Understanding your spine and how it works can help you better understand some of the problems that occur from aging or injury. Many demands are placed on your spine. It holds up your head, shoulders, and upper body. It gives you support to stand up straight, and gives you flexibility to bend and twist. It also protects your spinal cord.

1. Spine
Dr. MD. MONSUR RAHMAN (PT)
MPT-Musculoskeletal Disorders
4th semester, MMIPR, MM(DU).

2. Cervical Vertebrae
• The cervical spine is much more mobile than the thoracic or lumbar
regions of the spine.
 Typical Cervical Vertebra (C3-C7)
The bodies of these four vertebrae are small, and transverse diameter is greater than anterio-posterior and
height dimensions.
 Atypical Cervical Vertebrae (C1-C2)
C1
 The Atlas, C1, is the topmost vertebra, and along with the Axis; forms the joint connecting the skull and
spine.
 Its chief peculiarity is that it has no body, and this is due to the fact that the body of the atlas has fused
with that of the Axis.
C2
 The Axis, C2, forms the pivot upon which the Atlas rotates. The most distinctive characteristic of this
bone is the strong odontoid process (dens) that rises perpendicularly from the upper surface of the body.
 The body is deeper in front than behind, and prolonged downward anteriorly so as to overlap the upper
and front part of the third vertebra

4. There are 26 muscles in the neck-10 pairs of 2 and 2 sets of 3,
to be precise.
- Sternocleidomastoid
- Scalene
- Platysma
- Digastric
- Omohyoid
- Sternohyoid
- Sternothyroid
- Mylohyoid
- Stylohyoid
- Geniohyoid
- Thyrohyoid

5. Sternocleidomastoid Muscle
Origin: upper border of manubrium sterni and medial third of upper surface
of clavicle.
Insertion: mastoid process and lateral third of superior nuchal line.
Nerve supply: Spinal accessory nerve (motor) and C2,3 (proprioceptive).
Action:
Both muscles extend the atlanto-occipital joint and flex the other cervical
intervertebral joints.
One muscle turns the head to make the face looks upward and to the
opposite side.
On fixation of the insertion, the muscle act as accessory muscle of inspiration

7. Trapezius Muscle
Origin: Medial third of superior nuchal line, external occipital protuberance,
ligamentum nuchal, 7th cervical spine all the thoracic spines.
Insertion: lateral third of clavicle, acromion process and spine of scapula.
Nerve supply: Spinal accessory nerve (motor) and C3,4 (proprioceptive).
Action:
 muscles extend the neck.
 Upper fibers of one side lateral flex the neck.
 Upper fibers elevate the shoulder.
 Middle fibers retract the shoulder.
 Lower fibers depress the shoulder.

9. Platysma Muscle
Origin: deep fascia of the upper part of
thorax (covering pectoralismajor and
deltoid).
Insertion: lower border of the mandible.
Mentalis
Depressor labii inferioris
Depressor anguli oris
Nerve supply: Cervical branch of facial
nerve.
Action: Depression of the mandible.

11. Splenius Capitis Muscle
Origin:
1.Lower part of ligamentum nuchae.
2.Upper four thoracic spines.
Insertion: mastoid process and outer part of
superior nuchal line.
Nerve supply: segmental innervation from the
dorsal rami of spinal nerves
Action: Extension of the neck.

13. Levator scapulae muscle
Origin: Transverse processes of upper four cervical vertebrae.
Insertion: Upper part of medial border of scapula.
Nerve supply: C3,4 and dorsal scapular nerve (C5).
Action: Elevation of scapula.

14. Scalenus Medius Muscle
Origin: Transverse processes of
lower six cervical vertebrae (2-7).
Insertion: Upper surface of the
first rib.
Nerve supply: Segmental from
the ventral rami of cervical
nerves.
Action: Elevation of first rib and
lateral flexion the neck.

15. Scalenus anterior muscle
Origin: Transverse processes of typical
cervical vertebrae (3-6).
Insertion: Scalene tubercle of the first
rib.
Nerve supply: Segmental from the
ventral rami of 4th, 5thand 6thcervical
nerves.
Action: Elevation of first rib and lateral
flexion the neck

16. Thoracic Spine
• 12 thoracic vertebra
• Vertebral body is heart shaped.
• Presence of demi-facets on the sides of each vertebral body – these
articulate with the heads of the ribs
• Presence of costal facets on the transverse processes – these articulate with
the tubercles of the ribs. They are present on T1-T10 only.
• The spinous processes are long
• The superior facet articulates with the head of the adjacent rib, and the
inferior facet articulates with the head of the rib below
• T2- T9 is a typical vertebra these facets are demi-facets.

17. Atypical Vertebra
 T1 – Superior facet is not a demi facet, as this is the only vertebrae
to articulate with the 1st rib.
 T10 – A single pair of whole facets is present which articulate with
the 10th rib. These facets are located across both the vertebral
body and the pedicle.
 T11 and T12 – Each have a single pair of entire costal facets,
which are located on the pedicles.