Upper Quarter Muscle Anatomy

Origin/Insertion/Action

upper trapezius

origin: medial third of superior nuchal line, external occipital protuberance, spinous processes C7-T12; insertion: lateral third of clavicle, acromion process, and spine of scapula. Function: elevates and upwardly rotates the scapula.

levator scapulae

Origin: transverse processes of C1-C4 vertebrae; insertion: superior angle and medial border of scapula. Function: elevates the scapula and assists in downward rotation.

sternocleidomastoid

A muscle that originates from the manubrium of the sternum and the clavicle, inserting at the mastoid process of the temporal bone. It functions to flex and contralaterally rotate the head.

anterior scalene

A muscle that originates from the transverse processes of the cervical vertebrae C3-C6 and inserts at the first rib. It functions to elevate the first rib and helps in lateral flexion of the neck.

middle scalene

A muscle located in the lateral neck region, it originates from the posterior tubercles of transverse processes of cervical vertebrae C2-C7 and inserts on the first rib. Its function includes lateral flexion of the neck and elevating the first rib during inspiration.

posterior scalene

A muscle located posterior to the middle scalene, it originates from the transverse processes of cervical vertebrae C4-C6 and inserts on the second rib. Its primary function includes lateral flexion of the neck and elevating the second rib during inspiration.

Supraspinatus

Origin: supraspinous process of scapula

Insertion: superior facet of greater tubercle of humerus

Action: shoulder abduction

Infraspinatus

Origin: infraspinous fossa of scapula

Insertion: middle facet of greater tubercle of humerus

Action: UE external rotation

Subscapularis

Origin: subscapular fossa

Insertion: lesser tubercle of humerus on anterior shoulder

Action: internal rotation, adduction

Teres minor

Origin: lateral border of scapula

Insertion: inferior facet of greater tubercle of humerus and posterior capsule

Action: external rotation, stabilization

Teres Major

Origin: posterior aspect of inferior scapular angle

Insertion: medial lip of the intertubercular sulcus of humerus

Action: internal rotation and adduction of humerus, extension of humerus from a flexed position

Latissimus dorsi

Origin: Spinous processes of vertebrae T7-L5, thoracolumbar fascia, iliac crest, inferior 3 or 4 ribs and inferior angle of scapula

Insertion: floor of the intertubercular groove of the humerus

Action: Adducts, extends and internally rotates the arm when the insertion is moved towards the origin. When observing the muscle action of the origin towards the insertion, the lats are a very powerful rotator of the trunk

occipitalis

origin: Superior nuchal line of the occipital bone and mastoid process of the temporal bone

insertion: Galea aponeurosis

Action: Moves the scalp backand raises the eyebrows.

splenius cervicis

origin: spinous processes of T3-6

Insertion: transverse processes of C1-3

Action: B extension, unilateral sidebending and rotation

splenius capitis

origin: nuchal ligament and spinous process of C7-T3

insertion: mastoid process of temporal bone and lateral third of superior nuchal line
Action: extends and rotates the head.

frontalis

origin: galea aponeurosis

insertion: skin of the forehead at the orbicularis oculi muscles Action: raises the eyebrows and wrinkles the forehead.

procerus

origin: fascia over the nasal bone and cartilage

insertion: into the skin at the lower part of the forehead between the eyebrows

action: Draws the eyebrows down medially

temporalis

origin: Temporal lines on the parietal bone of the skull and the superior temporal surface of the sphenoid bone
insertion: Coronoid process of the mandible and retromolar fossa
action: elevates and retracts the mandible.

superior orbicularis occuli

Origin: frontal bone and medial orbital rim,

Insertion: skin of the eyelids, Lateral palpebral raphe

Action: closes the eyelids.

nasalis

origin: maxilla, near the canine tooth

insertion: skin over the bridge of the nose

action: flares the nostrils

zygomaticus

origin: zygomatic boneThe zygomaticus muscle consists of two parts, the zygomaticus major which aids in smiling and the zygomaticus minor which assists in elevating the upper lip.

Insertion: muscles at the angle of the mouth

Action: elevates the corners of the mouth.

pterygoid

origin: sphenoid bone, near the pterygoid process, and

insertion: angle of the mandible.

Action: aids in chewing by allowing side-to-side movement of the jaw.

masseter

origin: zygomatic arch and maxilla.

Insertion: angle and ramus of the mandible.

Action: elevates the mandible for chewing.

temporalis

origin: temporal bone.

Insertion: coronoid process of the mandible.

Action: elevates and retracts the mandible.

rhomboids

origin: nuchal ligaments, spinal processes of C7-T5

major: Spinous processes of the T2 to T5 vertebrae

minor: Spinous processes of C7-T1

Insertion: medial border of the scapula.

Action: Pulls scapulae medially, rotates scapulae, holds scapulae into thorax wall

biceps brachii

origin: Short head: coracoid process of the scapula.
Long head: supraglenoid tubercle

Insertion: Radial tuberosity and bicipital aponeurosis into deep fascia on medial part of forearm

Action: flexes the elbow and supinates the forearm.

triceps

origin: Long head: infraglenoid tubercle of scapula
Lateral head: above the radial groove
Medial head: below the radial groove

insertion: olecranon process of the ulna.

Action: Extends forearm, long head extends, adducts arm, extends shoulder

pectoralis major

origin: Clavicular head: anterior surface of the medial half of the clavicle.
Sternocostal head: anterior surface of the sternum, the superior six costal cartilages, and the aponeurosis of the external oblique muscle

Insertion: lateral lip of the bicipital groove of the humerus.

Action: Adducts, medially rotates, and flexes the humerus.

pectoralis minor

Origin: 3-5th ribs near the costochrondral junction

Insertion: corocoid process

Action: Stabilizes the scapula by drawing it inferiorly and anteriorly against the thoracic wall, raises ribs in inhalation