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)

Posterior Neck Muscles (that move the head):
 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 (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:
 12 th 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