BIOD 151 2026 STUDY GUIDE
DETAILED REVIEW SOLUTIONS
◉ Orbicularis oris.
Answer: Action: mouth closure: closes lips, protrudes lips forward,
presses lips against teeth
Innervation: facial nerve (CN VII)
◉ Zygomaticus major/minor.
Answer: Action: pull corners of lips upward
Innervation: facial nerve (CN VII)
◉ Risorius.
Answer: Action: pulls the corners of the mouth posteriorly (grin or
grimace)
Innervation: facial nerve (CN VII)
◉ Frontalis (occipitofrontailis).
Answer: Action: raise eyebrows
Innervation: facial nerve (CN VII)
,◉ Buccinator.
Answer: Action: compress cheeks
Innervation: facial nerve (CN VII)
◉ Masseter.
Answer: Action: jaw closure
Innervation: trigeminal nerve (CN V, mandibular branch)
◉ Temporalis.
Answer: Action: Elevates mandible, closes jaw
Innervation: trigeminal nerve (CN V, mandibular branch)
◉ lateral flexion.
Answer: Side-bending left or right
◉ neck flexion.
Answer: chin to chest
◉ bilateral.
Answer: both sides
,◉ unilateral.
Answer: one-sided
◉ Semispinalis Capitis.
Answer: Origin: articular processes of inferior cervical & transverse
process of superior thoracic vertebrae
Insertion: occipital bone
Action: Bilateral extend head Unilateral laterally flexes neck to same
side
Innervation: spinal nerves
◉ Sternocleidomastoid.
Answer: Origin: sternal end of clavicle and manubrium
Insertion: mastoid region of skull
Action:Bilateral: neck flexionUnilateral: turns face to opposite side
Innervation: accessory nerve (CN XI)
, ◉ Splenius Capitis.
Answer: Origin: spinous process AND ligaments of inferior cervical
vertebrae
Insertion: mastoid process, occipital bone of skull
Action:Bilateral extend headUnilateral laterally flexes neck to same side
Innervation: cervical spinal nerves
◉ Longissimus cervicis.
Answer: Origin: transverse processes of superior thoracic vertebrae
Insertion: transverse process of middle and superior cervical vertebrae
Action:Bilateral extend headUnilateral laterally flexes neck to same side
Innervation: cervical and thoracic spinal nerves
◉ Longissimus thoracis.
Answer: Origin: transverse process of all thoracic and lumbar vertebrae
Insertion: transverse processes of all thoracic vertebrae
DETAILED REVIEW SOLUTIONS
◉ Orbicularis oris.
Answer: Action: mouth closure: closes lips, protrudes lips forward,
presses lips against teeth
Innervation: facial nerve (CN VII)
◉ Zygomaticus major/minor.
Answer: Action: pull corners of lips upward
Innervation: facial nerve (CN VII)
◉ Risorius.
Answer: Action: pulls the corners of the mouth posteriorly (grin or
grimace)
Innervation: facial nerve (CN VII)
◉ Frontalis (occipitofrontailis).
Answer: Action: raise eyebrows
Innervation: facial nerve (CN VII)
,◉ Buccinator.
Answer: Action: compress cheeks
Innervation: facial nerve (CN VII)
◉ Masseter.
Answer: Action: jaw closure
Innervation: trigeminal nerve (CN V, mandibular branch)
◉ Temporalis.
Answer: Action: Elevates mandible, closes jaw
Innervation: trigeminal nerve (CN V, mandibular branch)
◉ lateral flexion.
Answer: Side-bending left or right
◉ neck flexion.
Answer: chin to chest
◉ bilateral.
Answer: both sides
,◉ unilateral.
Answer: one-sided
◉ Semispinalis Capitis.
Answer: Origin: articular processes of inferior cervical & transverse
process of superior thoracic vertebrae
Insertion: occipital bone
Action: Bilateral extend head Unilateral laterally flexes neck to same
side
Innervation: spinal nerves
◉ Sternocleidomastoid.
Answer: Origin: sternal end of clavicle and manubrium
Insertion: mastoid region of skull
Action:Bilateral: neck flexionUnilateral: turns face to opposite side
Innervation: accessory nerve (CN XI)
, ◉ Splenius Capitis.
Answer: Origin: spinous process AND ligaments of inferior cervical
vertebrae
Insertion: mastoid process, occipital bone of skull
Action:Bilateral extend headUnilateral laterally flexes neck to same side
Innervation: cervical spinal nerves
◉ Longissimus cervicis.
Answer: Origin: transverse processes of superior thoracic vertebrae
Insertion: transverse process of middle and superior cervical vertebrae
Action:Bilateral extend headUnilateral laterally flexes neck to same side
Innervation: cervical and thoracic spinal nerves
◉ Longissimus thoracis.
Answer: Origin: transverse process of all thoracic and lumbar vertebrae
Insertion: transverse processes of all thoracic vertebrae
