Thoracic muscles AHS1 Flashcards
What are the main bony landmarks?
Cranial and caudal angle of the scapula Olecranon (front leg) Costal arch Tuber coxae
What shows the dorsal boundary of the scapula?
A line from the tuber coxae to the caudal border of the scapula
What is the thin muscle that covers the trunk region?
Cutaneous trunci
What is the reflex that causes the skin twitch?
Panniculus reflex
What is the layer that covers the muscles called?
Deep fascia/epimysium
What are the septa?
They divide muscles into functional groups, extend deep into the muscles and can carry infection
What are the 2 parts that the brachiocephalicus is divided into?
Cleidocephalicus and cleidobrachialis
What is the function of brachiocephalicus?
Protraction of the foreleg
Where does omotransversarius insert?
On the shoulder
Where does omotransversarius originate?
The transverse processes of the cranial cervical vertebrae
What is the function of omotransversarius?
Protraction of the forelimb
Where does trapezius originate?
The median/midline of the neck
Where does trapezius insert?
On the scapula
What is the function of trapezius?
Raises the scapula to protract the forelimb
Where does the latissimus dorsi originate?
In the deep fascia
Where does the latissimus dorsi insert?
On the caudal aspect of the humorous
What is the function of latissimus dorsi?
Retraction
Where do the pectoral muscles originate?
The sturnum
Where do the pectoral muscles insert?
On the medial aspect of the humorous
What is the function of the pectoral muscles?
Adduction of the forelimb
Sling to hold the body up
Where does serratus ventralis originate?
On the ventral parts of the ribs
Where does serratus ventralis insert?
On the medial aspect of the scapula
What is the function of serratus ventralis?
Known as a girdle muscle - acts as a sling to hold the body between the forelimbs
Not a part of respiration - is an extrinsic muscle
What are the respiratory muscles?
Serratus dorsalis
Scalenous
What are the two parts of serratus dorsalis?
Serratus dorsalis cranialis
Serratus dorsalis caudalis
Where does serratus dorsalis originate?
The dorsal deep fascia
Where does serratus dorsalis insert?
On the proximal parts of the ribs
What is the function of serratus dorsalis cranialis?
It raises the rib cage
What is the function of serratus dorsalis caudalis?
It pulls the caudal part of the ribs downwards, so is active in expiration
Where does scalenus originate?
On the cervical vertebrae
Where does scalenus insert?
On the first 2 ribs
What is the function of scalenus?
It stabilises the ribcage and draws the ribcage forward in inspiration
Which intercostal muscles are involved in inspiration?
External intercostal muscles
Which way do the muscle fibres run in the external intercostal muscles?
Caudoventrally \\\\ (backward and down)
They pull ribcage up and out
Which way do the muscle fibres run in the internal intercostal muscles?
Cranioventrally ///////// (forward and down)
They pull the ribs together
What are the segmental nerves?
The nerves that run down the ribs and to the epaxial muscles from the rami
What do the nerves in the dorsal ramus supply?
Dorsal muscles like the epaxial muscles
Skin
What do the nerves in the ventral ramus supply?
Run through the intercostal spaces on the caudal edge of each rib
Also known as intercostal nerves
Some supple the skin
What is the order of tuff that runs along the caudal edge of the rib?
VAN
Vein
Artery
Nerve
What makes up the diaphragm?
A middle tendinous region and a muscular periphery
What are the 3 parts of the muscular periphery of the diaphragm?
The dorsal part, lateral/costal part and the ventral part
What are crura of the diaphragm?
Leg like attachments to the vertebral column
What are the epaxial muscles?
Wedges of muscle on either side of and dorsal to the spinal column
What is the function of epaxial muscles?
Support the spine
Extend the vertebral column when they contract
What are the two abdominal muscles?
Rectus abdominis
External abdominal oblique
What are the rectus abdominis?
Abs
Run from the last ribs/sternum to the pelvis
What is the function of rectus abdominis?
Hold the gut contents in
What is the external abdominal oblique?
A sheet like muscle that holds guts in
Has a thin aponeurosis
What is an aponeurosis?
A thin sheet like tendon
