Neck, Abdominal, and Back Muscles: Anatomy and Functions

Neck Muscles

Longus Colli

O: C3-C5, anterior tubercles of the transverse process; C5-T3, anterior surfaces of bodies; C2-C6, anterior surfaces
I: C2-C6 anterior surface
A: Laterally flexes head and neck, rotates head and neck towards the same side

Sternocleidomastoid

O: Mastoid process
I: 1/3 medial clavicular head
A: Flexes head and neck, laterally flexes head and neck, rotates head and neck to the opposite side

Longus Capitus

O: C3-C6
I: Occipital bone
A: Flexes head and trunk bilaterally

Rectus Capitus Anterior

O: C2 atlas
I: Occipital bone
A: Flexes head and neck

Splenius Capitus

O: Ligamentum nuchae
I: Temporal bone, mastoid process
A: Rotates head to the same side, extends head and neck

Splenius Cervicis

O: T3-T6 spinous processes
I: C2-C3 posterior tubercles
A: Extends head and neck, flexes head and neck

Obliquus Capitus Inferior

O: C1 axis
I: C2
A: Rotates head and neck to the same side

Rectus Capitus Posterior Minor

O: C2
I: Occiput
A: Extends the head

Scalenes

O: C3-C6, C2-C7, C5-C7
I: 1st rib, 2nd rib
A: Laterally flexes head and neck toward the opposite side, flexes (anterior only)

Semispinalis

O: T3-T6
I: C2-C3
A: Extends head and neck, laterally flexes head and neck

Levator Scapulae

O: C1-C4
I: Superior angle of the scapula
A: Elevates and downwardly rotates scapula

Abdominal Muscles

External Oblique

O: Ribs 5-12
I: Ilium
A: Laterally flexes, rotates, compresses, and supports abdominal organs

Internal Oblique

O: Iliac crest
I: Ribs 10-12
A: Laterally flexes vertebral column

Diaphragm

O: Ribs 7-12
I: Central tendon
A: Expands thoracic cavity during inhalation

Rectus Abdominis

O: Pubic crest
I: Ribs 5-7
A: Laterally flexes vertebral column

Quadratus Lumborum

O: Iliac crest
I: L1-L4
A: Extends vertebral column, lateral flexion

Intertransversarii

O: L5-C1
I: Vertebrae above spinous processes
A: Laterally flexes vertebral column

Transverse Abdominis

O: Ribs 7-12
I: Linea alba
A: Compresses and supports abdominal organs

Back Muscles

Spinalis

O: L2-T11
I: T1-T8
A: Extends vertebral column

Multifidus

O: L5-C4
I: L5-C2
A: Extends vertebral column

Iliocostalis

O: Sacrum
I: L1-L3
A: Extends vertebral column

Internal Intercostals

O: Ribs
I: Rib below
A: Depresses ribs during exhalation

Longissimus

O: Thoracolumbar aponeuroses
I: T1-T12
A: Extends vertebral column

Rotatores

O: L5-C1
I: Vertebrae above spinous process
A: Extends vertebral column

Latissimus Dorsi

O: T7-L5
I: Bicipital groove of humerus
A: Adducts, extends, and internally rotates shoulder