Axial Muscles Flashcards
4 groups of muscles
- Muscles of the head and neck
- Muscles of the vertebral column
- Muscles that form the wall of the abdominal and pelvic cavities
- Muscles of the perineal region and pelvic diaphragm
Muscles of facial expressions
- frontalis: raises eyebrows
- orbicularis oris: compresses and purses lips
- orbicularis oculi: tightly closes eye
- buccinator: compresses cheeks
Extrinsic Eye Muscles: Levator palpebrae superioris
- elevates upper eyelid
Extrinsic Eye Muscles: Superior oblique
- looks down and laterally
Extrinsic Eye Muscles: Inferior oblique
- looks up and laterally
Extrinsic Eye muscles: superior rectus
- eye looks up
Extrinsic Eye muscles: inferior rectus
- eye looks down
Extrinsic Eye Muscles: Medial rectus
- eye looks medially
Extrinsic Eye muscles: lateral rectus
- eye looks laterally
Muscles of Mastification: Superficial — Masseter
- origin: zygomatic arch
- insertion: lateral surface of mandible
- elevates mandible and closes jaw
Muscles of Mastification: Superficial — Temporalis
- origin: temporal bone
- insertion: coronoid process of mandible
- action: elevates mandible and closes jaws
Muscles of Mastification: Pterygoid Muscles (Deep) — Medial Pterygoid
- origin: inside surface of lateral pterygoid plate (sphenoid)
- insertion: medial surface of mandible
- action: elevates mandible and closes jaws, or moves mandible side to side
Muscles of Mastification: Pterygoid Muscles (Deep) — lateral pterygoid
- origin: outside surface of lateral pterygoid plate (sphenoid)
- insertion: mandibular neck and condyle
- action: opens jaws, protrudes mandible, or moves mandible side to side
Muscles of the tongue — genioglossus
- origin: medial surface of mandible around chin
- insertion: body of tongue, hyoid bone
- action: depresses and protracts tongue
Suprahyoid muscles
- elevate larynx and hyoid bone (or depress mandible)
- elevating larynx = close off our air tube so we don’t accidentally swallow food
Infrahyoid muscles
- most depress larynx and/or hyoid bone
- lowering larynx = important for opening that voice box so that we actually get air in there
Hyoid bone
- serves as an attachment point for the muscles
- allows us to either elevate our larynx or compress our larynx
Sternocleidomastoid
- origin: manubrium (sterno) clavicle (cleido—)
- insertion: mastoid process
- action: bilateral contraction flexes the neck, unilateral contraction flexes neck toward same side and rotates face to opposite side
Oblique and Rectus Muscles: Scalene Muscles (cervical)
- origin: transverse processes of vertebrae
- insertion: first two ribs
- action: elevates ribs/flexes neck/one side bends neck and rotates to the opposite side
- see someone breathing really hard and seeing their neck move up and down = scalene muscles are working
- contracting in order to elevate the ribs, get a little bit more space in the thoracic cavity for our lungs to expand into ours
Erector Spinae Muscles
- iliocostalis (lateralmost)
- longissimus (middle group)
- spinalis (most medial group)
- action: extends vertebral column (stand up) when contracted bilaterally; unilateral contraction flexes to that side
Oblique and Rectus Muscles: Thoracic Wall
- external intercostal and internal intercostal
- action: elevate ribs and depress ribs
Oblique and Rectus Muscles: Abdominal Wall
- External abdominal oblique muscles and internal abdominal oblique: flex and rotate trunk
- rectus abdominis: flexes trunk (bend over forward)
- transversus abdominus: compresses abdominal cavity
Diaphragm
- action: contraction increases volume of thoracic cavity
Muscles of the Pelvic Floor — Levator Ani Muscules
- action: tense pelvic floor, support pelvic organs, flex coccygeal joints, elevate and retract anus
Muscles of the Pelvic Floor — Coccygeus
- action: flex coccygeal joints, elevate, and support pelvic floor
Muscles of the Pelvic Floor — External anal sphincter
- closes anal opening
