Naming Skeletal Muscles

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Naming Skeletal Muscles

• Named according to a number of criteria
• Direction of muscle fibers relative to
  longitudinal axis of the muscle
• Rectus Fibers oriented straight with respect to
  longitudinal axis
• Oblique Fibers run at an angle to the
  longitudinal axis
• Orbicularis Fibers run in a circular path
• Relative size
• Major for bigger and minor for smaller
• Maximus for biggest, intermedius for middle and
  minimus for smallest
• Longus for longest and brevis for shortest.
• Location
• Pectoralis major is found in the chest region
• Rectus femoris is found near the femur
• Location of the origin and insertion
• Brachioradialis attaches to the humerus (origin)
  and the radius (insertion)
• Number of origins
• Biceps means two heads
• Triceps means three heads
• Shape
• Deltoid means triangular in shape.

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Skeletal Muscles Of Facial Expression
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Skeletal Muscles Of Facial Expression

• Frontalis Lies over forehead wrinkles forehead
  and raises eyebrows
• Orbicularis oculi Encircle eye close eyes,
  squint, blink and wink
• Zygomaticus From cheek to corner of mouth
  raises corners of mouth for smiling
• Orbicularis oris Present in lips closes mouth
  and protrudes lips
• Mentalis In mental region wrinkles chin,
  protrudes lower lip
• Buccinator Thin muscles, attach to orbicularis
  oris compress cheek as in whistling and sucking

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Skeletal Muscles Of Mastication

• Masseter Powerful muscle covering lateral aspect
  of mandibular ramus elevates mandible during
  chewing
• Temporalis Covers parts of temporal, frontal and
  parietal bones works with masseter to elevate
  mandible during chewing
• Digastric Two bellies united by an intermediate
  tendon, forming V shape under the chin open
  mouth and depress mandible

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Muscles That Act The Head And Neck

• Sternocleidomastoid
• Extends from manubrium of sternum and clavicle to
  mastoid process of temporal flexes and rotates
  the head laterally

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Muscles Of Respiration

• External intercostals Lie between ribs fibers
  run downwards and anteriorly pull ribs towards
  one another to lift rib cage
• Internal intercostals Lie between ribs fibers
  run deep and at right angles to external
  intercostals (i.e. run downward and posteriorly)
  depress rib cage
• Diaphragm

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Muscles Of Respiration

• Diaphragm Broad muscle, pierced by aorta,
  inferior vena cava and oesophagus forms floor of
  thoracic cavity fibers converge from margins of
  thoracic cage towards central tendon prime
  muscle for inspiration

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Muscles Of Abdominal Wall

• Rectus abdominis Medial superficial muscle pair
  extending from pubis to rib cage segmented by 3
  tendinous intersections used in sit ups and
  curls
• External oblique Largest and most superficial of
  3 lateral muscles fibers run downward and
  medially flex vertebral column and compress
  abdominal cavity
• Internal oblique Most fibers run upward and
  medially
• Transverse abdominis Deepest layer, fibers run
  horizontally compress abdominal contents
• Linea Alba Tendinous raphe (seam) between right
  and left rectus abdominus

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Muscles Of Anterior Thorax

• Pectoralis major Large fan-shaped muscle
  covering superior part of chest major muscle for
  flexion, rotation and adduction of arm
• Serratus anterior Fan-shaped muscle, inferior to
  pectoral muscles on lateral rib cage deep to
  scapula origins have saw-tooth appearance
  rotates scapula to inferior angle laterally and
  upwards

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Trapezius Of Posterior Thorax

• Kite-shaped flat muscle
• Upper fibers run inferiorly to scapula
• Middle fibers run horizontally to scapula
• Lower fibers run superiorly to scapula
• Major muscle for stabilizing, raising, retracting
  and rotating scapula

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Muscles Of Posterior Thorax

• Trapezius Most superficial muscle of posterior
  thorax stabilizes, raises, retracts and rotates
  scapula
• Levator scapulae Located at back and side of
  neck, deep to trapezius elevates or adducts
  scapula
• Rhomboids Deep to trapezius, inferior to levator
  scapulae the minor muscle is more superficial
  stabilize scapula

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Muscles Of The Arm

• Pectoralis major Prime mover of arm flexion
• Latissimus dorsi Prime mover of arm extension
• Deltoid Thick, rounded shoulder mass, common
  site of intramuscular injection prime mover of
  arm abduction
• Biceps brachii Two-headed fusiform muscle
  stabilizes shoulder joint flexes elbow joint and
  supinates forearm
• Brachialis Strong muscle, immediately deep to
  biceps brachii on humerus major forearm flexer
• Brachioradialis Superficial muscle of lateral
  forearm, extends from distal humerus to distal
  forearm forearm flexer
• Triceps brachii Large fleshy muscle of posterior
  compartment of arm, has 3 heads (long and lateral
  heads lie superficial to medial head) powerful
  forearm extensor

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Latissimus dorsi

• Broad, flat triangular muscle of lower back
  covered by trapezius superiorly
• Powerful mover of arm extension, adducts arm and
  medially rotates arm at shoulder

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Rotator Cuff Muscles

• Group of 4 muscles and their tendons in the
  shoulder
• Muscles form a cuff around shoulder joint and
  attach at upper portion of arm
• Supraspinatus Deep to trapezius, superior to
  scacpular spine stabilizes shoulder joint,
  prevents downward dislocation of humerus
• Infraspinatus Partially covered by deltoid and
  trapezius, inferior to scapular spine rotates
  humerus laterally
• Teres minor small elongated muscle, inferior to
  infraspinatus muscle rotates humerus laterally
• Subscapularis Forms part of posterior wall of
  axilla, tendon passes in front of shoulder joint
  chief medial rotator of humerus

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Muscles Of The Thigh, Leg, Foot And Ankle
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Muscles Of The Thigh, Leg, Foot And Ankle
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Muscles Of The Thigh, Leg, Foot And Ankle