Download Back muscles and space

Muscles Of Back
Extrinsic muscles:
• Move the upper limbs and
the ribs.
• Innervated by anterior
rami of spinal nerves.
Intrinsic muscles:
• Maintain posture and
move the vertebral
column.
• Innervated by the posterior
rami of spinal nerves.
Deep muscles ­ Back
• The intrinsic muscles are
also arranged in layers.
• Superficial layers ­ splenius
muscles , erector spinae.
• Deeper layers ­
spinotransverse group,
semi­spinalis, multifidus
the rotatores, and the
suboccipital muscles.
• Deepest­ interspinal and
intertransverse muscles.
Extrinsic (Superficial ) muscles:
•
•
•
•
•
Trapezius
Latissimus dorsi
Levator scapulae
Rhomboid minor
Rhomboid major
Trapezius - Origin:
• External occipital
protuberance
• Nuchal ligament
• Spinous processes
of vertebrae C7 to
T12
• Supraspinous
ligaments.
Trapezius ­ Insertion & Actions:
• Superior part -the lateral
one­third of the clavicle
(Elevates the scapula).
• Middle part - the
acromion and spine of the
scapula (Retracts the
scapula).
• Inferior part - the medial
end of the spine of the
scapula (Depresses the
scapula).
inferior
Spinal part of accessory , C3, C4
Latissimus dorsi
Origin: Iliac crest
• Thoracolumbar fascia
• Spinous process of T7­
T12
• Lower 4 Ribs
• Inferior angle of
scapula.
Insertion: Floor of
the intertubercular
sulcus
Latissimus dorsi
Action:
• Adduction, extension
and medial rotation of
shoulder
• Violent expiratory effort
• Hold inferior angle of
scapula
Thoraco Dorsal Nerve
Levator scapulae
Levator scapulae
m.
• Origin: Transverse
processes of C1, C2.
• Posterior tubercles
of transverse
processes of C3, C4.
• Insertion: Superior
angle & medial
border of the
scapula.
Levator scapulae
Action:
• Elevates the scapula
• Rotates the scapula to depress the glenoid cavity.
Dorsal scapular nerve, C3, C4
Rhomboid
• Rhomboid minor:
Rhomboid minor m.
Rhomboid major m.
Origin:
• Nuchal ligament
• Spinous processes of
vertebrae C7 and T1.
Insertion:
• Root of the spine of the
scapula near the spine.
Rhomboid
• Rhomboid major :
Rhomboid minor m.
Rhomboid major m.
Origin:
• Spinous processes of
vertebrae T2 to T5.
• Supraspinous
Ligaments.
Insertion:
• Medial border of the
scapula inferior to the
spine.
Rhomboid
Action:
• Retract the scapula.
• Steady the scapula.
Dorsal Scapular Nerve
Triangles of the Back
• The triangle of
auscultation ­ bounded by
the latissimus dorsi muscle,
the trapezius muscle, and
the scapula.
• The lumbar triangle­
bounded by the latissimus
dorsi muscle, the external
oblique muscle, and the
iliac crest.
Scapular spaces
1. Quadrangular space
2. Upper triangular
space.
3. Lower triangular
space.
Quadrangular spaces
Boundaries
• Above(from before
backwards) Subscapularies,
capsule of shoulder joint, &
teres minor.
• Below­Teres major.
• Medially -Long head of
triceps.
• Laterally­surgical neck of
Structures passing: Axillary
humerus.
nerve & posterior circumflex
humeral vessels.
Upper Triangular spaces
Boundaries:
• Above­Teres minor
• Below­Teres major
• Laterally­Long head of
triceps
Apex­lateral border of
scapula where teres
major & minor muscles
converge
Structures passing:
Circumflex scapular vessels
Lower triangular spaces
• Boundaries:
• Above­Teres major
• Medially­Long head of
triceps
• Laterally­shaft of
humerus.
Structures passing:
Radial nerve & profunda brachii
vessels
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