Chapter 11:The Muscular System

insertion

insertion

The moveable end of the muscle that attaches to the bone being pulled is called the muscle’s

origin

The end of the muscle attached to a fixed (stabilized) bone is called the

prime mover, or agonist.

Although a number of muscles may be involved in an action, the principal muscle involved is called the

antagonist

A muscle with the opposite action of the prime mover is called an

fascicle

When a group of muscle fibers is “bundled” as a unit within the whole muscle by an additional covering of a connective tissue called perimysium, that bundled group of muscle fibers is called a

Parallel muscles

have fascicles that are arranged in the same direction as the long axis of the muscle.

fusiform

When a parallel muscle has a central, large belly that is spindle-shaped, meaning it tapers as it extends to its origin and insertion, it sometimes is called

sphincters

Circular muscles are also called

convergent

When a muscle has a widespread expansion over a sizable area, but then the fascicles come to a single, common attachment point, the muscle is called

Pennate muscles

(penna = “feathers”) blend into a tendon that runs through the central region of the muscle for its whole length, somewhat like the quill of a feather with the muscle arranged similar to the feathers.

unipennate muscle

In a __ , the fascicles are located on one side of the tendon.

bipennate

A _ muscle has fascicles on both sides of the tendon.

orbicularis oris

is a circular muscle that moves the lips, and the orbicularis oculi is a circular muscle that closes the eye.

occipitofrontalis

muscle moves up the scalp and eyebrows.

epicranial aponeurosis

Instead, the two bellies are connected by a broad tendon called the

extrinsic eye muscles

The movement of the eyeball is under the control of the __

mastication

In anatomical terminology, chewing is called

masseter muscle

is the main muscle used for chewing because it elevates the mandible (lower jaw) to close the mouth

temporalis muscle

which retracts the mandible.

medial pterygoid and lateral pterygoid

muscles provide assistance in chewing and moving food within the mouth.

genioglossus

(genio = “chin”) originates on the mandible and allows the tongue to move downward and forward.

styloglossus

originates on the styloid bone, and allows upward and backward motion.

palatoglossus

originates on the soft palate to elevate the back of the tongue

hyoglossus

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

infrahyoid muscles

are located inferiorly.

stylohyoid

The**_**muscle moves the hyoid bone posteriorly, elevating the larynx,

mylohyoid

muscle lifts it and helps press the tongue to the top of the mouth.

geniohyoid

depresses the mandible in addition to raising and pulling the hyoid bone anteriorly.

omohyoid

The _ muscle, which has superior and inferior bellies, depresses the hyoid bone in conjunction with the sternohyoid and thyrohyoid muscles.

sternocleidomastoid

The major muscle that laterally flexes and rotates the head is the

splenius

The _ muscles originate at the midline and run laterally and superiorly to their insertions

splenius capitis

the __ inserts onto the head region, and the splenius cervicis extends onto the cervical region.

erector spinae group

The ___ forms the majority of the muscle mass of the back and it is the primary extensor of the vertebral column.

longissimus cervicis

the _ associated with the cervical region

longissimus thoracis

the_ , associated with the thoracic region

spinalis capitis

(head region)

spinalis cervicis

(cervical region)

spinalis thoracis

(thoracic region)

multifidus

The _ muscle of the lumbar region helps extend and laterally flex the vertebral column.

external oblique

The_ , closest to the surface, extend inferiorly and medially, in the direction of sliding one’s four fingers into pants pockets.

internal oblique

extending superiorly and medially, the direction the thumbs usually go when the other fingers are in the pants pocket.

transversus abdominis

is arranged transversely around the abdomen, similar to the front of a belt on a pair of pants.

linea alba

is a white, fibrous band that is made of the bilateral rectus sheaths that join at the anterior midline of the body.

tendinous intersections

Each muscle is segmented by three transverse bands of collagen fibers called the

intercostal muscles

which span each of the intercostal spaces.

external intercostal

muscles aid in inspiration of air during breathing because when they contract, they raise the rib cage, which expands it.

internal intercostal

muscles, just under the externals, are used for expiration because they draw the ribs together to constrict the rib cage

innermost intercostal

muscles are the deepest, and they act as synergists for the action of the internal intercostals.

pelvic diaphragm

spanning anteriorly to posteriorly from the pubis to the coccyx, comprises the levator ani and the ischiococcygeus.

perineum

is the diamond-shaped space between the pubic symphysis (anteriorly)

urogenital triangle

which includes the external genitals.

anal triangle

which contains the anus.

anterior muscles

the subclavius, pectoralis minor, and serratus anterior.

posterior muscles

the trapezius, rhomboid major, and rhomboid minor.

pectoralis major

is thick and fan-shaped, covering much of the superior portion of the anterior thorax.

deltoid

the thick muscle that creates the rounded lines of the shoulder is the major abductor of the arm, but it also facilitates flexing and medial rotation, as well as extension and lateral rotation.

subscapularis

originates on the anterior scapula and medially rotates the arm.

brachioradialis

can flex the forearm quickly or help lift a load slowly.

anterior compartment of the arm

These muscles and their associated blood vessels and nerves form the ___ (anterior flexor compartment of the arm).

extrinsic muscles of the hand.

The forearm is the origin of the

deep anterior compartment

produces flexion and bends fingers to make a fist.

deep posterior compartment of the forearm

(deep posterior extensor compartment of the forearm) originate on the radius and ulna.

retinacula

Fibrous bands called _ sheath the tendons at the wrist.

flexor retinaculum

extends over the palmar surface of the hand

extensor retinaculum

extends over the dorsal surface of the hand.

hypothenar

The _ muscles are on the medial aspect of the palm, and the intermediate muscles are midpalmar.

thenar eminence

the rounded contour of the base of the thumb, and all act on the thumb.

hypothenar eminence

the rounded contour of the little finger, and as such, they all act on the little finger.

gluteus medius

deep to the gluteus maximus is the

gluteus minimus

deep to the gluteus medius is the

tensor fascia lata

is a thick, squarish muscle in the superior aspect of the lateral thigh.

medial compartment of the thigh

The muscles in the ____ are responsible for adducting the femur at the hip

anterior compartment of the thigh

The muscles of the ____ flex the thigh and extend the leg.

rectus femoris

is on the anterior aspect of the thigh

astus lateralis

is on the lateral aspect of the thigh

vastus medialis

is on the medial aspect of the thigh

vastus intermedius

is between the vastus lateralis and vastus medialis and deep to the rectus femoris.

sartorius

is a band-like muscle that extends from the anterior superior iliac spine to the medial side of the proximal tibia.

hamstring group

The three long muscles on the back of the knee are the

fibularis tertius

a small muscle that originates on the anterior surface of the fibula, is associated with the extensor digitorum longus and sometimes fused to it, but is not present in all people.

superior extensor retinaculum

Thick bands of connective tissue called the __ (transverse ligament of the ankle)

inferior extensor retinaculum

hold the tendons of these muscles in place during dorsiflexion.