Мышцы спины

1. Soundarya V
I BDS
2009-2010

2.  The muscles of the neck can be grouped into
the following 4 layers :
 Trapezius and latissiumus dorsi .
 Levator scapulae, rhomboideus, serratus
posterior superior, serratus posterior inferior
and splenius.
 Erector spinae.

3.  The first layer consists of Trapezius and
latissiumus dorsi .
 The second layer comprises of splenius
muscle, Levator scapulae , rhomboideus
major and minor, serratus posterior superior
and serratus posterior inferior muscle .
 Third layer comprises of erector spinae .
 Fourth layer are Multifidus , rotatores,
interspinales , intertransversii and sub
occipital muscles.

4.  The muscles of the back will be divided into
3 main groups :
 superficial muscles associated with the
shoulder girdle.
 the intermediate muscles involved with
respiration.
 The deep muscles belonging to the vertebral
column.

5.  SKIN :
SENSORY NERVE SUPPLY
the skin of the back is supplied by the
posterior rami of the spinal nerves.
BLOOD SUPPLY :In the cervical region
branches from occipital, vertebral, deep
cervical and ascending cervical arteries
supply. In the thoracic region are the
posterior intercostal arteries and in the
lumbar region are lumbar and subcostal
arteries.

6. Venous drainage
 The veins form complicated plexuses
extending along the vertebral column from
the skull to the coccyx.
 Veins lying external to vertebral column form
the EXTERNAL VERTEBRAL VENOUS PLEXUS
 Within the vertebral canal form the
INTERNAL VERTEBRAL VENOUS PLEXUS.
 Tributaries from the vertebrae form
BASIVERTEBRAL VEINS drain into the internal
V V PLEXUS.
 INTERVERTEBRAL VEINS drain the internal
plexus

7. Venous drainage (continued)
 Veins communicate freely with venous
sinuses above through Foramen magnum and
with veins in the neck, thorax, abdomen and
pelvis.
 Finally tributaries from external plexus join
and drain via the vertebral, intercostal,
lumbar, and lateral sacral veins.
 All these veins are thin walled, valveless or
have incompetent valves.
 Venous flow is free and direction of flow
depends on the pressure difference between
regions.

9.  It is a large, flat, triangular muscle that
extends over the back of the neck and
thorax.
 ORIGIN : from the medial third of the
superior nuchal line of the occipital bone,
the external occipital protuberance,
ligamentum nuchae ; from the spine of the
seventh cervical vertebra and the spines and
the supraspinous ligaments of all the thoracic
vertebrae.

11.  INSERTION : The upper fibers are directed
downward and laterally into the lateral third
of the clavicle ;
 Middle fibers are directed horizontally into
the acromion and the upper border of the
spine of the scapula ;
 The lowest fibers are directed upwards and
laterally and are inserted on the medial end
of the spine of the scapula .

12.  NERVE SUPPLY : Motor fibers from the spinal
part of the XI cranial nerve ( accessory
nerve) .
Sensory fibers from the cervical nerves.(C3
and C4)
ACTION :
Suspends the shoulder from the skull and the
vertebral column .
Upper fibers

13. ACTION :
Suspends the shoulder from the skull and
the vertebral column .
Upper fibers elevate the scapula.
Middle fibers pull the scapula medially .
Lower fibers pull the medial border of the
scapula downward .

14.  It is a large , flat , triangular muscle that
extends over the lumbar region and the
lower part of the thorax.
 ORIGIN : From the posterior part of the iliac
crest , the lumbar fascia and the spines of
the lower six thoracic vertebrae, from the
lower three or four ribs and sometimes by a
few fibers from the inferior angle of the
scapula.

15.  INSERTION : Its tendon wraps around the
lower border of the Teres major muscle and
is inserted into the floor of the bicipital
groove of the humerus.
 NERVE SUPPLY : The thoracodorsal nerve , a
branch of the posterior cord of the brachial
plexus .
 ACTION : It extends , adducts and medially
rotates the arm.

17. MUSCLE ORIGIN INSERTION NERVE
SUPPLY
ACTION
Levator
scapulae
Rhomboid
minor
Transverse
process of
upper
cervical
vertebrae .
Lower part of
ligamentum
nuchae .
Medial border
of the scapulae
.
Medial border
of scapula
opposite to the
spine.
Third and
fourth
cervical
nerves.
C5
Raises the
scapulae
upwards and
braces the
shoulder
backwards.
Pulls the
scapula
medially
MUSCLES OF THE SECOND LAYER

18. MUSCLE ORIGIN INSERTION NERVE
SUPPLY
ACTION
Rhomboid
Major
Second to
fifth thoracic
spines
Medial border
of scapula
opposite to
the
infraspinous
fossa
C5 Pulls the
scapula
medially

19.  Erector spinae is the true muscle of the
back.
 It is supplied by the posterior rami of the
spinal nerves .
 ORIGIN : back of the sacrum between the
medial and lateral sacral crests from the
dorsal segment of the iliac crest.

20.  It splits into 3 columns .
 Iliocostalis in the lateral column .
 Longissimus in the middle column.
 Spinalis in the medial column.

22.  Multifidus, rotatores, interspinales and sub
occipital muscles.
 Arise from the mamillary processes of
lumbar vertebrae to be inserted into 2-3
spinous processes .
 Rotatores are the deepest group .
 They are well developed in the thoracic
region.