Skeletal muscles

Frontalis

O: Occipital Bone

I: Skin/muscle around the eye

Connected by Epicranial aponeurosis

raise eyebrows

Temporalis

O: Temporal bone/Zygomatic lower border

I: Lateral mandible

closes jaw;allows mastication

Orbicularis oculi

O: Frontal bone, maxillae 

I: Skin around eye

closes/protrudes eyes 

Masseter

O: Temporal bone/Zygomatic lower border

I: Lateral mandible

closes jaw;allows mastication

Orbicularis oris

O: Muscles near mouth

I: Skin of lips 

Closes/protrudes lips

Zygomaticus

O: Zygomatic bone

I: Orbic. oris

raises corners of the mouth 

Platysma

O: Upper chest fascia

I: Mandible lower border 

opens jaw/mouth  downward 

Sternocleidomastoid

O: Anterior sternum

I: Temporal Bone

pulls head to chest, raises to sternum  

Splenius capitis;

Semispinalis capitis

O: Lower cervical, upper thoracic vertebrae

I:Temporal and Occipital bones 

head rotation bending side to side 

extension upright position 

Trapezius

Origin(Descending): Occipital bone of the skull.

Insertion(Descending): Lateral third of the clavicle.

Origin(Transverse): Spinous processes of the vertebrae (T1-T4)

Insertion(Transverse): Spine of the scapula.

Origin(Ascending): Spinous process of the thoracic vertebrae (T1-T12)

Insertion(Ascending): Medial part of the spine of the scapula.

Elevates, retracts, and depresses the scapula. Extends the neck and laterally flexes the neck. Enables head rotation.

Pectoralis minor; Serratus anterior

Origin: Medial half of the clavicle.

Insertion: Coracoid process of the scapula

Responsible for moving the scapula forward and downward; elevates the ribs if the origin and insertion are reversed

Rhomboideus major

Origin: Attached to the Spinal column at the section of T2-T5 vertebrae 

Insertion: Inserts into the medial border of the scapula 

Retracts the scapula making it go in and out of the spinal column. Brings shoulder blades closer to the center of the body

Elevates the medial border of the scapula 

Levator scapulae

Origin: Transverse processes of the first four vertebrae of the spinal column

Insertion: Superior angle and medial border of the scapula 

Elevates the medial border of the scapula

Pectoralis major

underneath the breast tissue, the superior most and largest muscle of the anterior chest wall

pulls arm toward chest

Flexor–move arm up and forward 

Teres major

the inferior aspect of the scapula to the proximal part of the humeral shaft 

laterally or externally rotates the arm at the point of the shoulder joint

Teres minor;  Infraspinatus

teres minor: lateral border of the scapula (the thick edge of the bone)

infraspinatus: on the lower, slightly concave area on the dorsal area of the scapula

teres minor: assists in adduction and extension of the shoulder

infraspinatus: rotates/stabilizes shoulder joint, shoulder extension

Latissimus dorsi

lower shoulder blade, extend along spine to pelvis(back)

extend, abduct, and rotate the arm

Deltoid; 

Supraspinatus

spine of scapula

clavicle on the back of the shoulder 

moving your arm front, back, side, and toward the overhead position

Biceps brachii

against the agonist

- flexor; bends joint

- Antagonist: opposes triceps

Brachialis;

Brachioradialis

radial side of the forearm

flexes the elbow in all positions

Triceps brachii

on the dorsal part of the upper arm

(appears as the shape of a horseshoe on the posterior aspect of the arm)

extension of the elbow joint

Supinator

within the deep compartment of the posterior forearm

has 2 heads

forms floor of the cubital fossa

Pronators

anterior aspect of the forearm

2 different points of origin: the humeral head and the ulnar head

pronation of the forearm at the proximal radioulnar joint, flexion of the forearm at the elbow joint

*Flexors:

-carpi radialis

-carpi ulnaris

-digitorum

-Palmaris longus

(Summarize for whole muscle group)

Originates at the joint between the humerus and ulna (elbows)

The muscles stretch around the carpal bones 

(Summarize for whole muscle group)

Allows the arm from the elbow joint and down (proximal) to flex and extend. Some also allow a wide range of movement for the wrist

• Radialis allows for an extension of the wrist 

• Ulnaris enables flexion of the wrist 

• Digitorum flexes the fingers (adduction) but not the thumb

• Palmaris longus allows the wrist to flex

Synergist/antagonist:

• Prime mover: carpi ulnaris

• vs radialis (an extensor)

• w/ palmaris

*Extensors:

-carpi radialis longus, brevis

-carpi ulnaris

-digitorum

(Summarize for whole muscle group)

Originates at the humerus

Inserts at the carpals lateral side of the forearm

It crosses over the Ulna and the Radius and connects to the base of the pinkie from the joint at the elbow

from the outer lower arm near the elbow and connected to the middle of the fingers

(Summarize for whole muscle group)

Extends and deviates hands at the wrist for movement (CRL)

The carpi radialis brevis is functionally similar to the longus

Ulnaris is the most medial flexor which works to adduct the hand at the wrist

Digitorum helps bend your finger between the joints and your wrist.

Synergist/Antagonist:

Carpi Radialis Brevis vs Carpi Uinaris

Prime mover: extensor digitorum

vs. flexor digitorum profundus wi tibialis anterior

Rectus abdominis

Origin: Pubic crest and symphysis

Rectus abdominis

Insertion: Xiphoid process of the sternum;

costal cartilage of 5th - 7th rib

trunk flexion (up and down)

External oblique

Origin: external surface of ribs 5 - 12

Insertion: Linea alba, pubic tubercle,

and anterior half of iliac crest

rotation of trunk 

Internal oblique

Origin: Thoracolumbar fascia, anterior two-thirds of the iliac crest

Insertion: Inferior borders of ribs 10-12, linea alba, and pubic crest

• Lateral flexion of the trunk (side to side)

Transverse abdominis

Origin: Internal surfaces of costal

cartilages 7-12

Insertion: Linea alba, pubic crest, and pectineal line of pubis

• Compression of the abdomen

Psoas major;

Iliacus

Origin: Transverse processes of L1-L5

Insertion: Lesser trochanter of femur

• Flexes thigh at the hip

• Laterally rotates thigh at the hip

• Flexes vertebral column

Gluteus maximus

Origin: Surface of ilium posterior to posterior gluteal line and posterior inferior surface of sacrum and coccyx

Insertion: Gluteal tuberosity of femur and iliotibial tract

• Extends thigh at the hip

• Laterally rotates thigh at the hip

• Abducts thigh at the hip

Gluteus medius;

Gluteus minimus

Origin: Outer surface of ilium, between the posterior and anterior gluteal lines

Insertion: Lateral and superior surfaces of the greater trochanter of femur

• Abducts thigh at the hip

• Medially rotates thigh at the hip

• Laterally rotates thigh at the hip

Tensor fasciae latae

Origin: Anterior iliac crest

Insertion: Lateral condyle of tibia via iliotibial tract

• Abducts the thigh at the hip

• Flexes the thigh at the hip

Gracilis

Origin: Inferior border of pubic body near symphysis

Insertion: Proximal medial surface of tibia

• Adducts thigh at hip

Adductor longus; Adductor magnus

Origin(Longus): Superior aspect of pubis, below pubic tubercle

Insertion(Longus): Middle third of linea aspera of femur along medial lip

Origin(Magnus):

Oblique head - inferior ramus of pubis and ischial ramus

Vertical head - ischial tuberosity

Insertion(Magnus): 

Oblique head - gluteal tuberosity, linea aspera, and proximal supracondylar line of femur

Vertical head - adductor tubercle of femur

• Adducts the thigh at hip

• Flexes the thigh at hip

• Extends the thigh at the hip

Sartorius

Origin: Anterior superior iliac spine

Insertion: Medial aspect of the proximal part of the tibia

• Flexes leg at knee joint

• Medially rotates leg at knee joint

• Assists in flexion, abduction and lateral rotation of thigh at hip joint

*Quadriceps group:

-Rectus femoris

-Vastus lateralis

-Vastus medialis

-Vastus intermedius

(Summarize for whole muscle group)

Origin: The ilium and femur, come together in a tendon surrounding the patella

Insertion: The tibia

(Summarize for whole muscle group)

• Extends legs at the knee

• Hip flexion

• Maintenance of posture

• Proper stage of step/gait cycle

• Maintenance of patellar stability

*Hamstrings group:

-Biceps femoris

-Semitendinosus

-Semimembranosus

(Summarize for whole muscle group)

Origin: The ischial tuberosity of the pelvis, linea aspera on the posterior surface of the femur

Insertion: The head of the fibula

(Summarize for whole muscle group)

• Bending the knee joint

• Extending the hip joint

• Rotating the hip joint

Tibialis anterior

- Located in the anterior section of the leg

- Origin: Lateral condyle and superior 2/3 of the anterolateral surface of the tibia

- Insertion: Medial/plantar surfaces of medial cuneiform

• Dorsiflexes foot at the ankle

• Inverts food at the ankle

Fibularis longus

Origin(s): middle anterior surface of fibula, often fused with distal portion of extensor digitorum longus, interosseous margin

Insertion: Dorsal surface of base of 5th metatarsal

• Dorsiflexes foot at the ankle

• Everts foot at the ankle

Gastrocnemius

Origin:

Medial head - medial condyle of femur and area just above the condyle

Lateral head - lateral condyle of femur and area just above the condyle

Insertion: Posterior calcaneus via calcaneal tendon

• Plantar flexes foot

• Flexes the leg at the knee

Soleus

Origin: Proximal half of posterior surface of tibia along the soleal line, proximal ⅓ of posterior fibula

Insertion: Posterior calcaneus via calcaneal tendon

• Plantar flexes the foot