Human Anatomy – Axial Musculature

Vocabulary flashcards covering key muscles, groupings, functions, and innervations of the axial musculature from Chapter 10 of Human Anatomy, Ninth Edition.

Axial musculature

Skeletal muscles that position the head and vertebral column and move the rib cage.

Appendicular musculature

Skeletal muscles that stabilize or move the limbs and girdles of the appendicular skeleton.

Four groups of axial muscles

Head & neck; vertebral column; rib cage & abdominal/pelvic walls; pelvic floor.

Muscles of facial expression

Five regional groups of muscles (mouth, eyes, scalp, nose, neck) innervated by CN VII.

Extra-ocular muscles

Small muscles that move the eyeball within the orbit.

Muscles of mastication

Masseter, temporalis, and pterygoids; chew food; innervated by CN V.

Muscles of the tongue

Genioglossus, hyoglossus, palatoglossus, styloglossus; control tongue movements.

Muscles of the pharynx

Muscles that initiate swallowing and move the pharyngeal walls.

Anterior muscles of the neck

Suprahyoid and infrahyoid muscles that move the hyoid, larynx, or head.

Orbicularis oris

Circular muscle around the mouth; closes and purses the lips.

Buccinator

Cheek muscle; compresses cheek (e.g., blowing, sucking).

Temporoparietalis

Thin scalp muscle; tenses scalp and moves auricle of the ear.

Occipitofrontalis

Scalp muscle with frontal and occipital bellies; raises eyebrows, wrinkles forehead.

Platysma

Superficial neck muscle; tenses skin of neck, depresses mandible.

Cranial nerve VII (Facial nerve)

Innervates all muscles of facial expression.

Masseter

Powerful jaw elevator; closes mandible during chewing.

Temporalis

Broad temporal muscle; elevates and retracts mandible.

Pterygoids

Medial & lateral pairs; elevate, protract, or slide mandible side-to-side.

Cranial nerve V (Trigeminal nerve)

Motor nerve to all muscles of mastication.

Genioglossus

Tongue muscle; protracts and depresses tongue.

Hyoglossus

Flattens and depresses sides of tongue.

Palatoglossus

Elevates posterior tongue; helps initiate swallowing.

Styloglossus

Retracts and elevates tongue.

Digastric

Two-bellied suprahyoid muscle; depresses mandible, elevates hyoid.

Sternocleidomastoid

Neck muscle; flexes neck, rotates head to opposite side.

Omohyoid

Infrahyoid muscle with superior & inferior bellies; depresses hyoid bone.

Sternohyoid

Infrahyoid muscle; depresses hyoid after swallowing.

Sternothyroid

Infrahyoid muscle; depresses thyroid cartilage (larynx).

Thyrohyoid

Elevates larynx or depresses hyoid depending on fixation.

Superficial layer (extrinsic back)

Muscles that primarily move the neck; include splenius group.

Intermediate layer (extrinsic back)

Muscles that move the vertebral column; include erector spinae.

Deep layer (intrinsic back)

Short muscles that interconnect and stabilize vertebrae.

Splenius capitis

Superficial intrinsic muscle; extends, rotates, or laterally flexes head.

Splenius cervicis

Works with splenius capitis to extend or rotate cervical spine.

Erector spinae

Intermediate intrinsic group (spinalis, longissimus, iliocostalis) that extends vertebral column.

Spinalis

Medial column of erector spinae; extends spine.

Longissimus

Middle column of erector spinae; extends spine, laterally flexes torso.

Iliocostalis

Lateral column of erector spinae; extends and laterally flexes vertebral column.

Scalene muscles

Anterior, middle, posterior; elevate first two ribs during inhalation, flex neck.

Intercostal muscles

External and internal layers between ribs; move rib cage in breathing.

External intercostal

Elevates ribs; aids inhalation.

Internal intercostal

Depresses ribs; aids forced exhalation.

Transversus thoracis

Thin thoracic wall muscle; depresses ribs.

Serratus posterior superior

Upper thoracic muscle; elevates ribs.

Serratus posterior inferior

Lower thoracic muscle; depresses ribs.

External oblique

Superficial abdominal muscle; compresses abdomen, depresses ribs, lateral trunk flexion.

Internal oblique

Middle abdominal layer; functions like external oblique.

Transversus abdominis

Deep abdominal layer; compresses abdomen.

Rectus abdominis

Midline abdominal muscle; flexes vertebral column, depresses ribs.

Diaphragm

Primary breathing muscle; contraction lowers floor of thoracic cavity for inhalation.

Linea alba

Fibrous midline structure formed by fusion of abdominal aponeuroses.

Perineal region

Muscular pelvic floor divided into urogenital and anal triangles.

Urogenital triangle

Anterior perineal triangle containing external genitalia muscles.

Anal triangle

Posterior perineal triangle surrounding anus.

Pelvic diaphragm

Muscular floor of pelvis formed mainly by levator ani and coccygeus.

Superficial transverse perineal

Muscle that separates urogenital and anal triangles; stabilizes perineal body.

Ischiocavernosus

Superficial muscle; compresses crus of penis/clitoris to maintain erection.

Bulbospongiosus

Compresses bulb of penis or constricts vaginal orifice; aids erection.

Deep transverse perineal

Deep urogenital muscle; supports pelvic organs.

External urethral sphincter

Voluntary muscle that closes urethra; allows control of urination.

Coccygeus

Posterior pelvic diaphragm muscle; supports pelvic viscera, flexes coccyx.

Levator ani

Largest pelvic diaphragm muscle group; elevates anus, supports pelvic organs.

Iliococcygeus

Lateral component of levator ani; supports pelvic floor.

Pubococcygeus

Medial component of levator ani; maintains continence, supports viscera.

External anal sphincter

Voluntary muscle encircling anal canal; maintains fecal continence.