Human Anatomy – Chapter 11 Part 1: Muscles of the Body

Vocabulary flashcards covering fascicle arrangements, muscle actions and interactions, limb compartments, major skeletal muscles, respiratory and abdominal muscles, and key movement terminology from Chapter 11 Part 1: Muscles of the Body.

Fascicle

A bundle of skeletal muscle fibers wrapped by connective tissue.

Circular muscle

Muscle whose fascicles form concentric rings around an opening; acts as a sphincter (e.g., orbicularis oculi).

Convergent muscle

Muscle with broad origin and fascicles that converge toward a single tendon of insertion (e.g., pectoralis major).

Parallel muscle

Muscle whose fascicles run parallel to the long axis; includes fusiform (biceps brachii) and straplike (sartorius).

Pennate muscle

Muscle with short fascicles attaching obliquely to a long tendon; can be uni-, bi-, or multipennate (e.g., deltoid).

Unipennate

Pennate muscle with fascicles on one side of the tendon (e.g., extensor digitorum longus).

Bipennate

Pennate muscle with fascicles on both sides of the tendon (e.g., rectus femoris).

Multipennate

Pennate muscle with fascicles attaching to one large central tendon from many directions (e.g., deltoid).

Agonist (prime mover)

Muscle chiefly responsible for producing a particular movement.

Antagonist

Muscle that opposes or reverses the action of an agonist.

Synergist

Muscle that aids a prime mover by adding force or reducing undesirable movements.

Muscle compartment

Group of muscles in a limb surrounded by deep fascia that share similar functions, blood supply, and innervation.

Anterior arm compartment

Contains elbow flexors (biceps brachii, brachialis); innervated by musculocutaneous nerve.

Posterior arm compartment

Contains elbow extensors (triceps brachii); innervated by radial nerve.

Anterior forearm compartment

Houses wrist/digital flexors and pronators; innervated by median or ulnar nerve.

Posterior forearm compartment

Houses wrist/digital extensors; innervated by radial nerve.

Anterior thigh compartment

Contains hip flexors/knee extensors; innervated by femoral nerve.

Posterior thigh compartment

Contains hip extensors/knee flexors; innervated by tibial branch of sciatic nerve.

Medial thigh compartment

Contains thigh adductors; innervated by obturator nerve.

Anterior leg compartment

Contains ankle dorsiflexors/digital extensors; innervated by deep fibular nerve.

Posterior leg compartment

Contains ankle plantar flexors/digital flexors; innervated by tibial nerve.

Lateral leg compartment

Contains evertors/plantar flexors of foot; innervated by superficial fibular nerve.

Deltoid

Multipennate shoulder muscle; prime mover of arm abduction.

Pectoralis major

Convergent chest muscle; prime mover of arm flexion and adduction.

Latissimus dorsi

Broad back muscle; prime mover of arm extension and adduction.

Rotator cuff

Group of four muscles (supraspinatus, infraspinatus, teres minor, subscapularis) stabilizing the glenohumeral joint.

Biceps brachii

Anterior arm muscle; flexes elbow and supinates forearm.

Triceps brachii

Posterior arm muscle; prime mover of elbow extension.

Brachialis

Deep to biceps; strong elbow flexor.

Brachioradialis

Forearm muscle on lateral radius; flexes elbow.

Pronator teres

Superficial anterior forearm muscle; pronates forearm.

Pronator quadratus

Deep anterior forearm muscle; primary forearm pronator.

Supinator

Deep posterior forearm muscle; assists in forearm supination.

Flexor carpi radialis

Anterior forearm muscle; flexes and abducts hand at wrist.

Flexor carpi ulnaris

Anterior forearm muscle; flexes and adducts hand at wrist.

Palmaris longus

Anterior forearm muscle; tenses palmar fascia.

Flexor digitorum superficialis

Anterior forearm muscle; flexes wrist and middle phalanges of fingers 2–5.

Flexor digitorum profundus

Deep anterior forearm muscle; flexes distal interphalangeal joints.

Flexor pollicis longus

Deep anterior forearm muscle; flexes thumb.

Extensor digitorum

Superficial posterior forearm muscle; prime mover of finger extension.

Extensor carpi radialis longus

Posterior forearm muscle; extends and abducts wrist.

Extensor carpi ulnaris

Posterior forearm muscle; extends and adducts wrist.

Abductor pollicis longus

Deep posterior forearm muscle; abducts and extends thumb.

Extensor pollicis brevis/longus

Deep posterior muscles; extend thumb joints.

Extensor indicis

Deep posterior forearm muscle; extends index finger.

Flexor retinaculum

Fibrous band on anterior wrist anchoring flexor tendons.

Extensor retinaculum

Fibrous band on posterior wrist anchoring extensor tendons.

Thenar muscles

Intrinsic hand muscles at thumb base (abductor, flexor, opponens pollicis, adductor pollicis).

Hypothenar muscles

Intrinsic hand muscles at little-finger base (abductor, flexor, opponens digiti minimi).

Midpalmar muscles

Intrinsic hand group including lumbricals and palmar/dorsal interossei for fine finger movements.

Orbicularis oris

Circular muscle around the mouth; closes and protrudes lips.

Orbicularis oculi

Circular muscle around the eye; closes eyelids.

Zygomaticus major

Muscle extending from cheekbone to mouth; raises corners of mouth (smiling).

Buccinator

Cheek muscle; compresses cheek (whistling) and assists in chewing.

Masseter

Powerful jaw-closing muscle; prime mover of mastication.

Temporalis

Fan-shaped muscle on side of skull; elevates and retracts mandible.

Medial/Lateral pterygoids

Deep mastication muscles; provide side-to-side grinding of mandible.

Sternocleidomastoid

Paired neck muscle; flexes head (bilateral) and rotates/laterally flexes head (unilateral).

Scalenes

Deep neck muscles; aid in lateral flexion and head rotation and elevate first two ribs during inspiration.

Trapezius

Large superficial back muscle; elevates, retracts, rotates scapula; extends head.

Levator scapulae

Posterior neck muscle; elevates and downwardly rotates scapula.

Rhomboid major/minor

Deep to trapezius; retract and stabilize scapula.

Serratus anterior

Lateral thoracic muscle; protracts and upwardly rotates scapula (boxer’s muscle).

Pectoralis minor

Thin chest muscle; protracts and depresses scapula.

Subclavius

Small muscle under clavicle; stabilizes and depresses pectoral girdle.

Erector spinae

Iliocostalis, longissimus, spinalis muscle columns; prime movers of trunk extension and lateral flexion.

Quadratus lumborum

Posterior abdominal wall muscle; lateral flexion of vertebral column.

External intercostals

Superficial rib muscles; elevate ribs during inspiration.

Internal intercostals

Deep rib muscles; depress ribs during forced expiration.

Diaphragm

Primary muscle of respiration; flattens to enlarge thoracic cavity on inspiration.

External oblique

Largest superficial abdominal wall muscle; fibers run inferomedially; trunk flexion & rotation.

Internal oblique

Middle abdominal muscle; fibers run superomedially; aids flexion & rotation.

Transversus abdominis

Deep abdominal muscle; horizontal fibers; compresses abdominal contents.

Rectus abdominis

Medial vertical abdominal muscle (“six-pack”); trunk flexion.

Linea alba

Midline tendinous seam uniting abdominal muscles from sternum to pubic symphysis.

Aponeurosis

Broad sheet-like tendon connecting muscles to each other or to bone (e.g., abdominal wall).

Pectoral girdle

Bones and joints of shoulder; attachment site for thoracic muscles controlling scapula.

Flexion

Movement that decreases the angle between two body parts (e.g., bending elbow).

Extension

Movement that increases the angle between body parts (e.g., straightening knee).

Abduction

Movement away from the body’s midline (e.g., raising arm laterally).

Adduction

Movement toward the body’s midline (e.g., lowering arm).

Pronation

Rotating forearm so palm faces posteriorly or downward.

Supination

Rotating forearm so palm faces anteriorly or upward.

Dorsiflexion

Lifting the foot so its superior surface approaches shin.

Plantar flexion

Depressing foot toward the sole (pointing toes).