LAB TERM LESSON 8

external abdominal oblique

Paired outermost layer of lateral abdominal wall; compresses abdomen, rotates trunk, aids forced expiration

internal abdominal oblique

Paired middle layer of lateral abdominal wall; compresses abdomen, rotates trunk, aids forced expiration

transverse abdominis

Deepest abdominal muscle; compresses abdominal wall and aids forced expiration

rectus abdominis

Vertical muscle on anterior medial abdominal wall; compresses abdomen and flexes spine

linea alba

Vertical midline band of connective tissue within the abdominal wall

inguinal ligament

Extends from crest of ilium to pubic tubercle

psoas major

Round muscle next to iliacus; flexes hip, laterally rotates femur, and flexes vertebral column

quadratus lumborum

Deep muscle near kidneys; originates on iliac crest and extends lumbar spine

erector spinae

Three muscle groups: spinalis, longissimus, and iliocostalis; extends vertebral column

spinalis part of erector spinae

; extends vertebral column; runs between spinous processes

longissimus part of erector spinae

; extends vertebral column; runs between transverse processes and ribs

iliocostalis part of erector spinae

extends vertebral column; runs between ribs, ilium, and cervical vertebrae

serratus posterior superior

Located on superior back, deep to rhomboids

serratus posterior inferior

Located on inferior lateral back, deep to latissimus dorsi

thoracolumbar fascia

Aponeuroses of the oblique muscles of the posterior abdominal wall

rhomboid major

Rectangular upper-back muscle; elevates and retracts scapula

rhomboid minor

Superior to rhomboid major; elevates and retracts scapula

epicranius

Group of muscles located above the skull

frontalis

Forehead muscle that raises the eyebrows

epicranial aponeurosis

Tendinous covering of skull connecting frontalis and occipitalis

occipitalis

Posterior skull muscle that moves scalp posteriorly

temporalis

Deep muscle on temporal bone that elevates mandible

orbicularis oculi

Circles the eye and closes/squints the eye

nasalis

Muscle on nasal bone that elevates corners of nostrils

levator labii superioris

Lateral to nasalis; elevates corner of mouth and flares nostrils

levator anguli oris

Deep to levator labii superioris; elevates corner of mouth

zygomaticus major and minor

Lateral to levator labii superioris; elevates lateral part of mouth

masseter

Inferior to temporalis; powerful elevator of mandible

Origin:zygomatic arch and maxilla

Insertion: Coronoid process and ramus of mandible

Action: elevates and protracts mandible

buccinator

Deep cheek muscle that compresses cheek during sucking

medial pterygoid

Runs vertically inside ramus; elevates mandible and allows excursion

lateral pterygoid

Runs horizontally above medial pterygoid; depresses mandible and allows excursion

orbicularis oris

Circles the mouth and closes the lips

depressor anguli oris

Triangular muscle that pulls corner of mouth downward into a frown

depressor labii inferioris

Inferior to mouth; pulls lower lip downward

mentalis

Medial chin muscle; elevates and wrinkles chin skin and protrudes lower lip

platysma

Broad vertical neck muscle; pulls lower lip laterally and downward

omohyoid

Strap muscle that helps depress the hyoid bone

sternohyoid

Strap muscle that helps depress the hyoid bone

sternothyroid

Strap muscle that helps depress the hyoid bone

thyrohyoid

Strap muscle that helps depress the hyoid bone

digastric

Two-headed muscle under chin; lowers mandible

mylohyoid

Muscle under chin that acts on hyoid and aids swallowing

sternocleidomastoid

Neck muscle from sternum/clavicle to mastoid; rotates head and aids forced inhalation

sternocleidomastoid origin

Sternum and clavicle

sternocleidomastoid insertion

Mastoid process

sternocleidomastoid action

Rotates head and flexes neck

scalenes

Three deep lateral neck muscles; flex neck, elevate ribs 1–2, aid forced inhalation

splenius capitis

Deep to trapezius; laterally rotates the head

splenius cervicis

Deep back/neck muscles from T3–T6 to C1–C2; rotate, bend, and extend head/neck

semispinalis capitis

Posterior head muscle deep to splenius capitis; aids lateral rotation of head

semispinalis capitis regions

Contains capitis, cervicis, and thoracic regions

rectus abdominis origin

Pubic crest

rectus abdominis insertion

Costal cartilage of ribs 5–7 and xiphoid process

rectus abdominis action

Flexes spine

masseter origin

Zygomatic arch and maxilla

masseter insertion

Coronoid process and ramus of mandible

masseter action

Elevates and protracts mandible