Extrinsic Muscles of the Thoracic Limb Flashcards
those that attached the limb to the axial skeleton
Extrinsic muscles
the muscles that are attached to the limb
Intrinsic Muscles
extrinsic muscles of the thoracic limb (8)
- Superficial pectoral
- Deep pectoral
- Brachiocephalicus
- Omotransversarius
- Trapezius
- Rhomboideus
- Latissimus dorsi
- Serratus ventralis
superficial pectoral m. is divided into 2;
descending pectoral
transverse pectoral
superficial and smaller than transverse pectoral; innervated by cranial pectoral nerve;
descending pectoral
arises from 1st 2 – 3 sternebrae and inserts into greater tubercle of humerus
transverse pectoral
*Extrinsic muscle
to adduct the limb and prevent abduction when bearing weight
Superficial Pectoral m.
*Extrinsic muscle
larger and longer than superficial pectoral; from cranial part of sternum and humerus
Deep pectoral m.
*Extrinsic muscle
- adduction of limb
- to draw limb backwards or pull trunk forward
Deep pectoral muscle
*3 sections of the brachiocephalicus
– attaches to the neck
Cleidocervicalis
– attaches to the skull
Cleidomastoideus
3 sections of brachiocephalicus
m. cleidobrachialis
m. cleidocervicalis
m. clediomastoideus
O: Clavicle (vestigial) or clavicular intersection
I: distal third of the humerus
A: to advance the limb; to extend the shoulder and draw head and neck to the side
Brachiocephalicus
- Innervated by accessory nerve and ventral branches of cervical spinal nerves
- clavicular intersection
Brachiocephalicus
arises from the manubrium and inserts in the mastoid part of the temporal bone and the nuchal crest of the occipital bone; ventral part is closely united with cleidomastoideus;
Sternocephalicus
*Sternocephalicus
cranial part divides into 2 parts:
– a. mastoid part– ventral part
– b. occipital part – dorsal part
- Innervated by accessory nerve and ventral branches of cervical nerves.
- This is where the external jugular vein can be located
Sternocephalicus
to draw the head and neck to the side (2)
sternomastoideus and
sternooccipitalis
to draw the larynx and tongue caudally (2)
sternohyoideus and
sternothyroideus
- straplike and extends from the distal end of the spine of scapula to the atlas;
- innervated by the accessory nerve
Omotransversarius
cutting the OMOTRANSVERSARIUS at its middle will expose ____ ___ __ __
superficial cervical lymph nodes
advance the limb and flex neck laterally
Omotransversarius
– Strong wrapping that extends under the sternocephalicus, cleidomastoideus, omotransversarius and cleidocervicalis n.
Deep fascia of the neck
– Deep fascia that covers the common carotid artery, vagosympathetic nerve trunk, internal jugular vein and lymphatic trunk
Carotid sheath
– Connects the dorsal aspects of all vertebral spines except the cervical vertebrae
Supraspinous ligament
– Extends from the spine of the first thoracic vertebra to the spine of the axis
Nuchal ligament
– A longitudinal fibrous septum that serves as an attachment for many of the cervical muscles
Median raphe of
the neck
*Extrinsic muscles
thin and triangular muscle with cervical and thoracic parts
* extends from the median raphe of the neck and the supraspinous ligament (C3 – T9) to the spine of scapula
* innervated by accessory nerve
Trapezius
*Extrinsic muscles
*trapezius
elevate and abduct the forelimb
cervical trapezius
*Extrinsic muscles
*trapezius
elevate and abduct the forelimb
thoracic trapezius
*Extrinsic muscles
Innervated by ventral branches of cervical and thoracic nerves
Rhomboideus
rhomboideus is divided into 3 parts:
capital
cervical
thoracic
rhomboideus capitis
capital
rhomboideus cervicis
Cervical
rhomboideus thoracis
Thoracic
to elevate the forelimb and draw scapula to the trunk
Rhomboideus
*Extrinsic muscles
- large and roughly triangular;
- lies caudal to the scapula where it covers most of the dorsal and some of the lateral thoracic wall;
- innervated by thoracodorsal nerve
Latissimus dorsi
*Extrinsic muscles
to draw limb caudally
Latissimus dorsi
*Extrinsic muscles
- a large, fan-shaped muscle that acts as a sling to support the body between the limbs;
- from C5 transverse processes and first 7
or 8 ribs to the serrated face of the scapula; - innervated by ventral branches of cervical nerve and long thoracic nerve
- has cervical and thoracic parts
Serratus ventralis
which part of serratus ventralis supports the trunk?
cervical part:
*serratus ventralis
lateral surface of the ribs
thoracic part:
