Skeletal Muscles Review

If an anterior muscle contracts it flexes the segment around the horizontal axis of rotation.

If a posterior muscle contracts it extends the segments around the horizontal axis of rotation.

Skeletal Muscle

• It causes a muscle to contract.

• A muscle must cross a joint to move the joint

• Most anterior muscles are flexors and medial rotators EXCEPTION: KNEE DOWN

• Most posterior muscles are extensors and lateral rotators, EXCEPTION KNEE DOWN

• Muscles superior to the joint are abduction.

• Muscles inferior to the joint are adduction.

ATTACHMENT SITE

• Origin- Fixed point, acts like the anchor

• Insertion- moves towards the origin, one pulling bone, bone that gets pulled

• Agonist- muscle involved in the characteristic movement of the joint.

• Antagonist- the muscle that works against/opposes the agonist, opposite function same joint.43

• Ex triceps and biceps branchii

Muscles of Facial Expression

1. Frontalis

2. Orbicularis oculi

3. orbicularis oris

4. zygomaticus minor and major- Smile

5. buccinator- expand cheeks

6. Levator labii superioris- raised upper lip

7. Depressor labii

Muscles of Mastication

1. Temporalis- Origin- Temporal and frontal bone suture, Insertion- mandible angle

2. MASSETER - ORIGIN- ZYGOMATIC ARCH, INSERTION- MANDIBLE, LEAD TO CHEWING.

3. Both these muscles work the TMJ ( Temporomandibular joint)

Anterior neck muscles-

1. suprahyoid muscles- elevate hyoid bone, depress the mandible

2. infrahyoid muscles- depress hyoid bone, elevates pharynx and larynx.

3. Sternocleidomastoid- Head and neck rotator. Flexor/lateral flexor rotates head left and right and back and forth.

Muscles of the tongue- move the tongue

Extrinsic eye muscles- control the direction of eye movement

Muscles of the Pharynx and larynx- control voice, pitching, and opening

Posterior muscles of the neck- head and neck extensors

Vertebral column muscles

- Group function- extends trunk/Keeps it erect

Anterior Body Wall Muscles

1. Rectus Abdominis- trunk floor

2. External oblique-trunk rotation

3. Internal oblique-trunk rotation

4. Transverse abdominis- flattens stomach

5. External and internal intercostals- Maintain space between ribs expand and contract for breathing.

6. Diaphragm- Breathing in the diaphragm contract- flattens to allow lung expansion. Breathing out diaphragm relaxes- and expands to push air out of the lungs.

   Located directly inferior to lungs

Pelvic Floor Muscles

1. Urethral Sphincter- Controls urination

2. Anal Sphincter- Controls defecation

Anterior Trunk Muscles

1. Serratus Anterior- Shoulder/ Scapular protraction, ANTAGONIST: RHOMBOID GROUP, weak serratus anterior results in a winged scapula.

2. Pectoralis Major- Moves shoulder, Horizontal adduction, and medial rotation.

Posterior Trunk Muscles

• Trapezius - Elevates, retracts, and rotates the scapula; important for shoulder movement and stability.

• Latissimus Dorsi - Extends, adducts, and medially rotates the arm; plays a key role in pulling movements.

• Levator Scapulae- Shoulder/ Scapula elevation, deep to trapezius

• Rhomboid Group ( Major and minor)- Moves scapula retraction, ANTAGONIST TO Serratus ANTERIOR

Shoulder and rotator cuff muscles

1. Accessory muscles- Rotator cuff

2. Deltoid- Shoulder abduction primary action, works around all axes of rotation. ANTAGONIST-LATISSSMIS DORSII

3. Muscles (SITS)- Joint protectors and stabilizers

   1. Supraspinatus- Shoulder adduction

   2. Infraspinatus-shoulder lateral rotation

   3. Teres Minor- shoulder lateral rotation

   4. Subscapularis- Medial rotation ( anterior)

Anterior arm muscles

1. Biceps Brachii- Main movement elbow flexion some shoulder flexion and supination, ANTAGONIST TRICEPS BRACHII

2. Brachialis- elbow flexors, lateral

3. Coracobrachialis- shoulder flexor, medial.

Posterior arm muscles

1. Triceps brachii- arm and forearm extensors, ANTAGONIST- BICEPS BRACHII

Anterior Forearm Muscles

1. Pronator teres- pronation

2. Flexor carpi radials- wrist flexion

3. Flexor carpi ulnaris- Wrist flexion flexion

4. Brachioradialis- Handshake muscle Deep muscles

5. Flexor Pollicis longus- Flex thumb

6. Flexor digitorum- Digit/ finger flexion

Posterior Forearm Muscles

Superfical

• Extensor Carpi Radialis Longus - Wrist extension and abduction

• Extensor Carpi Radialis Brevis - Wrist extension

• Extensor Carpi Ulnaris - Wrist extension and adduction

• Extensor Digittorum- Finger extension

Deep

1. Adductor Pollicis longus- Thumb adduction

2. Extensor Pollcis brevis- thumb extension

Deeper

Supinator- supination

Hand Muscles

1. Palmar surface- flexor

2. Dorsal surface- extensor

Gluteal Muscles

1. Gluteus Maximus- Hip extension, lateral rotation

2. Gluteus Medius- hip extension, some abduction

3. Piriformis- Hip abduction, lateral rotation

4. Gluteus Minimus- Hip adduction, hip extension

Pelvis Muscles

hip flexors

1. iliacus

2. Psoas Major

3. Gracilis- knee movement and adduction

Pelvis and medial thigh Muscles

Medial rotation

Adductor Group

1. Pectineus - assists in hip flexion and adduction

2. Adductor Longus - primarily involved in hip adduction and flexion

3. Adductor Brevis - works alongside the longus for hip adduction

4. Adductor Magnus - has both adductor and hamstring components, contributing to hip adduction and extension.

Posterior Thigh Muscles

Movement- knee flexion, hip extension

Origin- ischium

Insertion- posterior tibia

1. Includes- Semimembranosus, semitendinosus, biceps femoris

Anterior Thigh Muscles

Quadriceps group ( ONLY group that extends the knee)

1. Rectus femoris- Knee extension

2. Vastus Lateralis -Knee extension

3. Vastus medialis - Knee extension

4. Vastus Intermedius- knee extension

5. Sartorius- Knee Flexion ( ONLY ONE IN GROUP WITH KNEE FLEXION)

Anterior leg muscles ( AFTER THE KNEE DOWN THEY FLIP WITH FLEXION AND EXTENSION

1. Tibialis anterior- ankle extension(dorsiflexion)

2. Extensor digitorum longus- extend toes

3. Extensor hallucis longus- Hallux extension of BIG TOE

Lateral Leg Muscles ( FLEXION FOR BOTH OF THESE MUSCLES)

1. Fibularis longus - plantar flexion

2. Fibularis brevis- plantar flexion

Posterior Leg muscles

1. Gastrocnemius( Attach to achillies)- Plantar flexion

2. Soleus- Plantar Flexion

3. Flexor Digitorum longus- toe flexion

4. Flexor Hallucis longus- hallux flexion

Foot Muscles

Dorsal- toe extension

Plantar- Toe flexion 2

Ankle Flexion- Ankle flexion refers to the movement where the foot moves upward toward the shin, which is technically called dorsiflexion.

Plantar flexion- Plantar flexion is when the foot moves downward, away from the shin—essentially pointing the toes downward. This is the action you see when you're standing on your toes.

Dorsiflexion: This is when the foot moves upward (toward the shin). It's like when you're lifting your foot off the ground to take a step or when you pull your toes toward your shin.

The hypothenar and thenar can be found in the palmar surface of the hand.

Tensor fasciae latte- hip extension, rotation, and abduction

Glossus= tongue