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AVIAN
MUSCLE
INTRODUCTION
Most birds have approximately 175 different muscles, mainly
controlling the wings, skin, and legs.
 The largest muscles in the bird are the pectorals, or the breast muscles,
which control the wings and make up about 15 - 25% of a flighted bird’s
body weight. They provide the powerful wing stroke essential for flight.
 The muscle ventral (underneath) to the pectorals is the
supracoracoideus. It raises the wing between wingbeats.
 The supracoracoideus and the pectorals together make up about 25 –
35% of the bird's full body weight.
The skin muscles help a bird in its flight by adjusting the feathers,
which are attached to the skin muscle and help the bird in its flight
maneuvers.
There are only a few muscles in the trunk and the tail, but they are very
strong and are essential for the bird.
 The pygostyle controls all the movement in the tail and controls the
feathers in the tail. This gives the tail a larger surface area which helps
keep the bird in the air.
AVIAN
MUSCLE
Anatomy of avian
MUSCLES
•
•
•
•
ORIGIN
INSERTION
INNERVATION
ACTION
UNIQUE MUSCLE
CONFIGURATIONS
• Pectoralis major
• Supracoracoideus
• Wing mechanics
Superficial pectoral (pectoralis)
Origin: keel, clavicle, coracoid and
sternal ribs
Insertion: ventral pectoral crest,
proximal humerus
Innervation: pectoral nerves
Action: downstroke of the wing,
depresses leading edge of pars
longus of the propatagialis tendon.
Detach the pectoralis muscle from
its mutliple sites of origin along the
keel, beginning distally, and reflect it
towards its point of insertion. The
supracoracoideus lies deep and
medial to the pectoralis -- note
airsac that lies between the two
muscles.
Supracoracoideus
Origin: sternum, clavicle and
coracoid .
Insertion: by means of a
prominent tendon upon the lateral
tubercle of the humerus. The
tendon passes through the
triosseal foramen.
 Action: elevates the wing
Coracobrachialis caudalis (ventralis)
Origin: lateral surface of the
coracoid.
Insertion: medial (ventral)
tubercle of the humerus .
Action: depresses the wing along
with the pectoralis muscle
Clinically: frequently torn with
shoulder dislocations rendering the
bird significantly impaired for flight
Propatagialis (pars brevis and pars longus)
Origin: Distal end of the coracoid bone
Insertion: 2 parts
1.Pars longus: inserts on the carpo-metacarpus and forms the leading edge
of the wing. The patagium is attached to it.
2.Pars brevis: attaches to apeunerosis arising from dorsal musculature in the
proximal 1/3 of the antebrachium.
Actions:
-Tenses the patagium (elastic web)
-Extends the carpus
-Serves as a check ligament to prevent overextension of the elbow joint.
Brachialis
Origin: distal end of the
humerus
Insertion: proximal portion
of the ulna
Action: flexes the elbow
joint
There are four muscles of the
antebrachium that are
important; all are located on
the dorsal or lateral aspect
Muscle of Pectoral Limb
modifications for flight.
comprise 35% of the body
weight.
shifted craniad under the
center of lift have long
tendons reaching distally to
the portion of the limb
controlled by them
MUSCULATURE OF PECTORAL LIMBS :
HUMERUS
Biceps
Triceps
Deltoid
Biceps brachii
Origin: distal end of
coracoid and bicipital crest of
humerus
Insertion: radius and ulna
dorsal aspect
Actions: flexes the elbow
joint and extends the
shoulder
Triceps brachii
Origin: One head
from scapula, the other
from proximal humerus
Insertion: olecranon
of the ulna
Action: extension of
the elbow joint
Deltoideus major
Origin: scapula
and clavicle
Insertion: dorsal
surface of humerus
Action: elevates
the wing
MUSCULATURE OF PECTORAL LIMB :
ANTEBRACHIUM
• Extensor carpi radialis
• Common digital extensor
• Extensor metacarpi ulnaris
• Supinator
Extensor metacarpi radialis
Origin: lateral epicondyle of
the humerus.
Innervation:radial
vein,patagial vein
Insertion: dorsal surface of
the carpometacarpus
 Action: extends the
metacarpus
Extensor digitorum communis
(common digital extensor)
Origin: lateral epicondyle of
the humerus and extend to
medial forearm.
Innervation:basilic,deep
brachial vein.
Insertion: dorsal surface of
the proximal phalanx of digit III
with a short link to the alula
Action: extends the carpus,
metacarpus, and alula
EXTENSOR METACARPI ULNARIS
(ULNARIS LATERALIS)
Origin: lateral epicondyle of the
humerus,posterior border and
medial side of ulnar and insert at
the base of metacarpus.
Innervation:ulnar vein,deep
brachial vein,basilic vein.
Insertion: carpometacarpus
Action: flexes the metacarpus
(when wing is extended ) only
flexor located on lateral (dorsal)
surface of the wing.
Supinator
Origin: lateral epicondyle of the
humerus (deep) and curved to upper
third of radius.
Inervation:radial vein,patagial
veinbasilic vein,brachial vein.
Insertion: cranial surface of the
radius
Action: elevates the cranial border
of the antebrachium and supinates
(rotates upward) the cranial edge of
the wing
PELVIC LIMB
• Pelvic Limb Myology:
• Movement to center of mass with long
tendons going to extemities; tendons are often
ossified.
MUSCULATURE OF PELVIC LIMB : HIP &
FEMUR
Quadriceps equivalent
1. Iliotibialis cranialis
2. Iliotibialis lateralis
 Iliofibularis
 Femerotibialus externus
Iliotibialis cranialis (sartorious)
–
–
–
–
Origin: cranial portion of the
iliac crest. A strap-shaped
muscle
Insertion: medial aspect of
patella and tibiotarsus
Action: flexes the hip joint
and extends the stifle
Clinical: cranial edge serves
as a landmark for endoscopic
entry point for sexing and
general abdominal
examination.
Iliotibialis lateralis
• Origin: most of the length of
the iliac crest. . A sheet-like
muscle.
• Insertion: joints the fascia of
the femorotibilais and inserts
with that muscle upon the
patella and tibiotarsus
• Action: flexes the hip and
extends the stifle
• Clinical: large muscle in
vultures and fowl, small in
psittacines and raptors.
Surgical approach to femur
lies along its caudal border
Iliofibularis
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–
–
–
Origin: iliac crest caudal to
the acetabulum
Insertion: proximal end of
the fibula
Action: flexes the stifle
Clinical: Surgical approach
to the femur lies between
this muscle and iliotibialis
lateralis. A large
neurovascular bundle lies
deep and must be preserved
Femorotibialis externus
• Origin: adherent to most of the length
of the craniolateral femur
• Insertion: patella and proximal
tibiotarsus
• Action: extends the stifle
• Clinical: typically needs to be
periosteally elevated from shaft of
femur during surgical approaches.
MUSCULATURE OF PELVIC LIMB :
TIBIOTARSAL REGION
• Gastronemius – 3 heads
• Fibularis longus
• Tibialis cranialis
• Extensor digitorum longus
Gastrocnemius complex (3
heads)
•
•
•
•
Origins:
1) lateral head -- lateral femoral
condyle
2) intermediate head -- area near
medial femoral condyle
3) medial head -- popliteal area
fascia and medial femoral condyle
Insertion: All three heads form a
common tendon that inserts on the
prominent hypotarsal protuberance
Action: strong extender of the hock
joint
Clinical: medial surgical approach to
tibiotarsus occurs along cranial edge
of medial grastroc.
Fibularis longus (peroneus
longus)
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–
–
Origin: patella, cranial and
lateral cnemial crests and
the lateral fibula
Insertion: caudal
tarsometarsus and tendon of
the flexor perforatus digiti
III.
Action: extends the
intertarsal joint (hock)
Tibialis cranialis: lateral and medial
heads
–
–
–
Origins: lateral headlateral condyle of the
femur, medial head lateral and medial
cnemial crests and
rotular crest
Insertion: two heads
unite to form a common
tendon inserting on the
dorsal metatarsal groove.
Actions: flexes the hock
Extensor digitorum longus
–
–
–
Origin: cranial surface
of the tibiotarsus
between the medial and
lateral cnemial crests
Insertion: the dorsum of
the distal-most phalanx
of digits II-IV
Action: extends the
forward digits