11.3 Axial Muscles of the Head, Neck, and Back

anatomy & physiology

what categories are skeletal muscles divided into?

* axial and appendicular

what are axial muscles?

* muscles of the trunk and head
* grouped based on location, function, or both.

what are appendicular muscle?

* muscles of the arms and legs

where are the origins of muscle of facial expression?

* on the surface level of the bone

true or false: because the muscles insert in the skin rather than on bone, when they contract, the skin moves to create facial expression.

* true

what is the orbicularis oris?

* the circular muscle that moves the lips

what is the orbicularis oculi?

* the circular muscle that closes the eye

what is the occipitofrontalis?

* muscle that moves up the scalp and eyebrows
* this muscle has a frontal and occipital belly

true or false: there is muscle all over the head.

false.

* there is muscle on the forehead and the back of the head, but there is no muscle along the top of the head.

what is the tendon that connect the two bellies of the occipitofrontalis?

* epicranial aponeurosis

what is the buccinator muscle?

* large portion of the face, compresses the cheek.
* this muscle allows you to blow, whistle, suck, and contributes to chewing.

what is the prime mover of the eyebrows?

* corrugator supercilii

where do extrinsic eye muscles originate?

* inside the eye socket and insert onto the outer surface of the white of the eye.

what is mastication?

* chewing

what is the masseter?

* main muscle for chewing
* elevates the mandible to close the mouth

what is the temporalis?

* assists the masseter
* retracts the mandible

what are the medial and lateral pterygoid?

* muscles that help move food within the mouth

why is the tongue important?

* tasting food, mastication, deglutition (swallowing), and speech.

what is the difference between extrinsic and intrinsic tongue muscles?

* extrinsic muscles insert into the tongue from outside origins
* intrinsic muscles insert into the tongue from the origins within it.

what is the genioglossus?

* originates on the mandible
* allows tongue to move downward and forward

what is the styloglossus?

* originates on the styloid bone
* allows upward and backward motion of tongue.

what is the palatoglossus?

* originates on the soft palate.
* allows elevation of the back of the tongue.

what is the hyoglossus?

* originates on the hyoid bone
* can move the tongue downward and flatten it.

where is the suprahyoid muscle?

* superior to the hyoid bone

where is the infrahyoid muscle?

* inferior to the hyoid bone