Muscles of the Neck, Back, and Abdomen

Flexion and extension of the head

Lateral flexion and rotation:

Muscles that move the head

Anterior: Rectus capitis anterior

Longus capitis

Scalenes (support and respiration)

Muscles that move the head

Anterior/Lateral: Sternocleidomastoid

Sternocleidomastoid

Sternocleidomastoid:

Origin:

Manubrium (sternum) and clavicle.

Insertion: Mastoid process (temporal bone)

Action(s): Both: flexion of the head and neck

Single: rotation and lateral flexion

Muscles that move the head

Posterior: Longissimus capitis (part of erector spinae)

Spinalis capitis

Splenius capitis

Semispinalis capitis

Longissimus capitis

Longissimus Capitis

Part of the Erector Spinae group

Origin: Spinous processes of cervical and thoracic

vertebrae

Insertion: Mastoid process

Action: Extension of the head at the neck (both)

Lateral flexion and rotation of the head at the neck (one side)

Spinalis capitis (medial) and Semispinalis capitis (lateral)

Spinalis capitis

Part of the Erector Spinae group

Origin: Spinous processes of cervical and

thoracic vertebrae

Insertion: Occipital bone

Action:

Extension of the head at the neck

Splenius capitis

Splenius Capitis

Origin: Spinous process of cervical and thoracic

vertebrae (and ligamentum nuchae)

Insertion: Mastoid process (temporal bone) and occipital

bone

Action: Extension of the head at the neck (both)

Lateral flexion and rotation of the head at the neck (one side)

Semispinalis capitis

Semispinalis capitis

Origin:

Transverse processes of C4-T7 vertebrae

Insertion: Occipital bone

Action: Extension of the head at the neck (both)

Rotation of the head at the neck (one side)

Origins: Longissimus capitis=cervical and thoracic vertebrae

Splenius capitis= cervical and thoracic vertebrae

Spinalis capitis= cervical and thoracic vertebrae

Semispinalis capitis= cervical and thoracic vertebrae

Insertions: Longissimus capitis= mastoid process

Splenius capitis= mastoid process and occipital bone

Spinalis capitis= occipital bone

Semispinalis capitis= occipital bone

Posterior Neck Muscles (that move the head):

Posterior Neck Muscles (actions)

Actions: Longissimus capitis= extension and

lateral flexion of the head at the neck

Splenius capitis= extension, lateral flexion, and rotation of the head at the neck

Spinalis capitis= extension and lateral flexion of the head at the neck

Semispinalis capitis= extension and rotation of the head at the neck

Muscles of the vertebral column that move the back/torso:

Superficial muscles (Erector Spinae)

Spinalis group (medial): capitis, cervicis, thoracis

Longissimus group (intermediate): capitis, cervicis, thoracis

Iliocostalis group (lateral): cervicis, thoracis, lumborum

Erector spinae:Iliocostalis Longissimus Spinalis

Spinalis group (cervicis and thoracis)

Longissimus Group ( cervicis and thoracis)

Iliocostalis cervicis

Iliocostalis thoracis and lumborum

Semispinalis cervicis

Semispinalis Thoracis

Muscles of the Vertebral column

Deep muscles

Interspinalis

Intertransversales

Multifidus

Rotatores

Semispinalis cervicis and thoracis

Psoas minor

Quadratus lumborum

Interspinalis

Intertransversarius

Rotatores

Multifidus

Quadratus Lumborum

Quadratus Lumborum

Quadratus Lumborum

Origin: Iliac crest (pelvis)

Insertion: 12th rib

Lumbar vertebrae (transverse processes)

Action: Lateral flexion of the lumbar spine.

Also functions to stabilize the pelvis/lumbar spine

Muscles of the abdomen

Rectus abdominis

External oblique

Internal oblique

Transverse abdominis

Rectus Abdominis:

Origin: pubis (pubic crest, symphysis pubis)

Insertion: sternum and ribs (xiphoid process, cartilage)

Actions: Both=flexion,

compression

Single= lateral flexion

Rectus Abdominis:

External Obliques:

Origin: ribs (lower 8)

Insertion: Iliac crest, pubis, inguinal ligament, linea alba

Actions: Both: flexion

Single: lateral flexion, rotation

External Oblique

External oblique

Internal Obliques:

Origin: Iliac crest, inguinal ligament

Insertion: ribs, linea alba

Actions: Both: flexion

Single: lateral flexion, rotation

Internal Oblique

Internal oblique

Transverse Abdominis:

Origin: Iliac crest,

cartilage of ribs

Insertion: Pubis, linea alba

Action: Compression,

forced expiration

Transverse Abdominis

Transverse abdominis

Muscles of the Thorax:

Used for respiration Scalenes

Anterior, middle, and posterior

Elevates the first two ribs to increase thoracic volume

Intercostals

External intercostals: expand the chest

Internal intercostals: forced expiration

Diaphram

Responsible for most of breathing movements

Scalenes (muscles in the neck)

Anterior Scalene

Middle Scalene

Posterior Scalene

These assist with respiration (elevates upper ribs).

They also produce lateral flexion and rotation at the cervical spine.

Anterior Scalene (lateral view)

Middle Scalene (anterior view)

Posterior Scalene (lateral view)

External Intercostals

Internal intercostals

Diaphram