looks awkward/deformed Painful to touch/move Inability to use joint

Injury Treatment

Recognizing an Injury SHARP

Swelling Heat Altered function Red Pain

Treating RICE

Rest Ice Compression Elevation

NEVER use heat to initially treat an injury Why?

How Can We Protect Our Joints?

strengthen surrounding muscles Stretch muscles Proper conditioning Warm up before exercising Proprioceptive training

Muscles Causing Movement at the Hip Joint Iliopsoas Adductor Muscles Gluteus Maximus Gluteus Medius

Muscles Causing Movement at the Knee Joint Sartorius Quadriceps Group

Rectus Femoris Vastus Muscles

Hamstring Group Biceps Femoris Semimembranosus

Semitendinosus Muscles Causing Movement at the Ankle and Foot Tibialis Anterior Peroneus Muscles Gastrocnemius