the muscular system. five golden rules of skeletal muscle activity table 6.2
TRANSCRIPT
The Muscular System
Five Golden Rules of Skeletal Muscle Activity
Table 6.2
Muscles and Body MovementsMovement is attained due to a muscle
moving an attached boneMuscles are attached to at least two points
OriginAttachment to a moveable bone
InsertionAttachment to an immovable bone
Muscles and Body Movements
Figure 6.12
Types of Ordinary Body MovementsFlexion
Decreases the angle of the jointBrings two bones closer togetherTypical of hinge joints like knee and elbow
ExtensionOpposite of flexionIncreases angle between two bones
Types of Ordinary Body Movements
Types of Ordinary Body Movements
Figure 6.13b
Types of Ordinary Body MovementsRotation
Movement of a bone around its longitudinal axis
Common in ball-and-socket jointsExample is when you move atlas around the
dens of axis (shake your head “no”)
Types of Ordinary Body Movements
Figure 6.13c
Types of Ordinary Body MovementsAbduction
Movement of a limb away from the midlineAdduction
Opposite of abductionMovement of a limb toward the midline
Types of Ordinary Body Movements
Figure 6.13d
Types of Ordinary Body MovementsCircumduction
Combination of flexion, extension, abduction, and adduction
Common in ball-and-socket joints
Types of Ordinary Body Movements
Figure 6.13d
Special MovementsDorsiflexion
Lifting the foot so that the superior surface approaches the shin
Plantar flexionDepressing the foot (pointing the toes)
Special Movements
Figure 6.13e
Special MovementsInversion
Turn sole of foot mediallyEversion
Turn sole of foot laterally
Special Movements
Figure 6.13f
Special MovementsSupination
Forearm rotates laterally so palm faces anteriorly
PronationForearm rotates medially so palm faces
posteriorly
Special Movements
Figure 6.13g
Special MovementsOpposition
Move thumb to touch the tips of other fingers on the same hand
Special Movements
Figure 6.13h
Types of MusclesPrime mover—muscle with the major
responsibility for a certain movementAntagonist—muscle that opposes or
reverses a prime moverSynergist—muscle that aids a prime mover
in a movement and helps prevent rotationFixator—stabilizes the origin of a prime
mover
Naming Skeletal MusclesBy direction of muscle fibers
Example: Rectus (straight)By relative size of the muscle
Example: Maximus (largest)
Naming Skeletal MusclesBy location of the muscle
Example: Temporalis (temporal bone)By number of origins
Example: Triceps (three heads)
Naming Skeletal MusclesBy location of the muscle’s origin and
insertionExample: Sterno (on the sternum)
By shape of the muscleExample: Deltoid (triangular)
By action of the muscleExample: Flexor and extensor (flexes or
extends a bone)
Arrangement of Fascicles
Figure 6.14
Head and Neck MusclesFacial muscles
Frontalis—raises eyebrowsOrbicularis oculi—closes eyes, squints, blinks,
winksOrbicularis oris—closes mouth and protrudes
the lipsBuccinator—flattens the cheek, chewsZygomaticus—raises corners of the mouth
Chewing musclesMasseter—closes the jaw and elevates
mandibleTemporalis—synergist of the masseter,
closes jaw
Head and Neck MusclesNeck muscles
Platysma—pulls the corners of the mouth inferiorly
Sternocleidomastoid—flexes the neck, rotates the head
Head and Neck Muscles
Figure 6.15
Muscles of Trunk, Shoulder, ArmAnterior muscles
Pectoralis major—adducts and flexes the humerus
Intercostal muscles External intercostals—raise rib cage during
inhalationInternal intercostals—depress the rib cage to move
air out of the lungs when you exhale forcibly
Anterior Muscles of Trunk, Shoulder, Arm
Figure 6.16a
Muscles of Trunk, Shoulder, ArmMuscles of the abdominal girdle
Rectus abdominis—flexes vertebral column and compresses abdominal contents (defecation, childbirth, forced breathing)
External and internal obliques—flex vertebral column; rotate trunk and bend it laterally
Transversus abdominis—compresses abdominal contents
Anterior Muscles of Trunk, Shoulder, Arm
Figure 6.16b
Muscles of Trunk, Shoulder, ArmPosterior muscles
Trapezius—elevates, depresses, adducts, and stabilizes the scapula
Latissimus dorsi—extends and adducts the humerus
Erector spinae—back extensionQuadratus lumborum—flexes the spine
laterallyDeltoid—arm abduction
Muscles of Posterior Neck, Trunk, Arm
Figure 6.17a
Muscles of Posterior Neck, Trunk, Arm
Figure 6.17b
Muscles of the Upper LimbBiceps brachii—supinates forearm, flexes
elbowBrachialis—elbow flexionBrachioradialis—weak muscleTriceps brachii—elbow extension
(antagonist to biceps brachii)
Anterior Muscles of Trunk, Shoulder, Arm
Figure 6.16a
Muscles of Posterior Neck, Trunk, Arm
Figure 6.17a
Muscles of the Lower LimbGluteus maximus—hip extensionGluteus medius—hip abduction, steadies
pelvis when walkingIliopsoas—hip flexion, keeps the upper
body from falling backward when standing erect
Adductor muscles—adduct the thighs
Muscles of the Pelvis, Hip, Thigh
Figure 6.19a
Muscles of the Pelvis, Hip, Thigh
Figure 6.19c
Muscles of the Lower LimbMuscles causing movement at the knee
jointHamstring group—thigh extension and knee
flexionBiceps femorisSemimembranosusSemitendinosus
Muscles of the Pelvis, Hip, Thigh
Figure 6.19a
Muscles of the Lower LimbMuscles causing movement at the knee
jointSartorius—flexes the thighQuadriceps group—extends the knee
Rectus femorisVastus muscles (three)
Muscles of the Pelvis, Hip, Thigh
Figure 6.19c
Muscles of the Lower LimbMuscles causing movement at ankle and
footTibialis anterior—dorsiflexion and foot
inversionExtensor digitorum longus—toe extension
and dorsiflexion of the footFibularis muscles—plantar flexion, everts the
footSoleus—plantar flexion
Muscles of the Lower Leg
Figure 6.20a
Muscles of the Lower Leg
Figure 6.20b
Superficial Muscles: Anterior
Figure 6.21
Superficial Muscles: Posterior
Figure 6.22
Superficial Anterior Muscles of the Body
Table 6.3 (1 of 3)
Superficial Anterior Muscles of the Body
Table 6.3 (2 of 3)
Superficial Anterior Muscles of the Body
Table 6.3 (3 of 3)
Superficial Posterior Muscles of the Body
Table 6.4 (1 of 3)
Superficial Posterior Muscles of the Body
Table 6.4 (2 of 3)
Superficial Posterior Muscles of the Body
Table 6.4 (3 of 3)