Chapter 10 Flashcards
origin
fixed end; usually the most stationary, proximal end of the muscle; some muscles have multiple origins
head
In the case of multiple origins, each origin is also called a head
insertion
mobile end; usually the distal end of the muscle attached to the bone undergoing the greatest movement.
belly
The part of the muscle between the origin and the insertion
tendons
how each muscle is connected to bone at the attachment point
aponeuroses
broad and sheetlike tendons
action
the movement accomplished when it contracts.
agonist
A muscle that accomplishes a certain movement, such as flexion
antagonist
A muscle acting in opposition to an agonist
synergists
Members of a group of muscles working together to produce a movement
prime mover
Among a group of synergists, this is the one muscle that plays the major role in accomplishing the movement
Fixators
muscles that hold one bone in place relative to the body while a usually more distal bone is moved.
pennate or bipennate muscles
The fasciculi of some muscles are arranged like the
barbs of a feather on two sides of a common tendon and called this
semipennate or unipennate
A muscle with all fasciculi on one side of the tendon
multipennate
a muscle with fasciculi arranged at many places around the central tendon
straight muscles
fasciculi are organized parallel to the long axis of the muscle
Orbicular or circular muscles
such as the orbicularis oris and orbicularis oculi have their fasciculi arranged in a circle around an opening and act as sphincters to close the opening.
lever
a rigid shaft capable of turning about a hinge, or pivot point, called a fulcrum (F) and transferring a force applied at one point along the lever to a weight (W) , or resistance, placed at another point along the lever.
pull (P)
When muscles contract, the pull (P), or force, of muscle contraction is applied to the levers (bones), causing them to move.
class I lever system
the fulcrum is located between the pull and the weight
class II lever system
the weight is located between the fulcrum and the pull
class III lever system
the most common type in the body, the pull is located between the fulcrum and the weight
sternocleidomastoid muscle
prime mover of the lateral group; easily seen on the anterior and lateral sides of the neck, especially if the head is extended slightly and rotated to one side
occipitofrontalis
raises the eyebrows and furrows the skin of the forehead.
orbicularis oculi
closes the eyelids and causes “crow’s-feet” wrinkles in the skin at the lateral corners of the eyes.
levator palpebrae superioris
raises the upper lids
ptosis
this droopy eyelid on one side usually indicates that the nerve to the levator palpebrae superioris, or the part
of the brain controlling that nerve, has been damaged.
corrugator supercilii
draws the eyebrows inferiorly and medially, producing vertical corrugations (furrows) in the skin between the eyes
orbicularis oris and buccinator
the kissing muscles, pucker the mouth.
zygomaticus major and minor, the levator anguli oris, and the risorius
smiling muscles
levator labii superioris
Sneering muscles
depressor anguli oris, the depressor labii inferioris, and the mentalis
frowning or pouting
muscles of mastication and the hyoid muscles
move the mandible when chewing; elevators of the mandible are some of the strongest muscles of the body;
The tongue consists of a mass of intrinsic muscles
and extrinsic muscles
- intrinsic muscles (entirely within the tongue), which are involved in changing the shape of the tongue
- extrinsic muscles (outside of the tongue but attached to it), which help change the shape and move the tongues
The hyoid muscles are divided into 2 groups:
a suprahyoid group superior to the hyoid bone and an infrahyoid group inferior to it.
When we swallow, muscles elevate the pharynx and larynx and then constrict the pharynx
Specifically the palatopharyngeus elevates the pharynx,
and the salpingopharyngeus muscles then constrict the pharynx from superior to inferior, forcing food into the esophagus.
Laryngospasm
a tetanic contraction of the muscles that narrows the opening of the larynx (arytenoids, lateral cricoarytenoids) and affects speech and breathing.
erector spinae group of muscles on each side of the back consists of three subgroups:
the iliocostalis, the longissimus and the spinalis. The longissimus group accounts for most of the muscle mass in the lower back
scalene muscles
elevate the first two ribs during more forceful inspiration.
external intercostals
elevate the ribs during quiet, resting inspiration.
internal intercostals and transversus thoracis muscles
depress the ribs during forced expiration.
diaphragm
causes the major movement produced during quiet breathing.
linea alba
white line; In a relatively muscular person with little fat, this vertical line is visible. It extends from the area of the xiphoid process of the sternum through the navel to the pubis; it’s devoid of muscle and consists of white connective tissue
rectus abdominis
On each side of the linea alba is the rectus abdominis, surrounded by a rectus sheath
Tendinous intersections (tendinous inscriptions)
transect the rectus abdominis at three, or sometimes more, locations, causing the abdominal wall of a lean, well-muscled person to appear segmented (a “six-pack”).
linea semilunaris
a crescent or half-moon-shaped line lateral to the rectus
abdominis
lateral to the linea semilunarisare three layers of muscle:
external abdominal oblique, internal abdominal oblique,
and transversus abdominis
Most of the pelvic floor is formed by:
the coccygeus muscle and the levator ani muscle, referred to jointly as the pelvic diaphragm.
The muscles attaching the scapula to the thorax include:
the trapezius, levator scapulae, rhomboideus major and rhomboideus minor, serratus anterior, and pectoralis minor. These muscles move the scapula, permitting a wide range of movements of the upper limb, or they act as fixators to hold the scapula firmly in position when the arm muscles contract.
the arm is attached to the thorax by several muscles, including:
the pectoralis major and the latissimus dorsi
deltoid muscle
a flexor and an extensor; is like three muscles in one: the anterior fibers flex the shoulder, the lateral fibers abduct the arm, and the posterior fibers extend the shoulder; part of the group of muscles that binds the humerus to the scapula.
rotator cuff muscles
the primary muscles holding the head of the humerus in the glenoid cavity are these muscles because they form a cuff or cap over the proximal humerus
Biceps tendinitis
inflammation of the biceps brachii long head tendon, can also cause shoulder pain; commonly caused by
throwing a baseball or football.
Extension of the elbow is accomplished by:
the triceps brachii and the anconeus
flexion of the elbow is accomplished by:
the brachialis, the biceps brachii , and the brachioradialis
Supination of the forearm and hand is accomplished by muscles acting on the forearm:
the supinator and the biceps brachii
Pronation
a function of the pronator quadratus and the pronator teres
extrinsic hand muscles
in the forearm but have tendons that extend into the hand
extensor retinaculum
this strong band of fibrous connective tissue covers the flexor and extensor tendons and holds them in place around the wrist so that they do not “bowstring”
(pull away from the bone) during muscle contraction
flexor carpi radialis and three posterior muscles
Two major anterior muscles that flex the wrist
extensor carpi radialis longus, the extensor carpi radialis brevis, and the extensor carpi ulnaris
three posterior muscles that extend the wrist.
tennis elbow or lateral epicondylitis
condition where forceful, repetitive use of the forearm extensor muscles can damage them where they attach to the lateral epicondyle
medial epicondylitis or golfer’s elbow
inflammation where the medial forearm tendons attach to the medial epicondyle of the humerus.
Flexion of the four medial digits is a function of the:
flexor digitorum superficialis and the flexor digitorum profundus
extensor digitorum
Extension of the four medial digits
extensor digiti minimi
extensor in the little finger
extensor indicis
extensor of the index finger
abductor pollicis longus, the extensor pollicis longus, and the extensor pollicis brevis
Movement of the thumb is caused by these tendons that form the sides of a depression on the posterolateral side of the wrist called the “anatomical snuffbox”
intrinsic hand muscles
entirely within the hand
Abduction of the fingers is accomplished by:
the dorsal interossei and the abductor digiti minimi, whereas adduction is a function of the palmar interossei .
thenar eminence
this fleshy prominence at the base of the thumb formed by the flexor pollicis brevis, the abductor pollicis brevis, and
the opponens pollicis
abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi
constitute the hypothenar eminence on the ulnar side of the hand. The thenar and hypothenar muscles are involved in controlling of the thumb and little finger and little finger.
iliacus and the psoas major
anterior muscles that flex the hip; Because these muscles share an insertion and produce the same movement, they are often referred to collectively as the iliopsoas
gluteal muscles and the tensor fasciae latae
posterolateral hip muscles
gluteus maximus
contributes most of the mass that can be seen as the buttocks
gluteus medius
common site for injections, creates a smaller mass just superior and lateral to the gluteus maximus.
Three groups of thigh muscles have been identified based on their location in the thigh and are organized into compartments:
The muscles of the anterior compartment flex the hip and/or extend the knee; the muscles of the medial compartment adduct the thigh; and the muscles of the posterior compartment extend the hip and flex the knee
quadriceps femoris and the sartorius
The anterior thigh muscles
quadriceps femoris
four muscles: the rectus femoris, the vastus lateralis, the vastus medialis, and the vastus intermedius. The quadriceps group extends the knee. The rectus femoris also flexes the hip because it crosses both the hip and knee joints.
The posterior thigh muscles, collectively called the hamstring muscles, consist of:
the biceps femoris, the semi-membranosus, and the semitendinosus. Their tendons are easily seen or felt on the medial and lateral posterior aspect of a slightly bent knee
extrinsic foot muscles are divided into three groups, each located within a separate compartment of the leg:
anterior, posterior, and lateral; The anterior leg muscles are extensor muscles involved in dorsiflexion and eversion or inversion of the foot and extension of the toes; The lateral muscles are primarily everters of the foot, but they also aid plantar flexion.
fibularis brevis
inserts onto the fifth metatarsal bone and everts and plantar flexes the foot.
fibularis longus crosses under the lateral four metatarsal
fibularis longus crosses under the lateral four metatarsal
The superficial muscles of the posterior compartment:
the gastrocnemius and the soleus, form the bulge of the calf; join with the small plantaris muscle to form the common calcaneal tendon or Achilles tendon; these muscles are involved in plantar flexion of the foot. The deep muscles of the posterior compartment plantar flex and invert the foot and flex the toes
Intrinsic foot muscles
located within the foot itself, flex, extend, abduct, and adduct the toes.
plantar fasciitis
inflammation of the plantar aponeurosis
fibularis (longus and brevis)
evert the foot
tibialis anterior and extensor hallucis longus
invert the foot
soleus
plantar flexion
