Final test review!! (Muscles)

Muscle tissue

Consists of all contractile tissues (skeletal, cardiac, and smooth muscle)

Muscles

Can only pull; never push

Prime mover (agonist)

Major responsibility for producing a specific movement

Antagonist

Opposes or reverses a particular movement

Prime mover and antagonist location

Located on opposite sides of the joint across which they act

Synergist

Helps prime movers; adds extra force to same movement; reduces undesirable or unnecessary movement

Fixators

Type of synergist that immobilizes bone or muscle's origin, giving the prime mover a stable base on which to act

Muscle location (naming criterion)

Named for the bone or body region associated (e.g., temporalis over temporal bone)

Muscle shape (naming criterion)

Named for distinctive shapes (e.g., deltoid = triangle)

Muscle size (naming criterion)

Example: maximus (largest), minimus (smallest), longus (long)

Direction of muscle fibers or fascicles (naming criterion)

Example: rectus (fibers run straight), transversus (fibers run at right angles), oblique (fibers run at angles)

Number of origins (naming criterion)

Example: biceps (two origins), triceps (three origins)

Location of attachments (naming criterion)

Named according to origin and insertion (origin named first) (e.g., sternocleidomastoid attaches to sternum and clavicle, inserts on mastoid process)

Muscle action (naming criterion)

Named for the action they produce (e.g., flexor or extensor)

Fascicles

Bundles of muscle fibers that make up skeletal muscles

Common fascicle arrangements

Circular, convergent, parallel, fusiform, and pennate

Fascicles determine

____ ____ the muscle's range of motion (movement when shortened) and muscle's power

Lever system

Most skeletal muscles move using leverage

Lever

Rigid bar (bone) that moves on a fixed point called a fulcrum (joint)

Fulcrum

Fixed point on which the lever (bone) moves

Effort

Force supplied by muscle contraction

Load

Resistance (bone, tissue, or added weight)

Mechanical advantage (power lever)

Load is close to fulcrum and effort applied far; slower but stronger; used when strength is a priority

Mechanical disadvantage (speed lever)

Load is far from fulcrum and effort applied near; less force, but more speed and range of motion

First-class lever

Fulcrum is between load and effort (example: seesaw, scissors)

Second-class lever

Load is between fulcrum and effort (example: wheelbarrow, standing on toes)

Third-class lever

Effort is between fulcrum and load (example: tweezers, most skeletal muscles)

Facial expression muscles

Insert into skin, not bone; important for nonverbal communication; all innervated by cranial nerve VII (facial nerve)

Suprahyoid muscles

Four deep muscles involved in swallowing; move hyoid bone and larynx; form floor of oral cavity; anchor tongue; elevate hyoid bone

Infrahyoid muscles

Four straplike muscles; depress hyoid bone and larynx during swallowing and speaking

Inspiration (inhaling)

One of the two phases of breathing (1st)

Expiration (exhaling)

One of the two phases of breathing (2nd)

Inspiratory muscles

Diaphragm and external intercostals; their contraction enlarges the rib cage

Diaphragm

Divides thoracic and abdominal cavities

Expiration mechanism

Caused by relaxation of inspiratory muscles and contraction of internal intercostals; decreases rib cage size

Muscles of the pelvic diaphragm

Levator ani and coccygeus; support pelvic organs, resist pressure, lift pelvic floor to release feces

Extrinsic shoulder muscles

Fix the scapula and move it to increase range of arm movements; perform elevation, depression, rotation, protraction, and retraction

Nine muscles crossing shoulder joint

Insert on and move the humerus; originate from scapula or axial skeleton; perform flexion, extension, and adduction

Three prime movers of the arm (shoulder joint)

Pectoralis major, Latissimus dorsi, and Deltoid

Rotator cuff muscles

Supraspinatus, Infraspinatus, Teres minor, and Subscapularis; stabilize shoulder joint and prevent dislocation

Coracobrachialis and teres major

Synergists to the prime movers of the arm

Anterior forearm muscles

Mostly flexors; insert via flexor retinaculum

Posterior forearm muscles

Mostly extensors; insert via extensor retinaculum

Pronator teres and pronator quadratus

Muscles that pronate the forearm

Supinator

Synergist with biceps brachii in forearm supination

Intrinsic muscles of the hand

Cause fine finger movements; include Thenar eminence, Hypothenar eminence, and Midpalmar muscles

Thenar eminence

Ball of thumb; includes flexor, abductor, and opponens muscles

Hypothenar eminence

Ball of the little finger; includes flexor, abductor, and opponens muscles

Lumbricals and interossei

Midpalmar muscles ; extend fingers

Interossei muscles

Abduct and adduct fingers

Thigh muscle groups

Divided into anterior, medial, and posterior compartments

Most anterior thigh muscles

Flex femur at hip and extend leg at knee (foreswing of walking)

Most posterior thigh muscles

Extend thigh and flex leg (backswing of walking)

Medial thigh muscles

Adduct thigh

Fascia lata

Fibrous connective tissue that encloses all three thigh muscle groups

Thigh flexors

Pass in front of hip joint; include Iliopsoas, Tensor fasciae latae, and Rectus femoris; assisted by medial adductors and sartorius

Iliopsoas (iliacus and psoas major)

Prime mover of hip flexion

Thigh extensors

Hamstring muscles are the prime movers of thigh extension

Adductors (medial thigh muscles)

Medially rotate the thigh and press thighs together

Adductor muscles

Adductor magnus, Adductor longus, Adductor brevis, Pectineus, and Gracilis

Pulled groin

Overstretched or torn thigh adductor muscles

Quadriceps femoris

Four-headed muscle; powerful knee extensor

Quadriceps femoris insertion

Insert into quadriceps tendon → patella → patellar ligament → tibial tuberosity

Anterior compartment of the leg

Muscles that dorsiflex the ankle

Lateral compartment of the leg

Muscles that plantar flex and evert the foot

Posterior compartment of the leg

Muscles that plantar flex the ankle; all innervated by the tibial nerve; divided into superficial and deep groups

Intrinsic muscles of the foot

Responsible for toe movement and arch support; consist of four plantar layers (superficial to deepest)

minimus

smallest

Tensor fascia lata

a muscle that stretches a part + bandage + side

Quadriceps femoris

four + heads + thigh

Vastus

large

lateralis

side

medialis

middle

intermedius

in between

Rectus femoris

straight + thigh

Biceps femoris

two + heads + thigh

Semitendinosus

half tendon

Semimembranosus

half membrane

Gracilis

slender, thin

Sartorius

to mend or patch; tailor's muscle

Adductor femoris

to lead to

longus (Adductor femoris)

long

brevis (Adductor femoris)

short

magnus (Adductor femoris)

big

Pectineus

honey-comb

Tibialis anterior

shin + front

Peroneus longus

fibula + long

Extensor digitorum (Lower leg)

extend + fingers

Gastrocnemius

belly + leg

Soleus

alone

Rectus superior

above

Rectus inferior

below

Rectus medial

middle

Rectus lateral

side

Oblique superior

above

Oblique inferior eye

below

Coracobrachialis

raven's beak + upper arm

Epitrochlearis

upon + pulley

Latissimus dorsi

side + back

Biceps brachii

two + head + arm