The muscular system in birds is highly modified to adapt with the aerial mode of life.

1. Flight Muscles of Birds
Prof. Archana Das
Dept. of Zoology

2. What is Flight Muscle ?
The special muscles of birds which help
them to fly are called as Flight Muscles.
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3. The muscular system in birds is highly
modified to adapt with the aerial mode
of life.
According to activities, the muscles for
flight in birds are of two types.
They are :
1. Flight Muscle : To help in flying
2.Perching Muscle : To help in perching
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4. In birds Flight Muscle can be of three types.
They are :
Pectoral Muscles
Accessory Muscles
Tensor Muscles
Flight Muscle
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5. The muscles of birds which maintain the upstroke &
downstroke of the wings during flight are called as
Pectoral Muscles
Pectoral Muscles
They are of two types.
1. Pectoralis major : They are paired muscles of large size with
triangular shape. They cover the whole breast of the birds and hence
called as “Breast Muscle”. They are dark red in colour and maintain the
downstroke & forward stroke of the wings.
2. Pectoralis minor : They are present on the dorsal side of the
pactoralis major and arises from the anterior part of the sternum
bone. They control the upstroke & backward stroke besides helping the
birds in quick take off.
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6. Accessory Muscles
Besides pectoral muscles,
the accessory muscles also
help to elevate or depress
the wings during flight.
They are of three types :
1. Coraco-brachialis longus
2. Coraco-brachialis brevis
3. The biceps and triceps
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7. 1. Coraco-brachialis longus:
It is present beneath the pectoral muscles. It arises from the
coracoid and the costal process of sternum. Its tendon is
attached to the posterior side of the head of humerus. It lowers
the hinder aspect of the wing.
2. Coraco-brachialis brevis:
Another smaller and narrow muscle is coraco-brachialis lies
in front of the longus. It also extends from girdle to humerus &
raises the hinder edge of the wing. Both the muscles rotate the
wings in the glenoid cavity.
3. The biceps and triceps :
They are the intrinsic muscles of the upper arm which
operate the elbow and perform adjustments during flight.
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8. Tensor Muscles
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Three muscles keep the prepatagium fully stretched
when the wing is extended in flight.
They are of three types:
1. Tensor longus,
2. Tensor brevis, and
3. Tensor accessorius

9. PerchingMuscles
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Some large and strong muscles and tendons of
hind legs in birds have special arrangement so that a
can sit on a perch and the toes get mechanically flexed
around the perch.
Such muscles in the hind legs of a bird are called
as Perching Muscles. They are of two types :
1. Extensor Muscle
2. Flexor Muscle
Perching Muscles

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Flexor Muscles
Flexor muscles help the birds during perching
by flexing the phalanges. They remain attached to the
tibio tarsus and knee joint.
The Flexor muscles of bird are :
1. Peroneus muscles
2. Flexor perforans
3. Ambiens
4. Gastrocnemius

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1. Peroneus muscles: Two sets of peroneus muscles
Peroneus longus & Peronues brevis help in extension and
abduction of the tarsometatarsus
2. Flexor perforans: Four sets of flexor perforans originate
from various parts of the tibia and connect to the all
four digits of each leg.
3. Ambiens: They arise from ilium and extend down the
thigh. They provide strength to the legs during perching.
4. Gastrocnemius: This muscle is originated from the three
heads of femur, tibia and ilium. It hepls in the extension
of the tarsometatarsus.
The Flexor muscles

14. Extensor Muscles
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Attached to the tibiotarsus there are several extensor
muscles in birds. They are:
1. Plantoris: It hepls in the extension of tarsometatarsus
2. Tibialis anticus: It flexes the tarsometatarsus.
3. External digitorium longus: It serves as common extensor
of all the digits.
4. Tibialis anterior: They help in the opening of the toes in
both the legs during perching.

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