Post on 24-Feb-2016
description
Names of Muscles are Descriptive• Relative size
– Pectoralis major: major = large size• Shape
– Deltoid: like a delta or triangle• Location
– Extensor digitorum: digits = fingers or toes
• Action– Extensor digitorum: extension
• Number of attachments– Biceps brachii: biceps = 2 heads
• Direction of fibers– External obliques: oblique =
anglular
Muscle Facts• The human body has over 600
distinct skeletal muscles– The face contains over 60
muscles• 40 of which are used to frown• 20 of which are used to smile
– The stapedius in the middle ear is the smallest muscle in the body
– The gluteus maximus in the buttock is the largest muscle in the body
– The sartorius in the thigh is the longest muscle in the body
Temporomandibular Joint (TMJ)• Articulation between the
mandibular condyle of the mandible and the mandibular fossa of the temporal bone
• Strain of the joint may be caused by – Grinding the teeth– Hyperextending the lower jaw
• The condition of having strained the joint is called temporomandibular joint syndrome or TMJ syndrome
• Symptoms include headache, earache, and pain in the jaw, neck, or shoulder
Muscles of Facial Expression (p. 195)• Enable communication through
facial expressions of surprise, sadness, anger, fear, disgust, and pain
• Examples: – Epicranius – lifts eyebrow
• Made up of the frontalis & occipitalis
– Orbicularis oris – closes lips– Orbicularis oculi – closes eyes– Buccinator – compresses
cheeks– Zygomaticus – raises corner of
mouth– Platysma – draws angle of
mouth downward
Muscles of Mastication (p. 195)• Enable chewing movements• Three pairs of these muscles
are used in biting movements:– Masseter – elevates the
mandible– Temporalis – elevates the
mandible– Sphenomandibularis
• Newly discovered muscle• Extends about an inch and
a half from behind the eyes to the inside of the jawbone
• Thought to help produce the movements of chewing
Muscles That Move the Head (p. 196)• Result from the actions of paired
muscles in the neck and upper back
• Examples:– Sternocleidomastoid
• Pulls head to one side• Pulls head toward chest• Raises sternum
– Splenius capitis• Rotates head• Bends head to one side• Brings head upright
– Semispinalis capitis• Extends head• Bends head to one side• Rotates head
Muscles That Move the Pectoral Girdle• See page 196• Closely associated with
muscles that move the arm• Examples:
– Trapezius• Rotates scapula & raises
arm• Raises scapula• Pulls scapula medially• Pulls scapula and shoulder
downward– Rhomboid major
• Raises and adducts scapula– Levator scapulae
• Elevates scapula
Muscles That Move the Pectoral Girdle• See page 196• Continued
– Serratus anterior• Pulls scapula
anteriorly and downward
– Pectoralis minor• Pulls scapula
anteriorly and downward
• Raises ribs
Muscles That Move the Arm (p. 198)• The arm is one of the more
freely movable parts of the body
• Muscles connect the humerus to many other parts including the pectoral girdle, ribs, and vertebral column
• Examples:– Coracobrachialis
• Flexes and adducts arm– Pectoralis major
• Pulls arm anteriorly and across chest
• Rotates humerus• Adducts arm
Muscles That Move the Arm (p. 198)• Arm muscles (continued)
– Teres major• Extends humerus• Adducts and rotates arm
medially– Latissimus dorsi
• Extends and adducts arm• Rotates humerus inwardly• Pulls shoulder downward
and posteriorly– Supraspinatus
• Abducts arm– Deltoid
• Abducts arm, • Extends or flexes humerus
Muscles That Move the Arm (p. 198)• Arm muscles (continued)
– Subscapularis• Rotates arm medially
– Infraspinatus• Rotates arm laterally
– Teres minor• Rotates arm laterally
Muscles That Move the Forearm (p. 199)• Muscles that connect the
radius or ulna to the humerus or pectoral girdle produce most of the forearm movements
• Examples:– Biceps brachii
• Flexes forearm at the elbow• Rotates hand laterally
– Brachialis• Flexes forearm at elbow
– Brachioradialis• Flexes forearm at elbow
– Triceps brachii• Extends forearm at elbow
Muscles That Move the Forearm (p. 199)• Forearm muscles (continued)• Examples:
– Supinator• Rotates forearm at elbow
– Pronator teres• Rotates forearm medially
– Pronator quadratus• Rotates forearm medially
Muscles That Move the Hand (p. 200)• Muscles that move the hand
originate from the distal end of the humerus and from the radius and ulna
• Two major groups:– Flexors – anterior forearm– Extensors – posterior
forearm• Examples
– Flexor carpi radialis• Flexes and abducts the
wrist– Flexor carpi ulnaris
• Flexes and adducts wrist
Muscles That Move the Hand (p. 200)• Hand muscles (continued)
– Palmaris longus• Flexes wrist
– Flexor digitorum profundus
• Flexes distal joints of fingers
– Extensor carpi radialis longus
• Extends wrist • Abducts hand
– Extensor carpi radialis brevis
• Extends wrist• Abducts hand
Muscles That Move the Hand (p. 200)• Hand muscles (continued)
– Extensor carpi ulnaris• Extends and adducts
wrist– Extensor digitorum
• Extends fingers
Muscles of Abdominal Wall (p. 201)• Bone supports the walls of the
chest and pelvis, but not the walls of the abdomen
• The anterior and lateral walls of the abdomen are composed of layers of broad, flat muscles– Connect the rib cage and vertebral
column to the pelvic girdle• Linea alba
– Band of tough connective tissue– Extends from the xiphoid process
of the sternum to the symphysis pubis
– Attachment for abdominal muscles
Muscles of Abdominal Wall (p. 201)• Abdominal muscles (continued)
– External obliques• Tenses abdominal wall• Compresses abdominal
contents– Internal obliques
• Tenses abdominal wall• Compresses abdominal
contents– Transverse abdominis
• Tenses abdominal wall• Compresses abdominal
contents
Muscles of Abdominal Wall (p. 201)• Abdominal muscles (continued)
– Rectus abdominis• Tenses abdominal wall• Compresses abdominal
contents• Flexes vertebral column
Muscles of Pelvic Outlet (p. 202)• Two muscular sheets
span the outlet of the pelvis– Pelvic diaphragm
• Deeper• Forms the floor of
the pelvic cavity– Urogenital
diaphragm • More superficial• Fills the space
within the pubic arch
Muscles of Pelvic Outlet (p. 202)• Pelvic Diaphragm
– Levator ani• Supports pelvic viscera• Provides sphincter-like action
in anal canal and vagina• Urogenital Diaphragm
– Superficial transversus perinei• Supports pelvic viscera
– Bulbospongiosus• Males: assists emptying of
urethra• Females: constricts vagina
– Ischiocavernosis• Assists function of
bulbospongiosus
Muscles of Pelvic Outlet (p. 202)
Muscles That Move the Thigh (p. 203)• Attached to the femur and to some
part of the pelvic girdle• Occur in anterior and posterior
groups– Anterior groups primarily flex the
thigh– Posterior groups extend, abduct,
and rotate the thigh• Examples:
– Psoas major• Flexes thigh
– Iliacus• Flexes thigh
Muscles That Move the Thigh (p. 203)– Gluteus maximus
• Extends thigh– Gluteus medius
• Abducts and rotates thigh medially– Gluteus minimus
• Abducts and rotates thigh medially
Muscles That Move the Thigh (p. 203)– Tensor fasciae latae
• Abducts, flexes, and rotates thigh medially
– Adductor longus• Adducts, flexes, and rotates
thigh laterally– Adductor magnus
• Adducts, extends, and rotates thigh laterally
– Gracilis• Adducts thigh• Flexes and rotates lower limb
medially
Muscles That Move the Leg (p. 204)• Connect the tibia or fibula to the
femur or the pelvic girdle• Can be separated into two major
groups– Those that flex the knee– Those that extend the knee
• Examples:– Sartorious
• Flex leg and thigh• Abducts thigh• Rotates thigh laterally• Rotates leg medially
Muscles That Move the Leg (p. 204)• Hamstring group
– Biceps femoris• Flexes leg• Extends thigh
– Semitendinosus• Flexes leg• Extends thigh
– Semimembranosus• Flexes leg• Extends thigh
Muscles That Move the Leg (p. 204)• Quadriceps femoris group
– Rectus femoris• Extends leg at knee
– Vastus lateralis• Extends leg at knee
– Vastus medialis• Extends leg at knee
– Vastus intermedius• Extends leg at knee
Muscles That Move the Foot (p. 205)• Attach the femur, tibia, and
fibula to the bones of the foot• Move the foot upward
(dorsiflexion) or downward (plantarflexion)
• Turn the sole of the foot medially (inversion) or laterally (eversion)
• Examples:– Tibialis anterior
• Dorsiflexes and inverts the foot
– Fibularis tertius• Dorsiflexes and everts the
foot
Muscles That Move the Foot (p. 205)– Extensor digitorum longus
• Dorsiflexion and eversion of foot
• Extension of toes– Gastrocnemius
• Plantarflexion of foot• Flexion of leg at knee
– Soleus• Plantar flexion of foot
Muscles That Move the Foot (p. 205)– Flexor digitorum longus
• Plantarflexion and inversion of foot
• Flexion of the four lateral toes
– Tibialis posterior• Plantarflexion• Inversion of foot
– Fibularis longus• Plantarflexion• Eversion of foot• Supports arch of foot