Muscular Interactions, Shapes, and Head and Neck Muscles

Vocabulary practice flashcards covering muscle shapes, fascicle patterns, facial expression muscles, extrinsic eye muscles, mastication muscles, and neck musculature.

Muscle Shapes

The structural arrangements of skeletal muscle fibers, categorized into circular, convergent, parallel, pennate (unipennate, bipennate, and multipennate), and fusiform.

Circular Muscles

Round muscles, also called sphincters, that encircle body openings; they increase the size of the opening when relaxed and contract to shrink or close it.

Convergent Muscles

Muscles whose origin is wider than the point of insertion, starting narrow at the tendon and spreading out fan-like across the muscle body.

Parallel Muscles

Muscles whose fibers run parallel to each other, sometimes referred to as strap muscles; they make up the majority of skeletal muscles in the body.

Pennate Muscles

Feather-like muscles whose fibers converge along a tendon running through the central region for its entire length; they pack many fibers per unit, generating great strength but tiring easily.

Fusiform Muscles

Spindle-shaped muscles that attach via narrow tendons at both ends and widen into a prominent muscle belly in the middle.

Facial Expression Muscles

A specialized group of superficial muscles that are unique because they insert into and move the skin rather than moving a skeletal joint.

Epicranial Aponeurosis

A broad, sheet-like fibrous aponeurosis covering the upper surface of the cranium and scalp.

Orbicularis Oris

A circular sphincter muscle located around the mouth that controls movement of the lips.

Orbicularis Oculi

A circular sphincter muscle encircling each eye orbit responsible for closing the eyelids.

Platysma

A broad, thin sheet of strap-like superficial muscle located on the anterolateral neck and lower face.

Buccinator

A facial muscle forming the wall of the cheek that plays an important role in chewing and assisting in swallowing.

Masseter

The powerful muscle of mastication on the side of the jaw that elevates the mandible to close the mouth.

Temporalis

A fan-shaped chewing muscle located on the side of the skull that retracts the mandible.

Extrinsic Eye Muscles

A group of six muscles (superior oblique, inferior oblique, superior rectus, inferior rectus, medial rectus, and lateral rectus) located within the eye socket that control eye movement.

Glossus

The anatomical root word meaning "tongue"; all muscles acting on the tongue incorporate this root in their naming.

Sternocleidomastoid

A strap-like muscle of the neck extending from the sternum and clavicle to the mastoid process, serving as the prime mover of neck flexion and rotating the head.

Trapezius

A superficial muscle that begins on top of the shoulders and extends around to the back of the neck.

Hyoid Bone

A bone in the neck controlled by head and neck muscles that functions as a foundation for the tongue, aiding in swallowing and speech.