Muscular System (Gross Anatomy) — Key Vocabulary

A set of vocabulary-style flashcards covering core terms and concepts from the gross anatomy of the muscular system, including muscle terminology, naming conventions, lever mechanics, major muscle groups, and key muscles and anatomical features mentioned in the notes.

Origin

Muscle end attached to the more stationary of two bones.

Insertion

Muscle end attached to the bone with the greatest movement.

Belly

The largest portion of a muscle between its origin and insertion.

Tendons

Connective tissue that attach muscles to bones.

Aponeurosis

A very broad tendon.

Agonist

Muscle that, when it contracts, produces a specific movement.

Antagonist

Muscle that opposes the action of the agonist.

Synergist

Muscle that assists a prime mover to produce a movement.

Prime mover

Muscle that plays the major role in accomplishing a movement.

Fixator

Muscle that stabilizes the joint or origin of the prime mover to prevent movement.

Lever

A system with a fulcrum, weight, and pull to move a load; a basic mechanical model of body movement.

Fulcrum

The pivot point on a lever; in the body, often a joint.

Weight

The load being moved in a lever system.

Pull

The force produced by muscle contraction that moves the weight.

Class I lever

Fulcrum between force and weight; example: head at the atlantooccipital joint.

Class II lever

Weight between fulcrum and pull; example: wheelbarrow; e.g., standing on toes.

Class III lever

Pull between fulcrum and weight; example: biceps brachii with elbow as fulcrum.

Muscle naming — Location

Names indicate anatomical location (e.g., pectoralis, gluteus, brachial).

Muscle naming — Size

Names indicate size (e.g., maximus, minimus, longus, brevis).

Muscle naming — Shape

Names indicate shape (e.g., deltoid, quadratus, teres).

Muscle naming — Orientation of fascicles

Names indicate fascicle direction (e.g., rectus, oblique).

Muscle naming — Origin and insertion

Names may reflect origin and insertion (e.g., sternocleidomastoid).

Muscle naming — Number of heads

Names indicate number of muscle heads (e.g., biceps, triceps).

Muscle naming — Function

Names indicate function (e.g., extensor, abductor, adductor).

Anterior neck muscles (function)

Function primarily in lateral head movements.

Deep neck muscles

Located along the anterior margins of the vertebral bodies; function in flexion.

Posterior neck muscles

Attached to the occipital bone; function in extension.

Muscles of facial expression

Cutaneous muscles with origins and insertions in superficial fascia; move the skin; confined to head and neck.

Mastication

Chewing; involves elevation/depression of the mandible and grinding; aided by hyoid muscles.

Suprahyoid muscles

Group of muscles superior to the hyoid that can depress the mandible when the hyoid is fixed.

Infrahyoid muscles

Group of muscles inferior to the hyoid that stabilize the hyoid from below.

Thyrohyoid

An infrahyoid muscle that can elevate the larynx when the hyoid is fixed.

Intrinsic tongue muscles

Muscles found entirely within the tongue.

Extrinsic tongue muscles

Muscles found outside the tongue but attached to it.

Tongue roles in mastication and speech

Manipulates food, holds it, pushes it to palate and pharynx, and modifies sound during speech.

Swallowing and the larynx — palatopharyngeus

Elevates the pharynx during swallowing.

Swallowing and the larynx — salpingopharyngeus

Constricts the pharynx to guide food into the esophagus.

Retinacula

Bands of deep fascia that hold tendons close to the wrist; include flexor and extensor retinacula.

Flexor retinaculum

Transverse carpal ligament on the flexor (anterior) aspect of the wrist.

Extensor retinaculum

Dorsal carpal ligament on the extensor (posterior) aspect of the wrist.

Rotator cuff muscles

Primary muscles holding the humeral head in the glenoid cavity: infraspinatus, subscapularis, supraspinatus, teres minor.

Forearm movements — flexion

Flexion of the elbow produced by biceps brachii, brachialis, and brachioradialis.

Forearm movements — extension

Extension of the elbow produced by triceps brachii and anconeus.

Forearm movements — supination

Supination of the forearm produced by supinator and biceps brachii.

Forearm movements — pronation

Pronation of the forearm produced by pronator quadratus and pronator teres.

Wrist, hand, and finger muscles — anterior surface

Flexion and abduction/adduction of the wrist.

Wrist, hand, and finger muscles — posterior surface

Extension and abduction of the wrist.

Intrinsic hand muscles

Muscles found entirely within the hand; move the fingers.

Compartment of the thigh — anterior

Flex the hip and/or extend the knee; includes quadriceps and sartorius.

Compartment of the thigh — medial

Adduct the thigh; includes adductor group, gracilis, pectineus.

Compartment of the thigh — posterior

Extend the hip and flex the knee; includes the hamstrings.

Quadriceps femoris

Group on the anterior thigh; extends the leg; rectus femoris can flex the hip; insert via the patellar tendon.

Rectus femoris

Part of quadriceps; also flexes the hip.

Sartorius

Flexes the hip and knee; laterally rotates the thigh.

Patellar tendon

Extends from the patella to the tibial tuberosity; part of the quadriceps insertion mechanism.

Adductor group

Medial thigh muscles that adduct the thigh.

Gracilis

Medial thigh muscle contributing to adduction.

Pectineus

Medial thigh muscle contributing to adduction.

Hamstrings

Posterior thigh muscles that extend the hip and flex the knee.

Gastrocnemius

Superficial posterior leg muscle; plantar flexes the foot; part of the Achilles tendon.

Calcaneal (Achilles) tendon

Common tendon for plantar flexors of the foot.

Plantaris

Small posterior leg muscle with tiny role in plantar flexion.

Anterior leg compartment

Extensors; dorsiflexion and toe extension; includes dorsiflexors.

Lateral leg compartment

Plantar flexion and eversion of the foot.

Posterior leg compartment

Superficial muscles perform plantar flexion (Achilles tendon); deep muscles plantar flex and invert.

Plantar aponeurosis

Deep fascia thickened into a plantar fascia supporting the sole of the foot.