Muscle Anatomy and Function

Flashcards covering key muscles, their origins, insertions, actions, innervation, and antagonists.

Biceps brachii

A muscle located in the upper arm that is responsible for flexion at the elbow and shoulder.

Origin of Biceps brachii

Coracoid process (short head) and tubercle of the scapula (long head).

Insertion of Biceps brachii

Tuberosity of the Radius.

Action of Biceps brachii

Flexion at elbow and shoulder.

Innervation of Biceps brachii

C5-C6 spinal nerves.

Antagonist of Biceps brachii

Triceps brachii.

Triceps brachii

A muscle located in the back of the upper arm that is responsible for extension at the elbow.

Origin of Triceps brachii

Superior, lateral humerus.

Insertion of Triceps brachii

Olecranon of Ulna.

Action of Triceps brachii

Extension at the elbow.

Innervation of Triceps brachii

C6-C8 spinal nerves.

Antagonist of Triceps brachii

Biceps brachii.

Supinator

A muscle that assists in the supination of the forearm.

Origin of Supinator

Lateral epicondyle of humerus and radial notch.

Insertion of Supinator

Radius.

Action of Supinator

Supination.

Innervation of Supinator

C6-C8 spinal nerves.

Antagonist of Supinator

Pronator teres.

Pronator teres

A muscle that assists in the pronation of the forearm.

Origin of Pronator teres

Medial epicondyle of humerus and coronoid process.

Insertion of Pronator teres

Radius.

Action of Pronator teres

Pronation.

Innervation of Pronator teres

C7 spinal nerve.

Antagonist of Pronator teres

Supinator.

Sternocleidomastoid

A muscle that flexes the neck and turns the head.

Origin of Sternocleidomastoid

Clavicular head (sternal end of clavicle) and sternal head.

Insertion of Sternocleidomastoid

Mastoid process of the skull.

Action of Sternocleidomastoid

Flex neck, bend head, turn face.

Innervation of Sternocleidomastoid

C2-C3 spinal nerves.

Longus capitis

A muscle that assists in flexing the head and neck.

Iliopsoas

A major hip flexor muscle comprising psoas major and iliacus.

Origin of Iliopsoas

Psoas major and iliacus muscles.

Insertion of Iliopsoas

Lesser trochanter of femur.

Action of Iliopsoas

Flexion at the hip.

Innervation of Iliopsoas

L2-L3 spinal nerves.

Gluteus maximus

The largest muscle in the buttock that aids in hip extension.