Muscles of head, trunk, arm and leg: Origin, insertion and action PDF

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Muscles of head, trunk, arm and leg: Origin, insertion and action ...

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Muscles Lab Use your lab book, Unit 13, as a reference. Remember, you may be tested on any bold word during your lab exam. Define origin – Define insertion – **useful rule of thumb: The origin is usually proximal and the insertion is usually distal, especially in the limbs; the insertion is usually pulled toward the origin. Note: If you learned your bones, the origin and insertion of almost every muscle you will identify should be familiar to you. When the origin or insertion is familiar, I included it into the table below. You will only be tested on the name of the muscle. You will NOT be tested on the origin, insertion, or action. However, such information often helps you to determine the muscle’s name and/or location. Muscles of the Head: Muscle Orbicularis oris

Origin Muscle fibers surrounding opening of mouth

Insertion Skin at corner of mouth

Action Closes & protrudes lips, as in kissing; shapes lips during speech

Buccinator

Alveolar processes of maxilla and mandible

Orbicularis oris

Presses cheeks against teeth & lips as in whistling; assists in mastication (chewing)

Masseter

Maxilla

Ramus of mandible

Elevates mandible; as in closing mouth (prime muscle)

Temporalis

Temporal bone

Coronoid process of mandible

Elevates mandible, as in closing the mouth (synergistic muscle)

Orbicularis oculi

Medial wall of orbit

Skin around orbit

Closes eye

Sternocleidomastoid

Sternum and clavicle

Mastoid process of temporal bone

Flexes head laterally

Zygomaticus major

Zygomatic bone

Skin at corner of mouth

Draws angle of mouth laterally; smile

Occiptofrontalis

Raises eyebrows and wrinkles forehead, as in a look of surprise

Before moving on, label the muscles of the head in the attached figure (Fig 11-4) and study them. Only move on to the next group of muscles after you have memorized this group.

Muscles of the Trunk: Muscle External intercostal

Origin Inferior border of rib above

Insertion Superior border of rib below

Action Elevates ribs during inhalation

Internal intercostal

Superior border of rib below

Inferior border of rib above

Depresses ribs during exhalation

External oblique

Ribs (5-12)

Ilium of pelvic bone (iliac crest)

Flex and rotate vertebral column

Rectus abdominis

Pubis of pelvic bone (pubic symphysis)

Ribs ( 5th-7th) and xiphoid process of sternum

Compresses abdomen to aid in defecation, urination, child birth

Transverse abominis

Ilium of pelvic bone (iliac crest)

Xiphoid process of sternum

Compresses abdomen

Pectoralis major

Clavicle, sternum, & ribs (2-6)

Humerus

Adducts arm at shoulder joint

Serratus anterior

Ribs 1-8

scapula

Protracts shoulder

Latissimus dorsi

Spines of vertebrae (T7L5), sacrum

Humerus

Adducts arm at shoulder joint

Trapezius

Occipital bone & spines of C7-T12 vertebrae

Clavicle and scapula (acromion and spine)

Rotate & elevate scapula

Diaphragm

Required for breathing (contraction = inhalation; relaxation = exhalation)

Before moving on, label the muscles of the trunk in the attached figures (11-13a, 11-13b, 11-11) and study them. Only move on to the next group of muscles after you have memorized this group.

Muscles of the Arm: *Note: Anterior muscles tend to function as flexors and posterior muscles tend to function as extensors. Muscle Origin Insertion Action Clavicle (acromial end Humerus Abduct arm at shoulder Deltoid of) & scapula joint (acromion) Biceps brachii

Scapula

Radius

Flexion at elbow

Brachioradialis

Humerus

Radius (styloid process)

Flexion at elbow

Brachialis

Humerus

Ulna

Flexion at elbow

Triceps brachii

Scapula and humerus

Ulna (olecranon process)

Extension at elbow

Flexor carpi ulnaris

Humerus

Fifth metacarpal

Flexion at wrist

Extensor carpi ulnaris

Humerus and ulna

Fifth metacarpal

Extension at wrist

Before moving on, label the muscles of the arm in the attached figures (11-15a, 11-15b, 11-16a, 11-16b) and study them. Only move on to the next group of muscles after you have memorized this group.

Muscles of the Leg: *Note: Medial muscles tend to function as adductors and lateral muscles tend to function as abductors. Muscle Origin Insertion Action Pubis (inferior ramus) Tibia Adduction at hip; Gracilis flexion at knee

Gluteus maximus

Ilium of pelvic bone (iliac crest), sacrum, coccyx

Femur

Extension at hip (think “stairmaster”)

Sartorius (longest muscle in body)

Ilium of pelvic bone (anterior superior spine)

Tibia (tuberosity)

Flexion at knee; flexion and lateral rotation at hip; allow us to “cross our legs”

Hamstring group: - Bisceps femoris - Semimembranosus - Semitendinosus

Ischium of pelvic bone

Tibia (lateral and medial condyles) and fibula (head)

Flexion at knee

Quadriceps group: - Rectus femoris - Vastus lateralis - Vastus medialis - Vastus intermedius (muscle is deep to rectus femoris & not visible on figure) Gastrocnemius

Ilium of pelvic bone and femur

Patella and tibia

Extension at knee

Femur (lateral and medial condyles)

Calcaneus

Plantar flexes foot at ankle joint

Soleus

Fibula and tibia

Calcaneus

Extension at ankle

Tibialis anterior

Tibia (lateral condyle)

First metatarsal and first (medial) cuneiform

Dorsiflexes foot at ankle joint

Label the muscles of the leg in the attached figures (11-20a, 11-20b, 11-21a, 11-21bc) and study them. After studying each body region, label as many muscles as you can on the overview figures (11-3a, 11-3b)....