A&P Muscle Functions

Lab 6 - Origin, Insertion, Action

Orbicularis Oculi

(A) Open / Close Eyes

Masseter

(O) Zygomatic Bone

(I) Angle & Ramus of Mandable

(A) Elevates Mandable at Jaw

Sternocleidomastoid

(O) Manubrium of the Sternal Medial Clavicle

(I) Inserts at the Mastoid Process of the Temporal Bone
(A) Rotates the Head and flexes Neck

Pectoralis Major

(A) Flex Shoulder & Rotate Arm at Shoulder

Latissimus Dorsi

(A) Adduct & Rotate Arm at Shoulder

Serratus Anterior

(A) Rotate Scapula and Elevate Ribs

Diaphragm

(A) Expands Thoratic Cavity with Inferior Contraction

Deltoid

(O) Calavice Spine & Acromion of the Scapula

(I) Deltoid Tuberosity of Humerus

(A) Abduct, Flex, Extend& Rotate Arm at Shoulder

Rotator Cuff Muscles

(O) Scapula

(I) Humerus

(A) Rotate Arm in all directions at Shoulder, Arm Circumduction

Biceps Brachii

(O) Supraglenoid Tubercle and Coracold Process of the Scapula

(I) Radial Tuberosity of Humerus

(A) Flex the Forearm at the Elebow and Supinate the Arm at Shoulder

Brachilis

(A) Synergist to Biceps Brachii

Triceps Brachii

(O) Infraglenoid Tubercle of Scapula and Posterior Surface of Humerus (I) Olecranon Process of Ulna
(A) Extend the Forearm at the Elbow and Extend Arm

Brachioradialis

(A) Flex the Forearm at the Elbow

Pronator Teres

(A) Pronates Forearm

Flexor Carpi Radialis

(O) Medial Epicondyle of Humerus

(I) Second and Third Metacarpals

(A) Flex and Abduct Wrist

Flexor Carpi Ulnaris

(O) Medial Epicondyle of Humerus Olecranon Process of Ulna

(I) Carpal Bones Fifth Metacarpal

(A) Flex and Abduct Wrist

Extensor Carpi Ulnaris

(A) Extends and Adducts Wrist

Extensor Digitorum

(A) Extends Didets

Extensor Carpi Radialis

(A) Extend and Abduct Wrist

Ilipsoas

(A) Flex Thigh and Trunk

Gluteus Maximus

(A) Extend, Abduct, Rotate Thigh at Hip

Quadriceps Femoris Group

(A) Extend Leg at Knee

Rectus Femoris

(O) Anterior Inferior Iliac spine of Ilium & Acetabulum of Coxal Bone

(I) Patella - tibial Tuberosity of Tibia

(A) Extend Leg at Knee

Adductor Longus

(A) Adduct Thigh at Hip

Hamstings Group

(A) Flex Leg at Knee and Rotate Thigh at Hip

Biceps Femoris

(A) Flex Leg at Knee and Rotate Thigh at Hip

Tibialis Anterior

(O) Lateral Condyle and Tibial Diaphysis of Tibia

(I) Tarsal Bone & First Meta Tarsal

(A) Dorsiflex foot at Ankle

Extensor Digitorum Longus

(A) Extend & Dorsiflex Toes

Gastrocnemius

(O) Lateral and Medial Condyles of Femur

(I) Calcaneus by way of Calcanal Tendon

(A) Plantar Flex Foot at Ankle

Soleus

(A) Plantar Flex Foot at Ankle

Skeletal Muscle Tissue

A type of muscle tissue that is under voluntary control, responsible for movement of the skeleton.

2 Key Charisticts include striations and multiple nuclei.

Cardiac Muscle Tissue

A type of muscle tissue found in the heart, responsible for involuntary contraction and pumping blood throughout the body. It is characterized by striations and intercalated disks between cells.

Smooth Muscle Tissue

A type of muscle tissue that is not under voluntary control, found in various organs and structures such as the intestines and blood vessels. It is characterized by a lack of striations and single, centrally located nuclei.

Dense Regular Tissue

A type of connective tissue characterized by closely packed collagen fibers aligned in parallel, providing strength and resistance to tensile forces. It is commonly found in tendons and ligaments.

Origin

The point at which a muscle attaches to a stationary bone, serving as the muscle's anchor during contraction.

Insertion

The point at which a muscle attaches to a movable bone, allowing for movement during contraction.

Action

The specific movement produced by a muscle when it contracts, often described in terms of the direction and type of movement generated at a joint.

Belly

The main fleshy part of a muscle, located between the origin and insertion, which contains the muscle fibers responsible for contraction.

Agonists

Muscles that primarily cause a specific movement by contracting, often working in opposition to antagonists.

Antagonists

Muscles that oppose the action of agonists by relaxing and lengthening during movement, allowing for smooth and controlled motion.

Synergists

Muscles that assist agonists in performing a movement by helping to stabilize or reduce unwanted movements.

Fixators

Muscles that stabilize a joint or body part during movement, ensuring that agonists can function effectively without unwanted movements by providing strength and stability

Prime Mover

The chief muscle responsible for a specific movement, typically the one that produces the most force during that action. It directly engages in the desired movement, functioning as the primary agent of motion.