Muscular System

Anatomy Lab 3

Trapezius actions

Elevates, retracts, depresses, and rotates the scapula

Trapezius attachment

Lateral clavicle, spine of the scapula

Serratus anterior actions

Protracts the scapula, holds the scapula against the rib cage

Serratus anterior attachments

Lateral margins of ribs, anterior humerus

Pectoralis major actions

Adducts, flexes and medially rotates the arm

Pectoralis major attachments

Sternum, clavicle, ribs, humerus

Pectoralis minor actions

Protracts, depresses, and rotates the scpaula

Pectoralis minor attachments

Anterior ribs and coracoid process of the scapula

Latissimus dorsi actions

Adduction, extension, and medial rotation the arm

Latissimus dorsi attatchments

Lower back and humerus

Teres major actions

Extension, adduction, and internal rotation of the humerus

Teres major attachments

Scapula and humerus

Deltoid actions

Abducts, flexes, extends, and medially and laterally rotates the arm

Deltoid attachments

Clavicle, scapular spine, humerus

Rotator cuff muscles (SITS)

• Support an surround glenohumeral joint (shoulder)

• Responsible for rotational movements of the arm

Subscapularis actions

Medially rotates arm

Subscapularis attachments

Subscapular fossa of scapula and lesser tubercle of the humerus

Infraspinatus actions

Laterally rotates the arm

Infraspinatus attachments

Infraspinous fossa of scapula and greater tubercle of the humerus

Supraspinatus actions

Initiates abduction

Supraspinatus attatchments

Supraspinous fossa of the scapula and greater tubercle of the humerus

Teres minor actions

Laterally rotates the arm

Teres minor attachments

Lateral margin of the scapula and the greater tubercle of the humerus

Anterior compartment of the arm

• Biceps brachii

• Coracobrachialis

• Brachialis

Biceps brachii actions

Flex arm at shoulder, flex forearm at elbow, supinates forearm

Biceps brachii attachments

Scapula and radial tuberosity

Corabrachialis action

Flex arm at shoulder

Corabrachialis attachments

Coracoid process of scapula and humerus

Brachialis actions

Flex forearm at elbow

Brachialis attachments

Ulnar tuberosity and humerus

Posterior compartment of the arm

Triceps brachii

Triceps brachii actions

Extend arm (long head only) and extend forearm (all heads)

Triceps brachii attachments

Olecranon process of ulna, scapula (long head), humerus (medial and lateral heads)

Anterior compartment of the forearm

Mostly synergists that flex wrist and digits and collectively the “flexor group” muscles

Flexor group actions

Flex wrist and digits

Flexor group attachments

Medial epicondyle of the humerus, wrist, and digits

Brachioradialis action

Flex the forearm at the elbow

Brachioradialis attachments

Lateral epicondyle and distal radius

Posterior compartment of the forearm

Mostly a group of synergists that extend wrist and digits, collectively the “extensor group” muscles

Flexor group muscles

• Flexor carpi ulnar

• Flexor carpi radialis

• Flexor digitorum superficialis

• Flexor digitorum profundus

• Pronator teres

Extensor group actions

Extend the wrist and digits

Extensor group attachments

Lateral epicondyle of the humerus, wrist, and digits

Extensor group muscles

• Extensor carpi ulnar

• Extensor carpi radialis longis

• Extensor carpi radialis brevis

• Extensor digitorum

Thenar muscle actions

Moves thumb, flexion abduction, opposition

Thenar muscle attachments

Carpals and pollex phalanges

Thenar muscles

• Flexor pollicis brevis

• Abductor pollicis brevis

• Opponens pollicis

Hypothenar muscle actions

Moves digit 5, flexion, abduction, and opposition

Hypothenar muscle attachments

Carpals and digit 5 phalanges

Hypothenar muscles

• Flexor digiti minimi brevis

• Abductor digiti minimi

• Opponens digiti minimi

Interossei muscles

• Between metacarpals

• Palmar and dorsal types

Palmar interossei actions

Adducts digits

Dorsal interossei actions

Abducts digits

Interosseous muscle attachments

Metacarpals 2-5 and phalanges 2-5

Gluteus maximus actions

Extend and laterally rotate thigh

Gluteus maximus attachments

Ilium, sacrum, and femur

Gluteus medius and gluteus minimus actions

Abduct thing/hip

Gluteus medius and gluteus minimus attachments

Ilium- greater trochanter

Tensor fasciae latae action

Flexes and abducts thigh

Tensor fasciae latae attachments

Ilium- fascia lata

Anterior compartment of the thigh

• Quadriceps femoris

• Sartorius

Sartorius action

Flexes, abducts, and laterally rotates thigh, flexes leg

Quadriceps femoris heads

• Rectus femoris

• Vastus intermedius

• Vastus medialis

• Vastus lateralis

Rectus femoris action

Extends knee and flexes hip

Rectus femoris attachment

Ilium and femur- tibial tuberosity via patella

Vastus intermedius, medialis, and lateralis actions

Extend knee

Vastus intermedius, medialis, and lateralis attachment

Femur and tibial tuberosity via patella

Iliopsoas (liacus + Psoas major) actions

Flexes thigh

Iliopsoas (liacus + Psoas major) attachments

Ilium, lumbar vertebra – lesser trochanter of femur

Posterior compartment of the thigh

Hamstring group

• Biceps femoris (L)

• Semitendinosus

• Semimembranosus

Hamstring actions

Extension of hip, flexion of knee

Hamstring attachments

Ischial tuberosity – Tibia or fibula

Medial Compartment of the Thigh

• Adductor magnus

• Adductor brevis

• Adductor longus

• Gracilis

Adductor magnus, adductor brevis, adductor longus, gracilis actions

Adduction of hip/thigh (G) flex leg

Adductor magnus, adductor brevis, adductor longus, gracilis attachment

Pubis and Femur (G) tibia.

Tibialis anterior actions

Dorsiflexion and inversion

Tibialis anterior attachments

Tibia and dorsum of foot (tarsals)

Extensor digitorum longus actions

Dorsiflexion and extension of toes

Extensor digitorum longus attachments

Fibular and interosseous membrane and dorsum of phalanges

Fibularis longus and brevis actions

Plantarflexion and eversion

Fibularis longus and brevis attachment

Fibula and foot

Triceps surae

• Gastrocnemius

• Soleus

Gastrocnemius actions

Flexion of the leg and plantarflexion of the foot

Gastrocnemius attachments

Femur and calcaneus

Soleus actions

Plantar flexion

Soleus attachments

Soleal line (tibia) and calcaneus

Posterior Compartment of the Leg

• Flexor hallucis longus

• Flexor digitorum longus

• Tibialis posterior

Flexor hallucis longus, flexor digitorum longus, and tibialis posterior action

Plantarflexion of the hallux and foot, plantarflexion of

digits II–V and foot

Flexor hallucis longus, flexor digitorum longus, and tibialis posterior attachment

(H) Fibula and Hallux, (D) Tibia and Digits 2 to 5

Dorsum of the foot

• Extensor digitorum brevis

  • Extends the digitis

• Tendons of the extensor digitorum longus

Sole of the Foot

• 4 layers

• Intrinsic foot muscles: both attachments are in the foot.

• Extrinsic foot muscles: muscle belly in the leg, tendon into the foot

• Muscles that flex the toes, abduct and adduct the digits

Muscles of facial expression

• Orbicularis oris

• Orbicularis oculi

• Buccinator

• Zygomaticus major

• Frontalis

Orbicularis oris action

Puckers/closes lips

Orbicularis oris attachments

Maxilla and mandible, skin around lips

Buccinator action

Tightens cheeks, keeps food on the teeth

Buccinator attachments

Maxilla and mandible, orbicularis oris

Zygomaticus major actions

Pulls side of lip laterally and superiorly (smile)

Zygomaticus major attachments

Zygomatic bone and soft tissue of the lip

Orbicularis oculi action

Closes eyelids

Orbicularis oculi attachment

Frontal bone, skin around eye

Frontalis action

Raises eyebrows