Muscles

 

Muscle # refers to Lab Skeleton Origin Insertion Joint Actions
Anconeus

82

Posterior surface of lateral epicondyle of humerus Lateral side of olecranon process and posterior surface of upper part of ulna Weak extensor of elbow; moves ulna in pronation
Biceps Brachii

 

Long head: upper margin of glenoid fossa

Short head: apex of coracoid process of scapula

Bicipital tuberosity of radius Supinates forearm; elbow flexion; weak flexion of shoulder
Biceps femoris

130

Long head: lower and medial impression on tuberosity of ishium

Short head: lateral lip of linea aspera

Lateral surface of head of fibula and lateral condyle of tibia Flexes & laterally rotates knee.  Long head extends hip
Brachialis Anterior surface of lower half of humerus Anterior surface of coronoid process of ulna Elbow flexor
Brachioradialis

84

Upper two-thirds of lateral supracondylar ridge of humerus Lateral side of base of styloid process of radius Flexes elbow; brings forearm into mid-prone position
Deltoid

72

Anterior: ant. border of outer 3rd of clavicle

middle: acromion process & outer end of clavicle

posterior: lower margin of spine of scapula

Lateral aspect of humerus near midpoint Abducts arm.

Anterior fibers flex & medially rotate.

Posterior fibers extend & laterally rotate

External Obliques

66

Anterior half of crest of ilium; aponeurosis from ribs to crest of pubis Lower border of lower 8 ribs by tendinous slips that interdigitate with those of serratus anterior Supports abdominal wall, aids forced respiration, raises intra-abdominal pressure
Gastrocnemius

139

Posterior surface of each femoral condyle and adjacent parts by two separate heads Posterior surface of calcaneus by means of calcaneal tendon (tendon of Achilles) Plantar flexes foot.

Flexes knee

Gluteus Maximus

112

Posterior gluteal line of ilium and adjacent portion of crest; posterior surface of lower part of sacrum and side of coccyx Posterior surface of femur on ridge below greater trochanter; iliotibial tract of fasacia lata Extends & laterally rotates hip.  Maintains knee extended via iliotibial tract
Gluteus Medius

113

Posterior surface of ilium between crest, posterior gluteal line, and anterior gluteal line Oblique ridge on lateral surface of greater trochanter Abducts & medially rotates hip.  Tilts pelvis on walking
Gracilis

128

Anterior aspect of lower half of symphysis pubis and upper half of pubic arch Medial surface of tibia just below condyle Adducts hip. Flexes knee & medially rotates flexed knee
Iliopsoas

111a,b

 

Psoas major: sides of bodies and intervertebral cartilages of last thoracic and all lumbar vertebrae; front and lower borders of transverse processes of lumbar vertebrae

Iliacus: anterior surface of ilium and base of sacrum

Both: lesser trochanter of femur and for a short distance below along medial border of shaft Psoas major: flexes & medially rotates hip. 

Iliacus: flexes & medially rotates hip

Infraspinatus

74

Axillary border and post. surface of scapula below scapular spine Posterior aspect of greater tuberosity of humerus Lateral rotation of arm; stabilizes shoulder joint
Internal Obliques

67

Inguinal ligament; crest of ilium; thoracolumbar fascia Anterior and middle fibers into crest of pubis, linea alba, and aponeurosis on front of body; posterior fibers by three separate slips, into cartilages of lower 3 ribs Abducts & rotates trunk.  Supports abdominal wall, aids forced respiration, raises intra-abdominal pressure
Latissimus Dorsi

47

Spinous processes of lower six thoracic and all lumbar vertebrae; post. surface of sacrum; crest of ilium; lower 3 ribs Anterior surface of humerus below head by flat tendon just anterior to, and parallel with, tendon of pectoralis major Extends, adducts, medially rotates arm.  Costal attachment aids in deep inspiration and forced expiration
Pectoralis Major

57

Medial two thirds of clavicle; anterior surface of sternum; cartilage of first 6 ribs; slip from aponeurosis of external oblique abdominal muscle Lateral surface of humerus just below head by flat tendon 2 to 3 inches wide Clavicular head: flexes & adducts arm

Sternal head: adducts & medially rotates arm

Peroneous Longus

137

Lateral condyle of tibia; lateral surface of head and upper two-thirds of fibula Lateral margin of plantar surface of first cuneiform and base of first metatarsal Plantar flexes and everts foot.  Supports longitudinal and transverse arches
Rectus Abdominus

64

Crest of pubis Cartilages of 5th, 6th, and 7th ribs Flexes trunk, aids forced inspiration, and raises intra-abdominal pressure.
Rectus femoris

112a

Anterior inferior iliac spine and groove above brim of acetabulum Base of patella, as part of quadriceps femoris tendon; by means of patellar ligament it attaches to the tibial tuberosity Extends leg at knee. 

Flexes thigh at hip

Rhomboids

48

Spinous processes of 7th cervical and first 5 thoracic vertebrae Vertebral border of scapula from spine to inferior angle Retracts scapula; rotates scapula to rest position
Sartorius

121

Anterior superior iliac spine and upper half of notch below it Anterior and medial surface of tibia just below condyle Flexes, abducts, & laterally rotates thigh at hip.

Flexes & medially rotates leg at knee

Semimembranosus

132

Upper and lateral impression on tuberosity of ischium Horizontal groove on posterior surface of medial condyle of tibia Flexes & medially rotates knee.  Extends hip
Semitendinosus

131

Lower and medial impression on tuberosity of ischium with biceps femoris Upper part of medial surface of shaft of tibia Flexes & medially rotates knee.  Extends hip
Serratus anterior

51

Outer surface of upper 9 ribs at side of chest Anterior surface of vertebral border and inferior angle of scapula Laterally rotates & protracts scapula
Soleus

139c

Posterior surface of head of fibula and upper two-thirds of shaft; popliteal line and medial border of middle third of tibia Posterior surface of calcaneus by means of calcaneal tendon (tendon of Achilles) Plantar flexes foot.  Aids venous return
Sterno-cleidomastoid

20

By two heads from top of sternum and medial third of clavicle Mastoid process of temporal bone and adjacent portion of occipital bone Flexes and laterally rotates cervical spine
Subscapularis

77

Entire anterior surface of scapula Lesser tuberosity of humerus

 

Medial rotation of arm; stabilizes shoulder joint
Supraspinatus

73

Medial two-thirds of supraspinatus fossa above scapular spine Top of greater tuberosity of humerus Abducts arm; stabilizes shoulder joint
Tensor fascia latae

115

Anterior part of outer lip of iliac crest and outer surface of anterior superior iliac spine Iliotibial tract of fascia latae on lateroanterior aspect of thigh, about one-third of the way down Maintains knee extended.  Abducts hip
Teres Major

76

Posterior surface of inferior angle of scapula Anterior surface of humerus below head, just medial to latissimus dorsi tendon Medial rotation & adduction of arm; stabilizes shoulder joint
Teres Minor

75

Axillary border and post. surface of scapula below scapular spine Posterior aspect of greater tuberosity of humerus Lateral rotation of arm; stabilizes shoulder joint

 

The three vasti

122b,c,d

Lateralis: upper part of intertrochanteric line; anterior and lower borders of greater trochanter; lateral lip of gluteal tuberosity; upper half of linea aspera

Intermedius: anterior and lateral surface of upper two-thirds of shaft of femur

Medialis: lower half of intertrochanteric line; medial lip of linea aspera; upper part of medial supracondylar line

The tendons of the three vasti muscles unite with that of rectus femoris to form the quadriceps femoris tendon; this Attaches to the base of the patella and, indirectly, by means of the patellar ligament, to the tuberosity of the tibia Lateralis: extends knee

Intermedius: extends knee

Medialis: extends knee & stabilizes patella

Tibialis anterior

133

Lateral condyle and upper two thirds of lateral surface of tibia Plantar surface of base of first metatarsal and medial surface of first cuneiform Dorsiflexes & inverts foot.  Supports medial longitudinal arch
Transversus Abdominus

68

Inguinal ligament, crest of ilium, thoracolumbar fascia, and cartilages of lower six ribs Linea alba and crest of pubis Supports abdominal wall, aids forced expiration, & raises intra-abdominal pressure
Trapezius

25

Occipital bone; ligamentum nuchae; spinous processes of 7th cervical and all thoracic vertebrae Part 1: posterior border of lateral third of clavicle

Part 2: top of acromion process

Part 3: upper border of scapular spine

Part 4: root of scapular spine

Laterally rotates, elevates, & retracts scapula. 

If scapula is fixed, lateral flexion & extension of neck

Triceps brachii

81a,b,c

Long head: infraglenoid tuberosity

Lateral head: posterior surface of upper half of humerus

Medial head: posterior surface of lower two-thirds of humerus

Olecranon process of ulna Extends elbow. 

Long head stabilizes shoulder joint. 

Medial head retracts capsule of elbow joint on extension

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