Chapter 10: The Muscular System

Comprehensive vocabulary flashcards covering the structural organization, naming, functional classifications, and regional muscle groups of the human muscular system based on Chapter 10 lecture notes.

Endomysium

A thin sleeve of loose connective tissue that surrounds each individual muscle cell (fiber).

Perimysium

A thicker layer of connective tissue that wraps muscle fibers into bundles called fascicles.

Epimysium

A fibrous connective tissue sheath surrounding the entire skeletal muscle.

Fascia

A sheet of connective tissue that separates neighboring muscles from each other and from the subcutaneous tissue.

Muscle Compartment

A group of functionally related muscles enclosed by fascia, which also contains their supplying nerves and blood vessels.

Indirect Muscle Attachment

A bony attachment where tendons bridge the gap between muscle and bone, with collagen fibers of the endo-, peri-, and epimysium continuing into the tendon, periosteum, and bone matrix.

Direct (Fleshy) Attachment

A muscle attachment to bone characterized by little microscopic separation, making the muscular tissue appear to emerge directly from the bone surface.

Intrinsic Muscle

A muscle that is entirely contained within a designated region and produces its action entirely within that same region (e.g., intrinsic hand muscles).

Extrinsic Muscle

A muscle that acts upon a designated region but originates or has its belly located in a different region (e.g., forearm muscles moving the fingers).

Origin

The bony attachment site located at the stationary, relatively immobile end of a muscle.

Belly

The thicker middle region of a muscle located between its origin and insertion.

Insertion

The bony attachment site located at the mobile, moving end of a muscle.

Prime Mover (Agonist)

The muscle primarily responsible for producing a specific, designated joint movement.

Synergist

A muscle that assists the prime mover in performing a specific action.

Antagonist

A muscle that opposes or resists the action produced by a prime mover.

Fixator

A muscle that prevents the movement of a bone, stabilizing the foundation for other muscle actions.

Muscle Innervation

The specific nerve that supplies and delivers electrical signals to stimulate a muscle to contract.

Facial Nerve (CN VII)

The cranial nerve that innervates the muscles of facial expression; damage or paralysis causes facial sagging.

Extrinsic Muscles of the Tongue

Muscles ending with the suffix "-glossus" that push food between the molars during mastication, prepare food for swallowing (deglutition), and produce movements necessary for speech.

Muscles of Mastication

The four pairs of muscles that produce biting and chewing movements of the mandible: temporalis, masseter, medial pterygoid, and lateral pterygoid.

Pharyngeal Constrictors

Three pairs of circular muscles (superior, middle, and inferior) encircling the throat into a funnel shape that contract sequentially during swallowing to propel food into the esophagus.

Diaphragm

The primary breathing muscle between the thoracic and abdominal cavities; its contraction flattens it to enlarge the thoracic cavity for inspiration, while its relaxation allows it to rise for expiration.

External Intercostals

Thoracic muscles located between the ribs that elevate the rib cage to expand the thoracic cavity, facilitating air inflow (inspiration).

Internal Intercostals

Thoracic muscles located between the ribs that depress the rib cage to compress the thoracic cavity, driving forced air expulsion (expiration).

External Abdominal Oblique

The outermost muscle layer of the lateral abdominal wall; flexes and rotates the vertebral column.

Internal Abdominal Oblique

The intermediate layer of lateral abdominal muscles beneath the external oblique; flexes and rotates the vertebral column.

Transverse Abdominal

The deepest muscle layer of the lateral abdominal wall; acts to compress underlying abdominal contents.

Rectus Abdominis

A paired vertical abdominal muscle enclosed by the rectus sheath, segmented by three transverse tendinous intersections; flexes the lumbar spine and produces forward bending at the waist.

Inguinal Hernia

The most common form of hernia, occurring when abdominopelvic viscera protrude through a weak point into the inguinal canal or scrotum.

Perineum

The diamond-shaped anatomical region spanning the pelvic floor between the genitals and the anus.

Urogenital Triangle

The anterior triangular division of the perineum containing the external genitalia and urethra.

Anal Triangle

The posterior triangular division of the perineum containing the anus and external anal sphincter.

Rotator Cuff (SITS) Muscles

A group of four scapular muscles—Supraspinatus, Infraspinatus, Teres minor, and Subscapularis—whose tendons reinforce and stabilize the glenohumeral joint by holding the humerus head inside the glenoid cavity.

Brachialis

The principal prime mover of forearm/elbow flexion, located in the anterior compartment of the arm.

Triceps Brachii

The principal prime mover of elbow extension, situated in the posterior compartment of the brachium.

Pronator Quadratus

The quadrilateral prime mover responsible for pronating the forearm, located near the wrist.

Supinator

A muscle located in the proximal forearm that acts to rotate the forearm laterally into the supine position.

Extensor Digitorum

The primary extensor muscle of the digits located in the posterior compartment of the forearm.

Carpal Tunnel

A tight passage between the carpal bones and the fibrous flexor retinaculum through which flexor tendons and the median nerve travel.

Carpal Tunnel Syndrome

A condition where swelling and inflammation of flexor tendon sheaths compress the median nerve, leading to pain, numbness, and tingling across the palm and fingers.

Iliopsoas

A composite muscle group consisting of the iliacus and psoas major that serves as the principal flexor of the thigh at the hip.

Gluteus Maximus

The largest and heaviest posterior hip muscle; acts as the prime hip extensor and provides primary lift when climbing stairs.

Medial Thigh Adductors

A collection of five muscles located in the medial compartment of the thigh that adduct the femur: adductor longus, adductor brevis, adductor magnus, gracilis, and pectineus.

Quadriceps Femoris Group

The primary extensor group of the knee located in the anterior thigh, consisting of the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius.

Hamstring Group

The primary knee flexor group located in the posterior thigh, composed from lateral to medial of the biceps femoris, semitendinosus, and semimembranosus.

Gastrocnemius and Soleus

Superficial posterior calf muscles that insert via the calcaneal tendon to execute plantar flexion of the foot.